Patent Publication Number: US-2005119212-A1

Title: RNA interference mediated inhibition of FAS and FASL gene expression using short interfering nucleic acid (siNA)

Description:
This application is a continuation-in-part of International Patent Application No. PCT/US04/16390, filed May 24, 2004, which is a continuation-in-part of U.S. patent application Ser. No. 10/826,966, filed Apr. 16, 2004, which is continuation-in-part of U.S. patent application Ser. No. 10/757,803, filed Jan. 14, 2004, which is a continuation-in-part of U.S. patent application Ser. No. 10/720,448, filed Nov. 24, 2003, which is a continuation-in-part of U.S. patent application Ser. No. 10/693,059, filed Oct. 23, 2003, which is a continuation-in-part of U.S. patent application Ser. No. 10/444,853, filed May 23, 2003, which is a continuation-in-part of International Patent Application No. PCT/US03/05346, filed Feb. 20, 2003, and a continuation-in-part of International Patent Application No. PCT/US03/05028, filed Feb. 20, 2003, both of which claim the benefit of U.S. Provisional Application No. 60/358,580 filed Feb. 20, 2002, U.S. Provisional Application No. 60/363,124 filed Mar. 11, 2002, U.S. Provisional Application No. 60/386,782 filed Jun. 6, 2002, U.S. Provisional Application No. 60/406,784 filed Aug. 29, 2002, U.S. Provisional Application No. 60/408,378 filed Sep. 5, 2002, U.S. Provisional Application No. 60/409,293 filed Sep. 9, 2002, and U.S. Provisional Application No. 60/440,129 filed Jan. 15, 2003. This application is also a continuation-in-part of International Patent Application No. PCT/US04/13456, filed Apr. 30, 2004, which is a continuation of patent application Ser. No. 10/780,447, filed Feb. 13, 2004, which is a continuation-in-part of U.S. patent application Ser. No. 10/427,160, filed Apr. 30, 2003, which is a continuation-in-part of International Patent Application No. PCT/US02/15876 filed May 17, 2002, which claims the benefit of U.S. Provisional Application No. 60/362,016, filed Mar. 6, 2002, and U.S. Provisional Application No. 60/292,217, filed May 18, 2001. This application is also a continuation-in-part of U.S. patent application Ser. No. 10/727,780 filed Dec. 3, 2003. This application also claims the benefit of U.S. Provisional Application No. 60/543,480 filed Feb. 10, 2004. The instant application claims the benefit of all the listed applications, which are hereby incorporated by reference herein in their entireties, including the drawings.  
    
    
     FIELD OF THE INVENTION  
      The present invention relates to compounds, compositions, and methods for the study, diagnosis, and treatment of traits, diseases and conditions that respond to the modulation of Fas and/or Fas ligand (FasL) expression and/or activity. The present invention is also directed to compounds, compositions, and methods relating to traits, diseases and conditions that respond to the modulation of expression and/or activity of genes involved in Fas and/or FasL gene expression pathways or other cellular processes that mediate the maintenance or development of such traits, diseases and conditions. Specifically, the invention relates to small nucleic acid molecules, such as short interfering nucleic acid (siNA), short interfering RNA (siRNA), double-stranded RNA (dsRNA), micro-RNA (mRNA), and short hairpin RNA (shRNA) molecules capable of mediating RNA interference (RNAi) against Fas and/or FasL gene expression. Such small nucleic acid molecules are useful, for example, in providing compositions for treatment of traits, central nervous system (CNS) injuries and various demyelinating diseases and conditions that can respond to modulation of Fas and/or FasL gene expression in a subject, such as cerebrovascular accident (CVA, stroke), neurovirulent induced spongiform myeloencephalopathy, multiple sclerosis (MS), pathological motoneuron degeneration, HIV-1-associated dementia, spinal muscular atrophy, muscular dystrophy, Alzheimer&#39;s disease, global cerebra ischemia, neurodegenerative brain trauma, viral central nervous system infections (lymphocytic choriomeningitis virus), motoneuron death, amyotrophic lateral sclerosis (ALS), retrograde neuronal degeneration following cortical injury, HTLV-1-associated myelopathy, severe hypoxic ischemia, focal cerebral ischemia, traumatic brain injuries, Huntington&#39;s disease, Parkinson&#39;s, Creutzfeldt-Jakob disease, dementia, chemotherapy-induced neuropathy, ataxia, and other spinal cord injuries, other neurodegenerative disease states, and liver diseases and conditions such as cirrhosis and/or liver failure.  
     BACKGROUND OF THE INVENTION  
      The following is a discussion of relevant art pertaining to RNAi. The discussion is provided only for understanding of the invention that follows. The summary is not an admission that any of the work described below is prior art to the claimed invention.  
      RNA interference refers to the process of sequence-specific post-transcriptional gene silencing in animals mediated by short interfering RNAs (siRNAs) (Zamore et al., 2000, Cell, 101, 25-33; Fire et al., 1998 , Nature,  391, 806; Hamilton et al., 1999 , Science,  286, 950-951; Lin et al., 1999 , Nature,  402, 128-129; Sharp, 1999, Genes &amp; Dev., 13:139-141; and Strauss, 1999 , Science,  286, 886). The corresponding process in plants (Heifetz et al., International PCT Publication No. WO 99/61631) is commonly referred to as post-transcriptional gene silencing or RNA silencing and is also referred to as quelling in fungi. The process of post-transcriptional gene silencing is thought to be an evolutionarily-conserved cellular defense mechanism used to prevent the expression of foreign genes and is commonly shared by diverse flora and phyla (Fire et al., 1999 , Trends Genet.,  15, 358). Such protection from foreign gene expression may have evolved in response to the production of double-stranded RNAs (dsRNAs) derived from viral infection or from the random integration of transposon elements into a host genome via a cellular response that specifically destroys homologous single-stranded RNA or viral genomic RNA. The presence of dsRNA in cells triggers the RNAi response through a mechanism that has yet to be fully characterized. This mechanism appears to be different from other known mechanisms involving double stranded RNA-specific ribonucleases, such as the interferon response that results from dsRNA-mediated activation of protein kinase PKR and 2′,5′-oligoadenylate synthetase resulting in non-specific cleavage of mRNA by ribonuclease L (see for example U.S. Pat. Nos. 6,107,094; 5,898,031; Clemens et al., 1997 , J. Interferon  &amp;  Cytokine Res.,  17, 503-524; Adah et al., 2001 , Curr. Med. Chem.,  8, 1189).  
      The presence of long dsRNAs in cells stimulates the activity of a ribonuclease III enzyme referred to as dicer (Bass, 2000, Cell, 101, 235; Zamore et al., 2000, Cell, 101, 25-33; Hammond et al., 2000, Nature, 404, 293). Dicer is involved in the processing of the dsRNA into short pieces of dsRNA known as short interfering RNAs (siRNAs) (Zamore et al., 2000, Cell, 101, 25-33; Bass, 2000, Cell, 101, 235; Berstein et al., 2001 , Nature,  409, 363). Short interfering RNAs derived from dicer activity are typically about 21 to about 23 nucleotides in length and comprise about 19 base pair duplexes (Zamore et al., 2000, Cell, 101, 25-33; Elbashir et al., 2001 , Genes Dev.,  15, 188). Dicer has also been implicated in the excision of 21- and 22-nucleotide small temporal RNAs (stRNAs) from precursor RNA of conserved structure that are implicated in translational control (Hutvagner et al., 2001 , Science,  293, 834). The RNAi response also features an endonuclease complex, commonly referred to as an RNA-induced silencing complex (RISC), which mediates cleavage of single-stranded RNA having sequence complementary to the antisense strand of the siRNA duplex. Cleavage of the target RNA takes place in the middle of the region complementary to the antisense strand of the siRNA duplex (Elbashir et al., 2001 , Genes Dev.,  15, 188).  
      RNAi has been studied in a variety of systems. Fire et al., 1998 , Nature,  391, 806, were the first to observe RNAi in  C. elegans . Bahramian and Zarbl, 1999 , Molecular and Cellular Biology,  19, 274-283 and Wianny and Goetz, 1999 , Nature Cell Biol.,  2, 70, describe RNAi mediated by dsRNA in mammalian systems. Hammond et al., 2000 , Nature,  404, 293, describe RNAi in  Drosophila  cells transfected with dsRNA. Elbashir et al., 2001 , Nature,  411, 494 and Tuschl et al, International PCT Publication No. WO 01/75164, describe RNAi induced by introduction of duplexes of synthetic 21-nucleotide RNAs in cultured mammalian cells including human embryonic kidney and HeLa cells. Recent work in  Drosophila  embryonic lysates (Elbashir et al., 2001 , EMBO J.,  20, 6877 and Tuschl et al., International PCT Publication No. WO 01/75164) has revealed certain requirements for siRNA length, structure, chemical composition, and sequence that are essential to mediate efficient RNAi activity. These studies have shown that 21-nucleotide siRNA duplexes are most active when containing 3′-terminal dinucleotide overhangs. Furthermore, complete substitution of one or both siRNA strands with 2′-deoxy (2′-H) or 2′-O-methyl nucleotides abolishes RNAi activity, whereas substitution of the 3′-terminal siRNA overhang nucleotides with 2′-deoxy nucleotides (2′-H) was shown to be tolerated. Single mismatch sequences in the center of the siRNA duplex were also shown to abolish RNAi activity. In addition, these studies also indicate that the position of the cleavage site in the target RNA is defined by the 5′-end of the siRNA guide sequence rather than the 3′-end of the guide sequence (Elbashir et al., 2001 , EMBO J.,  20, 6877). Other studies have indicated that a 5′-phosphate on the target-complementary strand of a siRNA duplex is required for siRNA activity and that ATP is utilized to maintain the 5′-phosphate moiety on the siRNA (Nykanen et al., 2001 , Cell,  107, 309).  
      Studies have shown that replacing the 3′-terminal nucleotide overhanging segments of a 21-mer siRNA duplex having two-nucleotide 3′-overhangs with deoxyribonucleotides does not have an adverse effect on RNAi activity. Replacing up to four nucleotides on each end of the siRNA with deoxyribonucleotides has been reported to be well tolerated, whereas complete substitution with deoxyribonucleotides results in no RNAi activity (Elbashir et al., 2001 , EMBO J.,  20, 6877 and Tuschl et al., International PCT Publication No. WO 01/75164). In addition, Elbashir et al., supra, also report that substitution of siRNA with 2′-O-methyl nucleotides completely abolishes RNAi activity. Li et al., International PCT Publication No. WO 00/44914, and Beach et al., International PCT Publication No. WO 01/68836 preliminarily suggest that siRNA may include modifications to either the phosphate-sugar backbone or the nucleoside to include at least one of a nitrogen or sulfur heteroatom, however, neither application postulates to what extent such modifications would be tolerated in siRNA molecules, nor provides any further guidance or examples of such modified siRNA. Kreutzer et al., Canadian Patent Application No. 2,359,180, also describe certain chemical modifications for use in dsRNA constructs in order to counteract activation of double-stranded RNA-dependent protein kinase PKR, specifically 2′-amino or 2′-O-methyl nucleotides, and nucleotides containing a  2 ′-O or 4′-C methylene bridge. However, Kreutzer et al. similarly fails to provide examples or guidance as to what extent these modifications would be tolerated in dsRNA molecules.  
      Parrish et al., 2000 , Molecular Cell,  6, 1077-1087, tested certain chemical modifications targeting the unc-22 gene in  C. elegans  using long (&gt;25 nt) siRNA transcripts. The authors describe the introduction of thiophosphate residues into these siRNA transcripts by incorporating thiophosphate nucleotide analogs with T7 and T3 RNA polymerase and observed that RNAs with two phosphorothioate modified bases also had substantial decreases in effectiveness as RNAi. Further, Parrish et al. reported that phosphorothioate modification of more than two residues greatly destabilized the RNAs in vitro such that interference activities could not be assayed. Id. at 1081. The authors also tested certain modifications at the 2′-position of the nucleotide sugar in the long siRNA transcripts and found that substituting deoxynucleotides for ribonucleotides produced a substantial decrease in interference activity, especially in the case of Uridine to Thymidine and/or Cytidine to deoxy-Cytidine substitutions. Id. In addition, the authors tested certain base modifications, including substituting, in sense and antisense strands of the siRNA, 4-thiouracil, 5-bromouracil, 5-iodouracil, and 3-(aminoallyl)uracil for uracil, and inosine for guanosine. Whereas 4-thiouracil and 5-bromouracil substitution appeared to be tolerated, Parrish reported that inosine produced a substantial decrease in interference activity when incorporated in either strand. Parrish also reported that incorporation of 5-iodouracil and 3-(aminoallyl)uracil in the antisense strand resulted in a substantial decrease in RNAi activity as well.  
      The use of longer dsRNA has been described. For example, Beach et al., International PCT Publication No. WO 01/68836, describes specific methods for attenuating gene expression using endogenously-derived dsRNA. Tuschl et al., International PCT Publication No. WO 01/75164, describe a  Drosophila  in vitro RNAi system and the use of specific siRNA molecules for certain functional genomic and certain therapeutic applications; although Tuschl, 2001 , Chem. Biochem.,  2, 239-245, doubts that RNAi can be used to cure genetic diseases or viral infection due to the danger of activating interferon response. Li et al., International PCT Publication No. WO 00/44914, describe the use of specific long (141 bp-488 bp) enzymatically synthesized or vector expressed dsRNAs for attenuating the expression of certain target genes. Zernicka-Goetz et al., International PCT Publication No. WO 01/36646, describe certain methods for inhibiting the expression of particular genes in mammalian cells using certain long (550 bp-714 bp), enzymatically synthesized or vector expressed dsRNA molecules. Fire et al., International PCT Publication No. WO 99/32619, describe particular methods for introducing certain long dsRNA molecules into cells for use in inhibiting gene expression in nematodes. Plaetinck et al., International PCT Publication No. WO 00/01846, describe certain methods for identifying specific genes responsible for conferring a particular phenotype in a cell using specific long dsRNA molecules. Mello et al., International PCT Publication No. WO 01/29058, describe the identification of specific genes involved in dsRNA-mediated RNAi. Pachuck et al., International PCT Publication No. WO 00/63364, describe certain long (at least 200 nucleotide) dsRNA constructs. Deschamps Depaillette et al., International PCT Publication No. WO 99/07409, describe specific compositions consisting of particular dsRNA molecules combined with certain anti-viral agents. Waterhouse et al., International PCT Publication No. 99/53050 and 1998 , PNAS,  95, 13959-13964, describe certain methods for decreasing the phenotypic expression of a nucleic acid in plant cells using certain dsRNAs. Driscoll et al., International PCT Publication No. WO 01/49844, describe specific DNA expression constructs for use in facilitating gene silencing in targeted organisms.  
      Others have reported on various RNAi and gene-silencing systems. For example, Parrish et al., 2000 , Molecular Cell,  6, 1077-1087, describe specific chemically-modified dsRNA constructs targeting the unc-22 gene of  C. elegans . Grossniklaus, International PCT Publication No. WO 01/38551, describes certain methods for regulating polycomb gene expression in plants using certain dsRNAs. Churikov et al., International PCT Publication No. WO 01/42443, describe certain methods for modifying genetic characteristics of an organism using certain dsRNAs. Cogoni et al., International PCT Publication No. WO 01/53475, describe certain methods for isolating a  Neurospora  silencing gene and uses thereof. Reed et al., International PCT Publication No. WO 01/68836, describe certain methods for gene silencing in plants. Honer et al., International PCT Publication No. WO 01/70944, describe certain methods of drug screening using transgenic nematodes as Parkinson&#39;s Disease models using certain dsRNAs. Deak et al., International PCT Publication No. WO 01/72774, describe certain  Drosophila -derived gene products that may be related to RNAi in  Drosophila . Arndt et al., International PCT Publication No. WO 01/92513 describe certain methods for mediating gene suppression by using factors that enhance RNAi. Tuschl et al., International PCT Publication No. WO 02/44321, describe certain synthetic siRNA constructs. Pachuk et al., International PCT Publication No. WO 00/63364, and Satishchandran et al., International PCT Publication No. WO 01/04313, describe certain methods and compositions for inhibiting the function of certain polynucleotide sequences using certain long (over 250 bp), vector expressed dsRNAs. Echeverri et al., International PCT Publication No. WO 02/38805, describe certain  C. elegans  genes identified via RNAi. Kreutzer et al., International PCT Publications Nos. WO 02/055692, WO 02/055693, and EP 1144623 B1 describes certain methods for inhibiting gene expression using dsRNA. Graham et al., International PCT Publications Nos. WO 99/49029 and WO 01/70949, and AU 4037501 describe certain vector expressed siRNA molecules. Fire et al., U.S. Pat. No. 6,506,559, describe certain methods for inhibiting gene expression in vitro using certain long dsRNA (299 bp-1033 bp) constructs that mediate RNAi. Martinez et al., 2002 , Cell,  110, 563-574, describe certain single stranded siRNA constructs, including certain 5′-phosphorylated single stranded siRNAs that mediate RNA interference in Hela cells. Harborth et al., 2003, Antisense &amp; Nucleic Acid Drug Development, 13, 83-105, describe certain chemically and structurally modified siRNA molecules. Chiu and Rana, 2003, RNA, 9, 1034-1048, describe certain chemically and structurally modified siRNA molecules. Woolf et al., International PCT Publication Nos. WO 03/064626 and WO 03/064625 describe certain chemically modified dsRNA constructs. Song et al., 2003 , Nature Medicine,  9, 347-351, describe certain siRNA molecules targeting FAS in mouse models of autoimmune hepatitis. Wang et al., 2003 , Transplantation Proceedings,  35, 1594-5, describes certain siRNA molecules targeting FAS in a mouse model of allogenic liver transplantation.  
     SUMMARY OF THE INVENTION  
      This invention relates to compounds, compositions, and methods useful for modulating Fas and/or FasL gene expression using short interfering nucleic acid (siNA) molecules. This invention also relates to compounds, compositions, and methods useful for modulating the expression and activity of other genes involved in pathways of Fas and/or FasL gene expression and/or activity by RNA interference (RNAi) using small nucleic acid molecules. In particular, the instant invention features small nucleic acid molecules, such as short interfering nucleic acid (siNA), short interfering RNA (siRNA), double-stranded RNA (dsRNA), micro-RNA (mRNA), and short hairpin RNA (shRNA) molecules and methods used to modulate the expression of Fas and/or FasL genes.  
      A siNA of the invention can be unmodified or chemically-modified. A siNA of the instant invention can be chemically synthesized, expressed from a vector or enzymatically synthesized. The instant invention also features various chemically-modified synthetic short interfering nucleic acid (siNA) molecules capable of modulating Fas and/or FasL gene expression or activity in cells by RNA interference (RNAi). The use of chemically-modified siNA improves various properties of native siNA molecules through increased resistance to nuclease degradation in vivo and/or through improved cellular uptake. Further, contrary to earlier published studies, siNA having multiple chemical modifications retains its RNAi activity. The siNA molecules of the instant invention provide useful reagents and methods for a variety of therapeutic, diagnostic, target validation, genomic discovery, genetic engineering, and pharmacogenomic applications.  
      In one embodiment, the invention features one or more siNA molecules and methods that independently or in combination modulate the expression of Fas and/or FasL genes encoding proteins, such as proteins comprising Fas antigen (Fas) or Fas ligand (FasL), such as genes encoding sequences comprising those sequences referred to by GenBank Accession Nos. shown in Table I, referred to herein generally as Fas and FasL respectively. The description below of the various aspects and embodiments of the invention is provided with reference to exemplary Fas antigen and Fas ligand genes referred to herein as Fas and FasL. However, the various aspects and embodiments are also directed to other Fas and/or FasL genes, such as Fas and/or FasL homolog genes, transcript variants, and polymorphisms (e.g., single nucleotide polymorphism, (SNPs)) associated with certain Fas and/or FasL genes, for example genes associated with diseases, traits, or conditions described herein or otherwise known in the art. As such, the various aspects and embodiments are also directed to other genes that are involved in Fas and/or FasL mediated pathways of signal transduction or gene expression. These additional genes can be analyzed for target sites using the methods described for Fas and/or FasL genes herein. Thus, the modulation of other genes and the effects of such modulation of the other genes can be performed, determined, and measured as described herein.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene, wherein said siNA molecule comprises about 19 to about 21 base pairs.  
      In one embodiment, the invention features a siNA molecule that down-regulates expression of a Fas gene, for example, wherein the Fas gene comprises Fas encoding sequence. In one embodiment, the invention features a siNA molecule that down-regulates expression of a Fas gene, for example, wherein the Fas gene comprises Fas non-coding sequence or regulatory elements involved in Fas gene expression.  
      In one embodiment, the invention features a siNA molecule that down-regulates expression of a FasL gene, for example, wherein the FasL gene comprises FasL encoding sequence. In one embodiment, the invention features a siNA molecule that down-regulates expression of a FasL gene, for example, wherein the FasL gene comprises FasL non-coding sequence or regulatory elements involved in FasL gene expression.  
      In one embodiment, a siNA of the invention is used to inhibit the expression of Fas and/or FasL genes or a Fas and/or FasL gene family, wherein the genes or gene family sequences share sequence homology. Such homologous sequences can be identified as is known in the art, for example using sequence alignments. siNA molecules can be designed to target such homologous sequences, for example using perfectly complementary sequences or by incorporating non-canonical base pairs, for example mismatches and/or wobble base pairs, that can provide additional target sequences. In instances where mismatches are identified, non-canonical base pairs, for example mismatches and/or wobble bases, can be used to generate siNA molecules that target both more than one gene sequences. In a non-limiting example, non-canonical base pairs such as UU and CC base pairs are used to generate siNA molecules that are capable of targeting sequences for differing Fas and/or FasL targets that share sequence homology (e.g., differing Fas or FasL genes or differing allelic variants thereof). As such, one advantage of using siNAs of the invention is that a single siNA can be designed to include nucleic acid sequence that is complementary to the nucleotide sequence that is conserved between the homologous genes. In this approach, a single siNA can be used to inhibit expression of more than one Fas and/or FasL gene instead of using more than one siNA molecule to target the different genes.  
      In one embodiment, the invention features a siNA molecule having RNAi activity against Fas and/or FasL RNA, wherein the siNA molecule comprises a sequence complementary to any RNA having Fas and/or FasL encoding sequence, such as those sequences having GenBank Accession Nos. shown in Table I. In another embodiment, the invention features a siNA molecule having RNAi activity against Fas and/or FasL RNA, wherein the siNA molecule comprises a sequence complementary to an RNA having variant Fas and/or FasL encoding sequence, for example other mutant Fas and/or FasL genes not shown in Table I but known in the art to be associated with diseases, traits, or conditions described herein or otherwise known in the art. Chemical modifications as shown in Tables III and IV or otherwise described herein can be applied to any siNA construct of the invention. In another embodiment, a siNA molecule of the invention includes a nucleotide sequence that can interact with nucleotide sequence of a Fas and/or FasL gene and thereby mediate silencing of Fas and/or FasL gene expression, for example, wherein the siNA mediates regulation of Fas and/or FasL gene expression by cellular processes that modulate the chromatin structure or methylation patterns of the Fas and/or FasL gene and prevent transcription of the Fas and/or FasL gene.  
      In one embodiment, siNA molecules of the invention are used to down regulate or inhibit the expression of Fas and/or FasL proteins arising from Fas and/or FasL haplotype polymorphisms that are associated with a disease or condition, (e.g., inflammatory, autoimmune, and/or neurodegenerative diseases, conditions, or traits). Analysis of Fas and/or FasL genes, or Fas and/or FasL protein or RNA levels can be used to identify subjects with such polymorphisms or those subjects who are at risk of developing traits, conditions, or diseases described herein. These subjects are amenable to treatment, for example, treatment with siNA molecules of the invention and any other composition useful in treating diseases related to Fas and/or FasL gene expression. As such, analysis of Fas and/or FasL protein or RNA levels can be used to determine treatment type and the course of therapy in treating a subject. Monitoring of Fas and/or FasL protein or RNA levels can be used to predict treatment outcome and to determine the efficacy of compounds and compositions that modulate the level and/or activity of certain Fas and/or FasL proteins associated with a trait, condition, or disease.  
      In one embodiment of the invention a siNA molecule comprises an antisense strand comprising a nucleotide sequence that is complementary to a nucleotide sequence or a portion thereof encoding a Fas and/or FasL protein. The siNA further comprises a sense strand, wherein said sense strand comprises a nucleotide sequence of a Fas and/or FasL gene or a portion thereof.  
      In another embodiment, the invention features a siNA molecule comprising a nucleotide sequence in the antisense region of the siNA molecule that is complementary to a nucleotide sequence or portion of sequence of a Fas and/or FasL gene. In another embodiment, the invention features a siNA molecule comprising a region, for example, the antisense region of the siNA construct, complementary to a sequence comprising a Fas and/or FasL gene sequence or a portion thereof.  
      In one embodiment, the antisense region of Fas and/or FasL siNA constructs comprises a sequence complementary to sequence having any of SEQ ID NOs. 1-150, 301404, 509-516, or 517-524. In one embodiment, the antisense region of Fas and/or FasL constructs comprises sequence having any of SEQ ID NOs. 151-300, 405-508, 533-540, 549-556, 565-572, 581-588, 597-604, 613-620, 629-636, 645-652, 661-668, 677-684, 686, 688, 690, 693, 695, 697, 699, or 702. In another embodiment, the sense region of Fas and/or FasL constructs comprises sequence having any of SEQ ID NOs. 1-150, 301-404, 509-532, 541-548, 557-564, 573-580, 589-596, 605-612, 621-628, 637-644, 653-660, 669-676, 685, 687, 689, 691, 692, 694, 696, 698, 700, or 701.  
      In one embodiment, a siNA molecule of the invention comprises any of SEQ ID NOs. 1-702. The sequences shown in SEQ ID NOs: 1-702 are not limiting. A siNA molecule of the invention can comprise any contiguous Fas and/or FasL sequence (e.g., about 19 to about 25, or about 19, 20, 21, 22, 23, 24, or 25 contiguous Fas and/or FasL nucleotides).  
      In yet another embodiment, the invention features a siNA molecule comprising a sequence, for example, the antisense sequence of the siNA construct, complementary to a sequence or portion of sequence comprising sequence represented by GenBank Accession Nos. shown in Table I. Chemical modifications in Tables III and IV and described herein can be applied to any siNA construct of the invention.  
      In one embodiment of the invention a siNA molecule comprises an antisense strand having about 19 to about 29 (e.g., about 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29) nucleotides, wherein the antisense strand is complementary to a RNA sequence encoding a Fas and/or FasL protein, and wherein said siNA further comprises a sense strand having about 19 to about 29 (e.g., about 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29) nucleotides, and wherein said sense strand and said antisense strand are distinct nucleotide sequences with at least about 19 complementary nucleotides.  
      In another embodiment of the invention a siNA molecule of the invention comprises an antisense region having about 19 to about 29 (e.g., about 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29) nucleotides, wherein the antisense region is complementary to a RNA sequence encoding a Fas and/or FasL protein, and wherein said siNA further comprises a sense region having about 19 to about 29 (e.g., about 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29) nucleotides, wherein said sense region and said antisense region comprise a linear molecule with at least about 19 complementary nucleotides.  
      In one embodiment, a siNA molecule of the invention has RNAi activity that modulates expression of RNA encoded by a Fas and/or FasL gene. Because Fas and/or FasL genes can share some degree of sequence homology with each other, siNA molecules can be designed to target a class of Fas and/or FasL genes or alternately specific Fas and/or FasL genes (e.g., polymorphic variants) by selecting sequences that are either shared amongst different Fas and/or FasL targets or alternatively that are unique for a specific Fas and/or FasL target. Therefore, in one embodiment, the siNA molecule can be designed to target conserved regions of Fas and/or FasL RNA sequences having homology among several Fas and/or FasL gene variants so as to target a class of Fas and/or FasL genes with one siNA molecule. Accordingly, in one embodiment, the siNA molecule of the invention modulates the expression of one or both Fas and/or FasL alleles in a subject. In another embodiment, the siNA molecule can be designed to target a sequence that is unique to a specific Fas and/or FasL RNA sequence (e.g., a single Fas and/or FasL allele or Fas and/or FasL single nucleotide polymorphism (SNP)) due to the high degree of specificity that the siNA molecule requires to mediate RNAi activity.  
      In one embodiment, nucleic acid molecules of the invention that act as mediators of the RNA interference gene silencing response are double-stranded nucleic acid molecules. In another embodiment, the siNA molecules of the invention consist of duplex nucleic acid molecules containing about 19 base pairs between oligonucleotides comprising about 19 to about 25 (e.g., about 19, 20, 21, 22, 23, 24, or 25) nucleotides. In yet another embodiment, siNA molecules of the invention comprise duplex nucleic acid molecules with overhanging ends of about about 1 to about 3 (e.g., about 1, 2, or 3) nucleotides, for example, about 21-nucleotide duplexes with about 19 base pairs and 3′-terminal mononucleotide, dinucleotide, or trinucleotide overhangs.  
      In one embodiment, the invention features one or more chemically-modified siNA constructs having specificity for Fas and/or FasL expressing nucleic acid molecules, such as RNA encoding a Fas and/or FasL protein. Non-limiting examples of such chemical modifications include without limitation phosphorothioate internucleotide linkages, 2′-deoxyribonucleotides, 2′-O-methyl ribonucleotides, 2′-deoxy-2′-fluoro ribonucleotides, “universal base” nucleotides, “acyclic” nucleotides, 5-C-methyl nucleotides, and terminal glyceryl and/or inverted deoxy abasic residue incorporation. These chemical modifications, when used in various siNA constructs, are shown to preserve RNAi activity in cells while at the same time, dramatically increasing the serum stability of these compounds. Furthermore, contrary to the data published by Parrish et al., supra, applicant demonstrates that multiple (greater than one) phosphorothioate substitutions are well-tolerated and confer substantial increases in serum stability for modified siNA constructs.  
      In one embodiment, a siNA molecule of the invention comprises modified nucleotides while maintaining the ability to mediate RNAi. The modified nucleotides can be used to improve in vitro or in vivo characteristics such as stability, activity, and/or bioavailability. For example, a siNA molecule of the invention can comprise modified nucleotides as a percentage of the total number of nucleotides present in the siNA molecule. As such, a siNA molecule of the invention can generally comprise about 5% to about 100% modified nucleotides (e.g., about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% modified nucleotides). The actual percentage of modified nucleotides present in a given siNA molecule will depend on the total number of nucleotides present in the siNA. If the siNA molecule is single stranded, the percent modification can be based upon the total number of nucleotides present in the single stranded siNA molecules. Likewise, if the siNA molecule is double stranded, the percent modification can be based upon the total number of nucleotides present in the sense strand, antisense strand, or both the sense and antisense strands.  
      One aspect of the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene. In one embodiment, the double stranded siNA molecule comprises one or more chemical modifications and each strand of the double-stranded siNA is about 21 nucleotides long. In one embodiment, the double-stranded siNA molecule does not contain any ribonucleotides. In another embodiment, the double-stranded siNA molecule comprises one or more ribonucleotides. In one embodiment, each strand of the double-stranded siNA molecule comprises about 19 to about 29 (e.g., about 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29) nucleotides, wherein each strand comprises about 19 nucleotides that are complementary to the nucleotides of the other strand. In one embodiment, one of the strands of the double-stranded siNA molecule comprises a nucleotide sequence that is complementary to a nucleotide sequence or a portion thereof of the Fas and/or FasL gene, and the second strand of the double-stranded siNA molecule comprises a nucleotide sequence substantially similar to the nucleotide sequence of the Fas and/or FasL gene or a portion thereof.  
      In another embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene comprising an antisense region, wherein the antisense region comprises a nucleotide sequence that is complementary to a nucleotide sequence of the Fas and/or FasL gene or a portion thereof, and a sense region, wherein the sense region comprises a nucleotide sequence substantially similar to the nucleotide sequence of the Fas and/or FasL gene or a portion thereof. In one embodiment, the antisense region and the sense region each comprise about 19 to about 23 (e.g. about 19, 20, 21, 22, or 23) nucleotides, wherein the antisense region comprises about 19 nucleotides that are complementary to nucleotides of the sense region.  
      In another embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene comprising a sense region and an antisense region, wherein the antisense region comprises a nucleotide sequence that is complementary to a nucleotide sequence of RNA encoded by the Fas and/or FasL gene or a portion thereof and the sense region comprises a nucleotide sequence that is complementary to the antisense region.  
      In one embodiment, a siNA molecule of the invention comprises blunt ends, i.e., ends that do not include any overhanging nucleotides. For example, a siNA molecule comprising modifications described herein (e.g., comprising nucleotides having Formulae I-VII or siNA constructs comprising “Stab 00”-“Stab 25” (Table IV) or any combination thereof (see Table IV)) and/or any length described herein can comprise blunt ends or ends with no overhanging nucleotides.  
      In one embodiment, any siNA molecule of the invention can comprise one or more blunt ends, i.e. where a blunt end does not have any overhanging nucleotides. In one embodiment, the blunt ended siNA molecule has a number of base pairs equal to the number of nucleotides present in each strand of the siNA molecule. In another embodiment, the siNA molecule comprises one blunt end, for example wherein the 5′-end of the antisense strand and the 3′-end of the sense strand do not have any overhanging nucleotides. In another example, the siNA molecule comprises one blunt end, for example wherein the 3′-end of the antisense strand and the 5′-end of the sense strand do not have any overhanging nucleotides. In another example, a siNA molecule comprises two blunt ends, for example wherein the 3′-end of the antisense strand and the 5′-end of the sense strand as well as the 5′-end of the antisense strand and 3′-end of the sense strand do not have any overhanging nucleotides. A blunt ended siNA molecule can comprise, for example, from about 18 to about 30 nucleotides (e.g., about 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 nucleotides). Other nucleotides present in a blunt ended siNA molecule can comprise mismatches, bulges, loops, or wobble base pairs, for example, to modulate the activity of the siNA molecule to mediate RNA interference.  
      By “blunt ends” is meant symmetric termini or termini of a double stranded siNA molecule having no overhanging nucleotides. The two strands of a double stranded siNA molecule align with each other without over-hanging nucleotides at the termini. For example, a blunt ended siNA construct comprises terminal nucleotides that are complementary between the sense and antisense regions of the siNA molecule.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene, wherein the siNA molecule is assembled from two separate oligonucleotide fragments wherein one fragment comprises the sense region and the second fragment comprises the antisense region of the siNA molecule. The sense region can be connected to the antisense region via a linker molecule, such as a polynucleotide linker or a non-nucleotide linker.  
      In one embodiment, the invention features double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene, wherein the siNA molecule comprises about 19 to about 21 base pairs, and wherein each strand of the siNA molecule comprises one or more chemical modifications. In another embodiment, one of the strands of the double-stranded siNA molecule comprises a nucleotide sequence that is complementary to a nucleotide sequence of a Fas and/or FasL gene or a portion thereof, and the second strand of the double-stranded siNA molecule comprises a nucleotide sequence substantially similar to the nucleotide sequence or a portion thereof of the Fas and/or FasL gene. In another embodiment, one of the strands of the double-stranded siNA molecule comprises a nucleotide sequence that is complementary to a nucleotide sequence of a Fas and/or FasL gene or portion thereof, and the second strand of the double-stranded siNA molecule comprises a nucleotide sequence substantially similar to the nucleotide sequence or portion thereof of the Fas and/or FasL gene. In another embodiment, each strand of the siNA molecule comprises about 19 to about 23 nucleotides, and each strand comprises at least about 19 nucleotides that are complementary to the nucleotides of the other strand. The Fas and/or FasL gene can comprise, for example, sequences referred to in Table I.  
      In one embodiment, a siNA molecule of the invention comprises no ribonucleotides. In another embodiment, a siNA molecule of the invention comprises ribonucleotides.  
      In one embodiment, a siNA molecule of the invention comprises an antisense region comprising a nucleotide sequence that is complementary to a nucleotide sequence of a Fas and/or FasL gene or a portion thereof, and the siNA further comprises a sense region comprising a nucleotide sequence substantially similar to the nucleotide sequence of the Fas and/or FasL gene or a portion thereof. In another embodiment, the antisense region and the sense region each comprise about 19 to about 23 nucleotides and the antisense region comprises at least about 19 nucleotides that are complementary to nucleotides of the sense region. The Fas and/or FasL gene can comprise, for example, sequences referred to in Table I.  
      In one embodiment, a siNA molecule of the invention comprises a sense region and an antisense region, wherein the antisense region comprises a nucleotide sequence that is complementary to a nucleotide sequence of RNA encoded by a Fas and/or FasL gene, or a portion thereof, and the sense region comprises a nucleotide sequence that is complementary to the antisense region. In one embodiment, the siNA molecule is assembled from two separate oligonucleotide fragments, wherein one fragment comprises the sense region and the second fragment comprises the antisense region of the siNA molecule. In another embodiment, the sense region is connected to the antisense region via a linker molecule. In another embodiment, the sense region is connected to the antisense region via a linker molecule, such as a nucleotide or non-nucleotide linker. The Fas and/or FasL gene can comprise, for example, sequences referred in to Table I.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene comprising a sense region and an antisense region, wherein the antisense region comprises a nucleotide sequence that is complementary to a nucleotide sequence of RNA encoded by the Fas and/or FasL gene or a portion thereof and the sense region comprises a nucleotide sequence that is complementary to the antisense region, and wherein the siNA molecule has one or more modified pyrimidine and/or purine nucleotides. In one embodiment, the pyrimidine nucleotides in the sense region are 2′-O-methyl pyrimidine nucleotides or 2′-deoxy-2′-fluoro pyrimidine nucleotides and the purine nucleotides present in the sense region are 2′-deoxy purine nucleotides. In another embodiment, the pyrimidine nucleotides in the sense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides and the purine nucleotides present in the sense region are 2′-O-methyl purine nucleotides. In another embodiment, the pyrimidine nucleotides in the sense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides and the purine nucleotides present in the sense region are 2′-deoxy purine nucleotides. In one embodiment, the pyrimidine nucleotides in the antisense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides and the purine nucleotides present in the antisense region are 2′-O-methyl or 2′-deoxy purine nucleotides. In another embodiment of any of the above-described siNA molecules, any nucleotides present in a non-complementary region of the sense strand (e.g. overhang region) are 2′-deoxy nucleotides.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene, wherein the siNA molecule is assembled from two separate oligonucleotide fragments wherein one fragment comprises the sense region and the second fragment comprises the antisense region of the siNA molecule, and wherein the fragment comprising the sense region includes a terminal cap moiety at the 5′-end, the 3′-end, or both of the 5′ and 3′ ends of the fragment. In one embodiment, the terminal cap moiety is an inverted deoxy abasic moiety or glyceryl moiety. In one embodiment, each of the two fragments of the siNA molecule comprise about 21 nucleotides.  
      In one embodiment, the invention features a siNA molecule comprising at least one modified nucleotide, wherein the modified nucleotide is a 2′-deoxy-2′-fluoro nucleotide. The siNA can be, for example, of length between about 12 and about 36 nucleotides. In one embodiment, all pyrimidine nucleotides present in the siNA are 2′-deoxy-2′-fluoro pyrimidine nucleotides. In one embodiment, the modified nucleotides in the siNA include at least one 2′-deoxy-2′-fluoro cytidine or 2′-deoxy-2′-fluoro uridine nucleotide. In another embodiment, the modified nucleotides in the siNA include at least one 2′-fluoro cytidine and at least one 2′-deoxy-2′-fluoro uridine nucleotides. In one embodiment, all uridine nucleotides present in the siNA are 2′-deoxy-2′-fluoro uridine nucleotides. In one embodiment, all cytidine nucleotides present in the siNA are 2′-deoxy-2′-fluoro cytidine nucleotides. In one embodiment, all adenosine nucleotides present in the siNA are 2′-deoxy-2′-fluoro adenosine nucleotides. In one embodiment, all guanosine nucleotides present in the siNA are 2′-deoxy-2′-fluoro guanosine nucleotides. The siNA can further comprise at least one modified internucleotidic linkage, such as phosphorothioate linkage. In one embodiment, the 2′-deoxy-2′-fluoronucleotides are present at specifically selected locations in the siNA that are sensitive to cleavage by ribonucleases, such as locations having pyrimidine nucleotides.  
      In one embodiment, the invention features a method of increasing the stability of a siNA molecule against cleavage by ribonucleases comprising introducing at least one modified nucleotide into the siNA molecule, wherein the modified nucleotide is a 2′-deoxy-2′-fluoro nucleotide. In one embodiment, all pyrimidine nucleotides present in the siNA are 2′-deoxy-2′-fluoro pyrimidine nucleotides. In one embodiment, the modified nucleotides in the siNA include at least one 2′-deoxy-2′-fluoro cytidine or 2′-deoxy-2′-fluoro uridine nucleotide. In another embodiment, the modified nucleotides in the siNA include at least one 2′-fluoro cytidine and at least one 2′-deoxy-2′-fluoro uridine nucleotides. In one embodiment, all uridine nucleotides present in the siNA are 2′-deoxy-2′-fluoro uridine nucleotides. In one embodiment, all cytidine nucleotides present in the siNA are 2′-deoxy-2′-fluoro cytidine nucleotides. In one embodiment, all adenosine nucleotides present in the siNA are 2′-deoxy-2′-fluoro adenosine nucleotides. In one embodiment, all guanosine nucleotides present in the siNA are 2′-deoxy-2′-fluoro guanosine nucleotides. The siNA can further comprise at least one modified internucleotidic linkage, such as phosphorothioate linkage. In one embodiment, the 2′-deoxy-2′-fluoronucleotides are present at specifically selected locations in the siNA that are sensitive to cleavage by ribonucleases, such as locations having pyrimidine nucleotides.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene comprising a sense region and an antisense region, wherein the antisense region comprises a nucleotide sequence that is complementary to a nucleotide sequence of RNA encoded by the Fas and/or FasL gene or a portion thereof and the sense region comprises a nucleotide sequence that is complementary to the antisense region, and wherein the purine nucleotides present in the antisense region comprise 2′-deoxy-purine nucleotides. In an alternative embodiment, the purine nucleotides present in the antisense region comprise 2′-O-methyl purine nucleotides. In either of the above embodiments, the antisense region can comprise a phosphorothioate internucleotide linkage at the 3′ end of the antisense region. Alternatively, in either of the above embodiments, the antisense region can comprise a glyceryl modification at the 3′ end of the antisense region. In another embodiment of any of the above-described siNA molecules, any nucleotides present in a non-complementary region of the antisense strand (e.g. overhang region) are 2′-deoxy nucleotides.  
      In one embodiment, the antisense region of a siNA molecule of the invention comprises sequence complementary to a portion of a Fas and/or FasL transcript having sequence unique to a particular Fas and/or FasL disease related allele, such as sequence comprising a single nucleotide polymorphism (SNP) associated with the disease specific allele. As such, the antisense region of a siNA molecule of the invention can comprise sequence complementary to sequences that are unique to a particular allele to provide specificity in mediating selective RNAi against the disease, condition, or trait related allele.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that down-regulates expression of a Fas and/or FasL gene, wherein the siNA molecule is assembled from two separate oligonucleotide fragments wherein one fragment comprises the sense region and the second fragment comprises the antisense region of the siNA molecule. In another embodiment about 19 nucleotides of each fragment of the siNA molecule are base-paired to the complementary nucleotides of the other fragment of the siNA molecule and wherein at least two 3′ terminal nucleotides of each fragment of the siNA molecule are not base-paired to the nucleotides of the other fragment of the siNA molecule. In one embodiment, each of the two 3′ terminal nucleotides of each fragment of the siNA molecule is a 2′-deoxy-pyrimidine nucleotide, such as a 2′-deoxy-thymidine. In another embodiment, all 21 nucleotides of each fragment of the siNA molecule are base-paired to the complementary nucleotides of the other fragment of the siNA molecule. In another embodiment, about 19 nucleotides of the antisense region are base-paired to the nucleotide sequence or a portion thereof of the RNA encoded by the Fas and/or FasL gene. In another embodiment, about 21 nucleotides of the antisense region are base-paired to the nucleotide sequence or a portion thereof of the RNA encoded by the Fas and/or FasL gene. In any of the above embodiments, the 5′-end of the fragment comprising said antisense region can optionally include a phosphate group.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that inhibits the expression of a Fas and/or FasL RNA sequence (e.g., wherein said target RNA sequence is encoded by a Fas and/or FasL gene involved in the Fas and/or FasL pathway), wherein the siNA molecule does not contain any ribonucleotides and wherein each strand of the double-stranded siNA molecule is about 21 nucleotides long. Examples of non-ribonucleotide containing siNA constructs are combinations of stabilization chemistries shown in Table IV in any combination of Sense/Antisense chemistries, such as Stab 7/8, Stab 7/11, Stab 8/8, Stab 18/8, Stab 18/11, Stab 12/13, Stab 7/13, Stab 18/13, Stab 7/19, Stab 8/19, Stab 18/19, Stab 7/20, Stab 8/20, or Stab 18/20.  
      In one embodiment, the invention features a chemically synthesized double stranded RNA molecule that directs cleavage of a Fas and/or FasL RNA via RNA interference, wherein each strand of said RNA molecule is about 21 to about 23 nucleotides in length; one strand of the RNA molecule comprises nucleotide sequence having sufficient complementarity to the Fas and/or FasL RNA for the RNA molecule to direct cleavage of the Fas and/or FasL RNA via RNA interference; and wherein at least one strand of the RNA molecule comprises one or more chemically modified nucleotides described herein, such as deoxynucleotides, 2′-O-methyl nucleotides, 2′-deoxy-2′-fluoro nucloetides, 2′-O-methoxyethyl nucleotides etc.  
      In one embodiment, the invention features a medicament comprising a siNA molecule of the invention.  
      In one embodiment, the invention features an active ingredient comprising a siNA molecule of the invention.  
      In one embodiment, the invention features the use of a double-stranded short interfering nucleic acid (siNA) molecule to down-regulate expression of a Fas and/or FasL gene, wherein the siNA molecule comprises one or more chemical modifications and each strand of the double-stranded siNA is about 18 to about 28 or more (e.g., about 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28 or more) nucleotides long.  
      In one embodiment, the invention features the use of a double-stranded short interfering nucleic acid (siNA) molecule that inhibits expression of a Fas and/or FasL gene, wherein one of the strands of the double-stranded siNA molecule is an antisense strand which comprises nucleotide sequence that is complementary to nucleotide sequence of Fas and/or FasL RNA or a portion thereof, the other strand is a sense strand which comprises nucleotide sequence that is complementary to a nucleotide sequence of the antisense strand and wherein a majority of the pyrimidine nucleotides present in the double-stranded siNA molecule comprises a sugar modification.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that inhibits expression of a Fas and/or FasL gene, wherein one of the strands of the double-stranded siNA molecule is an antisense strand which comprises nucleotide sequence that is complementary to nucleotide sequence of Fas and/or FasL RNA or a portion thereof, wherein the other strand is a sense strand which comprises nucleotide sequence that is complementary to a nucleotide sequence of the antisense strand and wherein a majority of the pyrimidine nucleotides present in the double-stranded siNA molecule comprises a sugar modification.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that inhibits expression of a Fas and/or FasL gene, wherein one of the strands of the double-stranded siNA molecule is an antisense strand which comprises nucleotide sequence that is complementary to nucleotide sequence of Fas and/or FasL RNA that encodes a protein or portion thereof, the other strand is a sense strand which comprises nucleotide sequence that is complementary to a nucleotide sequence of the antisense strand and wherein a majority of the pyrimidine nucleotides present in the double-stranded siNA molecule comprises a sugar modification. In one embodiment, each strand of the siNA molecule comprises about 18 to about 29 or more (e.g., about 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29 or more) nucleotides, wherein each strand comprises at least about 18 nucleotides that are complementary to the nucleotides of the other strand. In one embodiment, the siNA molecule is assembled from two oligonucleotide fragments, wherein one fragment comprises the nucleotide sequence of the antisense strand of the siNA molecule and a second fragment comprises nucleotide sequence of the sense region of the siNA molecule. In one embodiment, the sense strand is connected to the antisense strand via a linker molecule, such as a polynucleotide linker or a non-nucleotide linker. In a further embodiment, the pyrimidine nucleotides present in the sense strand are 2′-deoxy-2′-fluoro pyrimidine nucleotides and the purine nucleotides present in the sense region are 2′-deoxy purine nucleotides. In another embodiment, the pyrimidine nucleotides present in the sense strand are 2′-deoxy-2′-fluoro pyrimidine nucleotides and the purine nucleotides present in the sense region are 2′-O-methyl purine nucleotides. In still another embodiment, the pyrimidine nucleotides present in the antisense strand are 2′-deoxy-2′-fluoro pyrimidine nucleotides and any purine nucleotides present in the antisense strand are 2′-deoxy purine nucleotides. In another embodiment, the antisense strand comprises one or more 2′-deoxy-2′-fluoro pyrimidine nucleotides and one or more 2′-O-methyl purine nucleotides. In another embodiment, the pyrimidine nucleotides present in the antisense strand are 2′-deoxy-2′-fluoro pyrimidine nucleotides and any purine nucleotides present in the antisense strand are 2′-O-methyl purine nucleotides. In a further embodiment the sense strand comprises a 3′-end and a 5′-end, wherein a terminal cap moiety (e.g., an inverted deoxy abasic moiety or inverted deoxy nucleotide moiety such as inverted thymidine) is present at the 5′-end, the 3′-end, or both of the 5′ and 3′ ends of the sense strand. In another embodiment, the antisense strand comprises a phosphorothioate internucleotide linkage at the 3′ end of the antisense strand. In another embodiment, the antisense strand comprises a glyceryl modification at the 3′ end. In another embodiment, the 5′-end of the antisense strand optionally includes a phosphate group.  
      In any of the above-described embodiments of a double-stranded short interfering nucleic acid (siNA) molecule that inhibits expression of a Fas and/or FasL gene, wherein a majority of the pyrimidine nucleotides present in the double-stranded siNA molecule comprises a sugar modification, each of the two strands of the siNA molecule can comprise about 21 nucleotides. In one embodiment, about 21 nucleotides of each strand of the siNA molecule are base-paired to the complementary nucleotides of the other strand of the siNA molecule. In another embodiment, about 19 nucleotides of each strand of the siNA molecule are base-paired to the complementary nucleotides of the other strand of the siNA molecule, wherein at least two 3′ terminal nucleotides of each strand of the siNA molecule are not base-paired to the nucleotides of the other strand of the siNA molecule. In another embodiment, each of the two 3′ terminal nucleotides of each fragment of the siNA molecule is a 2′-deoxy-pyrimidine, such as 2′-deoxy-thymidine. In one embodiment, each strand of the siNA molecule is base-paired to the complementary nucleotides of the other strand of the siNA molecule. In one embodiment, about 19 nucleotides of the antisense strand are base-paired to the nucleotide sequence of the Fas and/or FasL RNA or a portion thereof. In one embodiment, about 21 nucleotides of the antisense strand are base-paired to the nucleotide sequence of the Fas and/or FasL RNA or a portion thereof.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that inhibits expression of a Fas and/or FasL gene, wherein one of the strands of the double-stranded siNA molecule is an antisense strand which comprises nucleotide sequence that is complementary to nucleotide sequence of Fas and/or FasL RNA or a portion thereof, the other strand is a sense strand which comprises nucleotide sequence that is complementary to a nucleotide sequence of the antisense strand and wherein a majority of the pyrimidine nucleotides present in the double-stranded siNA molecule comprises a sugar modification, and wherein the 5′-end of the antisense strand optionally includes a phosphate group.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that inhibits expression of a Fas and/or FasL gene, wherein one of the strands of the double-stranded siNA molecule is an antisense strand which comprises nucleotide sequence that is complementary to nucleotide sequence of Fas and/or FasL RNA or a portion thereof, the other strand is a sense strand which comprises nucleotide sequence that is complementary to a nucleotide sequence of the antisense strand and wherein a majority of the pyrimidine nucleotides present in the double-stranded siNA molecule comprises a sugar modification, and wherein the nucleotide sequence or a portion thereof of the antisense strand is complementary to a nucleotide sequence of the untranslated region or a portion thereof of the Fas and/or FasL RNA.  
      In one embodiment, the invention features a double-stranded short interfering nucleic acid (siNA) molecule that inhibits expression of a Fas and/or FasL gene, wherein one of the strands of the double-stranded siNA molecule is an antisense strand which comprises nucleotide sequence that is complementary to nucleotide sequence of Fas and/or FasL RNA or a portion thereof, wherein the other strand is a sense strand which comprises nucleotide sequence that is complementary to a nucleotide sequence of the antisense strand, wherein a majority of the pyrimidine nucleotides present in the double-stranded siNA molecule comprises a sugar modification, and wherein the nucleotide sequence of the antisense strand is complementary to a nucleotide sequence of the Fas and/or FasL RNA or a portion thereof that is present in the Fas and/or FasL RNA.  
      In one embodiment, the invention features a composition comprising a siNA molecule of the invention in a pharmaceutically acceptable carrier or diluent.  
      In a non-limiting example, the introduction of chemically-modified nucleotides into nucleic acid molecules provides a powerful tool in overcoming potential limitations of in vivo stability and bioavailability inherent to native RNA molecules that are delivered exogenously. For example, the use of chemically-modified nucleic acid molecules can enable a lower dose of a particular nucleic acid molecule for a given therapeutic effect since chemically-modified nucleic acid molecules tend to have a longer half-life in serum. Furthermore, certain chemical modifications can improve the bioavailability of nucleic acid molecules by targeting particular cells or tissues and/or improving cellular uptake of the nucleic acid molecule. Therefore, even if the activity of a chemically-modified nucleic acid molecule is reduced as compared to a native nucleic acid molecule, for example, when compared to an all-RNA nucleic acid molecule, the overall activity of the modified nucleic acid molecule can be greater than that of the native molecule due to improved stability and/or delivery of the molecule. Unlike native unmodified siNA, chemically-modified siNA can also minimize the possibility of activating interferon activity in humans.  
      In any of the embodiments of siNA molecules described herein, the antisense region of a siNA molecule of the invention can comprise a phosphorothioate internucleotide linkage at the 3′-end of said antisense region. In any of the embodiments of siNA molecules described herein, the antisense region can comprise about one to about five phosphorothioate internucleotide linkages at the 5′-end of said antisense region. In any of the embodiments of siNA molecules described herein, the 3′-terminal nucleotide overhangs of a siNA molecule of the invention can comprise ribonucleotides or deoxyribonucleotides that are chemically-modified at a nucleic acid sugar, base, or backbone. In any of the embodiments of siNA molecules described herein, the 3′-terminal nucleotide overhangs can comprise one or more universal base ribonucleotides. In any of the embodiments of siNA molecules described herein, the 3′-terminal nucleotide overhangs can comprise one or more acyclic nucleotides.  
      One embodiment of the invention provides an expression vector comprising a nucleic acid sequence encoding at least one siNA molecule of the invention in a manner that allows expression of the nucleic acid molecule. Another embodiment of the invention provides a mammalian cell comprising such an expression vector. The mammalian cell can be a human cell. The siNA molecule of the expression vector can comprise a sense region and an antisense region. The antisense region can comprise sequence complementary to a RNA or DNA sequence encoding Fas and/or FasL and the sense region can comprise sequence complementary to the antisense region. The siNA molecule can comprise two distinct strands having complementary sense and antisense regions. The siNA molecule can comprise a single strand having complementary sense and antisense regions.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule capable of mediating RNA interference (RNAi) against Fas and/or FasL inside a cell or reconstituted in vitro system, wherein the chemical modification comprises one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) nucleotides comprising a backbone modified internucleotide linkage having Formula I:  
                 
          wherein each R1 and R2 is independently any nucleotide, non-nucleotide, or polynucleotide which can be naturally-occurring or chemically-modified, each X and Y is independently O, S, N, alkyl, or substituted alkyl, each Z and W is independently O, S, N, alkyl, substituted alkyl, O-alkyl, S-alkyl, alkaryl, aralkyl, or acetyl and wherein W, X, Y, and Z are optionally not all 0. In another embodiment, a backbone modification of the invention comprises a phosphonoacetate and/or thiophosphonoacetate internucleotide linkage (see for example Sheehan et al., 2003 , Nucleic Acids Research,  31, 4109-4118).        

      The chemically-modified internucleotide linkages having Formula I, for example, wherein any Z, W, X, and/or Y independently comprises a sulphur atom, can be present in one or both oligonucleotide strands of the siNA duplex, for example, in the sense strand, the antisense strand, or both strands. The siNA molecules of the invention can comprise one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) chemically-modified internucleotide linkages having Formula I at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of the sense strand, the antisense strand, or both strands. For example, an exemplary siNA molecule of the invention can comprise about 1 to about 5 or more (e.g., about 1, 2, 3, 4, 5, or more) chemically-modified internucleotide linkages having Formula I at the 5′-end of the sense strand, the antisense strand, or both strands. In another non-limiting example, an exemplary siNA molecule of the invention can comprise one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) pyrimidine nucleotides with chemically-modified internucleotide linkages having Formula I in the sense strand, the antisense strand, or both strands. In yet another non-limiting example, an exemplary siNA molecule of the invention can comprise one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) purine nucleotides with chemically-modified internucleotide linkages having Formula I in the sense strand, the antisense strand, or both strands. In another embodiment, a siNA molecule of the invention having internucleotide linkage(s) of Formula I also comprises a chemically-modified nucleotide or non-nucleotide having any of Formulae I-VII.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule capable of mediating RNA interference (RNAi) against Fas and/or FasL inside a cell or reconstituted in vitro system, wherein the chemical modification comprises one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) nucleotides or non-nucleotides having Formula II:  
                 
 
 wherein each R3, R4, R5, R6, R7, R8, R10, R11 and R12 is independently H, OH, alkyl, substituted alkyl, alkaryl or aralkyl, F, Cl, Br, CN, CF3, OCF3, OCN, O-alkyl, S-alkyl, N-alkyl, O-alkenyl, S-alkenyl, N-alkenyl, SO-alkyl, alkyl-OSH, alkyl-OH, O-alkyl-OH, O-alkyl-SH, S-alkyl-OH, S-alkyl-SH, alkyl-S-alkyl, alkyl-O-alkyl, ONO2, NO2, N3, NH2, aminoalkyl, aminoacid, aminoacyl, ONH2,0-aminoalkyl, O-aminoacid, O-aminoacyl, heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalklylamino, substituted silyl, or group having Formula I or II; R9 is O, S, CH2, S═O, CHF, or CF2, and B is a nucleosidic base such as adenine, guanine, uracil, cytosine, thymine, 2-aminoadenosine, 5-methylcytosine, 2,6-diaminopurine, or any other non-naturally occurring base that can be complementary or non-complementary to target RNA or a non-nucleosidic base such as phenyl, naphthyl, 3-nitropyrrole, 5-nitroindole, nebularine, pyridone, pyridinone, or any other non-naturally occurring universal base that can be complementary or non-complementary to target RNA. 
 
      The chemically-modified nucleotide or non-nucleotide of Formula II can be present in one or both oligonucleotide strands of the siNA duplex, for example in the sense strand, the antisense strand, or both strands. The siNA molecules of the invention can comprise one or more chemically-modified nucleotide or non-nucleotide of Formula II at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of the sense strand, the antisense strand, or both strands. For example, an exemplary siNA molecule of the invention can comprise about 1 to about 5 or more (e.g., about 1, 2, 3, 4, 5, or more) chemically-modified nucleotides or non-nucleotides of Formula II at the 5′-end of the sense strand, the antisense strand, or both strands. In anther non-limiting example, an exemplary siNA molecule of the invention can comprise about 1 to about 5 or more (e.g., about 1, 2, 3, 4, 5, or more) chemically-modified nucleotides or non-nucleotides of Formula II at the 3′-end of the sense strand, the antisense strand, or both strands.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule capable of mediating RNA interference (RNAi) against Fas and/or FasL inside a cell or reconstituted in vitro system, wherein the chemical modification comprises one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) nucleotides or non-nucleotides having Formula III:  
                 
 
 wherein each R3, R4, R5, R6, R7, R8, R10, R11 and R12 is independently H, OH, alkyl, substituted alkyl, alkaryl or aralkyl, F, Cl, Br, CN, CF3, OCF3, OCN, O-alkyl, S-alkyl, N-alkyl, O-alkenyl, S-alkenyl, N-alkenyl, SO-alkyl, alkyl-OSH, alkyl-OH, O-alkyl-OH, O-alkyl-SH, S-alkyl-OH, S-alkyl-SH, alkyl-S-alkyl, alkyl-O-alkyl, ONO2, NO2, N3, NH2, aminoalkyl, aminoacid, aminoacyl, ONH2,0-aminoalkyl, O-aminoacid, O-aminoacyl, heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalklylamino, substituted silyl, or group having Formula I or II; R9 is O, S, CH2, S═O, CHF, or CF2, and B is a nucleosidic base such as adenine, guanine, uracil, cytosine, thymine, 2-aminoadenosine, 5-methylcytosine, 2,6-diaminopurine, or any other non-naturally occurring base that can be employed to be complementary or non-complementary to target RNA or a non-nucleosidic base such as phenyl, naphthyl, 3-nitropyrrole, 5-nitroindole, nebularine, pyridone, pyridinone, or any other non-naturally occurring universal base that can be complementary or non-complementary to target RNA. 
 
      The chemically-modified nucleotide or non-nucleotide of Formula III can be present in one or both oligonucleotide strands of the siNA duplex, for example, in the sense strand, the antisense strand, or both strands. The siNA molecules of the invention can comprise one or more chemically-modified nucleotide or non-nucleotide of Formula III at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of the sense strand, the antisense strand, or both strands. For example, an exemplary siNA molecule of the invention can comprise about 1 to about 5 or more (e.g., about 1, 2, 3, 4, 5, or more) chemically-modified nucleotide(s) or non-nucleotide(s) of Formula III at the 5′-end of the sense strand, the antisense strand, or both strands. In anther non-limiting example, an exemplary siNA molecule of the invention can comprise about 1 to about 5 or more (e.g., about 1, 2, 3, 4, 5, or more) chemically-modified nucleotide or non-nucleotide of Formula III at the 3′-end of the sense strand, the antisense strand, or both strands.  
      In another embodiment, a siNA molecule of the invention comprises a nucleotide having Formula II or III, wherein the nucleotide having Formula II or III is in an inverted configuration. For example, the nucleotide having Formula II or III is connected to the siNA construct in a 3′-3′,3′-2′,2′-3′, or 5′-5′ configuration, such as at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of one or both siNA strands.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule capable of mediating RNA interference (RNAi) against Fas and/or FasL inside a cell or reconstituted in vitro system, wherein the chemical modification comprises a 5′-terminal phosphate group having Formula IV:  
                 
 
 wherein each X and Y is independently O, S, N, alkyl, substituted alkyl, or alkylhalo; wherein each Z and W is independently O, S, N, alkyl, substituted alkyl, O-alkyl, S-alkyl, alkaryl, aralkyl, alkylhalo, or acetyl; and wherein W, X, Y and Z are not all 0. 
 
      In one embodiment, the invention features a siNA molecule having a 5′-terminal phosphate group having Formula IV on the target-complementary strand, for example, a strand complementary to a target RNA, wherein the siNA molecule comprises an all RNA siNA molecule. In another embodiment, the invention features a siNA molecule having a 5′-terminal phosphate group having Formula IV on the target-complementary strand wherein the siNA molecule also comprises about 1 to about 3 (e.g., about 1, 2, or 3) nucleotide 3′-terminal nucleotide overhangs having about 1 to about 4 (e.g., about 1, 2, 3, or 4) deoxyribonucleotides on the 3′-end of one or both strands. In another embodiment, a 5′-terminal phosphate group having Formula IV is present on the target-complementary strand of a siNA molecule of the invention, for example a siNA molecule having chemical modifications having any of Formulae I-VII.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule capable of mediating RNA interference (RNAi) against Fas and/or FasL inside a cell or reconstituted in vitro system, wherein the chemical modification comprises one or more phosphorothioate internucleotide linkages. For example, in a non-limiting example, the invention features a chemically-modified short interfering nucleic acid (siNA) having about 1, 2, 3, 4, 5, 6, 7, 8 or more phosphorothioate internucleotide linkages in one siNA strand. In yet another embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) individually having about 1, 2, 3, 4, 5, 6, 7, 8 or more phosphorothioate internucleotide linkages in both siNA strands. The phosphorothioate internucleotide linkages can be present in one or both oligonucleotide strands of the siNA duplex, for example in the sense strand, the antisense strand, or both strands. The siNA molecules of the invention can comprise one or more phosphorothioate internucleotide linkages at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of the sense strand, the antisense strand, or both strands. For example, an exemplary siNA molecule of the invention can comprise about 1 to about 5 or more (e.g., about 1, 2, 3, 4, 5, or more) consecutive phosphorothioate internucleotide linkages at the 5′-end of the sense strand, the antisense strand, or both strands. In another non-limiting example, an exemplary siNA molecule of the invention can comprise one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) pyrimidine phosphorothioate internucleotide linkages in the sense strand, the antisense strand, or both strands. In yet another non-limiting example, an exemplary siNA molecule of the invention can comprise one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) purine phosphorothioate internucleotide linkages in the sense strand, the antisense strand, or both strands.  
      In one embodiment, the invention features a siNA molecule, wherein the sense strand comprises one or more, for example, about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more phosphorothioate internucleotide linkages, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) 2′-deoxy, 2′-O-methyl, 2′-deoxy-2′-fluoro, and/or about one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) universal base modified nucleotides, and optionally a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of the sense strand; and wherein the antisense strand comprises about 1 to about 10 or more, specifically about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more phosphorothioate internucleotide linkages, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) 2′-deoxy, 2′-O-methyl, 2′-deoxy-2′-fluoro, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) universal base modified nucleotides, and optionally a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of the antisense strand. In another embodiment, one or more, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more, pyrimidine nucleotides of the sense and/or antisense siNA strand are chemically-modified with 2′-deoxy, 2′-O-methyl and/or 2′-deoxy-2′-fluoro nucleotides, with or without one or more, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more, phosphorothioate internucleotide linkages and/or a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends, being present in the same or different strand.  
      In another embodiment, the invention features a siNA molecule, wherein the sense strand comprises about 1 to about 5, specifically about 1, 2, 3, 4, or 5 phosphorothioate internucleotide linkages, and/or one or more (e.g., about 1, 2, 3, 4, 5, or more) 2′-deoxy, 2′-O-methyl, 2′-deoxy-2′-fluoro, and/or one or more (e.g., about 1, 2, 3, 4, 5, or more) universal base modified nucleotides, and optionally a terminal cap molecule at the 3-end, the 5′-end, or both of the 3′- and 5′-ends of the sense strand; and wherein the antisense strand comprises about 1 to about 5 or more, specifically about 1, 2, 3, 4, 5, or more phosphorothioate internucleotide linkages, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) 2′-deoxy, 2′-O-methyl, 2′-deoxy-2′-fluoro, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) universal base modified nucleotides, and optionally a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of the antisense strand. In another embodiment, one or more, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more, pyrimidine nucleotides of the sense and/or antisense siNA strand are chemically-modified with 2′-deoxy, 2′-O-methyl and/or 2′-deoxy-2′-fluoro nucleotides, with or without about 1 to about 5 or more, for example about 1, 2, 3, 4, 5, or more phosphorothioate internucleotide linkages and/or a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends, being present in the same or different strand.  
      In one embodiment, the invention features a siNA molecule, wherein the antisense strand comprises one or more, for example, about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more phosphorothioate internucleotide linkages, and/or about one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) 2′-deoxy, 2′-O-methyl, 2′-deoxy-2′-fluoro, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) universal base modified nucleotides, and optionally a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of the sense strand; and wherein the antisense strand comprises about 1 to about 10 or more, specifically about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more phosphorothioate internucleotide linkages, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) 2′-deoxy, 2′-O-methyl, 2′-deoxy-2′-fluoro, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) universal base modified nucleotides, and optionally a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of the antisense strand. In another embodiment, one or more, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more pyrimidine nucleotides of the sense and/or antisense siNA strand are chemically-modified with 2′-deoxy, 2′-O-methyl and/or 2′-deoxy-2′-fluoro nucleotides, with or without one or more, for example, about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more phosphorothioate internucleotide linkages and/or a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends, being present in the same or different strand.  
      In another embodiment, the invention features a siNA molecule, wherein the antisense strand comprises about 1 to about 5 or more, specifically about 1, 2, 3, 4, 5 or more phosphorothioate internucleotide linkages, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) 2′-deoxy, 2′-O-methyl, 2′-deoxy-2′-fluoro, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) universal base modified nucleotides, and optionally a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of the sense strand; and wherein the antisense strand comprises about 1 to about 5 or more, specifically about 1, 2, 3, 4, 5 or more phosphorothioate internucleotide linkages, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) 2′-deoxy, 2′-O-methyl, 2′-deoxy-2′-fluoro, and/or one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) universal base modified nucleotides, and optionally a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of the antisense strand. In another embodiment, one or more, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more pyrimidine nucleotides of the sense and/or antisense siNA strand are chemically-modified with 2′-deoxy, 2′-O-methyl and/or 2′-deoxy-2′-fluoro nucleotides, with or without about 1 to about 5, for example about 1, 2, 3, 4, 5 or more phosphorothioate internucleotide linkages and/or a terminal cap molecule at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends, being present in the same or different strand.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule having about 1 to about 5, specifically about 1, 2, 3, 4, 5 or more phosphorothioate internucleotide linkages in each strand of the siNA molecule.  
      In another embodiment, the invention features a siNA molecule comprising 2′-5′ internucleotide linkages. The 2′-5′ internucleotide linkage(s) can be at the 3′-end, the 5′-end, or both of the 3′- and 5′-ends of one or both siNA sequence strands. In addition, the 2′-5′ internucleotide linkage(s) can be present at various other positions within one or both siNA sequence strands, for example, about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more including every internucleotide linkage of a pyrimidine nucleotide in one or both strands of the siNA molecule can comprise a 2′-5′ internucleotide linkage, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more including every internucleotide linkage of a purine nucleotide in one or both strands of the siNA molecule can comprise a 2′-5′ internucleotide linkage.  
      In another embodiment, a chemically-modified siNA molecule of the invention comprises a duplex having two strands, one or both of which can be chemically-modified, wherein each strand is about 18 to about 27 (e.g., about 18, 19, 20, 21, 22, 23, 24, 25, 26, or 27) nucleotides in length, wherein the duplex has about 18 to about 23 (e.g., about 18, 19, 20, 21, 22, or 23) base pairs, and wherein the chemical modification comprises a structure having any of Formulae I-VII. For example, an exemplary chemically-modified siNA molecule of the invention comprises a duplex having two strands, one or both of which can be chemically-modified with a chemical modification having any of Formulae I-VII or any combination thereof, wherein each strand consists of about 21 nucleotides, each having a 2-nucleotide 3′-terminal nucleotide overhang, and wherein the duplex has about 19 base pairs. In another embodiment, a siNA molecule of the invention comprises a single stranded hairpin structure, wherein the siNA is about 36 to about 70 (e.g., about 36, 40, 45, 50, 55, 60, 65, or 70) nucleotides in length having about 18 to about 23 (e.g., about 18, 19, 20, 21, 22, or 23) base pairs, and wherein the siNA can include a chemical modification comprising a structure having any of Formulae I-VII or any combination thereof. For example, an exemplary chemically-modified siNA molecule of the invention comprises a linear oligonucleotide having about 42 to about 50 (e.g., about 42, 43, 44, 45, 46, 47, 48, 49, or 50) nucleotides that is chemically-modified with a chemical modification having any of Formulae I-VII or any combination thereof, wherein the linear oligonucleotide forms a hairpin structure having about 19 base pairs and a 2-nucleotide 3′-terminal nucleotide overhang. In another embodiment, a linear hairpin siNA molecule of the invention contains a stem loop motif, wherein the loop portion of the siNA molecule is biodegradable. For example, a linear hairpin siNA molecule of the invention is designed such that degradation of the loop portion of the siNA molecule in vivo can generate a double-stranded siNA molecule with 3′-terminal overhangs, such as 3′-terminal nucleotide overhangs comprising about 2 nucleotides.  
      In another embodiment, a siNA molecule of the invention comprises a hairpin structure, wherein the siNA is about 25 to about 50 (e.g., about 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50) nucleotides in length having about 3 to about 25 (e.g., about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25) base pairs, and wherein the siNA can include one or more chemical modifications comprising a structure having any of Formulae I-VII or any combination thereof. For example, an exemplary chemically-modified siNA molecule of the invention comprises a linear oligonucleotide having about 25 to about 35 (e.g., about 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35) nucleotides that is chemically-modified with one or more chemical modifications having any of Formulae I-VII or any combination thereof, wherein the linear oligonucleotide forms a hairpin structure having about 3 to about 23 (e.g., about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23) base pairs and a 5′-terminal phosphate group that can be chemically modified as described herein (for example a 5′-terminal phosphate group having Formula IV). In another embodiment, a linear hairpin siNA molecule of the invention contains a stem loop motif, wherein the loop portion of the siNA molecule is biodegradable. In one embodiment, a linear hairpin siNA molecule of the invention comprises a loop portion comprising a non-nucleotide linker.  
      In another embodiment, a siNA molecule of the invention comprises an asymmetric hairpin structure, wherein the siNA is about 25 to about 50 (e.g., about 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50) nucleotides in length having about 3 to about 20 (e.g., about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) base pairs, and wherein the siNA can include one or more chemical modifications comprising a structure having any of Formulae I-VII or any combination thereof. For example, an exemplary chemically-modified siNA molecule of the invention comprises a linear oligonucleotide having about 25 to about 35 (e.g., about 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35) nucleotides that is chemically-modified with one or more chemical modifications having any of Formulae I-VII or any combination thereof, wherein the linear oligonucleotide forms an asymmetric hairpin structure having about 3 to about 18 (e.g., about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18) base pairs and a 5′-terminal phosphate group that can be chemically modified as described herein (for example a 5′-terminal phosphate group having Formula IV). In one embodiment, an asymmetric hairpin siNA molecule of the invention contains a stem loop motif, wherein the loop portion of the siNA molecule is biodegradable. In another embodiment, an asymmetric hairpin siNA molecule of the invention comprises a loop portion comprising a non-nucleotide linker.  
      In another embodiment, a siNA molecule of the invention comprises an asymmetric double stranded structure having separate polynucleotide strands comprising sense and antisense regions, wherein the antisense region is about 16 to about 25 (e.g., about 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25) nucleotides in length, wherein the sense region is about 3 to about 18 (e.g., about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18) nucleotides in length, wherein the sense region and the antisense region have at least 3 complementary nucleotides, and wherein the siNA can include one or more chemical modifications comprising a structure having any of Formulae I-VII or any combination thereof. For example, an exemplary chemically-modified siNA molecule of the invention comprises an asymmetric double stranded structure having separate polynucleotide strands comprising sense and antisense regions, wherein the antisense region is about 18 to about 22 (e.g., about 18, 19, 20, 21, or 22) nucleotides in length and wherein the sense region is about 3 to about 15 (e.g., about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15) nucleotides in length, wherein the sense region the antisense region have at least 3 complementary nucleotides, and wherein the siNA can include one or more chemical modifications comprising a structure having any of Formulae I-VII or any combination thereof. In another embodiment, the asymmetric double stranded siNA molecule can also have a 5′-terminal phosphate group that can be chemically modified as described herein (for example a 5′-terminal phosphate group having Formula IV).  
      In another embodiment, a siNA molecule of the invention comprises a circular nucleic acid molecule, wherein the siNA is about 38 to about 70 (e.g., about 38, 40, 45, 50, 55, 60, 65, or 70) nucleotides in length having about 18 to about 23 (e.g., about 18, 19, 20, 21, 22, or 23) base pairs, and wherein the siNA can include a chemical modification, which comprises a structure having any of Formulae I-VII or any combination thereof. For example, an exemplary chemically-modified siNA molecule of the invention comprises a circular oligonucleotide having about 42 to about 50 (e.g., about 42, 43, 44, 45, 46, 47, 48, 49, or 50) nucleotides that is chemically-modified with a chemical modification having any of Formulae I-VII or any combination thereof, wherein the circular oligonucleotide forms a dumbbell shaped structure having about 19 base pairs and 2 loops.  
      In another embodiment, a circular siNA molecule of the invention contains two loop motifs, wherein one or both loop portions of the siNA molecule is biodegradable. For example, a circular siNA molecule of the invention is designed such that degradation of the loop portions of the siNA molecule in vivo can generate a double-stranded siNA molecule with 3′-terminal overhangs, such as 3′-terminal nucleotide overhangs comprising about 2 nucleotides.  
      In one embodiment, a siNA molecule of the invention comprises at least one (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) abasic moiety, for example a compound having Formula V:  
                 
 
 wherein each R3, R4, R5, R6, R7, R8, R10, R11, R12, and R13 is independently H, OH, alkyl, substituted alkyl, alkaryl or aralkyl, F, Cl, Br, CN, CF3, OCF3, OCN, O-alkyl, S-alkyl, N-alkyl, O-alkenyl, S-alkenyl, N-alkenyl, SO-alkyl, alkyl-OSH, alkyl-OH, O-alkyl-OH, O-alkyl-SH, S-alkyl-OH, S-alkyl-SH, alkyl-S-alkyl, alkyl-O-alkyl, ONO2, NO2, N3, NH2, aminoalkyl, aminoacid, aminoacyl, ONH2,0-aminoalkyl, O-aminoacid, O-aminoacyl, heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalklylamino, substituted silyl, or group having Formula I or II; and R9 is O, S, CH2, S═O, CHF, or CF2. 
 
      In one embodiment, a siNA molecule of the invention comprises at least one (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) inverted abasic moiety, for example a compound having Formula VI:  
                 
 
 wherein each R3, R4, R5, R6, R7, R8, R10, R11, R12, and R 13 is independently H, OH, alkyl, substituted alkyl, alkaryl or aralkyl, F, Cl, Br, CN, CF3, OCF3, OCN, O-alkyl, S-alkyl, N-alkyl, O-alkenyl, S-alkenyl, N-alkenyl, SO-alkyl, alkyl-OSH, alkyl-OH, O-alkyl-OH, O-alkyl-SH, S-alkyl-OH, S-alkyl-SH, alkyl-S-alkyl, alkyl-O-alkyl, ONO2, NO 2 , N3, NH2, aminoalkyl, aminoacid, aminoacyl, ONH2,0-aminoalkyl, O-aminoacid, O-aminoacyl, heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalklylamino, substituted silyl, or group having Formula I or II; R9 is O, S, CH2, S═O, CHF, or CF2, and either R2, R3, R8 or R13 serve as points of attachment to the siNA molecule of the invention. 
 
      In another embodiment, a siNA molecule of the invention comprises at least one (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) substituted polyalkyl moieties, for example a compound having Formula VII:  
                 
 
 wherein each n is independently an integer from 1 to 12, each R1, R2 and R3 is independently H, OH, alkyl, substituted alkyl, alkaryl or aralkyl, F, Cl, Br, CN, CF3, OCF3, OCN, O-alkyl, S-alkyl, N-alkyl, O-alkenyl, S-alkenyl, N-alkenyl, SO-alkyl, alkyl-OSH, alkyl-OH, O-alkyl-OH, O-alkyl-SH, S-alkyl-OH, S-alkyl-SH, alkyl-S-alkyl, alkyl-O-alkyl, ONO2, NO2, N3, NH2, aminoalkyl, aminoacid, aminoacyl, ONH2, O-aminoalkyl, O-aminoacid, O-aminoacyl, heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalklylamino, substituted silyl, or a group having Formula I, and R1, R2 or R3 serves as points of attachment to the siNA molecule of the invention. 
 
      In another embodiment, the invention features a compound having Formula VII, wherein R1 and R2 are hydroxyl (OH) groups, n=1, and R3 comprises 0 and is the point of attachment to the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of one or both strands of a double-stranded siNA molecule of the invention or to a single-stranded siNA molecule of the invention. This modification is referred to herein as “glyceryl” (for example modification 6 in  FIG. 10 ).  
      In another embodiment, a moiety having any of Formula V, VI or VII of the invention is at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of a siNA molecule of the invention. For example, a moiety having Formula V, VI or VII can be present at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of the antisense strand, the sense strand, or both antisense and sense strands of the siNA molecule. In addition, a moiety having Formula VII can be present at the 3′-end or the 5′-end of a hairpin siNA molecule as described herein.  
      In another embodiment, a siNA molecule of the invention comprises an abasic residue having Formula V or VI, wherein the abasic residue having Formula VI or VI is connected to the siNA construct in a 3′-3′,3′-2′,2′-3′, or 5′-5′ configuration, such as at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of one or both siNA strands.  
      In one embodiment, a siNA molecule of the invention comprises one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) locked nucleic acid (LNA) nucleotides, for example at the 5′-end, the 3′-end, both of the 5′ and 3′-ends, or any combination thereof, of the siNA molecule.  
      In another embodiment, a siNA molecule of the invention comprises one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) acyclic nucleotides, for example at the 5′-end, the 3′-end, both of the 5′ and 3′-ends, or any combination thereof, of the siNA molecule.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention comprising a sense region, wherein any (e.g., one or more or all) pyrimidine nucleotides present in the sense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and wherein any (e.g., one or more or all) purine nucleotides present in the sense region are 2′-deoxy purine nucleotides (e.g., wherein all purine nucleotides are 2′-deoxy purine nucleotides or alternately a plurality of purine nucleotides are 2′-deoxy purine nucleotides).  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention comprising a sense region, wherein any (e.g., one or more or all) pyrimidine nucleotides present in the sense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and wherein any (e.g., one or more or all) purine nucleotides present in the sense region are 2′-deoxy purine nucleotides (e.g., wherein all purine nucleotides are 2′-deoxy purine nucleotides or alternately a plurality of purine nucleotides are 2′-deoxy purine nucleotides), wherein any nucleotides comprising a 3′-terminal nucleotide overhang that are present in said sense region are 2′-deoxy nucleotides.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention comprising a sense region, wherein any (e.g., one or more or all) pyrimidine nucleotides present in the sense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and wherein any (e.g., one or more or all) purine nucleotides present in the sense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides).  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention comprising a sense region, wherein any (e.g., one or more or all) pyrimidine nucleotides present in the sense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), wherein any (e.g., one or more or all) purine nucleotides present in the sense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides), and wherein any nucleotides comprising a 3′-terminal nucleotide overhang that are present in said sense region are 2′-deoxy nucleotides.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention comprising an antisense region, wherein any (e.g., one or more or all) pyrimidine nucleotides present in the antisense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and wherein any (e.g., one or more or all) purine nucleotides present in the antisense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides).  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention comprising an antisense region, wherein any (e.g., one or more or all) pyrimidine nucleotides present in the antisense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), wherein any (e.g., one or more or all) purine nucleotides present in the antisense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides), and wherein any nucleotides comprising a 3′-terminal nucleotide overhang that are present in said antisense region are 2′-deoxy nucleotides.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention comprising an antisense region, wherein any (e.g., one or more or all) pyrimidine nucleotides present in the antisense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and wherein any (e.g., one or more or all) purine nucleotides present in the antisense region are 2′-deoxy purine nucleotides (e.g., wherein all purine nucleotides are 2′-deoxy purine nucleotides or alternately a plurality of purine nucleotides are 2′-deoxy purine nucleotides).  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention comprising an antisense region, wherein any (e.g., one or more or all) pyrimidine nucleotides present in the antisense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and wherein any (e.g., one or more or all) purine nucleotides present in the antisense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides).  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid (siNA) molecule of the invention capable of mediating RNA interference (RNAi) against Fas and/or FasL inside a cell or reconstituted in vitro system comprising a sense region, wherein one or more pyrimidine nucleotides present in the sense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and one or more purine nucleotides present in the sense region are 2′-deoxy purine nucleotides (e.g., wherein all purine nucleotides are 2′-deoxy purine nucleotides or alternately a plurality of purine nucleotides are 2′-deoxy purine nucleotides), and an antisense region, wherein one or more pyrimidine nucleotides present in the antisense region are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and one or more purine nucleotides present in the antisense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides). The sense region and/or the antisense region can have a terminal cap modification, such as any modification described herein or shown in  FIG. 10 , that is optionally present at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of the sense and/or antisense sequence. The sense and/or antisense region can optionally further comprise a 3′-terminal nucleotide overhang having about 1 to about 4 (e.g., about 1, 2, 3, or 4) 2′-deoxynucleotides. The overhang nucleotides can further comprise one or more (e.g., about 1, 2, 3, 4 or more) phosphorothioate, phosphonoacetate, and/or thiophosphonoacetate internucleotide linkages. Non-limiting examples of these chemically-modified siNAs are shown in  FIGS. 4 and 5  and Tables III and IV herein. In any of these described embodiments, the purine nucleotides present in the sense region are alternatively 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides) and one or more purine nucleotides present in the antisense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides). Also, in any of these embodiments, one or more purine nucleotides present in the sense region are alternatively purine ribonucleotides (e.g., wherein all purine nucleotides are purine ribonucleotides or alternately a plurality of purine nucleotides are purine ribonucleotides) and any purine nucleotides present in the antisense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides). Additionally, in any of these embodiments, one or more purine nucleotides present in the sense region and/or present in the antisense region are alternatively selected from the group consisting of 2′-deoxy nucleotides, locked nucleic acid (LNA) nucleotides, 2′-methoxyethyl nucleotides, 4′-thionucleotides, and 2′-O-methyl nucleotides (e.g., wherein all purine nucleotides are selected from the group consisting of 2′-deoxy nucleotides, locked nucleic acid (LNA) nucleotides, 2′-methoxyethyl nucleotides, 4′-thionucleotides, and 2′-O-methyl nucleotides or alternately a plurality of purine nucleotides are selected from the group consisting of 2′-deoxy nucleotides, locked nucleic acid (LNA) nucleotides, 2′-methoxyethyl nucleotides, 4′-thionucleotides, and 2′-O-methyl nucleotides).  
      In another embodiment, any modified nucleotides present in the siNA molecules of the invention, preferably in the antisense strand of the siNA molecules of the invention, but also optionally in the sense and/or both antisense and sense strands, comprise modified nucleotides having properties or characteristics similar to naturally occurring ribonucleotides. For example, the invention features siNA molecules including modified nucleotides having a Northern conformation (e.g., Northern pseudorotation cycle, see for example Saenger,  Principles of Nucleic Acid Structure , Springer-Verlag ed., 1984). As such, chemically modified nucleotides present in the siNA molecules of the invention, preferably in the antisense strand of the siNA molecules of the invention, but also optionally in the sense and/or both antisense and sense strands, are resistant to nuclease degradation while at the same time maintaining the capacity to mediate RNAi. Non-limiting examples of nucleotides having a northern configuration include locked nucleic acid (LNA) nucleotides (e.g., 2′-O, 4′-C-methylene-(D-ribofuranosyl) nucleotides); 2′-methoxyethoxy (MOE) nucleotides; 2′-methyl-thio-ethyl, 2′-deoxy-2′-fluoro nucleotides, 2′-deoxy-2′-chloro nucleotides, 2′-azido nucleotides, and 2′-O-methyl nucleotides.  
      In one embodiment, the sense strand of a double stranded siNA molecule of the invention comprises a terminal cap moiety, (see for example  FIG. 10 ) such as an inverted deoxyabaisc moiety, at the 3′-end, 5′-end, or both 3′ and 5′-ends of the sense strand.  
      In one embodiment, the invention features a chemically-modified short interfering nucleic acid molecule (siNA) capable of mediating RNA interference (RNAi) against Fas and/or FasL inside a cell or reconstituted in vitro system, wherein the chemical modification comprises a conjugate covalently attached to the chemically-modified siNA molecule. Non-limiting examples of conjugates contemplated by the invention include conjugates and ligands described in Vargeese et al., U.S. Ser. No. 10/427,160, filed Apr. 30, 2003, incorporated by reference herein in its entirety, including the drawings. In another embodiment, the conjugate is covalently attached to the chemically-modified siNA molecule via a biodegradable linker. In one embodiment, the conjugate molecule is attached at the 3′-end of either the sense strand, the antisense strand, or both strands of the chemically-modified siNA molecule. In another embodiment, the conjugate molecule is attached at the 5′-end of either the sense strand, the antisense strand, or both strands of the chemically-modified siNA molecule. In yet another embodiment, the conjugate molecule is attached both the 3′-end and 5′-end of either the sense strand, the antisense strand, or both strands of the chemically-modified siNA molecule, or any combination thereof. In one embodiment, a conjugate molecule of the invention comprises a molecule that facilitates delivery of a chemically-modified siNA molecule into a biological system, such as a cell. In another embodiment, the conjugate molecule attached to the chemically-modified siNA molecule is a polyethylene glycol, human serum albumin, or a ligand for a cellular receptor that can mediate cellular uptake. Examples of specific conjugate molecules contemplated by the instant invention that can be attached to chemically-modified siNA molecules are described in Vargeese et al., U.S. Ser. No. 10/201,394, filed Jul. 22, 2002 incorporated by reference herein. The type of conjugates used and the extent of conjugation of siNA molecules of the invention can be evaluated for improved pharmacokinetic profiles, bioavailability, and/or stability of siNA constructs while at the same time maintaining the ability of the siNA to mediate RNAi activity. As such, one skilled in the art can screen siNA constructs that are modified with various conjugates to determine whether the siNA conjugate complex possesses improved properties while maintaining the ability to mediate RNAi, for example in animal models as are generally known in the art.  
      In one embodiment, the invention features a short interfering nucleic acid (siNA) molecule of the invention, wherein the siNA further comprises a nucleotide, non-nucleotide, or mixed nucleotide/non-nucleotide linker that joins the sense region of the siNA to the antisense region of the siNA. In one embodiment, a nucleotide linker of the invention can be a linker of &gt;2 nucleotides in length, for example about 3, 4, 5, 6, 7, 8, 9, or 10 nucleotides in length. In another embodiment, the nucleotide linker can be a nucleic acid aptamer. By “aptamer” or “nucleic acid aptamer” as used herein is meant a nucleic acid molecule that binds specifically to a target molecule wherein the nucleic acid molecule has sequence that comprises a sequence recognized by the target molecule in its natural setting. Alternately, an aptamer can be a nucleic acid molecule that binds to a target molecule where the target molecule does not naturally bind to a nucleic acid. The target molecule can be any molecule of interest. For example, the aptamer can be used to bind to a ligand-binding domain of a protein, thereby preventing interaction of the naturally occurring ligand with the protein. This is a non-limiting example and those in the art will recognize that other embodiments can be readily generated using techniques generally known in the art. (See, for example, Gold et al., 1995 , Annu. Rev. Biochem.,  64, 763; Brody and Gold, 2000 , J. Biotechnol.,  74, 5; Sun, 2000 , Curr. Opin. Mol. Ther.,  2, 100; Kusser, 2000 , J. Biotechnol.,  74, 27; Hermann and Patel, 2000 , Science,  287, 820; and Jayasena, 1999 , Clinical Chemistry,  45, 1628.)  
      In yet another embodiment, a non-nucleotide linker of the invention comprises abasic nucleotide, polyether, polyamine, polyamide, peptide, carbohydrate, lipid, polyhydrocarbon, or other polymeric compounds (e.g. polyethylene glycols such as those having between 2 and 100 ethylene glycol units). Specific examples include those described by Seela and Kaiser,  Nucleic Acids Res.  1990, 18:6353 and  Nucleic Acids Res.  1987, 15:3113; Cload and Schepartz,  J. Am. Chem. Soc.  1991, 113:6324; Richardson and Schepartz,  J. Am. Chem. Soc.  1991, 113:5109; Ma et al.,  Nucleic Acids Res.  1993, 21:2585 and  Biochemistry  1993, 32:1751; Durand et al.,  Nucleic Acids Res.  1990, 18:6353; McCurdy et al.,  Nucleosides  &amp;  Nucleotides  1991, 10:287; Jschke et al.,  Tetrahedron Lett.  1993, 34:301; Ono et al.,  Biochemistry  1991, 30:9914; Arnold et al., International Publication No. WO 89/02439; Usman et al., International Publication No. WO 95/06731; Dudycz et al., International Publication No. WO 95/11910 and Ferentz and Verdine,  J. Am. Chem. Soc.  1991, 113:4000, all hereby incorporated by reference herein. A “non-nucleotide” further means any group or compound that can be incorporated into a nucleic acid chain in the place of one or more nucleotide units, including either sugar and/or phosphate substitutions, and allows the remaining bases to exhibit their enzymatic activity. The group or compound can be abasic in that it does not contain a commonly recognized nucleotide base, such as adenosine, guanine, cytosine, uracil or thymine, for example at the C1 position of the sugar.  
      In one embodiment, the invention features a short interfering nucleic acid (siNA) molecule capable of mediating RNA interference (RNAi) inside a cell or reconstituted in vitro system, wherein one or both strands of the siNA molecule that are assembled from two separate oligonucleotides do not comprise any ribonucleotides. For example, a siNA molecule can be assembled from a single oligonculeotide where the sense and antisense regions of the siNA comprise separate oligonucleotides that do not have any ribonucleotides (e.g., nucleotides having a 2′-OH group) present in the oligonucleotides. In another example, a siNA molecule can be assembled from a single oligonculeotide where the sense and antisense regions of the siNA are linked or circularized by a nucleotide or non-nucleotide linker as described herein, wherein the oligonucleotide does not have any ribonucleotides (e.g., nucleotides having a 2′-OH group) present in the oligonucleotide. Applicant has surprisingly found that the presence of ribonucleotides (e.g., nucleotides having a 2′-hydroxyl group) within the siNA molecule is not required or essential to support RNAi activity. As such, in one embodiment, all positions within the siNA can include chemically modified nucleotides and/or non-nucleotides such as nucleotides and or non-nucleotides having Formula I, II, III, IV, V, VI, or VII or any combination thereof to the extent that the ability of the siNA molecule to support RNAi activity in a cell is maintained.  
      In one embodiment, a siNA molecule of the invention is a single stranded siNA molecule that mediates RNAi activity in a cell or reconstituted in vitro system comprising a single stranded polynucleotide having complementarity to a target nucleic acid sequence. In another embodiment, the single stranded siNA molecule of the invention comprises a 5′-terminal phosphate group. In another embodiment, the single stranded siNA molecule of the invention comprises a 5′-terminal phosphate group and a 3′-terminal phosphate group (e.g., a 2′,3′-cyclic phosphate). In another embodiment, the single stranded siNA molecule of the invention comprises about 19 to about 29 (e.g., about 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29) nucleotides. In yet another embodiment, the single stranded siNA molecule of the invention comprises one or more chemically modified nucleotides or non-nucleotides described herein. For example, all the positions within the siNA molecule can include chemically-modified nucleotides such as nucleotides having any of Formulae I-VII, or any combination thereof to the extent that the ability of the siNA molecule to support RNAi activity in a cell is maintained.  
      In one embodiment, a siNA molecule of the invention is a single stranded siNA molecule that mediates RNAi activity in a cell or reconstituted in vitro system comprising a single stranded polynucleotide having complementarity to a target nucleic acid sequence, wherein one or more pyrimidine nucleotides present in the siNA are 2′-deoxy-2′-fluoro pyrimidine nucleotides (e.g., wherein all pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides or alternately a plurality of pyrimidine nucleotides are 2′-deoxy-2′-fluoro pyrimidine nucleotides), and wherein any purine nucleotides present in the antisense region are 2′-O-methyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-O-methyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-O-methyl purine nucleotides), and a terminal cap modification, such as any modification described herein or shown in  FIG. 10 , that is optionally present at the 3′-end, the 5′-end, or both of the 3′ and 5′-ends of the antisense sequence. The siNA optionally further comprises about 1 to about 4 or more (e.g., about 1, 2, 3, 4 or more) terminal 2′-deoxynucleotides at the 3′-end of the siNA molecule, wherein the terminal nucleotides can further comprise one or more (e.g., 1, 2, 3, 4 or more) phosphorothioate, phosphonoacetate, and/or thiophosphonoacetate internucleotide linkages, and wherein the siNA optionally further comprises a terminal phosphate group, such as a 5′-terminal phosphate group. In any of these embodiments, any purine nucleotides present in the antisense region are alternatively 2′-deoxy purine nucleotides (e.g., wherein all purine nucleotides are 2′-deoxy purine nucleotides or alternately a plurality of purine nucleotides are 2′-deoxy purine nucleotides). Also, in any of these embodiments, any purine nucleotides present in the siNA (i.e., purine nucleotides present in the sense and/or antisense region) can alternatively be locked nucleic acid (LNA) nucleotides (e.g., wherein all purine nucleotides are LNA nucleotides or alternately a plurality of purine nucleotides are LNA nucleotides). Also, in any of these embodiments, any purine nucleotides present in the siNA are alternatively 2′-methoxyethyl purine nucleotides (e.g., wherein all purine nucleotides are 2′-methoxyethyl purine nucleotides or alternately a plurality of purine nucleotides are 2′-methoxyethyl purine nucleotides). In another embodiment, any modified nucleotides present in the single stranded siNA molecules of the invention comprise modified nucleotides having properties or characteristics similar to naturally occurring ribonucleotides. For example, the invention features siNA molecules including modified nucleotides having a Northern conformation (e.g., Northern pseudorotation cycle, see for example Saenger,  Principles of Nucleic Acid Structure , Springer-Verlag ed., 1984). As such, chemically modified nucleotides present in the single stranded siNA molecules of the invention are preferably resistant to nuclease degradation while at the same time maintaining the capacity to mediate RNAi.  
      In one embodiment, the invention features a method for modulating the expression of a Fas and/or FasL gene within a cell comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL gene; and (b) introducing the siNA molecule into a cell under conditions suitable to modulate the expression of the Fas and/or FasL gene in the cell.  
      In one embodiment, the invention features a method for modulating the expression of a Fas and/or FasL gene within a cell comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL gene and wherein the sense strand sequence of the siNA comprises a sequence identical or substantially similar to the sequence of the target RNA; and (b) introducing the siNA molecule into a cell under conditions suitable to modulate the expression of the Fas and/or FasL gene in the cell.  
      In another embodiment, the invention features a method for modulating the expression of more than one Fas and/or FasL gene within a cell comprising: (a) synthesizing siNA molecules of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL genes; and (b) introducing the siNA molecules into a cell under conditions suitable to modulate the expression of the Fas and/or FasL genes in the cell.  
      In another embodiment, the invention features a method for modulating the expression of two or more Fas and/or FasL genes within a cell comprising: (a) synthesizing one or more siNA molecules of the invention, which can be chemically-modified, wherein the siNA strands comprise sequences complementary to RNA of the Fas and/or FasL genes and wherein the sense strand sequences of the siNAs comprise sequences identical or substantially similar to the sequences of the target RNAs; and (b) introducing the siNA molecules into a cell under conditions suitable to modulate the expression of the Fas and/or FasL genes in the cell.  
      In another embodiment, the invention features a method for modulating the expression of more than one Fas and/or FasL gene within a cell comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL gene and wherein the sense strand sequence of the siNA comprises a sequence identical or substantially similar to the sequences of the target RNAs; and (b) introducing the siNA molecule into a cell under conditions suitable to modulate the expression of the Fas and/or FasL genes in the cell.  
      In one embodiment, siNA molecules of the invention are used as reagents in ex vivo applications. For example, siNA reagents are introduced into tissue or cells that are transplanted into a subject for therapeutic effect. The cells and/or tissue can be derived from an organism or subject that later receives the explant, or can be derived from another organism or subject prior to transplantation. The siNA molecules can be used to modulate the expression of one or more genes in the cells or tissue, such that the cells or tissue obtain a desired phenotype or are able to perform a function when transplanted in vivo. In one embodiment, certain target cells from a patient are extracted. These extracted cells are contacted with siNAs targeting a specific nucleotide sequence within the cells under conditions suitable for uptake of the siNAs by these cells (e.g. using delivery reagents such as cationic lipids, liposomes and the like or using techniques such as electroporation to facilitate the delivery of siNAs into cells). The cells are then reintroduced back into the same patient or other patients. In one embodiment, the invention features a method of modulating the expression of a Fas and/or FasL gene in a tissue explant comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL gene; and (b) introducing the siNA molecule into a cell of the tissue explant derived from a particular organism under conditions suitable to modulate the expression of the Fas and/or FasL gene in the tissue explant. In another embodiment, the method further comprises introducing the tissue explant back into the organism the tissue was derived from or into another organism under conditions suitable to modulate the expression of the Fas and/or FasL gene in that organism.  
      In one embodiment, the invention features a method of modulating the expression of a Fas and/or FasL gene in a tissue explant comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL gene and wherein the sense strand sequence of the siNA comprises a sequence identical or substantially similar to the sequence of the target RNA; and (b) introducing the siNA molecule into a cell of the tissue explant derived from a particular organism under conditions suitable to modulate the expression of the Fas and/or FasL gene in the tissue explant. In another embodiment, the method further comprises introducing the tissue explant back into the organism the tissue was derived from or into another organism under conditions suitable to modulate the expression of the Fas and/or FasL gene in that organism.  
      In another embodiment, the invention features a method of modulating the expression of more than one Fas and/or FasL gene in a tissue explant comprising: (a) synthesizing siNA molecules of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL genes; and (b) introducing the siNA molecules into a cell of the tissue explant derived from a particular organism under conditions suitable to modulate the expression of the Fas and/or FasL genes in the tissue explant. In another embodiment, the method further comprises introducing the tissue explant back into the organism the tissue was derived from or into another organism under conditions suitable to modulate the expression of the Fas and/or FasL genes in that organism.  
      In one embodiment, the invention features a method of modulating the expression of a Fas and/or FasL gene in an organism comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL gene; and (b) introducing the siNA molecule into the organism under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism. The level of Fas and/or FasL protein or RNA can be determined as is known in the art.  
      In another embodiment, the invention features a method of modulating the expression of more than one Fas and/or FasL gene in an organism comprising: (a) synthesizing siNA molecules of the invention, which can be chemically-modified, wherein one of the siNA strands comprises a sequence complementary to RNA of the Fas and/or FasL genes; and (b) introducing the siNA molecules into the organism under conditions suitable to modulate the expression of the Fas and/or FasL genes in the organism. The level of Fas and/or FasL protein or RNA can be determined as is known in the art.  
      In one embodiment, the invention features a method for modulating the expression of a Fas and/or FasL gene within a cell comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein the siNA comprises a single stranded sequence having complementarity to RNA of the Fas and/or FasL gene; and (b) introducing the siNA molecule into a cell under conditions suitable to modulate the expression of the Fas and/or FasL gene in the cell.  
      In another embodiment, the invention features a method for modulating the expression of more than one Fas and/or FasL gene within a cell comprising: (a) synthesizing siNA molecules of the invention, which can be chemically-modified, wherein the siNA comprises a single stranded sequence having complementarity to RNA of the Fas and/or FasL gene; and (b) contacting the cell in vitro or in vivo with the siNA molecule under conditions suitable to modulate the expression of the Fas and/or FasL genes in the cell.  
      In one embodiment, the invention features a method of modulating the expression of a Fas and/or FasL gene in a tissue explant comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein the siNA comprises a single stranded sequence having complementarity to RNA of the Fas and/or FasL gene; and (b) contacting the cell of the tissue explant derived from a particular organism with the siNA molecule under conditions suitable to modulate the expression of the Fas and/or FasL gene in the tissue explant. In another embodiment, the method further comprises introducing the tissue explant back into the organism the tissue was derived from or into another organism under conditions suitable to modulate the expression of the Fas and/or FasL gene in that organism.  
      In another embodiment, the invention features a method of modulating the expression of more than one Fas and/or FasL gene in a tissue explant comprising: (a) synthesizing siNA molecules of the invention, which can be chemically-modified, wherein the siNA comprises a single stranded sequence having complementarity to RNA of the Fas and/or FasL gene; and (b) introducing the siNA molecules into a cell of the tissue explant derived from a particular organism under conditions suitable to modulate the expression of the Fas and/or FasL genes in the tissue explant. In another embodiment, the method further comprises introducing the tissue explant back into the organism the tissue was derived from or into another organism under conditions suitable to modulate the expression of the Fas and/or FasL genes in that organism.  
      In one embodiment, the invention features a method of modulating the expression of a Fas and/or FasL gene in an organism comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein the siNA comprises a single stranded sequence having complementarity to RNA of the Fas and/or FasL gene; and (b) introducing the siNA molecule into the organism under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism.  
      In another embodiment, the invention features a method of modulating the expression of more than one Fas and/or FasL gene in an organism comprising: (a) synthesizing siNA molecules of the invention, which can be chemically-modified, wherein the siNA comprises a single stranded sequence having complementarity to RNA of the Fas and/or FasL gene; and (b) introducing the siNA molecules into the organism under conditions suitable to modulate the expression of the Fas and/or FasL genes in the organism.  
      In one embodiment, the invention features a method of modulating the expression of a Fas and/or FasL gene in an organism comprising contacting the organism with a siNA molecule of the invention under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism.  
      In one embodiment, the invention features a method for treating or preventing a disease, condition, trait, genotype or phenotype in a subject, comprising administering to the subject a composition of the invention under conditions suitable for the treatment or prevention of the disease, condition, trait, genotype or phenotype in the subject, alone or in conjunction with one or more other therapeutic compounds. In yet another embodiment, the invention features a method for reducing or preventing tissue rejection (e.g., allograft rejection) in a subject comprising administering to the subject a composition of the invention under conditions suitable for the reduction or prevention of tissue rejection in the subject.  
      In one embodiment, the invention features a method for treating an inflammatory disease or condition in an organism comprising contacting the organism with a siNA molecule of the invention under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism.  
      In one embodiment, the invention features a method for treating or preventing an allergic reaction, disease, or condition in an organism comprising contacting the organism with a siNA molecule of the invention under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism.  
      In one embodiment, the invention features a method for treating or preventing an autoimmune disease or condition in an organism comprising contacting the organism with a siNA molecule of the invention under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism.  
      In one embodiment, the invention features a method for treating or preventing a neurodegenerative or neurological disease or condition in an organism comprising contacting the organism with a siNA molecule of the invention under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism.  
      In one embodiment, the invention features a method for treating or preventing viral disease or infection in an organism comprising contacting the organism with a siNA molecule of the invention under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism.  
      In one embodiment, the invention features a method for treating or preventing cirrhosis or liver failure in an organism comprising contacting the organism with a siNA molecule of the invention under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism. In another embodiment, the cirrhosis or liver failure is secondary to viral infection, such as HCV or HBV infection.  
      In one embodiment, the invention features a method for treating or preventing brain or spinal cord injury in an organism comprising contacting the organism with a siNA molecule of the invention under conditions suitable to modulate the expression of the Fas and/or FasL gene in the organism.  
      In one embodiment, an organism of the invention is a subject or patient.  
      In one embodiment, the method for treating or preventing a disease or condition of the invention comprises administering siNA compositions of the invention locally to the site of injury. For example, when treating spinal cord injury, the area of injury can be treated or perfused locally with siNA compositions of the invention under conditions suitable for treatment as are known in the art, such a with pumps, stents, catheters, etc. In another embodiment, the method for treating or preventing a disease or condition of the invention comprises administering siNA compositions of the invention systemically to the subject.  
      The nucleic acid molecules of the instant invention, individually, or in combination or in conjunction with other drugs, can be used to treat diseases or conditions discussed herein (e.g., viral infection, inflammatory disease, autoimmunity, neurological disease, etc.). For example, to treat a particular disease, condition, trait, genotype or phenotype, the siNA molecules can be administered to a subject or can be administered to other appropriate cells evident to those skilled in the art, individually or in combination with one or more drugs under conditions suitable for the treatment.  
      In another embodiment, the invention features a method of modulating the expression of more than one Fas or FasL gene in an organism comprising contacting the organism with one or more siNA molecules of the invention under conditions suitable to modulate the expression of the Fas and/or FasL genes in the organism.  
      The siNA molecules of the invention can be designed to down regulate or inhibit target (e.g., Fas and/or FasL) gene expression through RNAi targeting of a variety of RNA molecules. In one embodiment, the siNA molecules of the invention are used to target various RNAs corresponding to a target gene. Non-limiting examples of such RNAs include messenger RNA (mRNA), alternate RNA splice variants of target gene(s), post-transcriptionally modified RNA of target gene(s), pre-mRNA of target gene(s), and/or RNA templates. If alternate splicing produces a family of transcripts that are distinguished by usage of appropriate exons, the instant invention can be used to inhibit gene expression through the appropriate exons to specifically inhibit or to distinguish among the functions of gene family members. For example, a protein that contains an alternatively spliced transmembrane domain can be expressed in both membrane bound and secreted forms. Use of the invention to target the exon containing the transmembrane domain can be used to determine the functional consequences of pharmaceutical targeting of membrane bound as opposed to the secreted form of the protein. Non-limiting examples of applications of the invention relating to targeting these RNA molecules include therapeutic pharmaceutical applications, pharmaceutical discovery applications, molecular diagnostic and gene function applications, and gene mapping, for example using single nucleotide polymorphism mapping with siNA molecules of the invention. Such applications can be implemented using known gene sequences or from partial sequences available from an expressed sequence tag (EST).  
      In another embodiment, the siNA molecules of the invention are used to target conserved sequences corresponding to a gene family or gene families such as Fas and/or FasL family genes. As such, siNA molecules targeting multiple Fas and/or FasL targets can provide increased therapeutic effect. In addition, siNA can be used to characterize pathways of gene function in a variety of applications. For example, the present invention can be used to inhibit the activity of target gene(s) in a pathway to determine the function of uncharacterized gene(s) in gene function analysis, mRNA function analysis, or translational analysis. The invention can be used to determine potential target gene pathways involved in various diseases and conditions toward pharmaceutical development. The invention can be used to understand pathways of gene expression involved in, for example, inflammatory, autoimmune, or neurological disease.  
      In one embodiment, siNA molecule(s) and/or methods of the invention are used to down regulate the expression of gene(s) that encode RNA referred to by Genbank Accession, for example Fas and/or FasL genes encoding RNA sequence(s) referred to herein by Genbank Accession number, for example, Genbank Accession Nos. shown in Table I.  
      In one embodiment, the invention features a method comprising: (a) generating a library of siNA constructs having a predetermined complexity; and (b) assaying the siNA constructs of (a) above, under conditions suitable to determine RNAi target sites within the target RNA sequence. In one embodiment, the siNA molecules of (a) have strands of a fixed length, for example, about 23 nucleotides in length. In another embodiment, the siNA molecules of (a) are of differing length, for example having strands of about 19 to about 25 (e.g., about 19, 20, 21, 22, 23, 24, or 25) nucleotides in length. In one embodiment, the assay can comprise a reconstituted in vitro siNA assay as described herein. In another embodiment, the assay can comprise a cell culture system in which target RNA is expressed. In another embodiment, fragments of target RNA are analyzed for detectable levels of cleavage, for example by gel electrophoresis, northern blot analysis, or RNAse protection assays, to determine the most suitable target site(s) within the target RNA sequence. The target RNA sequence can be obtained as is known in the art, for example, by cloning and/or transcription for in vitro systems, and by cellular expression in in vivo systems.  
      In one embodiment, the invention features a method comprising: (a) generating a randomized library of siNA constructs having a predetermined complexity, such as of 4N, where N represents the number of base paired nucleotides in each of the siNA construct strands (eg. for a siNA construct having 21 nucleotide sense and antisense strands with 19 base pairs, the complexity would be 419); and (b) assaying the siNA constructs of (a) above, under conditions suitable to determine RNAi target sites within the target Fas and/or FasL RNA sequence. In another embodiment, the siNA molecules of (a) have strands of a fixed length, for example about 23 nucleotides in length. In yet another embodiment, the siNA molecules of (a) are of differing length, for example having strands of about 19 to about 25 (e.g., about 19, 20, 21, 22, 23, 24, or 25) nucleotides in length. In one embodiment, the assay can comprise a reconstituted in vitro siNA assay as described in Example 6 herein. In another embodiment, the assay can comprise a cell culture system in which target RNA is expressed. In another embodiment, fragments of Fas and/or FasL RNA are analyzed for detectable levels of cleavage, for example by gel electrophoresis, northern blot analysis, or RNAse protection assays, to determine the most suitable target site(s) within the target Fas and/or FasL RNA sequence. The target Fas and/or FasL RNA sequence can be obtained as is known in the art, for example, by cloning and/or transcription for in vitro systems, and by cellular expression in in vivo systems.  
      In another embodiment, the invention features a method comprising: (a) analyzing the sequence of a RNA target encoded by a target gene; (b) synthesizing one or more sets of siNA molecules having sequence complementary to one or more regions of the RNA of (a); and (c) assaying the siNA molecules of (b) under conditions suitable to determine RNAi targets within the target RNA sequence. In one embodiment, the siNA molecules of (b) have strands of a fixed length, for example about 23 nucleotides in length. In another embodiment, the siNA molecules of (b) are of differing length, for example having strands of about 19 to about 25 (e.g., about 19, 20, 21, 22, 23, 24, or 25) nucleotides in length. In one embodiment, the assay can comprise a reconstituted in vitro siNA assay as described herein. In another embodiment, the assay can comprise a cell culture system in which target RNA is expressed. Fragments of target RNA are analyzed for detectable levels of cleavage, for example by gel electrophoresis, northern blot analysis, or RNAse protection assays, to determine the most suitable target site(s) within the target RNA sequence. The target RNA sequence can be obtained as is known in the art, for example, by cloning and/or transcription for in vitro systems, and by expression in in vivo systems.  
      By “target site” is meant a sequence within a target RNA that is “targeted” for cleavage mediated by a siNA construct which contains sequences within its antisense region that are complementary to the target sequence.  
      By “detectable level of cleavage” is meant cleavage of target RNA (and formation of cleaved product RNAs) to an extent sufficient to discern cleavage products above the background of RNAs produced by random degradation of the target RNA. Production of cleavage products from 1-5% of the target RNA is sufficient to detect above the background for most methods of detection.  
      In one embodiment, the invention features a composition comprising a siNA molecule of the invention, which can be chemically-modified, in a pharmaceutically acceptable carrier or diluent. In another embodiment, the invention features a pharmaceutical composition comprising siNA molecules of the invention, which can be chemically-modified, targeting one or more genes in a pharmaceutically acceptable carrier or diluent. In another embodiment, the invention features a method for diagnosing a disease or condition in a subject comprising administering to the subject a composition of the invention under conditions suitable for the diagnosis of the disease or condition in the subject. In another embodiment, the invention features a method for treating or preventing a disease or condition in a subject, comprising administering to the subject a composition of the invention under conditions suitable for the treatment or prevention of the disease or condition in the subject, alone or in conjunction with one or more other therapeutic compounds. In yet another embodiment, the invention features a method for treating, reducing or preventing, for example, inflammatory, autoimmune, or neurologic disease in a subject, comprising administering to the subject a composition of the invention under conditions suitable for the treatment, reduction or prevention of inflammatory, autoimmune, or neurological diseases or conditions in the subject. In one embodiment, the disease or condition comprises brain injury or spinal cord injury. In another embodiment, the disease or condition comprises systemic lupus. In another embodiment, the disease or condition comprises transplant/allograft rejection. In another embodiment, the disease or condition comprises viral hepatitis or cirrhosis.  
      In one embodiment, the invention features a method for validating a Fas and/or FasL gene target, comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein one of the siNA strands includes a sequence complementary to RNA of a Fas and/or FasL target gene; (b) introducing the siNA molecule into a cell, tissue, or organism under conditions suitable for modulating expression of the Fas and/or FasL target gene in the cell, tissue, or organism; and (c) determining the function of the gene by assaying for any phenotypic change in the cell, tissue, or organism.  
      In another embodiment, the invention features a method for validating a Fas and/or FasL target comprising: (a) synthesizing a siNA molecule of the invention, which can be chemically-modified, wherein one of the siNA strands includes a sequence complementary to RNA of a Fas and/or FasL target gene; (b) introducing the siNA molecule into a biological system under conditions suitable for modulating expression of the Fas and/or FasL target gene in the biological system; and (c) determining the function of the gene by assaying for any phenotypic change in the biological system.  
      By “biological system” is meant, material, in a purified or unpurified form, from biological sources, including but not limited to human or animal, wherein the system comprises the components required for RNAi activity. The term “biological system” includes, for example, a cell, tissue, or organism, or extract thereof. The term biological system also includes reconstituted RNAi systems that can be used in an in vitro setting.  
      By “phenotypic change” is meant any detectable change to a cell that occurs in response to contact or treatment with a nucleic acid molecule of the invention (e.g., siNA). Such detectable changes include, but are not limited to, changes in shape, size, proliferation, motility, protein expression or RNA expression or other physical or chemical changes as can be assayed by methods known in the art. The detectable change can also include expression of reporter genes/molecules such as Green Florescent Protein (GFP) or various tags that are used to identify an expressed protein or any other cellular component that can be assayed.  
      In one embodiment, the invention features a kit containing a siNA molecule of the invention, which can be chemically-modified, that can be used to modulate the expression of a Fas and/or FasL target gene in a biological system, including, for example, in a cell, tissue, or organism. In another embodiment, the invention features a kit containing more than one siNA molecule of the invention, which can be chemically-modified, that can be used to modulate the expression of more than one Fas and/or FasL target gene in a biological system, including, for example, in a cell, tissue, or organism.  
      In one embodiment, the invention features a cell containing one or more siNA molecules of the invention, which can be chemically-modified. In another embodiment, the cell containing a siNA molecule of the invention is a mammalian cell. In yet another embodiment, the cell containing a siNA molecule of the invention is a human cell.  
      In one embodiment, the synthesis of a siNA molecule of the invention, which can be chemically-modified, comprises: (a) synthesis of two complementary strands of the siNA molecule; (b) annealing the two complementary strands together under conditions suitable to obtain a double-stranded siNA molecule. In another embodiment, synthesis of the two complementary strands of the siNA molecule is by solid phase oligonucleotide synthesis. In yet another embodiment, synthesis of the two complementary strands of the siNA molecule is by solid phase tandem oligonucleotide synthesis.  
      In one embodiment, the invention features a method for synthesizing a siNA duplex molecule comprising: (a) synthesizing a first oligonucleotide sequence strand of the siNA molecule, wherein the first oligonucleotide sequence strand comprises a cleavable linker molecule that can be used as a scaffold for the synthesis of the second oligonucleotide sequence strand of the siNA; (b) synthesizing the second oligonucleotide sequence strand of siNA on the scaffold of the first oligonucleotide sequence strand, wherein the second oligonucleotide sequence strand further comprises a chemical moiety than can be used to purify the siNA duplex; (c) cleaving the linker molecule of (a) under conditions suitable for the two siNA oligonucleotide strands to hybridize and form a stable duplex; and (d) purifying the siNA duplex utilizing the chemical moiety of the second oligonucleotide sequence strand. In one embodiment, cleavage of the linker molecule in (c) above takes place during deprotection of the oligonucleotide, for example under hydrolysis conditions using an alkylamine base such as methylamine. In one embodiment, the method of synthesis comprises solid phase synthesis on a solid support such as controlled pore glass (CPG) or polystyrene, wherein the first sequence of (a) is synthesized on a cleavable linker, such as a succinyl linker, using the solid support as a scaffold. The cleavable linker in (a) used as a scaffold for synthesizing the second strand can comprise similar reactivity as the solid support derivatized linker, such that cleavage of the solid support derivatized linker and the cleavable linker of (a) takes place concomitantly. In another embodiment, the chemical moiety of (b) that can be used to isolate the attached oligonucleotide sequence comprises a trityl group, for example a dimethoxytrityl group, which can be employed in a trityl-on synthesis strategy as described herein. In yet another embodiment, the chemical moiety, such as a dimethoxytrityl group, is removed during purification, for example, using acidic conditions.  
      In a further embodiment, the method for siNA synthesis is a solution phase synthesis or hybrid phase synthesis wherein both strands of the siNA duplex are synthesized in tandem using a cleavable linker attached to the first sequence which acts a scaffold for synthesis of the second sequence. Cleavage of the linker under conditions suitable for hybridization of the separate siNA sequence strands results in formation of the double-stranded siNA molecule.  
      In another embodiment, the invention features a method for synthesizing a siNA duplex molecule comprising: (a) synthesizing one oligonucleotide sequence strand of the siNA molecule, wherein the sequence comprises a cleavable linker molecule that can be used as a scaffold for the synthesis of another oligonucleotide sequence; (b) synthesizing a second oligonucleotide sequence having complementarity to the first sequence strand on the scaffold of (a), wherein the second sequence comprises the other strand of the double-stranded siNA molecule and wherein the second sequence further comprises a chemical moiety than can be used to isolate the attached oligonucleotide sequence; (c) purifying the product of (b) utilizing the chemical moiety of the second oligonucleotide sequence strand under conditions suitable for isolating the full-length sequence comprising both siNA oligonucleotide strands connected by the cleavable linker and under conditions suitable for the two siNA oligonucleotide strands to hybridize and form a stable duplex. In one embodiment, cleavage of the linker molecule in (c) above takes place during deprotection of the oligonucleotide, for example under hydrolysis conditions. In another embodiment, cleavage of the linker molecule in (c) above takes place after deprotection of the oligonucleotide. In another embodiment, the method of synthesis comprises solid phase synthesis on a solid support such as controlled pore glass (CPG) or polystyrene, wherein the first sequence of (a) is synthesized on a cleavable linker, such as a succinyl linker, using the solid support as a scaffold. The cleavable linker in (a) used as a scaffold for synthesizing the second strand can comprise similar reactivity or differing reactivity as the solid support derivatized linker, such that cleavage of the solid support derivatized linker and the cleavable linker of (a) takes place either concomitantly or sequentially. In one embodiment, the chemical moiety of (b) that can be used to isolate the attached oligonucleotide sequence comprises a trityl group, for example a dimethoxytrityl group.  
      In another embodiment, the invention features a method for making a double-stranded siNA molecule in a single synthetic process comprising: (a) synthesizing an oligonucleotide having a first and a second sequence, wherein the first sequence is complementary to the second sequence, and the first oligonucleotide sequence is linked to the second sequence via a cleavable linker, and wherein a terminal 5′-protecting group, for example, a 5′-O-dimethoxytrityl group (5′-O-DMT) remains on the oligonucleotide having the second sequence; (b) deprotecting the oligonucleotide whereby the deprotection results in the cleavage of the linker joining the two oligonucleotide sequences; and (c) purifying the product of (b) under conditions suitable for isolating the double-stranded siNA molecule, for example using a trityl-on synthesis strategy as described herein.  
      In another embodiment, the method of synthesis of siNA molecules of the invention comprises the teachings of Scaringe et al., U.S. Pat. Nos. 5,889,136; 6,008,400; and 6,111,086, incorporated by reference herein in their entirety.  
      In one embodiment, the invention features siNA constructs that mediate RNAi against Fas and/or FasL, wherein the siNA construct comprises one or more chemical modifications, for example, one or more chemical modifications having any of Formulae I-VII or any combination thereof that increases the nuclease resistance of the siNA construct.  
      In another embodiment, the invention features a method for generating siNA molecules with increased nuclease resistance comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having increased nuclease resistance.  
      In one embodiment, the invention features siNA constructs that mediate RNAi against Fas and/or FasL, wherein the siNA construct comprises one or more chemical modifications described herein that modulates the binding affinity between the sense and antisense strands of the siNA construct.  
      In another embodiment, the invention features a method for generating siNA molecules with increased binding affinity between the sense and antisense strands of the siNA molecule comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having increased binding affinity between the sense and antisense strands of the siNA molecule.  
      In one embodiment, the invention features siNA constructs that mediate RNAi against Fas and/or FasL, wherein the siNA construct comprises one or more chemical modifications described herein that modulates the binding affinity between the antisense strand of the siNA construct and a complementary target RNA sequence within a cell.  
      In one embodiment, the invention features siNA constructs that mediate RNAi against Fas and/or FasL, wherein the siNA construct comprises one or more chemical modifications described herein that modulates the binding affinity between the antisense strand of the siNA construct and a complementary target DNA sequence within a cell.  
      In another embodiment, the invention features a method for generating siNA molecules with increased binding affinity between the antisense strand of the siNA molecule and a complementary target RNA sequence comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having increased binding affinity between the antisense strand of the siNA molecule and a complementary target RNA sequence.  
      In another embodiment, the invention features a method for generating siNA molecules with increased binding affinity between the antisense strand of the siNA molecule and a complementary target DNA sequence comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having increased binding affinity between the antisense strand of the siNA molecule and a complementary target DNA sequence.  
      In one embodiment, the invention features siNA constructs that mediate RNAi against Fas and/or FasL, wherein the siNA construct comprises one or more chemical modifications described herein that modulate the polymerase activity of a cellular polymerase capable of generating additional endogenous siNA molecules having sequence homology to the chemically-modified siNA construct.  
      In another embodiment, the invention features a method for generating siNA molecules capable of mediating increased polymerase activity of a cellular polymerase capable of generating additional endogenous siNA molecules having sequence homology to a chemically-modified siNA molecule comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules capable of mediating increased polymerase activity of a cellular polymerase capable of generating additional endogenous siNA molecules having sequence homology to the chemically-modified siNA molecule.  
      In one embodiment, the invention features chemically-modified siNA constructs that mediate RNAi against Fas and/or FasL in a cell, wherein the chemical modifications do not significantly effect the interaction of siNA with a target RNA molecule, DNA molecule and/or proteins or other factors that are essential for RNAi in a manner that would decrease the efficacy of RNAi mediated by such siNA constructs.  
      In another embodiment, the invention features a method for generating siNA molecules with improved RNAi activity against Fas and/or FasL comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having improved RNAi activity.  
      In yet another embodiment, the invention features a method for generating siNA molecules with improved RNAi activity against Fas and/or FasL target RNA comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having improved RNAi activity against the target RNA.  
      In yet another embodiment, the invention features a method for generating siNA molecules with improved RNAi activity against Fas and/or FasL target DNA comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having improved RNAi activity against the target DNA.  
      In one embodiment, the invention features siNA constructs that mediate RNAi against Fas and/or FasL, wherein the siNA construct comprises one or more chemical modifications described herein that modulates the cellular uptake of the siNA construct.  
      In another embodiment, the invention features a method for generating siNA molecules against Fas and/or FasL with improved cellular uptake comprising (a) introducing nucleotides having any of Formula I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having improved cellular uptake.  
      In one embodiment, the invention features siNA constructs that mediate RNAi against Fas and/or FasL, wherein the siNA construct comprises one or more chemical modifications described herein that increases the bioavailability of the siNA construct, for example, by attaching polymeric conjugates such as polyethyleneglycol or equivalent conjugates that improve the pharmacokinetics of the siNA construct, or by attaching conjugates that target specific tissue types or cell types in vivo. Non-limiting examples of such conjugates are described in Vargeese et al., U.S. Ser. No. 10/201,394 incorporated by reference herein.  
      In one embodiment, the invention features a method for generating siNA molecules of the invention with improved bioavailability, comprising (a) introducing a conjugate into the structure of a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having improved bioavailability. Such conjugates can include ligands for cellular receptors, such as peptides derived from naturally occurring protein ligands; protein localization sequences, including cellular ZIP code sequences; antibodies; nucleic acid aptamers; vitamins and other co-factors, such as folate and N-acetylgalactosamine; polymers, such as polyethyleneglycol (PEG); phospholipids; cholesterol; polyamines, such as spermine or spermidine; and others.  
      In one embodiment, the invention features a double stranded short interfering nucleic acid (siNA) molecule that comprises a first nucleotide sequence complementary to a target RNA sequence or a portion thereof, and a second sequence having complementarity to said first sequence, wherein said second sequence is chemically modified in a manner that it can no longer act as a guide sequence for efficiently mediating RNA interference and/or be recognized by cellular proteins that facilitate RNAi.  
      In one embodiment, the invention features a double stranded short interfering nucleic acid (siNA) molecule that comprises a first nucleotide sequence complementary to a target RNA sequence or a portion thereof, and a second sequence having complementarity to said first sequence, wherein the second sequence is designed or modified in a manner that prevents its entry into the RNAi pathway as a guide sequence or as a sequence that is complementary to a target nucleic acid (e.g., RNA) sequence. Such design or modifications are expected to enhance the activity of siNA and/or improve the specificity of siNA molecules of the invention. These modifications are also expected to minimize any off-target effects and/or associated toxicity.  
      In one embodiment, the invention features a double stranded short interfering nucleic acid (siNA) molecule that comprises a first nucleotide sequence complementary to a target RNA sequence or a portion thereof, and a second sequence having complementarity to said first sequence, wherein said second sequence is incapable of acting as a guide sequence for mediating RNA interference.  
      In one embodiment, the invention features a double stranded short interfering nucleic acid (siNA) molecule that comprises a first nucleotide sequence complementary to a target RNA sequence or a portion thereof, and a second sequence having complementarity to said first sequence, wherein said second sequence does not have a terminal 5′-hydroxyl (5′-OH) or 5′-phosphate group.  
      In one embodiment, the invention features a double stranded short interfering nucleic acid (siNA) molecule that comprises a first nucleotide sequence complementary to a target RNA sequence or a portion thereof, and a second sequence having complementarity to said first sequence, wherein said second sequence comprises a terminal cap moiety at the 5′-end of said second sequence. In one embodiment, the terminal cap moiety comprises an inverted abasic, inverted deoxy abasic, inverted nucleotide moiety, a group shown in  FIG. 10 , an alkyl or cycloalkyl group, a heterocycle, or any other group that prevents RNAi activity in which the second sequence serves as a guide sequence or template for RNAi.  
      In one embodiment, the invention features a double stranded short interfering nucleic acid (siNA) molecule that comprises a first nucleotide sequence complementary to a target RNA sequence or a portion thereof, and a second sequence having complementarity to said first sequence, wherein said second sequence comprises a terminal cap moiety at the 5′-end and 3′-end of said second sequence. In one embodiment, each terminal cap moiety individually comprises an inverted abasic, inverted deoxy abasic, inverted nucleotide moiety, a group shown in  FIG. 10 , an alkyl or cycloalkyl group, a heterocycle, or any other group that prevents RNAi activity in which the second sequence serves as a guide sequence or template for RNAi.  
      In one embodiment, the invention features a method for generating siNA molecules of the invention with improved specificity for down regulating or inhibiting the expression of a target nucleic acid (e.g., a DNA or RNA such as a gene or its corresponding RNA), comprising (a) introducing one or more chemical modifications into the structure of a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having improved specificity. In another embodiment, the chemical modification used to improve specificity comprises terminal cap modifications at the 5′-end, 3′-end, or both 5′ and 3′-ends of the siNA molecule. The terminal cap modifications can comprise, for example, structures shown in  FIG. 10  (e.g. inverted deoxyabasic moieties) or any other chemical modification that renders a portion of the siNA molecule (e.g. the sense strand) incapable of mediating RNA interference against an off target nucleic acid sequence. In a non-limiting example, a siNA molecule is designed such that only the antisense sequence of the siNA molecule can serve as a guide sequence for RISC mediated degradation of a corresponding target RNA sequence. This can be accomplished by rendering the sense sequence of the siNA inactive by introducing chemical modifications to the sense strand that preclude recognition of the sense strand as a guide sequence by RNAi machinery. In one embodiment, such chemical modifications comprise any chemical group at the 5′-end of the sense strand of the siNA, or any other group that serves to render the sense strand inactive as a guide sequence for mediating RNA interference. These modifications, for example, can result in a molecule where the 5′-end of the sense strand no longer has a free 5′-hydroxyl (5′-OH) or a free 5′-phosphate group (e.g., phosphate, diphosphate, triphosphate, cyclic phosphate etc.). Non-limiting examples of such siNA constructs are described herein, such as “Stab 9/10”, “Stab 7/8”, “Stab 7/19”, “Stab 17/22”, “Stab 23/24”, and “Stab 24/25” chemistries and variants thereof (see Table IV) wherein the 5′-end and 3′-end of the sense strand of the siNA do not comprise a hydroxyl group or phosphate group.  
      In one embodiment, the invention features a method for generating siNA molecules of the invention with improved specificity for down regulating or inhibiting the expression of a target nucleic acid (e.g., a DNA or RNA such as a gene or its corresponding RNA), comprising introducing one or more chemical modifications into the structure of a siNA molecule that prevent a strand or portion of the siNA molecule from acting as a template or guide sequence for RNAi activity. In one embodiment, the inactive strand or sense region of the siNA molecule is the sense strand or sense region of the siNA molecule, i.e. the strand or region of the siNA that does not have complementarity to the target nucleic acid sequence. In one embodiment, such chemical modifications comprise any chemical group at the 5′-end of the sense strand or region of the siNA that does not comprise a 5′-hydroxyl (5′-OH) or 5′-phosphate group, or any other group that serves to render the sense strand or sense region inactive as a guide sequence for mediating RNA interference. Non-limiting examples of such siNA constructs are described herein, such as “Stab 9/10”, “Stab 7/8”, “Stab 7/19”, “Stab 17/22”, “Stab 23/24”, and “Stab 24/25” chemistries and variants thereof (see Table IV) wherein the 5′-end and 3′-end of the sense strand of the siNA do not comprise a hydroxyl group or phosphate group.  
      In one embodiment, the invention features a method for screening siNA molecules that are active in mediating RNA interference against a target nucleic acid sequence comprising (a) generating a plurality of unmodified siNA molecules, (b) screening the siNA molecules of step (a) under conditions suitable for isolating siNA molecules that are active in mediating RNA interference against the target nucleic acid sequence, and (c) introducing chemical modifications (e.g. chemical modifications as described herein or as otherwise known in the art) into the active siNA molecules of (b). In one embodiment, the method further comprises re-screening the chemically modified siNA molecules of step (c) under conditions suitable for isolating chemically modified siNA molecules that are active in mediating RNA interference against the target nucleic acid sequence.  
      In one embodiment, the invention features a method for screening chemically modified siNA molecules that are active in mediating RNA interference against a target nucleic acid sequence comprising (a) generating a plurality of chemically modified siNA molecules (e.g. siNA molecules as described herein or as otherwise known in the art), and (b) screening the siNA molecules of step (a) under conditions suitable for isolating chemically modified siNA molecules that are active in mediating RNA interference against the target nucleic acid sequence.  
      The term “ligand” refers to any compound or molecule, such as a drug, peptide, hormone, or neurotransmitter, that is capable of interacting with another compound, such as a receptor, either directly or indirectly. The receptor that interacts with a ligand can be present on the surface of a cell or can alternately be an intercullular receptor. Interaction of the ligand with the receptor can result in a biochemical reaction, or can simply be a physical interaction or association.  
      In another embodiment, the invention features a method for generating siNA molecules of the invention with improved bioavailability comprising (a) introducing an excipient formulation to a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having improved bioavailability. Such excipients include polymers such as cyclodextrins, lipids, cationic lipids, polyamines, phospholipids, nanoparticles, receptors, ligands, and others.  
      In another embodiment, the invention features a method for generating siNA molecules of the invention with improved bioavailability comprising (a) introducing nucleotides having any of Formulae I-VII or any combination thereof into a siNA molecule, and (b) assaying the siNA molecule of step (a) under conditions suitable for isolating siNA molecules having improved bioavailability.  
      In another embodiment, polyethylene glycol (PEG) can be covalently attached to siNA compounds of the present invention. The attached PEG can be any molecular weight, preferably from about 2,000 to about 50,000 daltons (Da).  
      The present invention can be used alone or as a component of a kit having at least one of the reagents necessary to carry out the in vitro or in vivo introduction of RNA to test samples and/or subjects. For example, preferred components of the kit include a siNA molecule of the invention and a vehicle that promotes introduction of the siNA into cells of interest as described herein (e.g., using lipids and other methods of transfection known in the art, see for example Beigelman et al, U.S. Pat. No. 6,395,713). The kit can be used for target validation, such as in determining gene function and/or activity, or in drug optimization, and in drug discovery (see for example Usman et al., U.S. Ser. No. 60/402,996). Such a kit can also include instructions to allow a user of the kit to practice the invention.  
      The term “short interfering nucleic acid”, “siNA”, “short interfering RNA”, “siRNA”, “short interfering nucleic acid molecule”, “short interfering oligonucleotide molecule”, or “chemically-modified short interfering nucleic acid molecule” as used herein refers to any nucleic acid molecule capable of inhibiting or down regulating gene expression or viral replication, for example by mediating RNA interference “RNAi” or gene silencing in a sequence-specific manner; see for example Zamore et al., 2000, Cell, 101, 25-33; Bass, 2001 , Nature,  411, 428-429; Elbashir et al., 2001 , Nature,  411, 494-498; and Kreutzer et al., International PCT Publication No. WO 00/44895; Zernicka-Goetz et al., International PCT Publication No. WO 01/36646; Fire, International PCT Publication No. WO 99/32619; Plaetinck et al., International PCT Publication No. WO 00/01846; Mello and Fire, International PCT Publication No. WO 01/29058; Deschamps-Depaillette, International PCT Publication No. WO 99/07409; and Li et al., International PCT Publication No. WO 00/44914; Allshire, 2002 , Science,  297, 1818-1819; Volpe et al., 2002 , Science,  297, 1833-1837; Jenuwein, 2002 , Science,  297, 2215-2218; and Hall et al., 2002 , Science,  297, 2232-2237; Hutvagner and Zamore, 2002 , Science,  297, 2056-60; McManus et al., 2002 , RNA,  8, 842-850; Reinhart et al., 2002 , Gene  &amp;  Dev.,  16, 1616-1626; and Reinhart &amp; Bartel, 2002 , Science,  297, 1831). Non limiting examples of siNA molecules of the invention are shown in  FIGS. 4-6 , and Tables II and III herein. For example the siNA can be a double-stranded polynucleotide molecule comprising self-complementary sense and antisense regions, wherein the antisense region comprises nucleotide sequence that is complementary to nucleotide sequence in a target nucleic acid molecule or a portion thereof and the sense region having nucleotide sequence corresponding to the target nucleic acid sequence or a portion thereof. The siNA can be assembled from two separate oligonucleotides, where one strand is the sense strand and the other is the antisense strand, wherein the antisense and sense strands are self-complementary (i.e. each strand comprises nucleotide sequence that is complementary to nucleotide sequence in the other strand; such as where the antisense strand and sense strand form a duplex or double stranded structure, for example wherein the double stranded region is about 19 base pairs); the antisense strand comprises nucleotide sequence that is complementary to nucleotide sequence in a target nucleic acid molecule or a portion thereof and the sense strand comprises nucleotide sequence corresponding to the target nucleic acid sequence or a portion thereof. Alternatively, the siNA is assembled from a single oligonucleotide, where the self-complementary sense and antisense regions of the siNA are linked by means of a nucleic acid based or non-nucleic acid-based linker(s). The siNA can be a polynucleotide with a duplex, asymmetric duplex, hairpin or asymmetric hairpin secondary structure, having self-complementary sense and antisense regions, wherein the antisense region comprises nucleotide sequence that is complementary to nucleotide sequence in a separate target nucleic acid molecule or a portion thereof and the sense region having nucleotide sequence corresponding to the target nucleic acid sequence or a portion thereof. The siNA can be a circular single-stranded polynucleotide having two or more loop structures and a stem comprising self-complementary sense and antisense regions, wherein the antisense region comprises nucleotide sequence that is complementary to nucleotide sequence in a target nucleic acid molecule or a portion thereof and the sense region having nucleotide sequence corresponding to the target nucleic acid sequence or a portion thereof, and wherein the circular polynucleotide can be processed either in vivo or in vitro to generate an active siNA molecule capable of mediating RNAi. The siNA can also comprise a single stranded polynucleotide having nucleotide sequence complementary to nucleotide sequence in a target nucleic acid molecule or a portion thereof (for example, where such siNA molecule does not require the presence within the siNA molecule of nucleotide sequence corresponding to the target nucleic acid sequence or a portion thereof), wherein the single stranded polynucleotide can further comprise a terminal phosphate group, such as a 5′-phosphate (see for example Martinez et al., 2002 , Cell.,  110, 563-574 and Schwarz et al., 2002 , Molecular Cell,  10, 537-568), or 5′,3′-diphosphate. In certain embodiments, the siNA molecule of the invention comprises separate sense and antisense sequences or regions, wherein the sense and antisense regions are covalently linked by nucleotide or non-nucleotide linkers molecules as is known in the art, or are alternately non-covalently linked by ionic interactions, hydrogen bonding, van der waals interactions, hydrophobic interactions, and/or stacking interactions. In certain embodiments, the siNA molecules of the invention comprise nucleotide sequence that is complementary to nucleotide sequence of a target gene. In another embodiment, the siNA molecule of the invention interacts with nucleotide sequence of a target gene in a manner that causes inhibition of expression of the target gene. As used herein, siNA molecules need not be limited to those molecules containing only RNA, but further encompasses chemically-modified nucleotides and non-nucleotides. In certain embodiments, the short interfering nucleic acid molecules of the invention lack 2′-hydroxy (2′-OH) containing nucleotides. Applicant describes in certain embodiments short interfering nucleic acids that do not require the presence of nucleotides having a 2′-hydroxy group for mediating RNAi and as such, short interfering nucleic acid molecules of the invention optionally do not include any ribonucleotides (e.g., nucleotides having a 2′-OH group). Such siNA molecules that do not require the presence of ribonucleotides within the siNA molecule to support RNAi can however have an attached linker or linkers or other attached or associated groups, moieties, or chains containing one or more nucleotides with 2′-OH groups. Optionally, siNA molecules can comprise ribonucleotides at about 5, 10, 20, 30, 40, or 50% of the nucleotide positions. The modified short interfering nucleic acid molecules of the invention can also be referred to as short interfering modified oligonucleotides “siMON.” As used herein, the term siNA is meant to be equivalent to other terms used to describe nucleic acid molecules that are capable of mediating sequence specific RNAi, for example short interfering RNA (siRNA), double-stranded RNA (dsRNA), micro-RNA (mRNA), short hairpin RNA (shRNA), short interfering oligonucleotide, short interfering nucleic acid, short interfering modified oligonucleotide, chemically-modified siRNA, post-transcriptional gene silencing RNA (ptgsRNA), and others. In addition, as used herein, the term RNAi is meant to be equivalent to other terms used to describe sequence specific RNA interference, such as post transcriptional gene silencing, translational inhibition, or epigenetics. For example, siNA molecules of the invention can be used to epigenetically silence genes at both the post-transcriptional level or the pre-transcriptional level. In a non-limiting example, epigenetic regulation of gene expression by siNA molecules of the invention can result from siNA mediated modification of chromatin structure or methylation pattern to alter gene expression (see, for example, Verdel et al., 2004 , Science,  303, 672-676; Pal-Bhadra et al., 2004 , Science,  303, 669-672; Allshire, 2002 , Science,  297, 1818-1819; Volpe et al., 2002 , Science,  297, 1833-1837; Jenuwein, 2002 , Science,  297, 2215-2218; and Hall et al., 2002 , Science,  297, 2232-2237).  
      In one embodiment, a siNA molecule of the invention is a duplex forming oligonucleotide “DFO”, (see for example  FIGS. 14-15  and Vaish et al., U.S. Ser. No. 10/727,780 filed Dec. 3, 2003 and McSwiggen et al., PCT/US04/16390, filed May 24, 2004).  
      In one embodiment, a siNA molecule of the invention is a multifunctional siNA, (see for example  FIGS. 16-21  and Jadhav et al., U.S. Ser. No. 60/543,480 filed Feb. 10, 2004 and McSwiggen et al., PCT/US04/16390, filed May 24, 2004). The multifunctional siNA of the invention can comprise sequence targeting, for example, two regions of Fas and/or FasL RNA (see for example target sequences in Tables II and III).  
      By “asymmetric hairpin” as used herein is meant a linear siNA molecule comprising an antisense region, a loop portion that can comprise nucleotides or non-nucleotides, and a sense region that comprises fewer nucleotides than the antisense region to the extent that the sense region has enough complementary nucleotides to base pair with the antisense region and form a duplex with loop. For example, an asymmetric hairpin siNA molecule of the invention can comprise an antisense region having length sufficient to mediate RNAi in a cell or in vitro system (e.g. about 19 to about 22, or about 19, 20, 21, or 22 nucleotides) and a loop region comprising about 4 to about 8 (e.g., about 4, 5, 6, 7, or 8) nucleotides, and a sense region having about 3 to about 18 (e.g., about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18) nucleotides that are complementary to the antisense region. The asymmetric hairpin siNA molecule can also comprise a 5′-terminal phosphate group that can be chemically modified. The loop portion of the asymmetric hairpin siNA molecule can comprise nucleotides, non-nucleotides, linker molecules, or conjugate molecules as described herein.  
      By “asymmetric duplex” as used herein is meant a siNA molecule having two separate strands comprising a sense region and an antisense region, wherein the sense region comprises fewer nucleotides than the antisense region to the extent that the sense region has enough complementary nucleotides to base pair with the antisense region and form a duplex. For example, an asymmetric duplex siNA molecule of the invention can comprise an antisense region having length sufficient to mediate RNAi in a cell or in vitro system e.g. about 19 to about 22 (e.g. about 19, 20, 21, or 22) nucleotides and a sense region having about 3 to about 18 (e.g., about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18) nucleotides that are complementary to the antisense region.  
      By “modulate” is meant that the expression of the gene, or level of RNA molecule or equivalent RNA molecules encoding one or more proteins or protein subunits, or activity of one or more proteins or protein subunits is up regulated or down regulated, such that expression, level, or activity is greater than or less than that observed in the absence of the modulator. For example, the term “modulate” can mean “inhibit,” but the use of the word “modulate” is not limited to this definition.  
      By “inhibit”, “down-regulate”, or “reduce”, it is meant that the expression of the gene, or level of RNA molecules or equivalent RNA molecules encoding one or more proteins or protein subunits, or activity of one or more proteins or protein subunits, is reduced below that observed in the absence of the nucleic acid molecules (e.g., siNA) of the invention. In one embodiment, inhibition, down-regulation or reduction with an siNA molecule is below that level observed in the presence of an inactive or attenuated molecule. In another embodiment, inhibition, down-regulation, or reduction with siNA molecules is below that level observed in the presence of, for example, an siNA molecule with scrambled sequence or with mismatches. In another embodiment, inhibition, down-regulation, or reduction of gene expression with a nucleic acid molecule of the instant invention is greater in the presence of the nucleic acid molecule than in its absence.  
      By “gene”, or “target gene”, is meant, a nucleic acid that encodes an RNA, for example, nucleic acid sequences including, but not limited to, structural genes encoding a polypeptide. A gene or target gene can also encode a functional RNA (fRNA) or non-coding RNA (ncRNA), such as small temporal RNA (stRNA), micro RNA (mRNA), small nuclear RNA (snRNA), short interfering RNA (siRNA), small nucleolar RNA (snRNA), ribosomal RNA (rRNA), transfer RNA (tRNA) and precursor RNAs thereof. Such non-coding RNAs can serve as target nucleic acid molecules for siNA mediated RNA interference in modulating the activity of fRNA or ncRNA involved in functional or regulatory cellular processes. Abberant fRNA or ncRNA activity leading to disease can therefore be modulated by siNA molecules of the invention. siNA molecules targeting fRNA and ncRNA can also be used to manipulate or alter the genotype or phenotype of an organism or cell, by intervening in cellular processes such as genetic imprinting, transcription, translation, or nucleic acid processing (e.g., transamination, methylation etc.). The target gene can be a gene derived from a cell, an endogenous gene, a transgene, or exogenous genes such as genes of a pathogen, for example a virus, which is present in the cell after infection thereof. The cell containing the target gene can be derived from or contained in any organism, for example a plant, animal, protozoan, virus, bacterium, or fungus. Non-limiting examples of plants include monocots, dicots, or gymnosperms. Non-limiting examples of animals include vertebrates or invertebrates. Non-limiting examples of fungi include molds or yeasts. For a review, see for example Snyder and Gerstein, 2003 , Science,  300, 258-260.  
      By “non-canonical base pair” is meant any non-Watson Crick base pair, such as mismatches and/or wobble base pairs, including flipped mismatches, single hydrogen bond mismatches, trans-type mismatches, triple base interactions, and quadruple base interactions. Non-limiting examples of such non-canonical base pairs include, but are not limited to, AC reverse Hoogsteen, AC wobble, AU reverse Hoogsteen, GU wobble, AA N7 amino, CC 2-carbonyl-amino(H1)-N-3-amino(H2), GA sheared, UC 4-carbonyl-amino, UU imino-carbonyl, AC reverse wobble, AU Hoogsteen, AU reverse Watson Crick, CG reverse Watson Crick, GC N3-amino-amino N3, AA N1-amino symmetric, AA N7-amino symmetric, GA N7-N1 amino-carbonyl, GA+ carbonyl-amino N7-N1, GG N1-carbonyl symmetric, GG N3-amino symmetric, CC carbonyl-amino symmetric, CC N3-amino symmetric, UU 2-carbonyl-imino symmetric, UU 4-carbonyl-imino symmetric, AA amino-N3, AA N1-amino, AC amino 2-carbonyl, AC N3-amino, AC N7-amino, AU amino-4-carbonyl, AU N1-imino, AU N3-imino, AU N7-imino, CC carbonyl-amino, GA amino-N1, GA amino-N7, GA carbonyl-amino, GA N3-amino, GC amino-N3, GC carbonyl-amino, GC N3-amino, GC N7-amino, GG amino-N7, GG carbonyl-imino, GG N7-amino, GU amino-2-carbonyl, GU carbonyl-imino, GU imino-2-carbonyl, GU N7-imino, psiU imino-2-carbonyl, UC 4-carbonyl-amino, UC imino-carbonyl, UU imino-4-carbonyl, AC C2-H—N3, GA carbonyl-C2-H, UU imino-4-carbonyl 2 carbonyl-C5-H, AC amino(A) N3(C)-carbonyl, GC imino amino-carbonyl, Gpsi imino-2-carbonyl amino-2-carbonyl, and GU imino amino-2-carbonyl base pairs.  
      By “Fas” is meant, any Fas polypeptide, protein and/or a polynucleotide encoding a Fas protein, peptide, or portion thereof (such as polynucleotides referred to by Genbank Accession numbers in Table I or any other Fas transcript derived from a Fas gene), also known as CD95, apoptosis antigen 1 (APT1), Fas antigen, or APO1. The term “Fas” is also meant to include other Fas encoding sequence, such as mutant Fas genes, splice variants of Fas genes, and Fas gene polymorphisms, such as those associated with a disease, trait, or condition.  
      By “Fas protein” is meant, any Fas peptide or protein or a component thereof, wherein the peptide or protein is encoded by a Fas gene or having Fas activity.  
      By “FasL” is meant, any Fas ligand polypeptide, protein and/or a polynucleotide encoding a Fas ligand protein, peptide, or portion thereof (such as polynucleotides referred to by Genbank Accession numbers in Table I or any other Fas ligand transcript derived from a Fas ligand gene), also known as Apoptosis Antigen Ligand 1, APT1LG1, CD95 Ligand, CD95L, CD178 Antigen, or CD178. The term “FasL” is also meant to include other Fas ligand encoding sequence, such as mutant FasL genes, splice variants of FasL genes, and FasL gene polymorphisms, such as those associated with a disease, trait, or condition.  
      By “Fas ligand protein” is meant, any FasL peptide or protein or a component thereof, wherein the peptide or protein is encoded by a FasL gene or having FasL activity.  
      By “homologous sequence” is meant, a nucleotide sequence that is shared by one or more polynucleotide sequences, such as genes, gene transcripts and/or non-coding polynucleotides. For example, a homologous sequence can be a nucleotide sequence that is shared by two or more genes encoding related but different proteins, such as different members of a gene family, different protein epitopes, different protein isoforms or completely divergent genes, such as a cytokine and its corresponding receptors. A homologous sequence can be a nucleotide sequence that is shared by two or more non-coding polynucleotides, such as noncoding DNA or RNA, regulatory sequences, introns, and sites of transcriptional control or regulation. Homologous sequences can also include conserved sequence regions shared by more than one polynucleotide sequence. Homology does not need to be perfect homology (e.g., 100%), as partially homologous sequences are also contemplated by the instant invention (e.g., 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, 80% etc.).  
      By “conserved sequence region” is meant, a nucleotide sequence of one or more regions in a polynucleotide does not vary significantly between generations or from one biological system or organism to another biological system or organism. The polynucleotide can include both coding and non-coding DNA and RNA.  
      By “sense region” is meant a nucleotide sequence of a siNA molecule having complementarity to an antisense region of the siNA molecule. In addition, the sense region of a siNA molecule can comprise a nucleic acid sequence having homology with a target nucleic acid sequence.  
      By “antisense region” is meant a nucleotide sequence of a siNA molecule having complementarity to a target nucleic acid sequence. In addition, the antisense region of a siNA molecule can optionally comprise a nucleic acid sequence having complementarity to a sense region of the siNA molecule.  
      By “target nucleic acid” is meant any nucleic acid sequence whose expression or activity is to be modulated. The target nucleic acid can be DNA or RNA.  
      By “complementarity” is meant that a nucleic acid can form hydrogen bond(s) with another nucleic acid sequence by either traditional Watson-Crick or other non-traditional types. In reference to the nucleic molecules of the present invention, the binding free energy for a nucleic acid molecule with its complementary sequence is sufficient to allow the relevant function of the nucleic acid to proceed, e.g., RNAi activity. Determination of binding free energies for nucleic acid molecules is well known in the art (see, e.g., Turner et al., 1987 , CSH Symp. Quant. Biol . LII pp. 123-133; Frier et al., 1986 , Proc. Nat. Acad. Sci. USA  83:9373-9377; Turner et al., 1987 , J. Am. Chem. Soc.  109:3783-3785). A percent complementarity indicates the percentage of contiguous residues in a nucleic acid molecule that can form hydrogen bonds (e.g., Watson-Crick base pairing) with a second nucleic acid sequence (e.g., 5, 6, 7, 8, 9, or 10 nucleotides out of a total of 10 nucleotides in the first oligonucleotide being based paired to a second nucleic acid sequence having 10 nucleotides represents 50%, 60%, 70%, 80%, 90%, and 100% complementary respectively). “Perfectly complementary” means that all the contiguous residues of a nucleic acid sequence will hydrogen bond with the same number of contiguous residues in a second nucleic acid sequence.  
      In one embodiment, siNA molecules of the invention that down regulate or reduce Fas and/or FasL gene expression are used for preventing or reducing transplant/allograft rejection, viral infection (e.g., viral hepatitis, HCV, HBV), inflammatory disease (e.g., cirrhosis, liver disease, psoriasis), autoimmunity (e.g., systemic lupus), neurological disease, liver disease, brain or spinal cord injury, or any other disease associated with Fas and/or FasL gene expression in a subject.  
      By “spinal cord injury” is meant, any injury to the spinal cord, including traumatic, degenerative or infectious spinal cord injuries involving inflammation, compression, tearing, severing, shearing, mechanical disruption, transection, extradural pathology, or distraction of neural elements of the spinal cord and resulting motor deficits resulting from such injury. The term “spinal cord injury” or “SCI” also encompasses anterior cord syndrome, Brown-Séquard syndrome, central cord syndrome, conus medullaris syndrome, and cauda equina syndrome and infectious conditions such as meningitis, infections involving the spinal canal including epidural abscesses (infection in the epidural space), meningitis (infection of the meninges), subdural abscesses (infections of the subdural space), and intramedullary abscesses (infections within the spinal cord).  
      By “brain injury” is meant, any injury to the brain, including traumatic, hypoxic, anoxic, degenerative or infectious brain injuries as are known in the art and resulting psychomotor deficits resulting from such injury.  
      By “transplant/allograft rejection” is meant the rejection of any transplanted organ or tissue in a subject, including liver, limb, pancreas, renal, dermal, cutaneous, corneal vascular, cardiac, or lung tissue/organs.  
      By “inflammatory disease” or “inflammatory condition” is meant any disease, condition, trait, genotype or phenotype characterized by an inflammatory or allergic process as is known in the art, such as inflammation, acute inflammation, chronic inflammation, atherosclerosis, restenosis, cirrhosis, asthma, allergic rhinitis, atopic dermatitis, psoriasis, septic shock, rheumatoid arthritis, inflammatory bowl disease, inflammatory pelvic disease, pain, ocular inflammatory disease, celiac disease, Leigh Syndrome, Glycerol Kinase Deficiency, Familial eosinophilia (FE), autosomal recessive spastic ataxia, laryngeal inflammatory disease; Tuberculosis, Chronic cholecystitis, Bronchiectasis, Silicosis and other pneumoconioses, and any other inflammatory disease, condition, trait, genotype or phenotype that can respond to the modulation of disease related gene expression in a cell or tissue, alone or in combination with other therapies.  
      By “autoimmune disease” or “autoimmune condition” is meant, any disease, condition, trait, genotype or phenotype characterized by autoimmunity as is known in the art, such as multiple sclerosis, diabetes mellitus, lupus, celiac disease, Crohn&#39;s disease, ulcerative colitis, Guillain-Barre syndrome, scleroderms, Goodpasture&#39;s syndrome, Wegener&#39;s granulomatosis, autoimmune epilepsy, Rasmussen&#39;s encephalitis, Primary biliary sclerosis, Sclerosing cholangitis, Autoimmune hepatitis, Addison&#39;s disease, Hashimoto&#39;s thyroiditis, Fibromyalgia, Menier&#39;s syndrome; transplantation rejection (e.g., prevention of allograft rejection) pernicious anemia, rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, Sjogren&#39;s syndrome, lupus erythematosus, multiple sclerosis, myasthenia gravis, Reiter&#39;s syndrome, Grave&#39;s disease, and any other autoimmune disease, condition, trait, genotype or phenotype that can respond to the modulation of disease related gene expression in a cell or tissue, alone or in combination with other therapies.  
      By “neurologic disease” or “neurological disease” or “neurodegenerative disease” is meant any disease, disorder, or condition affecting the central or peripheral nervous system, including ADHD, AIDS—Neurological Complications, Absence of the Septum Pellucidum, Acquired Epileptiform Aphasia, Acute Disseminated Encephalomyelitis, Adrenoleukodystrophy, Agenesis of the Corpus Callosum, Agnosia, Aicardi Syndrome, Alexander Disease, Alpers&#39; Disease, Alternating Hemiplegia, Alzheimer&#39;s Disease, Amyotrophic Lateral Sclerosis, Anencephaly, Aneurysm, Angelman Syndrome, Angiomatosis, Anoxia, Aphasia, Apraxia, Arachnoid Cysts, Arachnoiditis, Arnold-Chiari Malformation, Arteriovenous Malformation, Aspartame, Asperger Syndrome, Ataxia Telangiectasia, Ataxia, Attention Deficit-Hyperactivity Disorder, Autism, Autonomic Dysfunction, Back Pain, Barth Syndrome, Batten Disease, Behcet&#39;s Disease, Bell&#39;s Palsy, Benign Essential Blepharospasm, Benign Focal Amyotrophy, Benign Intracranial Hypertension, Bernhardt-Roth Syndrome, Binswanger&#39;s Disease, Blepharospasm, Bloch-Sulzberger Syndrome, Brachial Plexus Birth Injuries, Brachial Plexus Injuries, Bradbury-Eggleston Syndrome, Brain Aneurysm, Brain Injury, Brain and Spinal Tumors, Brown-Sequard Syndrome, Bulbospinal Muscular Atrophy, Canavan Disease, Carpal Tunnel Syndrome, Causalgia, Cavernomas, Cavernous Angioma, Cavernous Malformation, Central Cervical Cord Syndrome, Central Cord Syndrome, Central Pain Syndrome, Cephalic Disorders, Cerebellar Degeneration, Cerebellar Hypoplasia, Cerebral Aneurysm, Cerebral Arteriosclerosis, Cerebral Atrophy, Cerebral Beriberi, Cerebral Gigantism, Cerebral Hypoxia, Cerebral Palsy, Cerebro-Oculo-Facio-Skeletal Syndrome, Charcot-Marie-Tooth Disorder, Chiari Malformation, Chorea, Choreoacanthocytosis, Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), Chronic Orthostatic Intolerance, Chronic Pain, Cockayne Syndrome Type II, Coffin Lowry Syndrome, Coma, including Persistent Vegetative State, Complex Regional Pain Syndrome, Congenital Facial Diplegia, Congenital Myasthenia, Congenital Myopathy, Congenital Vascular Cavernous Malformations, Corticobasal Degeneration, Cranial Arteritis, Craniosynostosis, Creutzfeldt-Jakob Disease, Cumulative Trauma Disorders, Cushing&#39;s Syndrome, Cytomegalic Inclusion Body Disease (CIBD), Cytomegalovirus Infection, Dancing Eyes-Dancing Feet Syndrome, Dandy-Walker Syndrome, Dawson Disease, De Morsier&#39;s Syndrome, Dejerine-Klumpke Palsy, Dementia—Multi-Infarct, Dementia—Subcortical, Dementia With Lewy Bodies, Dermatomyositis, Developmental Dyspraxia, Devic&#39;s Syndrome, Diabetic Neuropathy, Diffuse Sclerosis, Dravet&#39;s Syndrome, Dysautonomia, Dysgraphia, Dyslexia, Dysphagia, Dyspraxia, Dystonias, Early Infantile Epileptic Encephalopathy, Empty Sella Syndrome, Encephalitis Lethargica, Encephalitis and Meningitis, Encephaloceles, Encephalopathy, Encephalotrigeminal Angiomatosis, Epilepsy, Erb&#39;s Palsy, Erb-Duchenne and Dejerine-Klumpke Palsies, Fabry&#39;s Disease, Fahr&#39;s Syndrome, Fainting, Familial Dysautonomia, Familial Hemangioma, Familial Idiopathic Basal Ganglia Calcification, Familial Spastic Paralysis, Febrile Seizures (e.g., GEFS and GEFS plus), Fisher Syndrome, Floppy Infant Syndrome, Friedreich&#39;s Ataxia, Gaucher&#39;s Disease, Gerstmann&#39;s Syndrome, Gerstmann-Straussler-Scheinker Disease, Giant Cell Arteritis, Giant Cell Inclusion Disease, Globoid Cell Leukodystrophy, Glossopharyngeal Neuralgia, Guillain-Barre Syndrome, HTLV-1 Associated Myelopathy, Hallervorden-Spatz Disease, Head Injury, Headache, Hemicrania Continua, Hemifacial Spasm, Hemiplegia Alterans, Hereditary Neuropathies, Hereditary Spastic Paraplegia, Heredopathia Atactica Polyneuritiformis, Herpes Zoster Oticus, Herpes Zoster, Hirayama Syndrome, Holoprosencephaly, Huntington&#39;s Disease, Hydranencephaly, Hydrocephalus—Normal Pressure, Hydrocephalus, Hydromyelia, Hypercortisolism, Hypersomnia, Hypertonia, Hypotonia, Hypoxia, Immune-Mediated Encephalomyelitis, Inclusion Body Myositis, Incontinentia Pigmenti, Infantile Hypotonia, Infantile Phytanic Acid Storage Disease, Infantile Refsum Disease, Infantile Spasms, Inflammatory Myopathy, Intestinal Lipodystrophy, Intracranial Cysts, Intracranial Hypertension, Isaac&#39;s Syndrome, Joubert Syndrome, Kearns-Sayre Syndrome, Kennedy&#39;s Disease, Kinsbourne syndrome, Kleine-Levin syndrome, Klippel Feil Syndrome, Klippel-Trenaunay Syndrome (KTS), Klüver-Bucy Syndrome, Korsakoff&#39;s Amnesic Syndrome, Krabbe Disease, Kugelberg-Welander Disease, Kuru, Lambert-Eaton Myasthenic Syndrome, Landau-Kleffner Syndrome, Lateral Femoral Cutaneous Nerve Entrapment, Lateral Medullary Syndrome, Learning Disabilities, Leigh&#39;s Disease, Lennox-Gastaut Syndrome, Lesch-Nyhan Syndrome, Leukodystrophy, Levine-Critchley Syndrome, Lewy Body Dementia, Lissencephaly, Locked-In Syndrome, Lou Gehrig&#39;s Disease, Lupus—Neurological Sequelae, Lyme Disease—Neurological Complications, Machado-Joseph Disease, Macrencephaly, Megalencephaly, Melkersson-Rosenthal Syndrome, Meningitis, Menkes Disease, Meralgia Paresthetica, Metachromatic Leukodystrophy, Microcephaly, Migraine, Miller Fisher Syndrome, Mini-Strokes, Mitochondrial Myopathies, Mobius Syndrome, Monomelic Amyotrophy, Motor Neuron Diseases, Moyamoya Disease, Mucolipidoses, Mucopolysaccharidoses, Multi-Infarct Dementia, Multifocal Motor Neuropathy, Multiple Sclerosis, Multiple System Atrophy with Orthostatic Hypotension, Multiple System Atrophy, Muscular Dystrophy, Myasthenia—Congenital, Myasthenia Gravis, Myelinoclastic Diffuse Sclerosis, Myoclonic Encephalopathy of Infants, Myoclonus, Myopathy—Congenital, Myopathy—Thyrotoxic, Myopathy, Myotonia Congenita, Myotonia, Narcolepsy, Neuroacanthocytosis, Neurodegeneration with Brain Iron Accumulation, Neurofibromatosis, Neuroleptic Malignant Syndrome, Neurological Complications of AIDS, Neurological Manifestations of Pompe Disease, Neuromyelitis Optica, Neuromyotonia, Neuronal Ceroid Lipofuscinosis, Neuronal Migration Disorders, Neuropathy-Hereditary, Neurosarcoidosis, Neurotoxicity, Nevus Cavernosus, Niemann-Pick Disease, O&#39;Sullivan-McLeod Syndrome, Occipital Neuralgia, Occult Spinal Dysraphism Sequence, Ohtahara Syndrome, Olivopontocerebellar Atrophy, Opsoclonus Myoclonus, Orthostatic Hypotension, Overuse Syndrome, Pain—Chronic, Paraneoplastic Syndromes, Paresthesia, Parkinson&#39;s Disease, Parmyotonia Congenita, Paroxysmal Choreoathetosis, Paroxysmal Hemicrania, Parry-Romberg, Pelizaeus-Merzbacher Disease, Pena Shokeir II Syndrome, Perineural Cysts, Periodic Paralyses, Peripheral Neuropathy, Periventricular Leukomalacia, Persistent Vegetative State, Pervasive Developmental Disorders, Phytanic Acid Storage Disease, Pick&#39;s Disease, Piriformis Syndrome, Pituitary Tumors, Polymyositis, Pompe Disease, Porencephaly, Post-Polio Syndrome, Postherpetic Neuralgia, Postinfectious Encephalomyelitis, Postural Hypotension, Postural Orthostatic Tachycardia Syndrome, Postural Tachycardia Syndrome, Primary Lateral Sclerosis, Prion Diseases, Progressive Hemifacial Atrophy, Progressive Locomotor Ataxia, Progressive Multifocal Leukoencephalopathy, Progressive Sclerosing Poliodystrophy, Progressive Supranuclear Palsy, Pseudotumor Cerebri, Pyridoxine Dependent and Pyridoxine Responsive Siezure Disorders, Ramsay Hunt Syndrome Type I, Ramsay Hunt Syndrome Type II, Rasmussen&#39;s Encephalitis and other autoimmune epilepsies, Reflex Sympathetic Dystrophy Syndrome, Refsum Disease—Infantile, Refsum Disease, Repetitive Motion Disorders, Repetitive Stress Injuries, Restless Legs Syndrome, Retrovirus-Associated Myelopathy, Rett Syndrome, Reye&#39;s Syndrome, Riley-Day Syndrome, SUNCT Headache, Sacral Nerve Root Cysts, Saint Vitus Dance, Salivary Gland Disease, Sandhoff Disease, Schilder&#39;s Disease, Schizencephaly, Seizure Disorders, Septo-Optic Dysplasia, Severe Myoclonic Epilepsy of Infancy (SMEI), Shaken Baby Syndrome, Shingles, Shy-Drager Syndrome, Sjogren&#39;s Syndrome, Sleep Apnea, Sleeping Sickness, Soto&#39;s Syndrome, Spasticity, Spina Bifida, Spinal Cord Infarction, Spinal Cord Injury, Spinal Cord Tumors, Spinal Muscular Atrophy, Spinocerebellar Atrophy, Steele-Richardson-Olszewski Syndrome, Stiff-Person Syndrome, Striatonigral Degeneration, Stroke, Sturge-Weber Syndrome, Subacute Sclerosing Panencephalitis, Subcortical Arteriosclerotic Encephalopathy, Swallowing Disorders, Sydenham Chorea, Syncope, Syphilitic Spinal Sclerosis, Syringohydromyelia, Syringomyelia, Systemic Lupus Erythematosus, Tabes Dorsalis, Tardive Dyskinesia, Tarlov Cysts, Tay-Sachs Disease, Temporal Arteritis, Tethered Spinal Cord Syndrome, Thomsen Disease, Thoracic Outlet Syndrome, Thyrotoxic Myopathy, Tic Douloureux, Todd&#39;s Paralysis, Tourette Syndrome, Transient Ischemic Attack, Transmissible Spongiform Encephalopathies, Transverse Myelitis, Traumatic Brain Injury, Tremor, Trigeminal Neuralgia, Tropical Spastic Paraparesis, Tuberous Sclerosis, Vascular Erectile Tumor, Vasculitis including Temporal Arteritis, Von Economo&#39;s Disease, Von Hippel-Lindau disease (VHL), Von Recklinghausen&#39;s Disease, Wallenberg&#39;s Syndrome, Werdnig-Hoffman Disease, Wernicke-Korsakoff Syndrome, West Syndrome, Whipple&#39;s Disease, Williams Syndrome, Wilson&#39;s Disease, X-Linked Spinal and Bulbar Muscular Atrophy, and Zellweger Syndrome.  
      By “infectious disease” is meant any disease, condition, trait, genotype or phenotype associated with an infectious agent, such as a virus, bacteria, fungus, prion, or parasite. Non-limiting examples of various viral genes that can be targeted using siNA molecules of the invention include Hepatitis C Virus (HCV, for example Genbank Accession Nos: D11168, D50483.1, L38318 and S82227), Hepatitis B Virus (HBV, for example GenBank Accession No. AF100308.1), Human Immunodeficiency Virus type 1 (HIV-1, for example GenBank Accession No. U51188), Human Immunodeficiency Virus type 2 (HIV-2, for example GenBank Accession No. X60667), West Nile Virus (WNV for example GenBank accession No. NC — 001563), cytomegalovirus (CMV for example GenBank Accession No. NC — 001347), respiratory syncytial virus (RSV for example GenBank Accession No. NC — 001781), influenza virus (for example GenBank Accession No. AF037412, rhinovirus (for example, GenBank accession numbers: D00239, X02316, X01087, L24917, M16248, K02121, X01087), papillomavirus (for example GenBank Accession No. NC — 001353), Herpes Simplex Virus (HSV for example GenBank Accession No. NC — 001345), and other viruses such as HTLV (for example GenBank Accession No. AJ430458). Due to the high sequence variability of many viral genomes, selection of siNA molecules for broad therapeutic applications would likely involve the conserved regions of the viral genome. Nonlimiting examples of conserved regions of the viral genomes include but are not limited to 5′-Non Coding Regions (NCR), 3′-Non Coding Regions (NCR) and/or internal ribosome entry sites (IRES). siNA molecules designed against conserved regions of various viral genomes will enable efficient inhibition of viral replication in diverse patient populations and may ensure the effectiveness of the siNA molecules against viral quasi species which evolve due to mutations in the non-conserved regions of the viral genome. Non-limiting examples of bacterial infections include Actinomycosis, Anthrax, Aspergillosis, Bacteremia, Bacterial Infections and Mycoses,  Bartonella  Infections, Botulism, Brucellosis,  Burkholderia  Infections,  Campylobacter  Infections, Candidiasis, Cat-Scratch Disease,  Chlamydia  Infections, Cholera,  Clostridium  Infections, Coccidioidomycosis, Cross Infection, Cryptococcosis, Dermatomycoses, Dermatomycoses, Diphtheria, Ehrlichiosis,  Escherichia coli  Infections, Fasciitis, Necrotizing,  Fusobacterium  Infections, Gas Gangrene, Gram-Negative Bacterial Infections, Gram-Positive Bacterial Infections, Histoplasmosis, Impetigo,  Klebsiella  Infections, Legionellosis, Leprosy, Leptospirosis,  Listeria  Infections, Lyme Disease, Maduromycosis, Melioidosis,  Mycobacterium  Infections,  Mycoplasma  Infections, Mycoses,  Nocardia  Infections, Onychomycosis, Ornithosis, Plague, Pneumococcal Infections,  Pseudomonas  Infections, Q Fever, Rat-Bite Fever, Relapsing Fever, Rheumatic Fever,  Rickettsia  Infections, Rocky Mountain Spotted Fever,  Salmonella  Infections, Scarlet Fever, Scrub Typhus, Sepsis, Sexually Transmitted Diseases—Bacterial, Bacterial Skin Diseases, Staphylococcal Infections, Streptococcal Infections, Tetanus, Tick-Borne Diseases, Tuberculosis, Tularemia, Typhoid Fever, Typhus, Epidemic Louse-Borne,  Vibrio  Infections, Yaws,  Yersinia  Infections, Zoonoses, and Zygomycosis. Non-limiting examples of fungal infections include Aspergillosis, Blastomycosis, Coccidioidomycosis, Cryptococcosis, Fungal Infections of Fingernails and Toenails, Fungal Sinusitis, Histoplasmosis, Histoplasmosis, Mucormycosis, Nail Fungal Infection, Paracoccidioidomycosis, Sporotrichosis, Valley Fever (Coccidioidomycosis), and Mold Allergy.  
      In one embodiment of the present invention, each sequence of a siNA molecule of the invention is independently about 18 to about 24 nucleotides in length, in specific embodiments about 18, 19, 20, 21, 22, 23, or 24 nucleotides in length. In another embodiment, the siNA duplexes of the invention independently comprise about 17 to about 23 base pairs (e.g., about 17, 18, 19, 20, 21, 22, or 23). In yet another embodiment, siNA molecules of the invention comprising hairpin or circular structures are about 35 to about 55 (e.g., about 35, 40, 45, 50 or 55) nucleotides in length, or about 38 to about 44 (e.g., about 38, 39, 40, 41, 42, 43, or 44) nucleotides in length and comprising about 16 to about 22 (e.g., about 16, 17, 18, 19, 20, 21 or 22) base pairs. Exemplary siNA molecules of the invention are shown in Table II. Exemplary synthetic siNA molecules of the invention are shown in Table III and/or  FIGS. 4-5 .  
      As used herein “cell” is used in its usual biological sense, and does not refer to an entire multicellular organism, e.g., specifically does not refer to a human. The cell can be present in an organism, e.g., birds, plants and mammals such as humans, cows, sheep, apes, monkeys, swine, dogs, and cats. The cell can be prokaryotic (e.g., bacterial cell) or eukaryotic (e.g., mammalian or plant cell). The cell can be of somatic or germ line origin, totipotent or pluripotent, dividing or non-dividing. The cell can also be derived from or can comprise a gamete or embryo, a stem cell, or a fully differentiated cell.  
      The siNA molecules of the invention are added directly, or can be complexed with cationic lipids, packaged within liposomes, or otherwise delivered to target cells or tissues. The nucleic acid or nucleic acid complexes can be locally administered to relevant tissues ex vivo, or in vivo through direct dermal application, transdermal application, or injection, with or without their incorporation in biopolymers. In particular embodiments, the nucleic acid molecules of the invention comprise sequences shown in Tables II-III and/or  FIGS. 4-5 . Examples of such nucleic acid molecules consist essentially of sequences defined in these tables and figures. Furthermore, the chemically modified constructs described in Table IV can be applied to any siNA sequence of the invention.  
      In another aspect, the invention provides mammalian cells containing one or more siNA molecules of this invention. The one or more siNA molecules can independently be targeted to the same or different sites.  
      By “RNA” is meant a molecule comprising at least one ribonucleotide residue. By “ribonucleotide” is meant a nucleotide with a hydroxyl group at the 2′ position of a β-D-ribofuranose moiety. The terms include double-stranded RNA, single-stranded RNA, isolated RNA such as partially purified RNA, essentially pure RNA, synthetic RNA, recombinantly produced RNA, as well as altered RNA that differs from naturally occurring RNA by the addition, deletion, substitution and/or alteration of one or more nucleotides. Such alterations can include addition of non-nucleotide material, such as to the end(s) of the siNA or internally, for example at one or more nucleotides of the RNA. Nucleotides in the RNA molecules of the instant invention can also comprise non-standard nucleotides, such as non-naturally occurring nucleotides or chemically synthesized nucleotides or deoxynucleotides. These altered RNAs can be referred to as analogs or analogs of naturally-occurring RNA.  
      By “subject” is meant an organism, which is a donor or recipient of explanted cells or the cells themselves. “Subject” also refers to an organism to which the nucleic acid molecules of the invention can be administered. A subject can be a mammal or mammalian cells, including a human or human cells.  
      The term “phosphorothioate” as used herein refers to an internucleotide linkage having Formula I, wherein Z and/or W comprise a sulfur atom. Hence, the term phosphorothioate refers to both phosphorothioate and phosphorodithioate internucleotide linkages.  
      The term “phosphonoacetate” as used herein refers to an internucleotide linkage having Formula I, wherein Z and/or W comprise an acetyl or protected acetyl group.  
      The term “thiophosphonoacetate” as used herein refers to an internucleotide linkage having Formula I, wherein Z comprises an acetyl or protected acetyl group and W comprises a sulfur atom or alternately W comprises an acetyl or protected acetyl group and Z comprises a sulfur atom.  
      The term “universal base” as used herein refers to nucleotide base analogs that form base pairs with each of the natural DNA/RNA bases with little discrimination between them. Non-limiting examples of universal bases include C-phenyl, C-naphthyl and other aromatic derivatives, inosine, azole carboxamides, and nitroazole derivatives such as 3-nitropyrrole, 4-nitroindole, 5-nitroindole, and 6-nitroindole as known in the art (see for example Loakes, 2001 , Nucleic Acids Research,  29, 2437-2447).  
      The term “acyclic nucleotide” as used herein refers to any nucleotide having an acyclic ribose sugar, for example where any of the ribose carbons (C1, C2, C3, C4, or C5), are independently or in combination absent from the nucleotide.  
      The nucleic acid molecules of the instant invention, individually, or in combination or in conjunction with other drugs, can be used to for preventing or treating transplant rejection, viral infection (e.g., viral hepatitis, HCV, HBV), inflammatory disease (e.g., cirrhosis, liver disease, psoriasis), autoimmunity (e.g., systemic lupus), neurologic disease, liver disease, brain or spinal cord injury, or other related diseases and conditions in a subject or organism. In one embodiment, siNA molecules of the invention are used in combination with anti-inflammatory agents or immune modulators as are known in the art.  
      For example, the siNA molecules can be administered to a subject or can be administered to other appropriate cells evident to those skilled in the art, individually or in combination with one or more drugs (e.g., statins, hypertensive agents etc.) under conditions suitable for the treatment.  
      In one embodiment, the invention features an expression vector comprising a nucleic acid sequence encoding at least one siNA molecule of the invention, in a manner which allows expression of the siNA molecule. For example, the vector can contain sequence(s) encoding both strands of a siNA molecule comprising a duplex. The vector can also contain sequence(s) encoding a single nucleic acid molecule that is self-complementary and thus forms a siNA molecule. Non-limiting examples of such expression vectors are described in Paul et al., 2002 , Nature Biotechnology,  19, 505; Miyagishi and Taira, 2002 , Nature Biotechnology,  19, 497; Lee et al., 2002 , Nature Biotechnology,  19, 500; and Novina et al., 2002 , Nature Medicine , advance online publication doi: 10.1038/nm725.  
      In another embodiment, the invention features a mammalian cell, for example, a human cell, including an expression vector of the invention.  
      In yet another embodiment, the expression vector of the invention comprises a sequence for a siNA molecule having complementarity to a RNA molecule referred to by a Genbank Accession numbers, for example Genbank Accession Nos. shown in Table I.  
      In one embodiment, an expression vector of the invention comprises a nucleic acid sequence encoding two or more siNA molecules, which can be the same or different.  
      In another aspect of the invention, siNA molecules that interact with target RNA molecules and down-regulate gene encoding target RNA molecules (for example target RNA molecules referred to by Genbank Accession numbers herein) are expressed from transcription units inserted into DNA or RNA vectors. The recombinant vectors can be DNA plasmids or viral vectors. siNA expressing viral vectors can be constructed based on, but not limited to, adeno-associated virus, retrovirus, adenovirus, or alphavirus. The recombinant vectors capable of expressing the siNA molecules can be delivered as described herein, and persist in target cells. Alternatively, viral vectors can be used that provide for transient expression of siNA molecules. Such vectors can be repeatedly administered as necessary. Once expressed, the siNA molecules bind and down-regulate gene function or expression via RNA interference (RNAi). Delivery of siNA expressing vectors can be systemic, such as by intravenous or intramuscular administration, by administration to target cells ex-planted from a subject followed by reintroduction into the subject, or by any other means that would allow for introduction into the desired target cell.  
      By “vectors” is meant any nucleic acid- and/or viral-based technique used to deliver a desired nucleic acid.  
      Other features and advantages of the invention will be apparent from the following description of the preferred embodiments thereof, and from the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows a non-limiting example of a scheme for the synthesis of siNA molecules. The complementary siNA sequence strands, strand 1 and strand 2, are synthesized in tandem and are connected by a cleavable linkage, such as a nucleotide succinate or abasic succinate, which can be the same or different from the cleavable linker used for solid phase synthesis on a solid support. The synthesis can be either solid phase or solution phase, in the example shown, the synthesis is a solid phase synthesis. The synthesis is performed such that a protecting group, such as a dimethoxytrityl group, remains intact on the terminal nucleotide of the tandem oligonucleotide. Upon cleavage and deprotection of the oligonucleotide, the two siNA strands spontaneously hybridize to form a siNA duplex, which allows the purification of the duplex by utilizing the properties of the terminal protecting group, for example by applying a trityl on purification method wherein only duplexes/oligonucleotides with the terminal protecting group are isolated.  
       FIG. 2  shows a MALDI-TOF mass spectrum of a purified siNA duplex synthesized by a method of the invention. The two peaks shown correspond to the predicted mass of the separate siNA sequence strands. This result demonstrates that the siNA duplex generated from tandem synthesis can be purified as a single entity using a simple trityl-on purification methodology.  
       FIG. 3  shows a non-limiting proposed mechanistic representation of target RNA degradation involved in RNAi. Double-stranded RNA (dsRNA), which is generated by RNA-dependent RNA polymerase (RdRP) from foreign single-stranded RNA, for example viral, transposon, or other exogenous RNA, activates the DICER enzyme that in turn generates siNA duplexes. Alternately, synthetic or expressed siNA can be introduced directly into a cell by appropriate means. An active siNA complex forms which recognizes a target RNA, resulting in degradation of the target RNA by the RISC endonuclease complex or in the synthesis of additional RNA by RNA-dependent RNA polymerase (RdRP), which can activate DICER and result in additional siNA molecules, thereby amplifying the RNAi response.  
       FIG. 4A -F shows non-limiting examples of chemically-modified siNA constructs of the present invention. In the figure, N stands for any nucleotide (adenosine, guanosine, cytosine, uridine, or optionally thymidine, for example thymidine can be substituted in the overhanging regions designated by parenthesis (N N). Various modifications are shown for the sense and antisense strands of the siNA constructs.  
       FIG. 4A : The sense strand comprises 21 nucleotides wherein the two terminal 3′-nucleotides are optionally base paired and wherein all nucleotides present are ribonucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. The antisense strand comprises 21 nucleotides, optionally having a 3′-terminal glyceryl moiety wherein the two terminal 3′-nucleotides are optionally complementary to the target RNA sequence, and wherein all nucleotides present are ribonucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. A modified internucleotide linkage, such as a phosphorothioate, phosphorodithioate or other modified internucleotide linkage as described herein, shown as “s”, optionally connects the (N N) nucleotides in the antisense strand.  
       FIG. 4B : The sense strand comprises 21 nucleotides wherein the two terminal 3′-nucleotides are optionally base paired and wherein all pyrimidine nucleotides that may be present are 2′deoxy-2′-fluoro modified nucleotides and all purine nucleotides that may be present are 2′-O-methyl modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. The antisense strand comprises 21 nucleotides, optionally having a 3′-terminal glyceryl moiety and wherein the two terminal 3′-nucleotides are optionally complementary to the target RNA sequence, and wherein all pyrimidine nucleotides that may be present are 2′-deoxy-2′-fluoro modified nucleotides and all purine nucleotides that may be present are 2′-O-methyl modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. A modified internucleotide linkage, such as a phosphorothioate, phosphorodithioate or other modified internucleotide linkage as described herein, shown as “s”, optionally connects the (N N) nucleotides in the sense and antisense strand.  
       FIG. 4C : The sense strand comprises 21 nucleotides having 5′- and 3′-terminal cap moieties wherein the two terminal 3′-nucleotides are optionally base paired and wherein all pyrimidine nucleotides that may be present are 2′-O-methyl or 2′-deoxy-2′-fluoro modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. The antisense strand comprises 21 nucleotides, optionally having a 3′-terminal glyceryl moiety and wherein the two terminal 3′-nucleotides are optionally complementary to the target RNA sequence, and wherein all pyrimidine nucleotides that may be present are 2′-deoxy-2′-fluoro modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. A modified internucleotide linkage, such as a phosphorothioate, phosphorodithioate or other modified internucleotide linkage as described herein, shown as “s”, optionally connects the (N N) nucleotides in the antisense strand.  
       FIG. 4D : The sense strand comprises 21 nucleotides having 5′- and 3′-terminal cap moieties wherein the two terminal 3′-nucleotides are optionally base paired and wherein all pyrimidine nucleotides that may be present are 2′-deoxy-2′-fluoro modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein and wherein and all purine nucleotides that may be present are 2′-deoxy nucleotides. The antisense strand comprises 21 nucleotides, optionally having a 3′-terminal glyceryl moiety and wherein the two terminal 3′-nucleotides are optionally complementary to the target RNA sequence, wherein all pyrimidine nucleotides that may be present are 2′-deoxy-2′-fluoro modified nucleotides and all purine nucleotides that may be present are 2′-O-methyl modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. A modified internucleotide linkage, such as a phosphorothioate, phosphorodithioate or other modified internucleotide linkage as described herein, shown as “s”, optionally connects the (N N) nucleotides in the antisense strand.  
       FIG. 4E : The sense strand comprises 21 nucleotides having 5′- and 3′-terminal cap moieties wherein the two terminal 3′-nucleotides are optionally base paired and wherein all pyrimidine nucleotides that may be present are 2′-deoxy-2′-fluoro modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. The antisense strand comprises 21 nucleotides, optionally having a 3′-terminal glyceryl moiety and wherein the two terminal 3′-nucleotides are optionally complementary to the target RNA sequence, and wherein all pyrimidine nucleotides that may be present are 2′-deoxy-2′-fluoro modified nucleotides and all purine nucleotides that may be present are 2′-O-methyl modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. A modified internucleotide linkage, such as a phosphorothioate, phosphorodithioate or other modified internucleotide linkage as described herein, shown as “s”, optionally connects the (N N) nucleotides in the antisense strand.  
       FIG. 4F : The sense strand comprises 21 nucleotides having 5′- and 3′-terminal cap moieties wherein the two terminal 3′-nucleotides are optionally base paired and wherein all pyrimidine nucleotides that may be present are 2′-deoxy-2′-fluoro modified nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein and wherein and all purine nucleotides that may be present are 2′-deoxy nucleotides. The antisense strand comprises 21 nucleotides, optionally having a 3′-terminal glyceryl moiety and wherein the two terminal 3′-nucleotides are optionally complementary to the target RNA sequence, and having one 3′-terminal phosphorothioate internucleotide linkage and wherein all pyrimidine nucleotides that may be present are 2′-deoxy-2′-fluoro modified nucleotides and all purine nucleotides that may be present are 2′-deoxy nucleotides except for (N N) nucleotides, which can comprise ribonucleotides, deoxynucleotides, universal bases, or other chemical modifications described herein. A modified internucleotide linkage, such as a phosphorothioate, phosphorodithioate or other modified internucleotide linkage as described herein, shown as “s”, optionally connects the (N N) nucleotides in the antisense strand. The antisense strand of constructs A-F comprise sequence complementary to any target nucleic acid sequence of the invention. Furthermore, when a glyceryl moiety (L) is present at the 3′-end of the antisense strand for any construct shown in  FIG. 4A -F, the modified internucleotide linkage is optional.  
       FIG. 5A -F shows non-limiting examples of specific chemically-modified siNA sequences of the invention. A-F applies the chemical modifications described in FIG.  4 A-F to a Fas siNA sequence. Such chemical modifications can be applied to any Fas and/or FasL sequence and/or Fas and/or FasL polymorphism sequence.  
       FIG. 6  shows non-limiting examples of different siNA constructs of the invention. The examples shown (constructs 1, 2, and 3) have 19 representative base pairs; however, different embodiments of the invention include any number of base pairs described herein. Bracketed regions represent nucleotide overhangs, for example comprising about 1, 2, 3, or 4 nucleotides in length, preferably about 2 nucleotides. Constructs 1 and 2 can be used independently for RNAi activity. Construct 2 can comprise a polynucleotide or non-nucleotide linker, which can optionally be designed as a biodegradable linker. In one embodiment, the loop structure shown in construct 2 can comprise a biodegradable linker that results in the formation of construct 1 in vivo and/or in vitro. In another example, construct 3 can be used to generate construct 2 under the same principle wherein a linker is used to generate the active siNA construct 2 in vivo and/or in vitro, which can optionally utilize another biodegradable linker to generate the active siNA construct 1 in vivo and/or in vitro. As such, the stability and/or activity of the siNA constructs can be modulated based on the design of the siNA construct for use in vivo or in vitro and/or in vitro.  
       FIG. 7A -C is a diagrammatic representation of a scheme utilized in generating an expression cassette to generate siNA hairpin constructs.  
       FIG. 7A : A DNA oligomer is synthesized with a 5′-restriction site (R1) sequence followed by a region having sequence identical (sense region of siNA) to a predetermined Fas and/or FasL target sequence, wherein the sense region comprises, for example, about 19, 20, 21, or 22 nucleotides (N) in length, which is followed by a loop sequence of defined sequence (X), comprising, for example, about 3 to about 10 nucleotides.  
       FIG. 7B : The synthetic construct is then extended by DNA polymerase to generate a hairpin structure having self-complementary sequence that will result in a siNA transcript having specificity for a Fas and/or FasL target sequence and having self-complementary sense and antisense regions.  
       FIG. 7C : The construct is heated (for example to about 95° C.) to linearize the sequence, thus allowing extension of a complementary second DNA strand using a primer to the 3′-restriction sequence of the first strand. The double-stranded DNA is then inserted into an appropriate vector for expression in cells. The construct can be designed such that a 3′-terminal nucleotide overhang results from the transcription, for example by engineering restriction sites and/or utilizing a poly-U termination region as described in Paul et al., 2002 , Nature Biotechnology,  29, 505-508.  
       FIG. 8A -C is a diagrammatic representation of a scheme utilized in generating an expression cassette to generate double-stranded siNA constructs.  
       FIG. 8A : A DNA oligomer is synthesized with a 5′-restriction (R1) site sequence followed by a region having sequence identical (sense region of siNA) to a predetermined Fas and/or FasL target sequence, wherein the sense region comprises, for example, about 19, 20, 21, or 22 nucleotides (N) in length, and which is followed by a 3′-restriction site (R2) which is adjacent to a loop sequence of defined sequence (X).  
       FIG. 8B : The synthetic construct is then extended by DNA polymerase to generate a hairpin structure having self-complementary sequence.  
       FIG. 8C : The construct is processed by restriction enzymes specific to R1 and R2 to generate a double-stranded DNA which is then inserted into an appropriate vector for expression in cells. The transcription cassette is designed such that a U6 promoter region flanks each side of the dsDNA which generates the separate sense and antisense strands of the siNA. Poly T termination sequences can be added to the constructs to generate U overhangs in the resulting transcript.  
       FIG. 9A -E is a diagrammatic representation of a method used to determine target sites for siNA mediated RNAi within a particular target nucleic acid sequence, such as messenger RNA.  
       FIG. 9A : A pool of siNA oligonucleotides are synthesized wherein the antisense region of the siNA constructs has complementarity to target sites across the target nucleic acid sequence, and wherein the sense region comprises sequence complementary to the antisense region of the siNA.  
      FIGS.  9 B&amp;C: ( FIG. 9B ) The sequences are pooled and are inserted into vectors such that ( FIG. 9C ) transfection of a vector into cells results in the expression of the siNA.  
       FIG. 9D : Cells are sorted based on phenotypic change that is associated with modulation of the target nucleic acid sequence.  
       FIG. 9E : The siNA is isolated from the sorted cells and is sequenced to identify efficacious target sites within the target nucleic acid sequence.  
       FIG. 10  shows non-limiting examples of different stabilization chemistries (1-10) that can be used, for example, to stabilize the 3′-end of siNA sequences of the invention, including (1) [3-3′]-inverted deoxyribose; (2) deoxyribonucleotide; (3) [5′-3′]-3′-deoxyribonucleotide; (4) [5′-3′]-ribonucleotide; (5) [5′-3′]-3′-O-methyl ribonucleotide; (6) 3′-glyceryl; (7) [3′-5′]-3′-deoxyribonucleotide; (8) [3′-3′]-deoxyribonucleotide; (9) [5′-2′]-deoxyribonucleotide; and (10) [5-3′]-dideoxyribonucleotide. In addition to modified and unmodified backbone chemistries indicated in the figure, these chemistries can be combined with different backbone modifications as described herein, for example, backbone modifications having Formula I. In addition, the 2′-deoxy nucleotide shown 5′ to the terminal modifications shown can be another modified or unmodified nucleotide or non-nucleotide described herein, for example modifications having any of Formulae I-VII or any combination thereof.  
       FIG. 11  shows a non-limiting example of a strategy used to identify chemically modified siNA constructs of the invention that are nuclease resistance while preserving the ability to mediate RNAi activity. Chemical modifications are introduced into the siNA construct based on educated design parameters (e.g. introducing 2′-mofications, base modifications, backbone modifications, terminal cap modifications etc). The modified construct in tested in an appropriate system (e.g. human serum for nuclease resistance, shown, or an animal model for PK/delivery parameters). In parallel, the siNA construct is tested for RNAi activity, for example in a cell culture system such as a luciferase reporter assay). Lead siNA constructs are then identified which possess a particular characteristic while maintaining RNAi activity, and can be further modified and assayed once again. This same approach can be used to identify siNA-conjugate molecules with improved pharmacokinetic profiles, delivery, and RNAi activity.  
       FIG. 12  shows non-limiting examples of phosphorylated siNA molecules of the invention, including linear and duplex constructs and asymmetric derivatives thereof.  
       FIG. 13  shows non-limiting examples of chemically modified terminal phosphate groups of the invention.  
       FIG. 14A  shows a non-limiting example of methodology used to design self complementary DFO constructs utilizing palidrome and/or repeat nucleic acid sequences that are identified in a target nucleic acid sequence. (i) A palindrome or repeat sequence is identified in a nucleic acid target sequence. (ii) A sequence is designed that is complementary to the target nucleic acid sequence and the palindrome sequence. (iii) An inverse repeat sequence of the non-palindrome/repeat portion of the complementary sequence is appended to the 3′-end of the complementary sequence to generate a self complementary DFO molecule comprising sequence complementary to the nucleic acid target. (iv) The DFO molecule can self-assemble to form a double stranded oligonucleotide.  FIG. 14B  shows a non-limiting representative example of a duplex forming oligonucleotide sequence.  FIG. 14C  shows a non-limiting example of the self assembly schematic of a representative duplex forming oligonucleotide sequence.  FIG. 14D  shows a non-limiting example of the self assembly schematic of a representative duplex forming oligonucleotide sequence followed by interaction with a target nucleic acid sequence resulting in modulation of gene expression.  
       FIG. 15  shows a non-limiting example of the design of self complementary DFO constructs utilizing palidrome and/or repeat nucleic acid sequences that are incorporated into the DFO constructs that have sequence complementary to any target nucleic acid sequence of interest. Incorporation of these palindrome/repeat sequences allow the design of DFO constructs that form duplexes in which each strand is capable of mediating modulation of target gene expression, for example by RNAi. First, the target sequence is identified. A complementary sequence is then generated in which nucleotide or non-nucleotide modifications (shown as X or Y) are introduced into the complementary sequence that generate an artificial palindrome (shown as XYXYXY in the Figure). An inverse repeat of the non-palindrome/repeat complementary sequence is appended to the 3′-end of the complementary sequence to generate a self complementary DFO comprising sequence complementary to the nucleic acid target. The DFO can self-assemble to form a double stranded oligonucleotide.  
       FIG. 16  shows non-limiting examples of multifunctional siNA molecules of the invention comprising two separate polynucleotide sequences that are each capable of mediating RNAi directed cleavage of differing target nucleic acid sequences.  FIG. 16A  shows a non-limiting example of a multifunctional siNA molecule having a first region that is complementary to a first target nucleic acid sequence (complementary region 1) and a second region that is complementary to a second target nucleic acid sequence (complementary region 2), wherein the first and second complementary regions are situated at the 3′-ends of each polynucleotide sequence in the multifunctional siNA. The dashed portions of each polynucleotide sequence of the multifunctional siNA construct have complementarity with regard to corresponding portions of the siNA duplex, but do not have complementarity to the target nucleic acid sequences.  FIG. 16B  shows a non-limiting example of a multifunctional siNA molecule having a first region that is complementary to a first target nucleic acid sequence (complementary region 1) and a second region that is complementary to a second target nucleic acid sequence (complementary region 2), wherein the first and second complementary regions are situated at the 5′-ends of each polynucleotide sequence in the multifunctional siNA. The dashed portions of each polynucleotide sequence of the multifunctional siNA construct have complementarity with regard to corresponding portions of the siNA duplex, but do not have complementarity to the target nucleic acid sequences.  
       FIG. 17  shows non-limiting examples of multifunctional siNA molecules of the invention comprising a single polynucleotide sequence comprising distinct regions that are each capable of mediating RNAi directed cleavage of differing target nucleic acid sequences.  FIG. 17A  shows a non-limiting example of a multifunctional siNA molecule having a first region that is complementary to a first target nucleic acid sequence (complementary region 1) and a second region that is complementary to a second target nucleic acid sequence (complementary region 2), wherein the second complementary region is situated at the 3′-end of the polynucleotide sequence in the multifunctional siNA. The dashed portions of each polynucleotide sequence of the multifunctional siNA construct have complementarity with regard to corresponding portions of the siNA duplex, but do not have complementarity to the target nucleic acid sequences.  FIG. 17B  shows a non-limiting example of a multifunctional siNA molecule having a first region that is complementary to a first target nucleic acid sequence (complementary region 1) and a second region that is complementary to a second target nucleic acid sequence (complementary region 2), wherein the first complementary region is situated at the 5′-end of the polynucleotide sequence in the multifunctional siNA. The dashed portions of each polynucleotide sequence of the multifunctional siNA construct have complementarity with regard to corresponding portions of the siNA duplex, but do not have complementarity to the target nucleic acid sequences. In one embodiment, these multifunctional siNA constructs are processed in vivo or in vitro to generate multifunctional siNA constructs as shown in  FIG. 16 .  
       FIG. 18  shows non-limiting examples of multifunctional siNA molecules of the invention comprising two separate polynucleotide sequences that are each capable of mediating RNAi directed cleavage of differing target nucleic acid sequences and wherein the multifunctional siNA construct further comprises a self complementary, palindrome, or repeat region, thus enabling shorter bifunctional siNA constructs that can mediate RNA interference against differing target nucleic acid sequences.  FIG. 18A  shows a non-limiting example of a multifunctional siNA molecule having a first region that is complementary to a first target nucleic acid sequence (complementary region 1) and a second region that is complementary to a second target nucleic acid sequence (complementary region 2), wherein the first and second complementary regions are situated at the 3′-ends of each polynucleotide sequence in the multifunctional siNA, and wherein the first and second complementary regions further comprise a self complementary, palindrome, or repeat region. The dashed portions of each polynucleotide sequence of the multifunctional siNA construct have complementarity with regard to corresponding portions of the siNA duplex, but do not have complementarity to the target nucleic acid sequences.  FIG. 18B  shows a non-limiting example of a multifunctional siNA molecule having a first region that is complementary to a first target nucleic acid sequence (complementary region 1) and a second region that is complementary to a second target nucleic acid sequence (complementary region 2), wherein the first and second complementary regions are situated at the 5′-ends of each polynucleotide sequence in the multifunctional siNA, and wherein the first and second complementary regions further comprise a self complementary, palindrome, or repeat region. The dashed portions of each polynucleotide sequence of the multifunctional siNA construct have complementarity with regard to corresponding portions of the siNA duplex, but do not have complementarity to the target nucleic acid sequences.  
       FIG. 19  shows non-limiting examples of multifunctional siNA molecules of the invention comprising a single polynucleotide sequence comprising distinct regions that are each capable of mediating RNAi directed cleavage of differing target nucleic acid sequences and wherein the multifunctional siNA construct further comprises a self complementary, palindrome, or repeat region, thus enabling shorter bifunctional siNA constructs that can mediate RNA interference against differing target nucleic acid sequences.  FIG. 19A  shows a non-limiting example of a multifunctional siNA molecule having a first region that is complementary to a first target nucleic acid sequence (complementary region 1) and a second region that is complementary to a second target nucleic acid sequence (complementary region 2), wherein the second complementary region is situated at the 3′-end of the polynucleotide sequence in the multifunctional siNA, and wherein the first and second complementary regions further comprise a self complementary, palindrome, or repeat region. The dashed portions of each polynucleotide sequence of the multifunctional siNA construct have complementarity with regard to corresponding portions of the siNA duplex, but do not have complementarity to the target nucleic acid sequences.  FIG. 19B  shows a non-limiting example of a multifunctional siNA molecule having a first region that is complementary to a first target nucleic acid sequence (complementary region 1) and a second region that is complementary to a second target nucleic acid sequence (complementary region 2), wherein the first complementary region is situated at the 5′-end of the polynucleotide sequence in the multifunctional siNA, and wherein the first and second complementary regions further comprise a self complementary, palindrome, or repeat region. The dashed portions of each polynucleotide sequence of the multifunctional siNA construct have complementarity with regard to corresponding portions of the siNA duplex, but do not have complementarity to the target nucleic acid sequences. In one embodiment, these multifunctional siNA constructs are processed in vivo or in vitro to generate multifunctional siNA constructs as shown in  FIG. 18 .  
       FIG. 20  shows a non-limiting example of how multifunctional siNA molecules of the invention can target two separate target nucleic acid molecules, such as separate RNA molecules encoding differing proteins, for example a cytokine and its corresponding receptor, differing viral strains, a virus and a cellular protein involved in viral infection or replication, or differing proteins involved in a common or divergent biologic pathway that is implicated in the maintenance of progression of disease. Each strand of the multifunctional siNA construct comprises a region having complementarity to separate target nucleic acid molecules. The multifunctional siNA molecule is designed such that each strand of the siNA can be utilized by the RISC complex to initiate RNA interference mediated cleavage of its corresponding target. These design parameters can include destabilization of each end of the siNA construct (see for example Schwarz et al., 2003 , Cell,  115, 199-208). Such destabilization can be accomplished for example by using guanosine-cytidine base pairs, alternate base pairs (e.g., wobbles), or destabilizing chemically modified nucleotides at terminal nucleotide positions as is known in the art.  
       FIG. 21  shows a non-limiting example of how multifunctional siNA molecules of the invention can target two separate target nucleic acid sequences within the same target nucleic acid molecule, such as alternate coding regions of a RNA, coding and non-coding regions of a RNA, or alternate splice variant regions of a RNA. Each strand of the multifunctional siNA construct comprises a region having complementarity to the separate regions of the target nucleic acid molecule. The multifunctional siNA molecule is designed such that each strand of the siNA can be utilized by the RISC complex to initiate RNA interference mediated cleavage of its corresponding target region. These design parameters can include destabilization of each end of the siNA construct (see for example Schwarz et al., 2003 , Cell,  115, 199-208). Such destabilization can be accomplished for example by using guanosine-cytidine base pairs, alternate base pairs (e.g., wobbles), or destabilizing chemically modified nucleotides at terminal nucleotide positions as is known in the art. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Mechanism of Action of Nucleic Acid Molecules of the Invention  
      The discussion that follows discusses the proposed mechanism of RNA interference mediated by short interfering RNA as is presently known, and is not meant to be limiting and is not an admission of prior art. Applicant demonstrates herein that chemically-modified short interfering nucleic acids possess similar or improved capacity to mediate RNAi as do siRNA molecules and are expected to possess improved stability and activity in vivo; therefore, this discussion is not meant to be limiting only to siRNA and can be applied to siNA as a whole. By “improved capacity to mediate RNAi” or “improved RNAi activity” is meant to include RNAi activity measured in vitro and/or in vivo where the RNAi activity is a reflection of both the ability of the siNA to mediate RNAi and the stability of the siNAs of the invention. In this invention, the product of these activities can be increased in vitro and/or in vivo compared to an all RNA siRNA or a siNA containing a plurality of ribonucleotides. In some cases, the activity or stability of the siNA molecule can be decreased (i.e., less than ten-fold), but the overall activity of the siNA molecule is enhanced in vitro and/or in vivo.  
      RNA interference refers to the process of sequence specific post-transcriptional gene silencing in animals mediated by short interfering RNAs (siRNAs) (Fire et al., 1998 , Nature,  391, 806). The corresponding process in plants is commonly referred to as post-transcriptional gene silencing or RNA silencing and is also referred to as quelling in fungi. The process of post-transcriptional gene silencing is thought to be an evolutionarily-conserved cellular defense mechanism used to prevent the expression of foreign genes which is commonly shared by diverse flora and phyla (Fire et al., 1999 , Trends Genet.,  15, 358). Such protection from foreign gene expression may have evolved in response to the production of double-stranded RNAs (dsRNAs) derived from viral infection or the random integration of transposon elements into a host genome via a cellular response that specifically destroys homologous single-stranded RNA or viral genomic RNA. The presence of dsRNA in cells triggers the RNAi response though a mechanism that has yet to be fully characterized. This mechanism appears to be different from the interferon response that results from dsRNA-mediated activation of protein kinase PKR and 2′,5′-oligoadenylate synthetase resulting in non-specific cleavage of mRNA by ribonuclease L.  
      The presence of long dsRNAs in cells stimulates the activity of a ribonuclease III enzyme referred to as Dicer. Dicer is involved in the processing of the dsRNA into short pieces of dsRNA known as short interfering RNAs (siRNAs) (Berstein et al., 2001 , Nature,  409, 363). Short interfering RNAs derived from Dicer activity are typically about 21 to about 23 nucleotides in length and comprise about 19 base pair duplexes. Dicer has also been implicated in the excision of 21- and 22-nucleotide small temporal RNAs (stRNAs) from precursor RNA of conserved structure that are implicated in translational control (Hutvagner et al., 2001 , Science,  293, 834). The RNAi response also features an endonuclease complex containing a siRNA, commonly referred to as an RNA-induced silencing complex (RISC), which mediates cleavage of single-stranded RNA having sequence homologous to the siRNA. Cleavage of the target RNA takes place in the middle of the region complementary to the guide sequence of the siRNA duplex (Elbashir et al., 2001 , Genes Dev.,  15, 188). In addition, RNA interference can also involve small RNA (e.g., micro-RNA or mRNA) mediated gene silencing, presumably though cellular mechanisms that regulate chromatin structure and thereby prevent transcription of target gene sequences (see for example Allshire, 2602 , Science,  297, 1818-1819; Volpe et al., 2002 , Science,  297, 1833-1837; Jenuwein, 2002 , Science,  297, 2215-2218; and Hall et al., 2002 , Science,  297, 2232-2237). As such, siNA molecules of the invention can be used to mediate gene silencing via interaction with RNA transcripts or alternately by interaction with particular gene sequences, wherein such interaction results in gene silencing either at the transcriptional level or post-transcriptional level.  
      RNAi has been studied in a variety of systems. Fire et al., 1998 , Nature,  391, 806, were the first to observe RNAi in  C. elegans . Wianny and Goetz, 1999 , Nature Cell Biol.,  2, 70, describe RNAi mediated by dsRNA in mouse embryos. Hammond et al., 2000 , Nature,  404, 293, describe RNAi in  Drosophila  cells transfected with dsRNA. Elbashir et al., 2001, Nature, 411, 494, describe RNAi induced by introduction of duplexes of synthetic 21-nucleotide RNAs in cultured mammalian cells including human embryonic kidney and HeLa cells. Recent work in  Drosophila  embryonic lysates has revealed certain requirements for siRNA length, structure, chemical composition, and sequence that are essential to mediate efficient RNAi activity. These studies have shown that 21 nucleotide siRNA duplexes are most active when containing two 2-nucleotide 3′-terminal nucleotide overhangs. Furthermore, substitution of one or both siRNA strands with 2′-deoxy or 2′-O-methyl nucleotides abolishes RNAi activity, whereas substitution of 3′-terminal siRNA nucleotides with deoxy nucleotides was shown to be tolerated. Mismatch sequences in the center of the siRNA duplex were also shown to abolish RNAi activity. In addition, these studies also indicate that the position of the cleavage site in the target RNA is defined by the 5′-end of the siRNA guide sequence rather than the 3′-end (Elbashir et al., 2001 , EMBO J.,  20, 6877). Other studies have indicated that a 5′-phosphate on the target-complementary strand of a siRNA duplex is required for siRNA activity and that ATP is utilized to maintain the 5′-phosphate moiety on the siRNA (Nykanen et al., 2001 , Cell,  107, 309); however, siRNA molecules lacking a 5′-phosphate are active when introduced exogenously, suggesting that 5′-phosphorylation of siRNA constructs may occur in vivo.  
      Synthesis of Nucleic Acid Molecules  
      Synthesis of nucleic acids greater than 100 nucleotides in length is difficult using automated methods, and the therapeutic cost of such molecules is prohibitive. In this invention, small nucleic acid motifs (“small” refers to nucleic acid motifs no more than 100 nucleotides in length, preferably no more than 80 nucleotides in length, and most preferably no more than 50 nucleotides in length; e.g., individual siNA oligonucleotide sequences or siNA sequences synthesized in tandem) are preferably used for exogenous delivery. The simple structure of these molecules increases the ability of the nucleic acid to invade targeted regions of protein and/or RNA structure. Exemplary molecules of the instant invention are chemically synthesized, and others can similarly be synthesized.  
      Oligonucleotides (e.g., certain modified oligonucleotides or portions of oligonucleotides lacking ribonucleotides) are synthesized using protocols known in the art, for example as described in Caruthers et al., 1992 , Methods in Enzymology  211, 3-19, Thompson et al., International PCT Publication No. WO 99/54459, Wincott et al., 1995 , Nucleic Acids Res.  23, 2677-2684, Wincott et al., 1997 , Methods Mol. Bio.,  74, 59, Brennan et al., 1998 , Biotechnol Bioeng.,  61, 33-45, and Brennan, U.S. Pat. No. 6,001,311. All of these references are incorporated herein by reference. The synthesis of oligonucleotides makes use of common nucleic acid protecting and coupling groups, such as dimethoxytrityl at the 5′-end, and phosphoramidites at the 3′-end. In a non-limiting example, small scale syntheses are conducted on a 394 Applied Biosystems, Inc. synthesizer using a 0.2 μmol scale protocol with a 2.5 min coupling step for 2′-O-methylated nucleotides and a 45 second coupling step for 2′-deoxy nucleotides or 2′-deoxy-2′-fluoro nucleotides. Table V outlines the amounts and the contact times of the reagents used in the synthesis cycle. Alternatively, syntheses at the 0.2 μmol scale can be performed on a 96-well plate synthesizer, such as the instrument produced by Protogene (Palo Alto, Calif.) with minimal modification to the cycle. A 33-fold excess (60 μL of 0.11 M=6.6 μmol) of 2′-O-methyl phosphoramidite and a 105-fold excess of S-ethyl tetrazole (60 μL of 0.25 M=15 μmol) can be used in each coupling cycle of 2′-O-methyl residues relative to polymer-bound 5′-hydroxyl. A 22-fold excess (40 μL of 0.11 M=4.4 μmol) of deoxy phosphoramidite and a 70-fold excess of S-ethyl tetrazole (40 μL of 0.25 M=10 μmol) can be used in each coupling cycle of deoxy residues relative to polymer-bound 5′-hydroxyl. Average coupling yields on the 394 Applied Biosystems, Inc. synthesizer, determined by colorimetric quantitation of the trityl fractions, are typically 97.5-99%. Other oligonucleotide synthesis reagents for the 394 Applied Biosystems, Inc. synthesizer include the following: detritylation solution is 3% TCA in methylene chloride (ABI); capping is performed with 16% N-methyl imidazole in THF (ABI) and 10% acetic anhydride/10% 2,6-lutidine in THF (ABI); and oxidation solution is 16.9 mM I 2 , 49 mM pyridine, 9% water in THF (PerSeptive Biosystems, Inc.). Burdick &amp; Jackson Synthesis Grade acetonitrile is used directly from the reagent bottle. S-Ethyltetrazole solution (0.25 M in acetonitrile) is made up from the solid obtained from American International Chemical, Inc. Alternately, for the introduction of phosphorothioate linkages, Beaucage reagent (3H-1,2-Benzodithiol-3-one 1,1-dioxide, 0.05 M in acetonitrile) is used.  
      Deprotection of the DNA-based oligonucleotides is performed as follows: the polymer-bound trityl-on oligoribonucleotide is transferred to a 4 mL glass screw top vial and suspended in a solution of 40% aqueous methylamine (1 mL) at 65° C. for 10 minutes. After cooling to −20° C., the supernatant is removed from the polymer support. The support is washed three times with 1.0 mL of EtOH:MeCN:H 2 O/3:1:1, vortexed and the supernatant is then added to the first supernatant. The combined supernatants, containing the oligoribonucleotide, are dried to a white powder.  
      The method of synthesis used for RNA including certain siNA molecules of the invention follows the procedure as described in Usman et al., 1987 , J. Am. Chem. Soc.,  109, 7845; Scaringe et al., 1990 , Nucleic Acids Res.,  18, 5433; and Wincott et al., 1995 , Nucleic Acids Res.  23, 2677-2684 Wincott et al., 1997 , Methods Mol. Bio.,  74, 59, and makes use of common nucleic acid protecting and coupling groups, such as dimethoxytrityl at the 5′-end, and phosphoramidites at the 3′-end. In a non-limiting example, small scale syntheses are conducted on a 394 Applied Biosystems, Inc. synthesizer using a 0.2 μmol scale protocol with a 7.5 min coupling step for alkylsilyl protected nucleotides and a 2.5 min coupling step for 2′-O-methylated nucleotides. Table V outlines the amounts and the contact times of the reagents used in the synthesis cycle. Alternatively, syntheses at the 0.2 μmol scale can be done on a 96-well plate synthesizer, such as the instrument produced by Protogene (Palo Alto, Calif.) with minimal modification to the cycle. A 33-fold excess (60 μL of 0.11 M=6.6 μmol) of 2′-O-methyl phosphoramidite and a 75-fold excess of S-ethyl tetrazole (60 μL of 0.25 M=15 μmol) can be used in each coupling cycle of 2′-O-methyl residues relative to polymer-bound 5′-hydroxyl. A 66-fold excess (120 μL of 0.11 M=13.2 mmol) of alkylsilyl (ribo) protected phosphoramidite and a 150-fold excess of S-ethyl tetrazole (120 μL of 0.25 M=30 μmol) can be used in each coupling cycle of ribo residues relative to polymer-bound 5′-hydroxyl. Average coupling yields on the 394 Applied Biosystems, Inc. synthesizer, determined by colorimetric quantitation of the trityl fractions, are typically 97.5-99%. Other oligonucleotide synthesis reagents for the 394 Applied Biosystems, Inc. synthesizer include the following: detritylation solution is 3% TCA in methylene chloride (ABI); capping is performed with 16% N-methyl imidazole in THF (ABI) and 10% acetic anhydride/10% 2,6-lutidine in THF (ABI); oxidation solution is 16.9 mM I 2, 49  mM pyridine, 9% water in THF (PerSeptive Biosystems, Inc.). Burdick &amp; Jackson Synthesis Grade acetonitrile is used directly from the reagent bottle. S-Ethyltetrazole solution (0.25 M in acetonitrile) is made up from the solid obtained from American International Chemical, Inc. Alternately, for the introduction of phosphorothioate linkages, Beaucage reagent (3H-1,2-Benzodithiol-3-one 1,1-dioxide 0.05 M in acetonitrile) is used.  
      Deprotection of the RNA is performed using either a two-pot or one-pot protocol. For the two-pot protocol, the polymer-bound trityl-on oligoribonucleotide is transferred to a 4 mL glass screw top vial and suspended in a solution of 40% aq. methylamine (1 mL) at 65° C. for 10 min. After cooling to −20° C., the supernatant is removed from the polymer support. The support is washed three times with 1.0 mL of EtOH:MeCN:H 2 O/3:1:1, vortexed and the supernatant is then added to the first supernatant. The combined supernatants, containing the oligoribonucleotide, are dried to a white powder. The base deprotected oligoribonucleotide is resuspended in anhydrous TEA/HF/NMP solution (300 μL of a solution of 1.5 mL N-methylpyrrolidinone, 750 μL TEA and 1 mL TEA.3HF to provide a 1.4 M HF concentration) and heated to 65° C. After 1.5 h, the oligomer is quenched with 1.5 M NH 4 HCO 3 .  
      Alternatively, for the one-pot protocol, the polymer-bound trityl-on oligoribonucleotide is transferred to a 4 mL glass screw top vial and suspended in a solution of 33% ethanolic methylamine/DMSO: 1/1 (0.8 mL) at 65° C. for 15 minutes. The vial is brought to room temperature TEA.3HF (0.1 mL) is added and the vial is heated at 65° C. for 15 minutes. The sample is cooled at −20° C. and then quenched with 1.5 M NH 4 HCO 3 .  
      For purification of the trityl-on oligomers, the quenched NH 4 HCO 3  solution is loaded onto a C-18 containing cartridge that had been prewashed with acetonitrile followed by 50 mM TEAA. After washing the loaded cartridge with water, the RNA is detritylated with 0.5% TFA for 13 minutes. The cartridge is then washed again with water, salt exchanged with 1 M NaCl and washed with water again. The oligonucleotide is then eluted with 30% acetonitrile.  
      The average stepwise coupling yields are typically &gt;98% (Wincott et al., 1995  Nucleic Acids Res.  23, 2677-2684). Those of ordinary skill in the art will recognize that the scale of synthesis can be adapted to be larger or smaller than the example described above including but not limited to 96-well format.  
      Alternatively, the nucleic acid molecules of the present invention can be synthesized separately and joined together post-synthetically, for example, by ligation (Moore et al., 1992 , Science  256, 9923; Draper et al., International PCT publication No. WO 93/23569; Shabarova et al., 1991 , Nucleic Acids Research  19, 4247; Bellon et al., 1997 , Nucleosides  &amp;  Nucleotides,  16, 951; Bellon et al., 1997 , Bioconjugate Chem.  8, 204), or by hybridization following synthesis and/or deprotection.  
      The siNA molecules of the invention can also be synthesized via a tandem synthesis methodology as described in Example 1 herein, wherein both siNA strands are synthesized as a single contiguous oligonucleotide fragment or strand separated by a cleavable linker which is subsequently cleaved to provide separate siNA fragments or strands that hybridize and permit purification of the siNA duplex. The linker can be a polynucleotide linker or a non-nucleotide linker. The tandem synthesis of siNA as described herein can be readily adapted to both multiwell/multiplate synthesis platforms such as 96 well or similarly larger multi-well platforms. The tandem synthesis of siNA as described herein can also be readily adapted to large scale synthesis platforms employing batch reactors, synthesis columns and the like.  
      A siNA molecule can also be assembled from two distinct nucleic acid strands or fragments wherein one fragment includes the sense region and the second fragment includes the antisense region of the RNA molecule.  
      The nucleic acid molecules of the present invention can be modified extensively to enhance stability by modification with nuclease resistant groups, for example, 2′-amino, 2′-C-allyl, 2′-fluoro, 2′-O-methyl, 2′-H (for a review see Usman and Cedergren, 1992 , TIBS  17, 34; Usman et al., 1994 , Nucleic Acids Symp. Ser.  31, 163). siNA constructs can be purified by gel electrophoresis using general methods or can be purified by high pressure liquid chromatography (HPLC; see Wincott et al., supra, the totality of which is hereby incorporated herein by reference) and re-suspended in water.  
      In another aspect of the invention, siNA molecules of the invention are expressed from transcription units inserted into DNA or RNA vectors. The recombinant vectors can be DNA plasmids or viral vectors. siNA expressing viral vectors can be constructed based on, but not limited to, adeno-associated virus, retrovirus, adenovirus, or alphavirus. The recombinant vectors capable of expressing the siNA molecules can be delivered as described herein, and persist in target cells. Alternatively, viral vectors can be used that provide for transient expression of siNA molecules.  
      Optimizing Activity of the Nucleic Acid Molecule of the Invention.  
      Chemically synthesizing nucleic acid molecules with modifications (base, sugar and/or phosphate) can prevent their degradation by serum ribonucleases, which can increase their potency (see e.g., Eckstein et al., International Publication No. WO 92/07065; Perrault et al., 1990  Nature  344, 565; Pieken et al., 1991 , Science  253, 314; Usman and Cedergren, 1992 , Trends in Biochem. Sci.  17, 334; Usman et al., International Publication No. WO 93/15187; and Rossi et al., International Publication No. WO 91/03162; Sproat, U.S. Pat. No. 5,334,711; Gold et al., U.S. Pat. No. 6,300,074; and Burgin et al., supra; all of which are incorporated by reference herein). All of the above references describe various chemical modifications that can be made to the base, phosphate and/or sugar moieties of the nucleic acid molecules described herein. Modifications that enhance their efficacy in cells, and removal of bases from nucleic acid molecules to shorten oligonucleotide synthesis times and reduce chemical requirements are desired.  
      There are several examples in the art describing sugar, base and phosphate modifications that can be introduced into nucleic acid molecules with significant enhancement in their nuclease stability and efficacy. For example, oligonucleotides are modified to enhance stability and/or enhance biological activity by modification with nuclease resistant groups, for example, 2′-amino, 2′-C-allyl, 2′-fluoro, 2′-O-methyl, 2′-O-allyl, 2′-H, nucleotide base modifications (for a review see Usman and Cedergren, 1992 , TIBS.  17, 34; Usman et al., 1994 , Nucleic Acids Symp. Ser.  31, 163; Burgin et al., 1996 , Biochemistry,  35, 14090). Sugar modification of nucleic acid molecules have been extensively described in the art (see Eckstein et al., International Publication PCT No. WO 92/07065; Perrault et al.  Nature,  1990, 344, 565-568; Pieken et al.  Science,  1991, 253, 314-317; Usman and Cedergren,  Trends in Biochem. Sci.,  1992, 17, 334-339; Usman et al. International Publication PCT No. WO 93/15187; Sproat, U.S. Pat. No. 5,334,711 and Beigelman et al., 1995 , J. Biol. Chem.,  270, 25702; Beigelman et al., International PCT publication No. WO 97/26270; Beigelman et al., U.S. Pat. No. 5,716,824; Usman et al., U.S. Pat. No. 5,627,053; Woolf et al., International PCT Publication No. WO 98/13526; Thompson et al., U.S. Ser. No. 60/082,404 which was filed on Apr. 20, 1998; Karpeisky et al., 1998 , Tetrahedron Lett.,  39, 1131; Earnshaw and Gait, 1998 , Biopolymers  ( Nucleic Acid Sciences ), 48, 39-55; Verma and Eckstein, 1998 , Annu. Rev. Biochem.,  67, 99-134; and Burlina et al., 1997 , Bioorg. Med. Chem.,  5, 1999-2010; all of the references are hereby incorporated in their totality by reference herein). Such publications describe general methods and strategies to determine the location of incorporation of sugar, base and/or phosphate modifications and the like into nucleic acid molecules without modulating catalysis, and are incorporated by reference herein. In view of such teachings, similar modifications can be used as described herein to modify the siNA nucleic acid molecules of the instant invention so long as the ability of siNA to promote RNAi is cells is not significantly inhibited.  
      While chemical modification of oligonucleotide internucleotide linkages with phosphorothioate, phosphorodithioate, and/or 5′-methylphosphonate linkages improves stability, excessive modifications can cause some toxicity or decreased activity. Therefore, when designing nucleic acid molecules, the amount of these internucleotide linkages should be minimized. The reduction in the concentration of these linkages should lower toxicity, resulting in increased efficacy and higher specificity of these molecules.  
      Short interfering nucleic acid (siNA) molecules having chemical modifications that maintain or enhance activity are provided. Such a nucleic acid is also generally more resistant to nucleases than an unmodified nucleic acid. Accordingly, the in vitro and/or in vivo activity should not be significantly lowered. In cases in which modulation is the goal, therapeutic nucleic acid molecules delivered exogenously should optimally be stable within cells until translation of the target RNA has been modulated long enough to reduce the levels of the undesirable protein. This period of time varies between hours to days depending upon the disease state. Improvements in the chemical synthesis of RNA and DNA (Wincott et al., 1995 , Nucleic Acids Res.  23, 2677; Caruthers et al., 1992 , Methods in Enzymology  211, 3-19 (incorporated by reference herein)) have expanded the ability to modify nucleic acid molecules by introducing nucleotide modifications to enhance their nuclease stability, as described above.  
      In one embodiment, nucleic acid molecules of the invention include one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) G-clamp nucleotides. A G-clamp nucleotide is a modified cytosine analog wherein the modifications confer the ability to hydrogen bond both Watson-Crick and Hoogsteen faces of a complementary guanine within a duplex, see for example Lin and Matteucci, 1998 , J. Am. Chem. Soc.,  120, 8531-8532. A single G-clamp analog substitution within an oligonucleotide can result in substantially enhanced helical thermal stability and mismatch discrimination when hybridized to complementary oligonucleotides. The inclusion of such nucleotides in nucleic acid molecules of the invention results in both enhanced affinity and specificity to nucleic acid targets, complementary sequences, or template strands. In another embodiment, nucleic acid molecules of the invention include one or more (e.g., about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) LNA “locked nucleic acid” nucleotides such as a 2′,4′-C methylene bicyclo nucleotide (see for example Wengel et al., International PCT Publication No. WO 00/66604 and WO 99/14226).  
      In another embodiment, the invention features conjugates and/or complexes of siNA molecules of the invention. Such conjugates and/or complexes can be used to facilitate delivery of siNA molecules into a biological system, such as a cell. The conjugates and complexes provided by the instant invention can impart therapeutic activity by transferring therapeutic compounds across cellular membranes, altering the pharmacokinetics, and/or modulating the localization of nucleic acid molecules of the invention. The present invention encompasses the design and synthesis of novel conjugates and complexes for the delivery of molecules, including, but not limited to, small molecules, lipids, cholesterol, phospholipids, nucleosides, nucleotides, nucleic acids, antibodies, toxins, negatively charged polymers and other polymers, for example proteins, peptides, hormones, carbohydrates, polyethylene glycols, or polyamines, across cellular membranes. In general, the transporters described are designed to be used either individually or as part of a multi-component system, with or without degradable linkers. These compounds are expected to improve delivery and/or localization of nucleic acid molecules of the invention into a number of cell types originating from different tissues, in the presence or absence of serum (see Sullenger and Cech, U.S. Pat. No. 5,854,038). Conjugates of the molecules described herein can be attached to biologically active molecules via linkers that are biodegradable, such as biodegradable nucleic acid linker molecules.  
      The term “biodegradable linker” as used herein, refers to a nucleic acid or non-nucleic acid linker molecule that is designed as a biodegradable linker to connect one molecule to another molecule, for example, a biologically active molecule to a siNA molecule of the invention or the sense and antisense strands of a siNA molecule of the invention. The biodegradable linker is designed such that its stability can be modulated for a particular purpose, such as delivery to a particular tissue or cell type. The stability of a nucleic acid-based biodegradable linker molecule can be modulated by using various chemistries, for example combinations of ribonucleotides, deoxyribonucleotides, and chemically-modified nucleotides, such as 2′-O-methyl, 2′-fluoro, 2′-amino, 2′-O-amino, 2′-C-allyl, 2′-O-allyl, and other 2′-modified or base modified nucleotides. The biodegradable nucleic acid linker molecule can be a dimer, trimer, tetramer or longer nucleic acid molecule, for example, an oligonucleotide of about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 nucleotides in length, or can comprise a single nucleotide with a phosphorus-based linkage, for example, a phosphoramidate or phosphodiester linkage. The biodegradable nucleic acid linker molecule can also comprise nucleic acid backbone, nucleic acid sugar, or nucleic acid base modifications.  
      The term “biodegradable” as used herein, refers to degradation in a biological system, for example enzymatic degradation or chemical degradation.  
      The term “biologically active molecule” as used herein, refers to compounds or molecules that are capable of eliciting or modifying a biological response in a system. Non-limiting examples of biologically active siNA molecules either alone or in combination with other molecules contemplated by the instant invention include therapeutically active molecules such as antibodies, cholesterol, hormones, antivirals, peptides, proteins, chemotherapeutics, small molecules, vitamins, co-factors, nucleosides, nucleotides, oligonucleotides, enzymatic nucleic acids, antisense nucleic acids, triplex forming oligonucleotides, 2,5-A chimeras, siNA, dsRNA, allozymes, aptamers, decoys and analogs thereof. Biologically active molecules of the invention also include molecules capable of modulating the pharmacokinetics and/or pharmacodynamics of other biologically active molecules, for example, lipids and polymers such as polyamines, polyamides, polyethylene glycol and other polyethers.  
      The term “phospholipid” as used herein, refers to a hydrophobic molecule comprising at least one phosphorus group. For example, a phospholipid can comprise a phosphorus-containing group and saturated or unsaturated alkyl group, optionally substituted with OH, COOH, oxo, amine, or substituted or unsubstituted aryl groups.  
      Therapeutic nucleic acid molecules (e.g., siNA molecules) delivered exogenously optimally are stable within cells until reverse transcription of the RNA has been modulated long enough to reduce the levels of the RNA transcript. The nucleic acid molecules are resistant to nucleases in order to function as effective intracellular therapeutic agents. Improvements in the chemical synthesis of nucleic acid molecules described in the instant invention and in the art have expanded the ability to modify nucleic acid molecules by introducing nucleotide modifications to enhance their nuclease stability as described above.  
      In yet another embodiment, siNA molecules having chemical modifications that maintain or enhance enzymatic activity of proteins involved in RNAi are provided. Such nucleic acids are also generally more resistant to nucleases than unmodified nucleic acids. Thus, in vitro and/or in vivo the activity should not be significantly lowered.  
      Use of the nucleic acid-based molecules of the invention will lead to better treatments by affording the possibility of combination therapies (e.g., multiple siNA molecules targeted to different genes; nucleic acid molecules coupled with known small molecule modulators; or intermittent treatment with combinations of molecules, including different motifs and/or other chemical or biological molecules). The treatment of subjects with siNA molecules can also include combinations of different types of nucleic acid molecules, such as enzymatic nucleic acid molecules (ribozymes), allozymes, antisense, 2,5-A oligoadenylate, decoys, and aptamers.  
      In another aspect a siNA molecule of the invention comprises one or more 5′ and/or a 3′-cap structure, for example on only the sense siNA strand, the antisense siNA strand, or both siNA strands.  
      By “cap structure” is meant chemical modifications, which have been incorporated at either terminus of the oligonucleotide (see, for example, Adamic et al., U.S. Pat. No. 5,998,203, incorporated by reference herein). These terminal modifications protect the nucleic acid molecule from exonuclease degradation, and may help in delivery and/or localization within a cell. The cap may be present at the 5′-terminus (5′-cap) or at the 3′-terminal (3′-cap) or may be present on both termini. In non-limiting examples, the 5′-cap includes, but is not limited to, glyceryl, inverted deoxy abasic residue (moiety); 4′,5′-methylene nucleotide; 1-(beta-D-erythrofuranosyl) nucleotide, 4′-thio nucleotide; carbocyclic nucleotide; 1,5-anhydrohexitol nucleotide; L-nucleotides; alpha-nucleotides; modified base nucleotide; phosphorodithioate linkage; threo-pentofuranosyl nucleotide; acyclic 3′,4′-seco nucleotide; acyclic 3,4-dihydroxybutyl nucleotide; acyclic 3,5-dihydroxypentyl nucleotide, 3′-3′-inverted nucleotide moiety; 3′-3′-inverted abasic moiety; 3′-2′-inverted nucleotide moiety; 3′-2′-inverted abasic moiety; 1,4-butanediol phosphate; 3′-phosphoramidate; hexylphosphate; aminohexyl phosphate; 3′-phosphate; 3′-phosphorothioate; phosphorodithioate; or bridging or non-bridging methylphosphonate moiety.  
      Non-limiting examples of the 3′-cap include, but are not limited to, glyceryl, inverted deoxy abasic residue (moiety), 4′,5′-methylene nucleotide; 1-(beta-D-erythrofuranosyl) nucleotide; 4′-thio nucleotide, carbocyclic nucleotide; 5′-amino-alkyl phosphate; 1,3-diamino-2-propyl phosphate; 3-aminopropyl phosphate; 6-aminohexyl phosphate; 1,2-aminododecyl phosphate; hydroxypropyl phosphate; 1,5-anhydrohexitol nucleotide; L-nucleotide; alpha-nucleotide; modified base nucleotide; phosphorodithioate; threo-pentofuranosyl nucleotide; acyclic 3′,4′-seco nucleotide; 3,4-dihydroxybutyl nucleotide; 3,5-dihydroxypentyl nucleotide, 5′-5′-inverted nucleotide moiety; 5′-5′-inverted abasic moiety; 5′-phosphoramidate; 5′-phosphorothioate; 1,4-butanediol phosphate; 5′-amino; bridging and/or non-bridging 5′-phosphoramidate, phosphorothioate and/or phosphorodithioate, bridging or non bridging methylphosphonate and 5′-mercapto moieties (for more details see Beaucage and Iyer, 1993 , Tetrahedron  49, 1925; incorporated by reference herein).  
      By the term “non-nucleotide” is meant any group or compound which can be incorporated into a nucleic acid chain in the place of one or more nucleotide units, including either sugar and/or phosphate substitutions, and allows the remaining bases to exhibit their enzymatic activity. The group or compound is abasic in that it does not contain a commonly recognized nucleotide base, such as adenosine, guanine, cytosine, uracil or thymine and therefore lacks a base at the 1′-position.  
      An “alkyl” group refers to a saturated aliphatic hydrocarbon, including straight-chain, branched-chain, and cyclic alkyl groups. Preferably, the alkyl group has 1 to 12 carbons. More preferably, it is a lower alkyl of from 1 to 7 carbons, more preferably 1 to 4 carbons. The alkyl group can be substituted or unsubstituted. When substituted the substituted group(s) is preferably, hydroxyl, cyano, alkoxy, ═O, ═S, NO 2  or N(CH3) 2 , amino, or SH. The term also includes alkenyl groups that are unsaturated hydrocarbon groups containing at least one carbon-carbon double bond, including straight-chain, branched-chain, and cyclic groups. Preferably, the alkenyl group has 1 to 12 carbons. More preferably, it is a lower alkenyl of from 1 to 7 carbons, more preferably 1 to 4 carbons. The alkenyl group may be substituted or unsubstituted. When substituted the substituted group(s) is preferably, hydroxyl, cyano, alkoxy, ═O, ═S, NO 2 , halogen, N(CH3) 2 , amino, or SH. The term “alkyl” also includes alkynyl groups that have an unsaturated hydrocarbon group containing at least one carbon-carbon triple bond, including straight-chain, branched-chain, and cyclic groups. Preferably, the alkynyl group has 1 to 12 carbons. More preferably, it is a lower alkynyl of from 1 to 7 carbons, more preferably 1 to 4 carbons. The alkynyl group may be substituted or unsubstituted. When substituted the substituted group(s) is preferably, hydroxyl, cyano, alkoxy, ═O, ═S, NO 2  or N(CH3) 2 , amino or SH.  
      Such alkyl groups can also include aryl, alkylaryl, carbocyclic aryl, heterocyclic aryl, amide and ester groups. An “aryl” group refers to an aromatic group that has at least one ring having a conjugated pi electron system and includes carbocyclic aryl, heterocyclic aryl and biaryl groups, all of which may be optionally substituted. The preferred substituent(s) of aryl groups are halogen, trihalomethyl, hydroxyl, SH, OH, cyano, alkoxy, alkyl, alkenyl, alkynyl, and amino groups. An “alkylaryl” group refers to an alkyl group (as described above) covalently joined to an aryl group (as described above). Carbocyclic aryl groups are groups wherein the ring atoms on the aromatic ring are all carbon atoms. The carbon atoms are optionally substituted. Heterocyclic aryl groups are groups having from 1 to 3 heteroatoms as ring atoms in the aromatic ring and the remainder of the ring atoms are carbon atoms. Suitable heteroatoms include oxygen, sulfur, and nitrogen, and include furanyl, thienyl, pyridyl, pyrrolyl, N-lower alkyl pyrrolo, pyrimidyl, pyrazinyl, imidazolyl and the like, all optionally substituted. An “amide” refers to an —C(O)—NH—R, where R is either alkyl, aryl, alkylaryl or hydrogen. An “ester” refers to an —C(O)—OR′, where R is either alkyl, aryl, alkylaryl or hydrogen.  
      By “nucleotide” as used herein is as recognized in the art to include natural bases (standard), and modified bases well known in the art. Such bases are generally located at the 1′ position of a nucleotide sugar moiety. Nucleotides generally comprise a base, sugar and a phosphate group. The nucleotides can be unmodified or modified at the sugar, phosphate and/or base moiety, (also referred to interchangeably as nucleotide analogs, modified nucleotides, non-natural nucleotides, non-standard nucleotides and other; see, for example, Usman and McSwiggen, supra; Eckstein et al., International PCT Publication No. WO 92/07065; Usman et al., International PCT Publication No. WO 93/15187; Uhlman &amp; Peyman, supra, all are hereby incorporated by reference herein). There are several examples of modified nucleic acid bases known in the art as summarized by Limbach et al., 1994 , Nucleic Acids Res.  22, 2183. Some of the non-limiting examples of base modifications that can be introduced into nucleic acid molecules include, inosine, purine, pyridin-4-one, pyridin-2-one, phenyl, pseudouracil, 2, 4, 6-trimethoxy benzene, 3-methyl uracil, dihydrouridine, naphthyl, aminophenyl, 5-alkylcytidines (e.g., 5-methylcytidine), 5-alkyluridines (e.g., ribothymidine), 5-halouridine (e.g., 5-bromouridine) or 6-azapyrimidines or 6-alkylpyrimidines (e.g. 6-methyluridine), propyne, and others (Burgin et al., 1996 , Biochemistry,  35, 14090; Uhlman &amp; Peyman, supra). By “modified bases” in this aspect is meant nucleotide bases other than adenine, guanine, cytosine and uracil at 1′ position or their equivalents.  
      In one embodiment, the invention features modified siNA molecules, with phosphate backbone modifications comprising one or more phosphorothioate, phosphorodithioate, methylphosphonate, phosphotriester, morpholino, amidate carbamate, carboxymethyl, acetamidate, polyamide, sulfonate, sulfonamide, sulfamate, formacetal, thioformacetal, and/or alkylsilyl, substitutions. For a review of oligonucleotide backbone modifications, see Hunziker and Leumann, 1995 , Nucleic Acid Analogues: Synthesis and Properties , in  Modern Synthetic Methods , VCH, 331-417, and Mesmaeker et al., 1994 , Novel Backbone Replacements for Oligonucleotides , in  Carbohydrate Modifications in Antisense Research , ACS, 24-39.  
      By “abasic” is meant sugar moieties lacking a base or having other chemical groups in place of a base at the 1′ position, see for example Adamic et al., U.S. Pat. No. 5,998,203.  
      By “unmodified nucleoside” is meant one of the bases adenine, cytosine, guanine, thymine, or uracil joined to the 1′ carbon of β-D-ribo-furanose.  
      By “modified nucleoside” is meant any nucleotide base which contains a modification in the chemical structure of an unmodified nucleotide base, sugar and/or phosphate. Non-limiting examples of modified nucleotides are shown by Formulae I-VII and/or other modifications described herein.  
      In connection with 2′-modified nucleotides as described for the present invention, by “amino” is meant 2′-NH 2  or 2′-O—NH 2 , which can be modified or unmodified. Such modified groups are described, for example, in Eckstein et al., U.S. Pat. No. 5,672,695 and Matulic-Adamic et al., U.S. Pat. No. 6,248,878, which are both incorporated by reference in their entireties.  
      Various modifications to nucleic acid siNA structure can be made to enhance the utility of these molecules. Such modifications will enhance shelf-life, half-life in vitro, stability, and ease of introduction of such oligonucleotides to the target site, e.g., to enhance penetration of cellular membranes, and confer the ability to recognize and bind to targeted cells.  
      Administration of Nucleic Acid Molecules  
      A siNA molecule of the invention can be adapted for use to prevent or treat transplant/allograft rejection, viral infection (e.g., viral hepatitis, HCV, HBV), inflammatory disease (e.g., cirrhosis, liver disease, psoriasis), autoimmunity (e.g., systemic lupus), neurologic disease, liver disease, brain or spinal cord injury, and any other related trait, disease or condition that is related to or will respond to the levels of Fas and/or FasL in a cell or tissue, alone or in combination with other therapies. For example, a siNA molecule can comprise a delivery vehicle, including liposomes, for administration to a subject, carriers and diluents and their salts, and/or can be present in pharmaceutically acceptable formulations. Methods for the delivery of nucleic acid molecules are described in Akhtar et al., 1992 , Trends Cell Bio.,  2, 139 ; Delivery Strategies for Antisense Oligonucleotide Therapeutics , ed. Akhtar, 1995, Maurer et al., 1999 , Mol. Membr. Biol.,  16, 129-140; Hofland and Huang, 1999 , Handb. Exp. Pharmacol.,  137, 165-192; and Lee et al., 2000 , ACS Symp. Ser.,  752, 184-192, all of which are incorporated herein by reference. Beigelman et al., U.S. Pat. No. 6,395,713 and Sullivan et al., PCT WO 94/02595 further describe the general methods for delivery of nucleic acid molecules. These protocols can be utilized for the delivery of virtually any nucleic acid molecule. Nucleic acid molecules can be administered to cells by a variety of methods known to those of skill in the art, including, but not restricted to, encapsulation in liposomes, by iontophoresis, or by incorporation into other vehicles, such as biodegradable polymers, hydrogels, cyclodextrins (see for example Gonzalez et al., 1999 , Bioconjugate Chem.,  10, 1068-1074; Wang et al., International PCT publication Nos. WO 03/47518 and WO 03/46185), poly(lactic-co-glycolic)acid (PLGA) and PLCA microspheres (see for example U.S. Pat. No. 6,447,796 and US Patent Application Publication No. U.S. 2002130430), biodegradable nanocapsules, and bioadhesive microspheres, or by proteinaceous vectors (O&#39;Hare and Normand, International PCT Publication No. WO 00/53722). In another embodiment, the nucleic acid molecules of the invention can also be formulated or complexed with polyethyleneimine and derivatives thereof, such as polyethyleneimine-polyethyleneglycol-N-acetylgalactosamine (PEI-PEG-GAL) or polyethyleneimine-polyethyleneglycol-tri-N-acetylgalactosamine (PEI-PEG-triGAL) derivatives.  
      In one embodiment, a siNA molecule of the invention is complexed with membrane disruptive agents such as those described in U.S. Patent Application Publication No. 20010007666, incorporated by reference herein in its entirety including the drawings. In another embodiment, the membrane disruptive agent or agents and the siNA molecule are also complexed with a cationic lipid or helper lipid molecule, such as those lipids described in U.S. Pat. No. 6,235,310, incorporated by reference herein in its entirety including the drawings.  
      In one embodiment, a siNA molecule of the invention is complexed with delivery systems as described in U.S. Patent Application Publication No. 2003077829 and International PCT Publication Nos. WO 00/03683 and WO 02/087541, all incorporated by reference herein in their entirety including the drawings.  
      In addition, the invention features the use of methods to deliver the nucleic acid molecules of the instant invention to the central nervous system and/or peripheral nervous system. Experiments have demonstrated the efficient in vivo uptake of nucleic acids by neurons. As an example of local administration of nucleic acids to nerve cells, Sommer et al., 1998 , Antisense Nuc. Acid Drug Dev.,  8, 75, describe a study in which a 15mer phosphorothioate antisense nucleic acid molecule to c-fos is administered to rats via microinjection into the brain. Antisense molecules labeled with tetramethylrhodamine-isothiocyanate (TRITC) or fluorescein isothiocyanate (FITC) were taken up by exclusively by neurons thirty minutes post-injection. A diffuse cytoplasmic staining and nuclear staining was observed in these cells. As an example of systemic administration of nucleic acid to nerve cells, Epa et al., 2000 , Antisense Nuc. Acid Drug Dev.,  10, 469, describe an in vivo mouse study in which beta-cyclodextrin-adamantane-oligonucleotide conjugates were used to target the p75 neurotrophin receptor in neuronally differentiated PC12 cells. Following a two week course of IP administration, pronounced uptake of p75 neurotrophin receptor antisense was observed in dorsal root ganglion (DRG) cells. In addition, a marked and consistent down-regulation of p75 was observed in DRG neurons. Additional approaches to the targeting of nucleic acid to neurons are described in Broaddus et al., 1998 , J. Neurosurg.,  88(4), 734; Karle et al., 1997 , Eur. J. Pharmocol.,  340(2/3), 153; Bannai et al., 1998 , Brain Research,  784(1,2), 304; Rajakumar et al., 1997 , Synapse,  26(3), 199; Wu-pong et al., 1999 , BioPharm,  12(1), 32; Bannai et al., 1998 , Brain Res. Protoc.,  3(1), 83; Simantov et al., 1996 , Neuroscience,  74(1), 39. Nucleic acid molecules of the invention are therefore amenable to delivery to and uptake by cells that express repeat expansion allelic variants for modulation of RE gene expression. The delivery of nucleic acid molecules of the invention, targeting RE is provided by a variety of different strategies. Traditional approaches to CNS delivery that can be used include, but are not limited to, intrathecal and intracerebroventricular administration, implantation of catheters and pumps, direct injection or perfusion at the site of injury or lesion, injection into the brain arterial system, or by chemical or osmotic opening of the blood-brain barrier. Other approaches can include the use of various transport and carrier systems, for example though the use of conjugates and biodegradable polymers. Furthermore, gene therapy approaches, for example as described in Kaplitt et al., U.S. Pat. No. 6,180,613 and Davidson, WO 04/013280, can be used to express nucleic acid molecules in the CNS.  
      In addition, the invention features the use of methods to deliver the nucleic acid molecules of the instant invention to hematopoietic cells, including monocytes and lymphocytes. These methods are described in detail by Hartmann et al., 1998 , J. Phamacol. Exp. Ther.,  285(2), 920-928; Kronenwett et al., 1998 , Blood,  91(3), 852-862; Filion and Phillips, 1997 , Biochim. Biophys. Acta.,  1329(2), 345-356; Ma and Wei, 1996 , Leuk. Res.,  20(11/12), 925-930; and Bongartz et al., 1994 , Nucleic Acids Research,  22(22), 4681-8. Such methods, as described above, include the use of free oligonucleotide, cationic lipid formulations, liposome formulations including pH sensitive liposomes and immunoliposomes, and bioconjugates including oligonucleotides conjugated to fusogenic peptides, for the transfection of hematopoietic cells with oligonucleotides.  
      In one embodiment, the siNA molecules of the invention and formulations or compositions thereof are administered directly or topically (e.g., locally) to the dermis or follicles as is generally known in the art (see for example Brand, 2001 , Curr. Opin. Mol. Ther.,  3, 244-8; Regnier et al., 1998 , J. Drug Target,  5, 275-89; Kanikkannan, 2002 , BioDrugs,  16, 339-47; Wraight et al., 2001 , Pharmacol. Ther.,  90, 89-104; and Preat and Dujardin, 2001, STP PharmaSciences, 11, 57-68.  
      In one embodiment, dermal delivery systems of the invention include, for example, aqueous and nonaqueous gels, creams, multiple emulsions, microemulsions, liposomes, ointments, aqueous and nonaqueous solutions, lotions, aerosols, hydrocarbon bases and powders, and can contain excipients such as solubilizers, permeation enhancers (e.g., fatty acids, fatty acid esters, fatty alcohols and amino acids), and hydrophilic polymers (e.g., polycarbophil and polyvinylpyrolidone). In one embodiment, the pharmaceutically acceptable carrier is a liposome or a transdermal enhancer. Examples of liposomes which can be used in this invention include the following: (1) CellFectin, 1:1.5 (M/M) liposome formulation of the cationic lipid N,NI,NII,NIII-tetramethyl-N,NI,NII,NIII-tetrapalmit-y-spermine and dioleoyl phosphatidylethanolamine (DOPE) (GIBCO BRL); (2) Cytofectin GSV, 2:1 (M/M) liposome formulation of a cationic lipid and DOPE (Glen Research); (3) DOTAP (N-[1-(2,3-dioleoyloxy)-N,N,N-tri-methyl-ammoniummethylsulfate) (Boehringer Manheim); and (4) Lipofectamine, 3:1 (M/M) liposome formulation of the polycationic lipid DOSPA and the neutral lipid DOPE (GIBCO BRL).  
      In one embodiment, transmucosal delivery systems of the invention include patches, tablets, suppositories, pessaries, gels and creams, and can contain excipients such as solubilizers and enhancers (e.g., propylene glycol, bile salts and amino acids), and other vehicles (e.g., polyethylene glycol, fatty acid esters and derivatives, and hydrophilic polymers such as hydroxypropylmethylcellulose and hyaluronic acid).  
      In one embodiment, nucleic acid molecules of the invention are administered to the central nervous system (CNS) or peripheral nervous system (PNS). Experiments have demonstrated the efficient in vivo uptake of nucleic acids by neurons. As an example of local administration of nucleic acids to nerve cells, Sommer et al., 1998 , Antisense Nuc. Acid Drug Dev.,  8, 75, describe a study in which a 15mer phosphorothioate antisense nucleic acid molecule to c-fos is administered to rats via microinjection into the brain. Antisense molecules labeled with tetramethylrhodamine-isothiocyanate (TRITC) or fluorescein isothiocyanate (FITC) were taken up by exclusively by neurons thirty minutes post-injection. A diffuse cytoplasmic staining and nuclear staining was observed in these cells. As an example of systemic administration of nucleic acid to nerve cells, Epa et al., 2000 , Antisense Nuc. Acid Drug Dev.,  10, 469, describe an in vivo mouse study in which beta-cyclodextrin-adamantane-oligonucleotide conjugates were used to target the p75 neurotrophin receptor in neuronally differentiated PC12 cells. Following a two week course of IP administration, pronounced uptake of p75 neurotrophin receptor antisense was observed in dorsal root ganglion (DRG) cells. In addition, a marked and consistent down-regulation of p75 was observed in DRG neurons. Additional approaches to the targeting of nucleic acid to neurons are described in Broaddus et al., 1998 , J. Neurosurg.,  88(4), 734; Karle et al., 1997 , Eur. J. Pharmocol.,  340(2/3), 153; Bannai et al., 1998 , Brain Research,  784(1,2), 304; Rajakumar et al., 1997 , Synapse,  26(3), 199; Wu-pong et al., 1999 , BioPharm,  12(1), 32; Bannai et al., 1998 , Brain Res. Protoc.,  3(1), 83; Simantov et al., 1996 , Neuroscience,  74(1), 39. Nucleic acid molecules of the invention are therefore amenable to delivery to and uptake by cells in the CNS and/or PNS.  
      The delivery of nucleic acid molecules of the invention to the CNS is provided by a variety of different strategies. Traditional approaches to CNS delivery that can be used include, but are not limited to, intrathecal and intracerebroventricular administration, implantation of catheters and pumps, direct injection or perfusion at the site of injury or lesion, injection into the brain arterial system, or by chemical or osmotic opening of the blood-brain barrier. Other approaches can include the use of various transport and carrier systems, for example though the use of conjugates and biodegradable polymers. Furthermore, gene therapy approaches, for example as described in Kaplitt et al., U.S. Pat. No. 6,180,613 and Davidson, WO 04/013280, can be used to express nucleic acid molecules in the CNS.  
      In one embodiment, siNA molecules of the invention are administered to a tissue or tissue explant, for example by bathing or immersing the tissue or tissue explant in an appropriate solution of siNA molecules, or alternately by iontophoresis or other methods as are known in the art.  
      In one embodiment, the nucleic acid molecules of the invention are administered via pulmonary delivery, such as by inhalation of an aerosol or spray dried formulation administered by an inhalation device or nebulizer, providing rapid local uptake of the nucleic acid molecules into relevant pulmonary tissues. Solid particulate compositions containing respirable dry particles of micronized nucleic acid compositions can be prepared by grinding dried or lyophilized nucleic acid compositions, and then passing the micronized composition through, for example, a 400 mesh screen to break up or separate out large agglomerates. A solid particulate composition comprising the nucleic acid compositions of the invention can optionally contain a dispersant which serves to facilitate the formation of an aerosol as well as other therapeutic compounds. A suitable dispersant is lactose, which can be blended with the nucleic acid compound in any suitable ratio, such as a 1 to 1 ratio by weight.  
      Aerosols of liquid particles comprising a nucleic acid composition of the invention can be produced by any suitable means, such as with a nebulizer (see for example U.S. Pat. No. 4,501,729). Nebulizers are commercially available devices which transform solutions or suspensions of an active ingredient into a therapeutic aerosol mist either by means of acceleration of a compressed gas, typically air or oxygen, through a narrow venturi orifice or by means of ultrasonic agitation. Suitable formulations for use in nebulizers comprise the active ingredient in a liquid carrier in an amount of up to 40% w/w preferably less than 20% w/w of the formulation. The carrier is typically water or a dilute aqueous alcoholic solution, preferably made isotonic with body fluids by the addition of, for example, sodium chloride or other suitable salts. Optional additives include preservatives if the formulation is not prepared sterile, for example, methyl hydroxybenzoate, anti-oxidants, flavorings, volatile oils, buffering agents and emulsifiers and other formulation surfactants. The aerosols of solid particles comprising the active composition and surfactant can likewise be produced with any solid particulate aerosol generator. Aerosol generators for administering solid particulate therapeutics to a subject produce particles which are respirable, as explained above, and generate a volume of aerosol containing a predetermined metered dose of a therapeutic composition at a rate suitable for human administration. One illustrative type of solid particulate aerosol generator is an insufflator. Suitable formulations for administration by insufflation include finely comminuted powders which can be delivered by means of an insufflator. In the insufflator, the powder, e.g., a metered dose thereof effective to carry out the treatments described herein, is contained in capsules or cartridges, typically made of gelatin or plastic, which are either pierced or opened in situ and the powder delivered by air drawn through the device upon inhalation or by means of a manually-operated pump. The powder employed in the insufflator consists either solely of the active ingredient or of a powder blend comprising the active ingredient, a suitable powder diluent, such as lactose, and an optional surfactant. The active ingredient typically comprises from 0.1 to 100 w/w of the formulation. A second type of illustrative aerosol generator comprises a metered dose inhaler. Metered dose inhalers are pressurized aerosol dispensers, typically containing a suspension or solution formulation of the active ingredient in a liquified propellant. During use these devices discharge the formulation through a valve adapted to deliver a metered volume to produce a fine particle spray containing the active ingredient. Suitable propellants include certain chlorofluorocarbon compounds, for example, dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane and mixtures thereof. The formulation can additionally contain one or more co-solvents, for example, ethanol, emulsifiers and other formulation surfactants, such as oleic acid or sorbitan trioleate, anti-oxidants and suitable flavoring agents. Other methods for pulmonary delivery are described in, for example U.S. Patent Application No. 20040037780, and U.S. Pat. Nos. 6,592,904; 6,582,728; 6,565,885.  
      In one embodiment, siNA molecules of the invention are formulated or complexed with polyethylenimine (e.g., linear or branched PEI) and/or polyethylenimine derivatives, including for example grafted PEIs such as galactose PEI, cholesterol PEI, antibody derivatized PEI, and polyethylene glycol PEI (PEG-PEI) derivatives thereof (see for example Ogris et al., 2001 , AAPA PharmSci,  3, 1-11; Furgeson et al., 2003, Bioconjugate Chem., 14, 840-847; Kunath et al., 2002, Pharmaceutical Research, 19, 810-817; Choi et al., 2001, Bull. Korean Chem. Soc., 22, 46-52; Bettinger et al., 1999, Bioconjugate Chem., 10, 558-561; Peterson et al., 2002, Bioconjugate Chem., 13, 845-854; Erbacher et al., 1999, Journal of Gene Medicine Preprint, 1, 1-18; Godbey et al., 1999., PNAS USA, 96, 5177-5181; Godbey et al., 1999, Journal of Controlled Release, 60, 149-160; Diebold et al., 1999, Journal of Biological Chemistry, 274, 19087-19094; Thomas and Klibanov, 2002, PNAS USA, 99, 14640-14645; and Sagara, U.S. Pat. No. 6,586,524, incorporated by reference herein.  
      In one embodiment, a siNA molecule of the invention comprises a bioconjugate, for example a nucleic acid conjugate as described in Vargeese et al., U.S. Ser. No. 10/427,160, filed Apr. 30, 2003; U.S. Pat. No. 6,528,631; U.S. Pat. No. 6,335,434; U.S. Pat. No. 6,235,886; U.S. Pat. No. 6,153,737; U.S. Pat. No. 5,214,136; U.S. Pat. No. 5,138,045, all incorporated by reference herein.  
      Thus, the invention features a pharmaceutical composition comprising one or more nucleic acid(s) of the invention in an acceptable carrier, such as a stabilizer, buffer, and the like. The polynucleotides of the invention can be administered (e.g., RNA, DNA or protein) and introduced into a subject by any standard means, with or without stabilizers, buffers, and the like, to form a pharmaceutical composition. When it is desired to use a liposome delivery mechanism, standard protocols for formation of liposomes can be followed. The compositions of the present invention can also be formulated and used as tablets, capsules or elixirs for oral administration, suppositories for rectal administration, sterile solutions, suspensions for injectable administration, and the other compositions known in the art.  
      The present invention also includes pharmaceutically acceptable formulations of the compounds described. These formulations include salts of the above compounds, e.g., acid addition salts, for example, salts of hydrochloric, hydrobromic, acetic acid, and benzene sulfonic acid.  
      A pharmacological composition or formulation refers to a composition or formulation in a form suitable for administration, e.g., systemic administration, into a cell or subject, including for example a human. Suitable forms, in part, depend upon the use or the route of entry, for example oral, transdermal, or by injection. Such forms should not prevent the composition or formulation from reaching a target cell (i.e., a cell to which the negatively charged nucleic acid is desirable for delivery). For example, pharmacological compositions injected into the blood stream should be soluble. Other factors are known in the art, and include considerations such as toxicity and forms that prevent the composition or formulation from exerting its effect.  
      By “systemic administration” is meant in vivo systemic absorption or accumulation of drugs in the blood stream followed by distribution throughout the entire body. Administration routes that lead to systemic absorption include, without limitation: intravenous, subcutaneous, intraperitoneal, inhalation, oral, intrapulmonary and intramuscular. Each of these administration routes exposes the siNA molecules of the invention to an accessible diseased tissue. The rate of entry of a drug into the circulation has been shown to be a function of molecular weight or size. The use of a liposome or other drug carrier comprising the compounds of the instant invention can potentially localize the drug, for example, in certain tissue types, such as the tissues of the reticular endothelial system (RES). A liposome formulation that can facilitate the association of drug with the surface of cells, such as, lymphocytes and macrophages is also useful. This approach can provide enhanced delivery of the drug to target cells by taking advantage of the specificity of macrophage and lymphocyte immune recognition of abnormal cells, such as cancer cells.  
      By “pharmaceutically acceptable formulation” is meant a composition or formulation that allows for the effective distribution of the nucleic acid molecules of the instant invention in the physical location most suitable for their desired activity. Non-limiting examples of agents suitable for formulation with the nucleic acid molecules of the instant invention include: P-glycoprotein inhibitors (such as Pluronic P85), which can enhance entry of drugs into the CNS (Jolliet-Riant and Tillement, 1999 , Fundam. Clin. Pharmacol.,  13, 16-26); biodegradable polymers, such as poly (DL-lactide-coglycolide) microspheres for sustained release delivery after intracerebral implantation (Emerich, D F et al, 1999 , Cell Transplant,  8, 47-58) (Alkermes, Inc. Cambridge, Mass.); and loaded nanoparticles, such as those made of polybutylcyanoacrylate, which can deliver drugs across the blood brain barrier and can alter neuronal uptake mechanisms ( Prog Neuropsychopharmacol Biol Psychiatry,  23, 941-949, 1999). Other non-limiting examples of delivery strategies for the nucleic acid molecules of the instant invention include material described in Boado et al., 1998 , J. Pharm. Sci.,  87, 1308-1315; Tyler et al., 1999 , FEBS Lett.,  421, 280-284; Pardridge et al., 1995 , PNAS USA.,  92, 5592-5596; Boado, 1995 , Adv. Drug Delivery Rev.,  15, 73-107; Aldrian-Herrada et al., 1998 , Nucleic Acids Res.,  26, 4910-4916; and Tyler et al., 1999 , PNAS USA.,  96, 7053-7058.  
      The invention also features the use of the composition comprising surface-modified liposomes containing poly (ethylene glycol) lipids (PEG-modified, or long-circulating liposomes or stealth liposomes). These formulations offer a method for increasing the accumulation of drugs in target tissues. This class of drug carriers resists opsonization and elimination by the mononuclear phagocytic system (MPS or RES), thereby enabling longer blood circulation times and enhanced tissue exposure for the encapsulated drug (Lasic et al.  Chem. Rev.  1995, 95, 2601-2627; Ishiwata et al.,  Chem. Pharm. Bull.  1995, 43, 1005-1011). Such liposomes have been shown to accumulate selectively in tumors, presumably by extravasation and capture in the neovascularized target tissues (Lasic et al.,  Science  1995, 267, 1275-1276; Oku et al., 1995 , Biochim. Biophys. Acta,  1238, 86-90). The long-circulating liposomes enhance the pharmacokinetics and pharmacodynamics of DNA and RNA, particularly compared to conventional cationic liposomes which are known to accumulate in tissues of the MPS (Liu et al.,  J. Biol. Chem.  1995, 42, 24864-24870; Choi et al., International PCT Publication No. WO 96/10391; Ansell et al., International PCT Publication No. WO 96/10390; Holland et al., International PCT Publication No. WO 96/10392). Long-circulating liposomes are also likely to protect drugs from nuclease degradation to a greater extent compared to cationic liposomes, based on their ability to avoid accumulation in metabolically aggressive MPS tissues such as the liver and spleen.  
      The present invention also includes compositions prepared for storage or administration that include a pharmaceutically effective amount of the desired compounds in a pharmaceutically acceptable carrier or diluent. Acceptable carriers or diluents for therapeutic use are well known in the pharmaceutical art, and are described, for example, in  Remington&#39;s Pharmaceutical Sciences , Mack Publishing Co. (A. R. Gennaro edit. 1985), hereby incorporated by reference herein. For example, preservatives, stabilizers, dyes and flavoring agents can be provided. These include sodium benzoate, sorbic acid and esters of p-hydroxybenzoic acid. In addition, antioxidants and suspending agents can be used.  
      A pharmaceutically effective dose is that dose required to prevent, inhibit the occurrence, or treat (alleviate a symptom to some extent, preferably all of the symptoms) of a disease state. The pharmaceutically effective dose depends on the type of disease, the composition used, the route of administration, the type of mammal being treated, the physical characteristics of the specific mammal under consideration, concurrent medication, and other factors that those skilled in the medical arts will recognize. Generally, an amount between 0.1 mg/kg and 100 mg/kg body weight/day of active ingredients is administered dependent upon potency of the negatively charged polymer.  
      The nucleic acid molecules of the invention and formulations thereof can be administered orally, topically, parenterally, by inhalation or spray, or rectally in dosage unit formulations containing conventional non-toxic pharmaceutically acceptable carriers, adjuvants and/or vehicles. The term parenteral as used herein includes percutaneous, subcutaneous, intravascular (e.g., intravenous), intramuscular, or intrathecal injection or infusion techniques and the like. In addition, there is provided a pharmaceutical formulation comprising a nucleic acid molecule of the invention and a pharmaceutically acceptable carrier. One or more nucleic acid molecules of the invention can be present in association with one or more non-toxic pharmaceutically acceptable carriers and/or diluents and/or adjuvants, and if desired other active ingredients. The pharmaceutical compositions containing nucleic acid molecules of the invention can be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsion, hard or soft capsules, or syrups or elixirs.  
      Compositions intended for oral use can be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions can contain one or more such sweetening agents, flavoring agents, coloring agents or preservative agents in order to provide pharmaceutically elegant and palatable preparations. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients that are suitable for the manufacture of tablets. These excipients can be, for example, inert diluents; such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, corn starch, or alginic acid; binding agents, for example starch, gelatin or acacia; and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets can be uncoated or they can be coated by known techniques. In some cases such coatings can be prepared by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monosterate or glyceryl distearate can be employed.  
      Formulations for oral use can also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example peanut oil, liquid paraffin or olive oil.  
      Aqueous suspensions contain the active materials in a mixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydropropyl-methylcellulose, sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents can be a naturally-occurring phosphatide, for example, lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyethylene sorbitan monooleate. The aqueous suspensions can also contain one or more preservatives, for example ethyl, or n-propyl p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose or saccharin.  
      Oily suspensions can be formulated by suspending the active ingredients in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. The oily suspensions can contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents and flavoring agents can be added to provide palatable oral preparations. These compositions can be preserved by the addition of an anti-oxidant such as ascorbic acid.  
      Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents or suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavoring and coloring agents, can also be present.  
      Pharmaceutical compositions of the invention can also be in the form of oil-in-water emulsions. The oily phase can be a vegetable oil or a mineral oil or mixtures of these. Suitable emulsifying agents can be naturally-occurring gums, for example gum acacia or gum tragacanth, naturally-occurring phosphatides, for example soy bean, lecithin, and esters or partial esters derived from fatty acids and hexitol, anhydrides, for example sorbitan monooleate, and condensation products of the said partial esters with ethylene oxide, for example polyoxyethylene sorbitan monooleate. The emulsions can also contain sweetening and flavoring agents.  
      Syrups and elixirs can be formulated with sweetening agents, for example glycerol, propylene glycol, sorbitol, glucose or sucrose. Such formulations can also contain a demulcent, a preservative and flavoring and coloring agents. The pharmaceutical compositions can be in the form of a sterile injectable aqueous or oleaginous suspension. This suspension can be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents that have been mentioned above. The sterile injectable preparation can also be a sterile injectable solution or suspension in a non-toxic parentally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that can be employed are water, Ringer&#39;s solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil can be employed including synthetic mono-or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables.  
      The nucleic acid molecules of the invention can also be administered in the form of suppositories, e.g., for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient that is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials include cocoa butter and polyethylene glycols.  
      Nucleic acid molecules of the invention can be administered parenterally in a sterile medium. The drug, depending on the vehicle and concentration used, can either be suspended or dissolved in the vehicle. Advantageously, adjuvants such as local anesthetics, preservatives and buffering agents can be dissolved in the vehicle.  
      Dosage levels of the order of from about 0.1 mg to about 140 mg per kilogram of body weight per day are useful in the treatment of the above-indicated conditions (about 0.5 mg to about 7 g per subject per day). The amount of active ingredient that can be combined with the carrier materials to produce a single dosage form varies depending upon the host treated and the particular mode of administration. Dosage unit forms generally contain between from about 1 mg to about 500 mg of an active ingredient.  
      It is understood that the specific dose level for any particular subject depends upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, route of administration, and rate of excretion, drug combination and the severity of the particular disease undergoing therapy.  
      For administration to non-human animals, the composition can also be added to the animal feed or drinking water. It can be convenient to formulate the animal feed and drinking water compositions so that the animal takes in a therapeutically appropriate quantity of the composition along with its diet. It can also be convenient to present the composition as a premix for addition to the feed or drinking water.  
      The nucleic acid molecules of the present invention can also be administered to a subject in combination with other therapeutic compounds to increase the overall therapeutic effect. The use of multiple compounds to treat an indication can increase the beneficial effects while reducing the presence of side effects.  
      In one embodiment, the invention comprises compositions suitable for administering nucleic acid molecules of the invention to specific cell types. For example, the asialoglycoprotein receptor (ASGPr) (Wu and Wu, 1987 , J. Biol. Chem.  262, 4429-4432) is unique to hepatocytes and binds branched galactose-terminal glycoproteins, such as asialoorosomucoid (ASOR). In another example, the folate receptor is overexpressed in many cancer cells. Binding of such glycoproteins, synthetic glycoconjugates, or folates to the receptor takes place with an affinity that strongly depends on the degree of branching of the oligosaccharide chain, for example, triatennary structures are bound with greater affinity than biatenarry or monoatennary chains (Baenziger and Fiete, 1980 , Cell,  22, 611-620; Connolly et al., 1982 , J. Biol. Chem.,  257, 939-945). Lee and Lee, 1987 , Glycoconjugate J.,  4, 317-328, obtained this high specificity through the use of N-acetyl-D-galactosamine as the carbohydrate moiety, which has higher affinity for the receptor, compared to galactose. This “clustering effect” has also been described for the binding and uptake of mannosyl-terminating glycoproteins or glycoconjugates (Ponpipom et al., 1981 , J. Med. Chem.,  24, 1388-1395). The use of galactose, galactosamine, or folate based conjugates to transport exogenous compounds across cell membranes can provide a targeted delivery approach to, for example, the treatment of liver disease, cancers of the liver, or other cancers. The use of bioconjugates can also provide a reduction in the required dose of therapeutic compounds required for treatment. Furthermore, therapeutic bioavailability, pharmacodynamics, and pharmacokinetic parameters can be modulated through the use of nucleic acid bioconjugates of the invention. Non-limiting examples of such bioconjugates are described in Vargeese et al., U.S. Ser. No. 10/201,394, filed Aug. 13, 2001; and Matulic-Adamic et al., U.S. Ser. No. 10/151,116, filed May 17, 2002. In one embodiment, nucleic acid molecules of the invention are complexed with or covalently attached to nanoparticles, such as Hepatitis B virus S, M, or L envelope proteins (see for example Yamado et al., 2003 , Nature Biotechnology,  21, 885). In one embodiment, nucleic acid molecules of the invention are delivered with specificity for human tumor cells, specifically non-apoptotic human tumor cells including for example T-cells, hepatocytes, breast carcinoma cells, ovarian carcinoma cells, melanoma cells, intestinal epithelial cells, prostate cells, testicular cells, non-small cell lung cancers, small cell lung cancers, etc.  
      In one embodiment, a siNA molecule of the invention is designed or formulated to specifically target endothelial cells or tumor cells. For example, various formulations and conjugates can be utilized to specifically target endothelial cells or tumor cells, including PEI-PEG-folate, PEI-PEG-RGD, PEI-PEG-biotin, PEI-PEG-cholesterol, and other conjugates known in the art that enable specific targeting to endothelial cells and/or tumor cells.  
      Alternatively, certain siNA molecules of the instant invention can be expressed within cells from eukaryotic promoters (e.g., Izant and Weintraub, 1985 , Science,  229, 345; McGarry and Lindquist, 1986 , Proc. Natl. Acad. Sci., USA  83, 399; Scanlon et al., 1991 , Proc. Natl. Acad. Sci. USA,  88, 10591-5; Kashani-Sabet et al., 1992 , Antisense Res. Dev.,  2, 3-15; Dropulic et al., 1992 , J. Virol.,  66, 1432-41; Weerasinghe et al, 1991 , J. Virol.,  65, 5531-4; Ojwang et al., 1992 , Proc. Natl. Acad. Sci. USA,  89, 10802-6; Chen et al., 1992 , Nucleic Acids Res.,  20, 4581-9; Sarver et al., 1990  Science,  247, 1222-1225; Thompson et al., 1995 , Nucleic Acids Res.,  23, 2259; Good et al., 1997 , Gene Therapy,  4, 45). Those skilled in the art realize that any nucleic acid can be expressed in eukaryotic cells from the appropriate DNA/RNA vector. The activity of such nucleic acids can be augmented by their release from the primary transcript by a enzymatic nucleic acid (Draper et al., PCT WO 93/23569, and Sullivan et al., PCT WO 94/02595; Ohkawa et al., 1992 , Nucleic Acids Symp. Ser.,  27, 15-6; Taira et al., 1991 , Nucleic Acids Res.,  19, 5125-30; Ventura et al., 1993 , Nucleic Acids Res.,  21, 3249-55; Chowrira et al., 1994 , J. Biol. Chem.,  269, 25856).  
      In another aspect of the invention, RNA molecules of the present invention can be expressed from transcription units (see for example Couture et al., 1996 , TIG.,  12, 510) inserted into DNA or RNA vectors. The recombinant vectors can be DNA plasmids or viral vectors. siNA expressing viral vectors can be constructed based on, but not limited to, adeno-associated virus, retrovirus, adenovirus, or alphavirus. In another embodiment, pol III based constructs are used to express nucleic acid molecules of the invention (see for example Thompson, U.S. Pats. Nos. 5,902,880 and 6,146,886). The recombinant vectors capable of expressing the siNA molecules can be delivered as described above, and persist in target cells. Alternatively, viral vectors can be used that provide for transient expression of nucleic acid molecules. Such vectors can be repeatedly administered as necessary. Once expressed, the siNA molecule interacts with the target mRNA and generates an RNAi response. Delivery of siNA molecule expressing vectors can be systemic, such as by intravenous or intra-muscular administration, by administration to target cells ex-planted from a subject followed by reintroduction into the subject, or by any other means that would allow for introduction into the desired target cell (for a review see Couture et al., 1996 , TIG.,  12, 510).  
      In one aspect the invention features an expression vector comprising a nucleic acid sequence encoding at least one siNA molecule of the instant invention. The expression vector can encode one or both strands of a siNA duplex, or a single self-complementary strand that self hybridizes into a siNA duplex. The nucleic acid sequences encoding the siNA molecules of the instant invention can be operably linked in a manner that allows expression of the siNA molecule (see for example Paul et al., 2002 , Nature Biotechnology,  19, 505; Miyagishi and Taira, 2002 , Nature Biotechnology,  19, 497; Lee et al., 2002 , Nature Biotechnology,  19, 500; and Novina et al., 2002 , Nature Medicine , advance online publication doi:10.1038/nm725).  
      In another aspect, the invention features an expression vector comprising: a) a transcription initiation region (e.g., eukaryotic pol I, II or III initiation region); b) a transcription termination region (e.g., eukaryotic pol I, II or III termination region); and c) a nucleic acid sequence encoding at least one of the siNA molecules of the instant invention, wherein said sequence is operably linked to said initiation region and said termination region in a manner that allows expression and/or delivery of the siNA molecule. The vector can optionally include an open reading frame (ORF) for a protein operably linked on the 5′ side or the 3′-side of the sequence encoding the siNA of the invention; and/or an intron (intervening sequences).  
      Transcription of the siNA molecule sequences can be driven from a promoter for eukaryotic RNA polymerase I (pol I), RNA polymerase II (pol II), or RNA polymerase III (pol III). Transcripts from pol II or pol III promoters are expressed at high levels in all cells; the levels of a given pol II promoter in a given cell type depends on the nature of the gene regulatory sequences (enhancers, silencers, etc.) present nearby. Prokaryotic RNA polymerase promoters are also used, providing that the prokaryotic RNA polymerase enzyme is expressed in the appropriate cells (Elroy-Stein and Moss, 1990 , Proc. Natl. Acad. Sci. U S A,  87, 6743-7; Gao and Huang 1993 , Nucleic Acids Res.,  21, 2867-72; Lieber et al., 1993 , Methods Enzymol.,  217, 47-66; Zhou et al., 1990 , Mol. Cell. Biol.,  10, 4529-37). Several investigators have demonstrated that nucleic acid molecules expressed from such promoters can function in mammalian cells (e.g. Kashani-Sabet et al., 1992 , Antisense Res. Dev.,  2, 3-15; Ojwang et al., 1992 , Proc. Natl. Acad. Sci. USA,  89, 10802-6; Chen et al., 1992 , Nucleic Acids Res.,  20, 4581-9; Yu et al., 1993 , Proc. Natl. Acad. Sci. USA,  90, 6340-4; L&#39;Huillier et al., 1992 , EMBO J.,  11, 4411-8; Lisziewicz et al., 1993 , Proc. Natl. Acad. Sci. U.S. A,  90, 8000-4; Thompson et al., 1995 , Nucleic Acids Res.,  23, 2259; Sullenger &amp; Cech, 1993 , Science,  262, 1566). More specifically, transcription units such as the ones derived from genes encoding U6 small nuclear (snRNA), transfer RNA (tRNA) and adenovirus VA RNA are useful in generating high concentrations of desired RNA molecules such as siNA in cells (Thompson et al., supra; Couture and Stinchcomb, 1996, supra; Noonberg et al., 1994 , Nucleic Acid Res.,  22, 2830; Noonberg et al., U.S. Pat. No. 5,624,803; Good et al., 1997 , Gene Ther.,  4, 45; Beigelman et al., International PCT Publication No. WO 96/18736. The above siNA transcription units can be incorporated into a variety of vectors for introduction into mammalian cells, including but not restricted to, plasmid DNA vectors, viral DNA vectors (such as adenovirus or adeno-associated virus vectors), or viral RNA vectors (such as retroviral or alphavirus vectors) (for a review see Couture and Stinchcomb, 1996, supra).  
      In another aspect the invention features an expression vector comprising a nucleic acid sequence encoding at least one of the siNA molecules of the invention in a manner that allows expression of that siNA molecule. The expression vector comprises in one embodiment; a) a transcription initiation region; b) a transcription termination region; and c) a nucleic acid sequence encoding at least one strand of the siNA molecule, wherein the sequence is operably linked to the initiation region and the termination region in a manner that allows expression and/or delivery of the siNA molecule.  
      In another embodiment the expression vector comprises: a) a transcription initiation region; b) a transcription termination region; c) an open reading frame; and d) a nucleic acid sequence encoding at least one strand of a siNA molecule, wherein the sequence is operably linked to the 3′-end of the open reading frame and wherein the sequence is operably linked to the initiation region, the open reading frame and the termination region in a manner that allows expression and/or delivery of the siNA molecule. In yet another embodiment, the expression vector comprises: a) a transcription initiation region; b) a transcription termination region; c) an intron; and d) a nucleic acid sequence encoding at least one siNA molecule, wherein the sequence is operably linked to the initiation region, the intron and the termination region in a manner which allows expression and/or delivery of the nucleic acid molecule.  
      In another embodiment, the expression vector comprises: a) a transcription initiation region; b) a transcription termination region; c) an intron; d) an open reading frame; and e) a nucleic acid sequence encoding at least one strand of a siNA molecule, wherein the sequence is operably linked to the 3′-end of the open reading frame and wherein the sequence is operably linked to the initiation region, the intron, the open reading frame and the termination region in a manner which allows expression and/or delivery of the siNA molecule.  
      Fas and FasL Biology and Biochemistry  
      Fas is a membrane protein belonging to the death receptor family. Cross-linking of Fas by its ligand, FasL, or agonistic anti-Fas antibodies, induces apoptosis of cells expressing Fas on the membrane by triggering a cascade of caspases. Fas is a known inducer of apoptosis and is important in the regulation of several aspects of the immune system, including cytotoxic killing of cells potentially harmful to the organism such as virus-infected or tumor cells. Fas induces apoptosis when bound by FasL.  
      Apoptosis is a morphologically defined form of programmed cell death seen in a variety of circumstances, including immune cell selection, carcinogenesis, and development. Several studies have begun to elucidate the role of Fas and FasL in the apoptotic pathway following ischemic or traumatic injuries and other central nervous system conditions such as neurodegenerative and demyelinating diseases. In a study by Crowe et al., apoptotic cells were found from 6 hours to 3 weeks after injury, especially in the spinal white matter of rats suffering from spinal cord injuries. Both secondary degeneration at the site of spinal cord injury and the chronic demyelination of tracts away from the injury appeared partly due to apoptosis. Crowe et al., 1997 , Nat Med.,  3, 73-6. Likewise, Ertel et al. found that soluble Fas ligand concentrations in cerebrospinal fluid correlated significantly with the severity of brain injuries leading to the conclusion that the Fas-Fas ligand-system may have a pivotal role in causing edema and local tissue destruction in the brain after severe head injury. Ertel et al., 1997 , J. Neuroimmunol.,  80, 93-6. In another study Casha et al found that FAS protein expression in astrocytes, oligodendrocytes and microglia, and some apoptotic glia after spinal cord injury. They found that FAS increased in expression in a temporal course, which mirrored the development of cellular apoptosis. They concluded that axonal degeneration after traumatic spinal cord injury is associated with glial, in particular oligodendroglial, apoptosis and activation of the FAS death receptor pathway might be involved in initiating this process. Casha et al., 2001 , Neuroscience,  103, 203-18. Similarly, Lenzlinger et al. found prolonged intrathecal release of soluble Fas following severe traumatic brain injury in humans. Lenzlinger et al., 2002 , J Neuroimmunol.  2002, 122, 167-74.  
      Because of the central role of Fas and FasL in the mediation of immune and inflammatory responses, modulation of Fas and/or FasL expression and/or activity can provide important functions in therpeutic and diagnostic applications. The use of small interfering nucleic acid molecules targeting Fas and/or FasL therefore provides a class of novel therapeutic agents that can be used in the treatment of inflammatory disease, autoimmune disease, infectious disease, neurologic disease, CNS injury, transplant rejection, or any other disease or condition that responds to modulation Fas and/or FasL genes.  
     EXAMPLES  
      The following are non-limiting examples showing the selection, isolation, synthesis and activity of nucleic acids of the instant invention.  
     Example 1  
     Tandem Synthesis of siNA Constructs  
      Exemplary siNA molecules of the invention are synthesized in tandem using a cleavable linker, for example, a succinyl-based linker. Tandem synthesis as described herein is followed by a one-step purification process that provides RNAi molecules in high yield. This approach is highly amenable to siNA synthesis in support of high throughput RNAi screening, and can be readily adapted to multi-column or multi-well synthesis platforms.  
      After completing a tandem synthesis of a siNA oligo and its complement in which the 5′-terminal dimethoxytrityl (5′-O-DMT) group remains intact (trityl on synthesis), the oligonucleotides are deprotected as described above. Following deprotection, the siNA sequence strands are allowed to spontaneously hybridize. This hybridization yields a duplex in which one strand has retained the 5′-O-DMT group while the complementary strand comprises a terminal 5′-hydroxyl. The newly formed duplex behaves as a single molecule during routine solid-phase extraction purification (Trityl-On purification) even though only one molecule has a dimethoxytrityl group. Because the strands form a stable duplex, this dimethoxytrityl group (or an equivalent group, such as other trityl groups or other hydrophobic moieties) is all that is required to purify the pair of oligos, for example, by using a C18 cartridge.  
      Standard phosphoramidite synthesis chemistry is used up to the point of introducing a tandem linker, such as an inverted deoxy abasic succinate or glyceryl succinate linker (see  FIG. 1 ) or an equivalent cleavable linker. A non-limiting example of linker coupling conditions that can be used includes a hindered base such as diisopropylethylamine (DIPA) and/or DMAP in the presence of an activator reagent such as Bromotripyrrolidinophosphoniumhexaflurorophosphate (PyBrOP). After the linker is coupled, standard synthesis chemistry is utilized to complete synthesis of the second sequence leaving the terminal the 5′-O-DMT intact. Following synthesis, the resulting oligonucleotide is deprotected according to the procedures described herein and quenched with a suitable buffer, for example with 50 mM NaOAc or 1.5M NH 4 H 2 CO 3 .  
      Purification of the siNA duplex can be readily accomplished using solid phase extraction, for example using a Waters C18 SepPak 1 g cartridge conditioned with 1 column volume (CV) of acetonitrile, 2 CV H 2 O, and 2 CV 50 mM NaOAc. The sample is loaded and then washed with 1 CV H 2 O or 50 mM NaOAc. Failure sequences are eluted with 1 CV 14% ACN (Aqueous with 50 mM NaOAc and 50 mM NaCl). The column is then washed, for example with 1 CV H 2 O followed by on-column detritylation, for example by passing 1 CV of 1% aqueous trifluoroacetic acid (TFA) over the column, then adding a second CV of 1% aqueous TFA to the column and allowing to stand for approximately 10 minutes. The remaining TFA solution is removed and the column washed with H 2 O followed by 1 CV 1M NaCl and additional H 2 O. The siNA duplex product is then eluted, for example, using 1 CV 20% aqueous CAN.  
       FIG. 2  provides an example of MALDI-TOF mass spectrometry analysis of a purified siNA construct in which each peak corresponds to the calculated mass of an individual siNA strand of the siNA duplex. The same purified siNA provides three peaks when analyzed by capillary gel electrophoresis (CGE), one peak presumably corresponding to the duplex siNA, and two peaks presumably corresponding to the separate siNA sequence strands. Ion exchange HPLC analysis of the same siNA contract only shows a single peak. Testing of the purified siNA construct using a luciferase reporter assay described below demonstrated the same RNAi activity compared to siNA constructs generated from separately synthesized oligonucleotide sequence strands.  
     Example 2  
     Identification of Potential siNA Target Sites in any RNA Sequence  
      The sequence of an RNA target of interest, such as a viral or human mRNA transcript, is screened for target sites, for example by using a computer folding algorithm. In a non-limiting example, the sequence of a gene or RNA gene transcript derived from a database, such as Genbank, is used to generate siNA targets having complementarity to the target. Such sequences can be obtained from a database, or can be determined experimentally as known in the art. Target sites that are known, for example, those target sites determined to be effective target sites based on studies with other nucleic acid molecules, for example ribozymes or antisense, or those targets known to be associated with a disease or condition such as those sites containing mutations or deletions, can be used to design siNA molecules targeting those sites. Various parameters can be used to determine which sites are the most suitable target sites within the target RNA sequence. These parameters include but are not limited to secondary or tertiary RNA structure, the nucleotide base composition of the target sequence, the degree of homology between various regions of the target sequence, or the relative position of the target sequence within the RNA transcript. Based on these determinations, any number of target sites within the RNA transcript can be chosen to screen siNA molecules for efficacy, for example by using in vitro RNA cleavage assays, cell culture, or animal models. In a non-limiting example, anywhere from 1 to 1000 target sites are chosen within the transcript based on the size of the siNA construct to be used. High throughput screening assays can be developed for screening siNA molecules using methods known in the art, such as with multi-well or multi-plate assays to determine efficient reduction in target gene expression.  
     Example 3  
     Selection of siNA Molecule Target Sites in a RNA  
      The following non-limiting steps can be used to carry out the selection of siNAs targeting a given gene sequence or transcript. 
      1. The target sequence is parsed in silico into a list of all fragments or subsequences of a particular length, for example 23 nucleotide fragments, contained within the target sequence. This step is typically carried out using a custom Perl script, but commercial sequence analysis programs such as Oligo, MacVector, or the GCG Wisconsin Package can be employed as well.     2. In some instances the siNAs correspond to more than one target sequence; such would be the case for example in targeting different transcripts of the same gene, targeting different transcripts of more than one gene, or for targeting both the human gene and an animal homolog. In this case, a subsequence list of a particular length is generated for each of the targets, and then the lists are compared to find matching sequences in each list. The subsequences are then ranked according to the number of target sequences that contain the given subsequence; the goal is to find subsequences that are present in most or all of the target sequences. Alternately, the ranking can identify subsequences that are unique to a target sequence, such as a mutant target sequence. Such an approach would enable the use of siNA to target specifically the mutant sequence and not effect the expression of the normal sequence.     3. In some instances the siNA subsequences are absent in one or more sequences while present in the desired target sequence; such would be the case if the siNA targets a gene with a paralogous family member that is to remain untargeted. As in case 2 above, a subsequence list of a particular length is generated for each of the targets, and then the lists are compared to find sequences that are present in the target gene but are absent in the untargeted paralog.     4. The ranked siNA subsequences can be further analyzed and ranked according to GC content. A preference can be given to sites containing 30-70% GC, with a further preference to sites containing 40-60% GC.     5. The ranked siNA subsequences can be further analyzed and ranked according to self-folding and internal hairpins. Weaker internal folds are preferred; strong hairpin structures are to be avoided.     6. The ranked siNA subsequences can be further analyzed and ranked according to whether they have runs of GGG or CCC in the sequence. GGG (or even more Gs) in either strand can make oligonucleotide synthesis problematic and can potentially interfere with RNAi activity, so it is avoided whenever better sequences are available. CCC is searched in the target strand because that will place GGG in the antisense strand.     7. The ranked siNA subsequences can be further analyzed and ranked according to whether they have the dinucleotide UU (uridine dinucleotide) on the 3′-end of the sequence, and/or AA on the 5′-end of the sequence (to yield 3′ UU on the antisense sequence). These sequences allow one to design siNA molecules with terminal TT thymidine dinucleotides.     8. Four or five target sites are chosen from the ranked list of subsequences as described above. For example, in subsequences having 23 nucleotides, the right 21 nucleotides of each chosen 23-mer subsequence are then designed and synthesized for the upper (sense) strand of the siNA duplex, while the reverse complement of the left 21 nucleotides of each chosen 23-mer subsequence are then designed and synthesized for the lower (antisense) strand of the siNA duplex (see Tables II and III). If terminal TT residues are desired for the sequence (as described in paragraph 7), then the two 3′ terminal nucleotides of both the sense and antisense strands are replaced by TT prior to synthesizing the oligos.     9. The siNA molecules are screened in an in vitro, cell culture or animal model system to identify the most active siNA molecule or the most preferred target site within the target RNA sequence.     10. Other design considerations can be used when selecting target nucleic acid sequences, see for example Reynolds et al., 2004 , Nature Biotechnology Advanced Online Publication,  1 Feb. 2004, doi:10.1038/nbt936 and Ui-Tei et al., 2004, Nucleic Acids Research, 32, doi:10.1093/nar/gkh247.    

      In an alternate approach, a pool of siNA constructs specific to a Fas and/or FasL target sequence is used to screen for target sites in cells expressing Fas and/or FasL RNA, such as cultured PC12 or HepG2 cells. The general strategy used in this approach is shown in  FIG. 9 . A non-limiting example of such is a pool comprising sequences having any of SEQ ID NOS 1-702. Cells expressing Fas and/or FasL (e.g., PC12 or HepG2 cells) are transfected with the pool of siNA constructs and cells that demonstrate a phenotype associated with Fas and/or FasL inhibition are sorted. The pool of siNA constructs can be expressed from transcription cassettes inserted into appropriate vectors (see for example  FIG. 7  and  FIG. 8 ). The siNA from cells demonstrating a positive phenotypic change (e.g., decreased Fas and/or FasL mRNA levels or decreased Fas and/or FasL protein expression), are sequenced to determine the most suitable target site(s) within the target Fas and/or FasL RNA sequence.  
     Example 4  
     Fas and FasL Targeted siNA Design  
      siNA target sites were chosen by analyzing sequences of the Fas and/or FasL RNA target and optionally prioritizing the target sites on the basis of folding (structure of any given sequence analyzed to determine siNA accessibility to the target), by using a library of siNA molecules as described in Example 3, or alternately by using an in vitro siNA system as described in Example 6 herein. siNA molecules were designed that could bind each target and are optionally individually analyzed by computer folding to assess whether the siNA molecule can interact with the target sequence. Varying the length of the siNA molecules can be chosen to optimize activity. Generally, a sufficient number of complementary nucleotide bases are chosen to bind to, or otherwise interact with, the target RNA, but the degree of complementarity can be modulated to accommodate siNA duplexes or varying length or base composition. By using such methodologies, siNA molecules can be designed to target sites within any known RNA sequence, for example those RNA sequences corresponding to the any gene transcript.  
      Chemically modified siNA constructs are designed to provide nuclease stability for systemic administration in vivo and/or improved pharmacokinetic, localization, and delivery properties while preserving the ability to mediate RNAi activity. Chemical modifications as described herein are introduced synthetically using synthetic methods described herein and those generally known in the art. The synthetic siNA constructs are then assayed for nuclease stability in serum and/or cellular/tissue extracts (e.g. liver extracts). The synthetic siNA constructs are also tested in parallel for RNAi activity using an appropriate assay, such as a luciferase reporter assay as described herein or another suitable assay that can quantity RNAi activity. Synthetic siNA constructs that possess both nuclease stability and RNAi activity can be further modified and re-evaluated in stability and activity assays. The chemical modifications of the stabilized active siNA constructs can then be applied to any siNA sequence targeting any chosen RNA and used, for example, in target screening assays to pick lead siNA compounds for therapeutic development (see for example  FIG. 11 ).  
     Example 5  
     Chemical Synthesis and Purification of siNA  
      siNA molecules can be designed to interact with various sites in the RNA message, for example, target sequences within the RNA sequences described herein. The sequence of one strand of the siNA molecule(s) is complementary to the target site sequences described above. The siNA molecules can be chemically synthesized using methods described herein. Inactive siNA molecules that are used as control sequences can be synthesized by scrambling the sequence of the siNA molecules such that it is not complementary to the target sequence. Generally, siNA constructs can by synthesized using solid phase oligonucleotide synthesis methods as described herein (see for example Usman et al., U.S. Pat. Nos. 5,804,683; 5,831,071; 5,998,203; 6,117,657; 6,353,098; 6,362,323; 6,437,117; 6,469,158; Scaringe et al., U.S. Pat. Nos. 6,111,086; 6,008,400; 6,111,086 all incorporated by reference herein in their entirety).  
      In a non-limiting example, RNA oligonucleotides are synthesized in a stepwise fashion using the phosphoramidite chemistry as is known in the art. Standard phosphoramidite chemistry involves the use of nucleosides comprising any of 5′-O-dimethoxytrityl, 2′-O-tert-butyldimethylsilyl, 3′-O-2-Cyanoethyl N,N-diisopropylphos-phoroamidite groups, and exocyclic amine protecting groups (e.g. N6-benzoyl adenosine, N4 acetyl cytidine, and N2-isobutyryl guanosine). Alternately, 2′-O-Silyl Ethers can be used in conjunction with acid-labile 2′-O-orthoester protecting groups in the synthesis of RNA as described by Scaringe supra. Differing 2′ chemistries can require different protecting groups, for example 2′-deoxy-2′-amino nucleosides can utilize N-phthaloyl protection as described by Usman et al., U.S. Pat. No. 5,631,360, incorporated by reference herein in its entirety).  
      During solid phase synthesis, each nucleotide is added sequentially (3′- to 5′-direction) to the solid support-bound oligonucleotide. The first nucleoside at the 3′-end of the chain is covalently attached to a solid support (e.g., controlled pore glass or polystyrene) using various linkers. The nucleotide precursor, a ribonucleoside phosphoramidite, and activator are combined resulting in the coupling of the second nucleoside phosphoramidite onto the 5′-end of the first nucleoside. The support is then washed and any unreacted 5′-hydroxyl groups are capped with a capping reagent such as acetic anhydride to yield inactive 5′-acetyl moieties. The trivalent phosphorus linkage is then oxidized to a more stable phosphate linkage. At the end of the nucleotide addition cycle, the 5′-O-protecting group is cleaved under suitable conditions (e.g., acidic conditions for trityl-based groups and Fluoride for silyl-based groups). The cycle is repeated for each subsequent nucleotide.  
      Modification of synthesis conditions can be used to optimize coupling efficiency, for example by using differing coupling times, differing reagent/phosphoramidite concentrations, differing contact times, differing solid supports and solid support linker chemistries depending on the particular chemical composition of the siNA to be synthesized. Deprotection and purification of the siNA can be performed as is generally described in Usman et al., U.S. Pat. No. 5,831,071, U.S. Pat. No. 6,353,098, U.S. Pat. No. 6,437,117, and Bellon et al., U.S. Pat. No. 6,054,576, U.S. Pat. No. 6,162,909, U.S. Pat. No. 6,303,773, or Scaringe supra, incorporated by reference herein in their entireties. Additionally, deprotection conditions can be modified to provide the best possible yield and purity of siNA constructs. For example, applicant has observed that oligonucleotides comprising 2′-deoxy-2′-fluoro nucleotides can degrade under inappropriate deprotection conditions. Such oligonucleotides are deprotected using aqueous methylamine at about 35° C. for 30 minutes. If the 2′-deoxy-2′-fluoro containing oligonucleotide also comprises ribonucleotides, after deprotection with aqueous methylamine at about 35° C. for 30 minutes, TEA-HF is added and the reaction maintained at about 65° C. for an additional 15 minutes.  
     Example 6  
     RNAi In Vitro Assay to Assess siNA Activity  
      An in vitro assay that recapitulates RNAi in a cell-free system is used to evaluate siNA constructs targeting Fas and/or FasL RNA targets. The assay comprises the system described by Tuschl et al., 1999 , Genes and Development,  13, 3191-3197 and Zamore et al., 2000 , Cell,  101, 25-33 adapted for use with Fas and/or FasL target RNA. A  Drosophila  extract derived from syncytial blastoderm is used to reconstitute RNAi activity in vitro. Target RNA is generated via in vitro transcription from an appropriate Fas and/or FasL expressing plasmid using T7 RNA polymerase or via chemical synthesis as described herein. Sense and antisense siNA strands (for example 20 uM each) are annealed by incubation in buffer (such as 100 mM potassium acetate, 30 mM HEPES-KOH, pH 7.4, 2 mM magnesium acetate) for 1 minute at 90° C. followed by 1 hour at 37° C., then diluted in lysis buffer (for example 100 mM potassium acetate, 30 mM HEPES-KOH at pH 7.4, 2 mM magnesium acetate). Annealing can be monitored by gel electrophoresis on an agarose gel in TBE buffer and stained with ethidium bromide. The  Drosophila  lysate is prepared using zero to two-hour-old embryos from Oregon R flies collected on yeasted molasses agar that are dechorionated and lysed. The lysate is centrifuged and the supernatant isolated. The assay comprises a reaction mixture containing 50% lysate [vol/vol], RNA (10-50 pM final concentration), and 10% [vol/vol] lysis buffer containing siNA (10 nM final concentration). The reaction mixture also contains 10 mM creatine phosphate, 10 ug/ml creatine phosphokinase, 100 um GTP, 100 uM UTP, 100 uM CTP, 500 uM ATP, 5 mM DTT, 0.1 U/uL RNasin (Promega), and 100 uM of each amino acid. The final concentration of potassium acetate is adjusted to 100 mM. The reactions are pre-assembled on ice and preincubated at 25° C. for 10 minutes before adding RNA, then incubated at 25° C. for an additional 60 minutes. Reactions are quenched with 4 volumes of 1.25×Passive Lysis Buffer (Promega). Target RNA cleavage is assayed by RT-PCR analysis or other methods known in the art and are compared to control reactions in which siNA is omitted from the reaction.  
      Alternately, internally-labeled target RNA for the assay is prepared by in vitro transcription in the presence of [alpha- 32 P] CTP, passed over a G 50 Sephadex column by spin chromatography and used as target RNA without further purification. Optionally, target RNA is 5′- 32 P-end labeled using T4 polynucleotide kinase enzyme. Assays are performed as described above and target RNA and the specific RNA cleavage products generated by RNAi are visualized on an autoradiograph of a gel. The percentage of cleavage is determined by PHOSPHOR IMAGER® (autoradiography) quantitation of bands representing intact control RNA or RNA from control reactions without siNA and the cleavage products generated by the assay.  
      In one embodiment, this assay is used to determine target sites the Fas and/or FasL RNA target for siNA mediated RNAi cleavage, wherein a plurality of siNA constructs are screened for RNAi mediated cleavage of the Fas and/or FasL RNA target, for example, by analyzing the assay reaction by electrophoresis of labeled target RNA, or by northern blotting, as well as by other methodology well known in the art.  
     Example 7  
     Nucleic Acid Inhibition of Fas and FasL Target RNA In Vitro  
      siNA molecules targeted to the human Fas and/or FasL RNA are designed and synthesized as described above. These nucleic acid molecules can be tested for cleavage activity in vivo, for example, using the following procedure. The target sequences and the nucleotide location within the Fas and/or FasL RNA are given in Table II and III.  
      Two formats are used to test the efficacy of siNAs targeting Fas and/or FasL. First, the reagents are tested in cell culture using, for example, PC12 or HepG2 cells, to determine the extent of RNA and protein inhibition. siNA reagents (e.g.; see Tables II and III) are selected against the Fas and/or FasL target as described herein. RNA inhibition is measured after delivery of these reagents by a suitable transfection agent to, for example, cultured PC12 or HepG2 cells. Relative amounts of target RNA are measured versus actin using real-time PCR monitoring of amplification (eg., ABI 7700 TAQMAN®). A comparison is made to a mixture of oligonucleotide sequences made to unrelated targets or to a randomized siNA control with the same overall length and chemistry, but randomly substituted at each position. Primary and secondary lead reagents are chosen for the target and optimization performed. After an optimal transfection agent concentration is chosen, a RNA time-course of inhibition is performed with the lead siNA molecule. In addition, a cell-plating format can be used to determine RNA inhibition.  
      Delivery of siNA to Cells  
      Cells (e.g., PC12 or HepG2 cells) are seeded, for example, at 1×10 5  cells per well of a six-well dish in EGM-2 (BioWhittaker) the day before transfection. siNA (final concentration, for example 20 nM) and cationic lipid (e.g., final concentration 2 μg/ml) are complexed in EGM basal media (Bio Whittaker) at 37° C. for 30 minutes in polystyrene tubes. Following vortexing, the complexed siNA is added to each well and incubated for the times indicated. For initial optimization experiments, cells are seeded, for example, at 1×10 3  in 96 well plates and siNA complex added as described. Efficiency of delivery of siNA to cells is determined using a fluorescent siNA complexed with lipid. Cells in 6-well dishes are incubated with siNA for 24 hours, rinsed with PBS and fixed in 2% paraformaldehyde for 15 minutes at room temperature. Uptake of siNA is visualized using a fluorescent microscope.  
      TAQMAN® (Real-Time PCR Monitoring of Amplification) and Lightcycler Quantification of mRNA  
      Total RNA is prepared from cells following siNA delivery, for example, using Qiagen RNA purification kits for 6-well or Rneasy extraction kits for 96-well assays. For TAQMAN® analysis (real-time PCR monitoring of amplification), dual-labeled probes are synthesized with the reporter dye, FAM or JOE, covalently linked at the 5′-end and the quencher dye TAMRA conjugated to the 3′-end. One-step RT-PCR amplifications are performed on, for example, an ABI PRISM 7700 Sequence Detector using 50 ill reactions consisting of 10 μl total RNA, 100 nM forward primer, 900 nM reverse primer, 100 nM probe, 1× TaqMan PCR reaction buffer (PE-Applied Biosystems), 5.5 mM MgCl 2 , 300 μM each dATP, dCTP, dGTP, and dTTP, 10U RNase Inhibitor (Promega), 1.25U AMPLITAQ GOLD® (DNA polymerase) (PE-Applied Biosystems) and 10U M-MLV Reverse Transcriptase (Promega). The thermal cycling conditions can consist of 30 minutes at 48° C., 10 minutes at 95° C., followed by 40 cycles of 15 seconds at 95° C. and 1 minute at 60° C. Quantitation of mRNA levels is determined relative to standards generated from serially diluted total cellular RNA (300, 100, 33, 11 ng/rxn) and normalizing to β-actin or GAPDH mRNA in parallel TAQMAN®(D reactions (real-time PCR monitoring of amplification). For each gene of interest an upper and lower primer and a fluorescently labeled probe are designed. Real time incorporation of SYBR Green I dye into a specific PCR product can be measured in glass capillary tubes using a lightcyler. A standard curve is generated for each primer pair using control cRNA. Values are represented as relative expression to GAPDH in each sample.  
      Western Blotting  
      Nuclear extracts can be prepared using a standard micro preparation technique (see for example Andrews and Faller, 1991 , Nucleic Acids Research,  19, 2499). Protein extracts from supernatants are prepared, for example using TCA precipitation. An equal volume of 20% TCA is added to the cell supernatant, incubated on ice for 1 hour and pelleted by centrifugation for 5 minutes. Pellets are washed in acetone, dried and resuspended in water. Cellular protein extracts are run on a 10% Bis-Tris NuPage (nuclear extracts) or 4-12% Tris-Glycine (supernatant extracts) polyacrylamide gel and transferred onto nitro-cellulose membranes. Non-specific binding can be blocked by incubation, for example, with 5% non-fat milk for 1 hour followed by primary antibody for 16 hour at 4° C. Following washes, the secondary antibody is applied, for example (1:10,000 dilution) for 1 hour at room temperature and the signal detected with SuperSignal reagent (Pierce).  
     Example 8  
     Animal Models Useful to Evaluate the Down-Regulation of Fas and FasL Gene Expression  
      Evaluating the efficacy of anti-Fas/FasL agents in animal models is an important prerequisite to human clinical trials. Zurita et al., 2001 , J Neurosurg.  94(2 Suppl), 257-64, describe an rat model of spinal cord injury in which the authors studied the presence and distribution of CD95 (Fas/APO1)-positive cells in injured spinal cord tissue. The presence and distribution of cells showing positive immunostaining for CD95 (Fas/APO1) were studied at 1, 4, 8, 24, 48, and 72 hours and at 1, 2, and 4 weeks after induction of experimental spinal cork injury in rats. The studies were conducted using a monoclonal antibody to the CD95 (Fas/APO1) protein. CD95 (Fas/APO1) was observed in apoptotic cells, mainly in the gray matter, 1 hour after trauma, and the number of immunostained cells increased for the first 8 hours, at which time the protein was expressed in both gray and white matter. From 24 to 72 hours postinjury, the number of immunostained cells decreased in the gray matter, but increased in the white matter. From then on, there were fewer CD95 (Fas/APO1)-positive cells, but some cells in the white matter still exhibited positive immunostaining 1 and 2 weeks after injury. At 4 weeks, there remained no CD95 (Fas/APO1)-positive cells in injured spinal cord. These findings indicate that CD95 (Fas/APO1) is expressed after spinal cord injury, suggesting a role for this protein in the development of apoptosis after trauma and the possibility of a new therapeutic approach to the treatment of spinal cord injury based on blocking the CD95 (Fas/APO1) system. This animal model can be used to evaluate the efficacy of nucleic acid molecules of the invention targeting Fas/FasL expression (e.g., phenotypic change, RNA and protein expression etc.) toward therapeutic use in treating spinal cord injury.  
      In a more recent study, Demjen et al., 2004 , Nature Medicine,  10, 389-95, investigated neutralization of the activity of CD95 ligand (CD95L) and/or TNF in spinal cord-injured mice. The authors found that therapeutic neutralization of CD95L, but not of TNF, significantly decreased apoptotic cell death after spinal cord injury in mice. Mice treated with CD95L-specific antibodies were capable of initiating active hind-limb movements several weeks after injury. The improvement in locomotor performance was mirrored by an increase in regenerating fibers and upregulation of growth-associated protein-43 (GAP-43). Thus, neutralization of CD95L promoted axonal regeneration and functional improvement in injured adult animals. The authors conclude that this therapeutic strategy may constitute a potent future treatment for human spinal injury. Similarly, other animal models of spinal cord injury as are known in the art can be used to evaluate nucleic acid molecules (e.g., siNA) of the invention toward therapeutic use, see for example Casha et al., 2001 , Neuroscience,  103, 203-18 and Li et al., 2000 , Acta Neuropathol  ( Berl ). 100, 75-81. These models can be used to evaluate the efficacy of siNA molecules of the invention targeting, for example, Fas and/or FasL for use is treating spinal cord injury and any other CNS/PNS injury that involves Fas or FasL mediated apoptosis, such as brain injury (e.g., resulting from trauma, hypoxia, ischemia), neurodegenerative disorders such as Alzheimer&#39;s disease, Huntington&#39;s disease, Parkinson&#39;s disease, ALS, stroke, prion disease (e.g., Creutzfield-Jacob and variant Creutzfield-Jacob disease), epilepsy and other neurologic diseases and conditions described herein or otherwise known in the art.  
      Other animal models can be used to evaluate siNA molecules of the invention for other diseases and condition. Song et al., 2003 , Nature Medicine,  9, 347-351, describe certain siRNA molecules targeting FAS in mouse models of autoimmune hepatitis. Wang et al., 2003 , Transplantation Proceedings,  35, 1594-5, describes certain siRNA molecules targeting FAS in a mouse model of allogenic liver transplantation. Mendlovic et al., 1988 , PNAS,  85, 2260-4, describe the induction of a systemic lupus erythematosus-like disease in mice by a common human anti-DNA idiotype. These models can similarly be used to evaluate the safety and efficacy of siNA molecules of the invention in a pre-clinical setting.  
     Example 9  
     RNAi Mediated Inhibition of Fas and FasL Expression in Cell Culture  
      Inhibition of Fas and FasL RNA Expression Using siNA Targeting Fas and FasL RNA  
      siNA constructs (Table III) are tested for efficacy in reducing Fas and/or FasL RNA expression in, for example, PC12 or HepG2 cells or any other cell line expressing Fas and/or FasL. Cells are plated approximately 24 hours before transfection in 96-well plates at 5,000-7,500 cells/well, 1001 μl/well, such that at the time of transfection cells are 70-90% confluent. For transfection, annealed siNAs are mixed with the transfection reagent (Lipofectamine 2000, Invitrogen) in a volume of 0.5 μl/well and incubated for 20 min. at room temperature. The siNA transfection mixtures are added to cells to give a final siNA concentration of 25 nM in a volume of 150 μl. Each siNA transfection mixture is added to 3 wells for triplicate siNA treatments. Cells are incubated at 37° for 24 h in the continued presence of the siNA transfection mixture. At 24 h, RNA is prepared from each well of treated cells. The supernatants with the transfection mixtures are first removed and discarded, then the cells are lysed and RNA prepared from each well. Target gene expression following treatment is evaluated by RT-PCR for the target gene and for a control gene (36B4, an RNA polymerase subunit) for normalization. The triplicate data is averaged and the standard deviations determined for each treatment. Normalized data are graphed and the percent reduction of target mRNA by active siNAs in comparison to their respective inverted control siNAs is determined. In a non-limiting example, chemically modified siNA constructs (Table III) are tested for efficacy as described above in reducing Fas or FasL RNA expression in Hela cells. Active siNAs are evaluated compared to untreated cells, matched chemistry inverted controls (IC), and a transfection control.  
     Example 10  
     Indications  
      The siNA molecule of the invention can be used to prevent, inhibit or treat transplant/allograft rejection, viral infection (e.g., viral hepatitis, HCV, HBV), inflammatory disease (e.g., cirrhosis, liver disease, psoriasis), autoimmunity (e.g., systemic lupus), neurologic disease, liver disease, brain or spinal cord injury, and any other related trait, disease or condition that is related to or will respond to the levels of Fas and/or FasL in a cell or tissue, alone or in combination with other therapies.  
      The use of monoclonal antibodies targeting Fas/FasL or Nogo/NoroR (eg; mAb IN-1) or other inhibitors of Fas/FasL or Nogo/NogoR (see for example U.S. Ser. No. 10/422,704, incorporated by reference herein), growth factors, anti-inflammatory compounds, for example methylprednisolone, calcium blockers, apoptosis inhibiting compounds, for example GM-1 ganglioside, and physical therapies, for example treadmill therapy, are all non-limiting examples of methods and/or agents that can be combined with or used in conjunction with the nucleic acid molecules (e.g. siNA molecules) of the instant invention. Immunomodulators, chemotherapeutics, and anti-viral compounds are additional non-limiting examples of pharmaceutical agents that can be combined with or used in conjunction with the nucleic acid molecules (e.g. siNA molecules) of the instant invention. Those skilled in the art will recognize that other drugs, compounds and therapies can similarly be readily combined with the nucleic acid molecules of the instant invention (e.g. siNA molecules) are hence within the scope of the instant invention.  
     Example 11  
     Diagnostic Uses  
      The siNA molecules of the invention can be used in a variety of diagnostic applications, such as in the identification of molecular targets (e.g., RNA) in a variety of applications, for example, in clinical, industrial, environmental, agricultural and/or research settings. Such diagnostic use of siNA molecules involves utilizing reconstituted RNAi systems, for example, using cellular lysates or partially purified cellular lysates. siNA molecules of this invention can be used as diagnostic tools to examine genetic drift and mutations within diseased cells or to detect the presence of endogenous or exogenous, for example viral, RNA in a cell. The close relationship between siNA activity and the structure of the target RNA allows the detection of mutations in any region of the molecule, which alters the base-pairing and three-dimensional structure of the target RNA. By using multiple siNA molecules described in this invention, one can map nucleotide changes, which are important to RNA structure and function in vitro, as well as in cells and tissues. Cleavage of target RNAs with siNA molecules can be used to inhibit gene expression and define the role of specified gene products in the progression of disease or infection. In this manner, other genetic targets can be defined as important mediators of the disease. These experiments will lead to better treatment of the disease progression by affording the possibility of combination therapies (e.g., multiple siNA molecules targeted to different genes, siNA molecules coupled with known small molecule inhibitors, or intermittent treatment with combinations siNA molecules and/or other chemical or biological molecules). Other in vitro uses of siNA molecules of this invention are well known in the art, and include detection of the presence of mRNAs associated with a disease, infection, or related condition. Such RNA is detected by determining the presence of a cleavage product after treatment with a siNA using standard methodologies, for example, fluorescence resonance emission transfer (FRET).  
      In a specific example, siNA molecules that cleave only wild-type or mutant forms of the target RNA are used for the assay. The first siNA molecules (i.e., those that cleave only wild-type forms of target RNA) are used to identify wild-type RNA present in the sample and the second siNA molecules (i.e., those that cleave only mutant forms of target RNA) are used to identify mutant RNA in the sample. As reaction controls, synthetic substrates of both wild-type and mutant RNA are cleaved by both siNA molecules to demonstrate the relative siNA efficiencies in the reactions and the absence of cleavage of the “non-targeted” RNA species. The cleavage products from the synthetic substrates also serve to generate size markers for the analysis of wild-type and mutant RNAs in the sample population. Thus, each analysis requires two siNA molecules, two substrates and one unknown sample, which is combined into six reactions. The presence of cleavage products is determined using an RNase protection assay so that full-length and cleavage fragments of each RNA can be analyzed in one lane of a polyacrylamide gel. It is not absolutely required to quantify the results to gain insight into the expression of mutant RNAs and putative risk of the desired phenotypic changes in target cells. The expression of mRNA whose protein product is implicated in the development of the phenotype (i.e., disease related or infection related) is adequate to establish risk. If probes of comparable specific activity are used for both transcripts, then a qualitative comparison of RNA levels is adequate and decreases the cost of the initial diagnosis. Higher mutant form to wild-type ratios are correlated with higher risk whether RNA levels are compared qualitatively or quantitatively.  
      All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. All references cited in this disclosure are incorporated by reference to the same extent as if each reference had been incorporated by reference in its entirety individually.  
      One skilled in the art would readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The methods and compositions described herein as presently representative of preferred embodiments are exemplary and are not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art, which are encompassed within the spirit of the invention, are defined by the scope of the claims.  
      It will be readily apparent to one skilled in the art that varying substitutions and modifications can be made to the invention disclosed herein without departing from the scope and spirit of the invention. Thus, such additional embodiments are within the scope of the present invention and the following claims. The present invention teaches one skilled in the art to test various combinations and/or substitutions of chemical modifications described herein toward generating nucleic acid constructs with improved activity for mediating RNAi activity. Such improved activity can comprise improved stability, improved bioavailability, and/or improved activation of cellular responses mediating RNAi. Therefore, the specific embodiments described herein are not limiting and one skilled in the art can readily appreciate that specific combinations of the modifications described herein can be tested without undue experimentation toward identifying siNA molecules with improved RNAi activity.  
      The invention illustratively described herein suitably can be practiced in the absence of any element or elements, limitation or limitations that are not specifically disclosed herein. Thus, for example, in each instance herein any of the terms “comprising”, “consisting essentially of”, and “consisting of” may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments, optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the description and the appended claims.  
      In addition, where features or aspects of the invention are described in terms of Markush groups or other grouping of alternatives, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group or other group.  
               TABLE I                       GenBank Accession Nos. for Fas and FasL genes                                    NM_000043         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6),       transcript variant 1, mRNA       gi|23510419|ref|NM_000043.3|[23510419]       BC012479         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6, transcript       variant 1, mRNA (cDNA clone MGC: 21432 IMAGE: 4514272),       complete cds       gi|15214691|gb|BC012479.1|[15214691]       X63717         H. sapiens  mRNA for APO-1 cell surface antigen       gi|28741|emb|X63717.1|HSAPO1[28741]       M67454       Human Fas antigen (fas) mRNA, complete cds       gi|182409|gb|M67454.1|HUMFas and/or FasLANT[182409]       NM_152873         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6),       transcript variant 4, mRNA       gi|23510424|ref|NM_152873.1|[23510424]       NM_152877         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6),       transcript variant 7, mRNA       gi|23510433|ref|NM_152877.1|[23510433]       NM_152875         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6),       transcript variant 5, mRNA       gi|23510428|ref|NM_152875.1|[23510428]       NM_152871         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6),       transcript variant 2, mRNA       gi|23510420|ref|NM_152871.1|[23510420]       NM_152876         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6),       transcript variant 6, mRNA       gi|23510430|ref|NM_152876.1|[23510430]       NM_152874         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6),       transcript variant 8, mRNA       gi|23510426|ref|NM_152874.1|[23510426]       NM_152872         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6),       transcript variant 3, mRNA       gi|23510422|ref|NM_152872.1|[23510422]       AL157394       Human DNA sequence from clone RP11-399O19 on chromosome 10,       complete sequence       gi|15384622|emb|AL157394.15|[15384622]       AY450925         Homo sapiens  tumor necrosis factor receptor superfamily,       member 6 (TNFRSF6)       gene, complete cds       gi|38045921|gb|AY450925.1|[38045921]       X81342         H. sapiens  APT gene, exon 9       gi|537417|emb|X81342.1|HSAPT9[537417]       X82286         H. sapiens  Fas, Apo-1 gene (exon IX)       gi|673412|emb|X82286.1|HSFas and/or FasLX9[673412]       X83490         H. sapiens  mRNA for Fas/Apo-1 (clone pCRTM11-Fasdelta(3, 4))       gi|971454|emb|X83490.1|HSFas and/or FasL34[971454]       Z66556         H. sapiens  Fas and/or FasLExo8Del mRNA       gi|1150412|emb|Z66556.1|HSFas and/or FasLAPOA[1150412]       X83491         H. sapiens  mRNA for Fas/Apo-1 (clone pCRTM11-       Fasdelta (3, 4, 6))       gi|971455|emb|X83491.1|HSFas and/or FasL346[971455]       X83493         H. sapiens  mRNA for Fas/Apo-1 (clone pCRTM11-FasdeltaTM)       gi|1971457|emb|X83493.1|HSFas and/or FasL6[971457]       Z70519         H. sapiens  Fas and/or FasL/Apo 1 mRNA for Fas and/or FasL       soluble protein (clone Fas and/or FasL Exo4Del)       gi|1418817|emb|Z70519.1|HSFas and/or FasL4DEL[1418817]       Z47994         H. sapiens  Fas and/or FasL Del 2 mRNA       gi|728579|emb|Z47994.1|HSFas and/or FasLCDS2[728579]       Z47993         H. sapiens  Fas and/or FasLTM Del mRNA       gi|728578|emb|Z47993.1|HSFas and/or FasLCDS1[728578]       X83492         H. sapiens  mRNA for Fas/Apo-1 (clone pCRTM11-Fasdelta(4, 7))       gi|971456|emb|X83492.1|HSFas and/or FasL47[971456]       Z47995         H. sapiens  Fas and/or FasL Del3 mRNA       gi|728580|emb|Z47995.1|HSFas and/or FasLCDS3[728580]       Z70520         H. sapiens  Fas and/or FasL/Apo 1 mRNA for Fas and/or FasL       soluble protein (clone Fas and/or FasL Exo4, 6Del)       gi|1418815|emb|Z70520.1|HSFas and/or FasL46DL[1418815]       X82279         H. sapiens  Fas, Apo-1 gene (promoter and exon I)       gi|673405|emb|X82279.1|HSFas and/or FasLX1[673405]       X81335         H. sapiens  APT gene, exon 1       gi|537410|emb|X81335.1|HSAPT1[537410]       D31968         Homo sapiens  gene for Fas antigen, partial cds and promoter       region       gi|961455|dbj|D31968.1|HUMFas and/or FasL[961455]       X87625         H. sapiens  CD95 gene 5′ flanking region       gi|902311|emb|X87625.1|HSCD955FR[902311]       AJ509181         Homo sapiens  partial CD95 gene for CD95 antigen, exon 9,       isolate E 285       gi|26801151|emb|AJ509181.1|HSA509181[26801151]       AJ509182         Homo sapiens  partial CD95 gene for CD95 antigen, exon 9,       isolate J 34       gi|26801153|emb|AJ509182.1|HSA509182[26801153]       AF530075         Macaca mulatta  Fas receptor CD95 mRNA, partial cds       gi|22324691|gb|AF530075.1|[22324691]       X89101         H. sapiens  mRNA for Fas (Apo-1, CD95)       gi|887457|emb|X89101.1|HSFas and/or FasLMRNA[887457]       AJ279011         Homo sapiens  partial CD95 gene for CD95 antigen (Apo-1       Fas), exon 1       gi|13539238|emb|AJ279011.1|HSA279011[13539238]       AJ279012         Homo sapiens  partial CD95 gene for CD95 antigen (Apo-1       Fas), exon 1, polymorphic       allele (+275)       gi|13539240|emb|AJ279012.1|HSA279012[13539240]       AJ279013         Homo sapiens  partial CD95 gene for CD95 antigen (Apo-1       Fas), exon 1, polymorphic       allele (+337)       gi|13539242|emb|AJ279013.1|HSA279013[13539242]       AJ509180         Homo sapiens  partial CD95 gene for CD95 antigen, exon 1,       isolate E 103       gi|26801149|emb|AJ509180.1|HSA509180[26801149]       AJ509179         Homo sapiens  partial CD95 gene for CD95 antigen, exon 1,       isolate E 94       gi|26801147|emb|AJ509179.1|HSA509179[26801147]       X81336         H. sapiens  APT gene, exon 2       gi|537411|emb|X81336.1|HSAPT2[537411]       X82281         H. sapiens  Fas, Apo-1 gene (exon III)       gi|673407|emb|X82281.1|HSFas and/or FasLX3[673407]       X81337         H. sapiens  APT gene, exon 3       gi|537412|emb|X81337.1|HSAPT3[537412]       X82282         H. sapiens  Fas, Apo-1 gene (exon IV)       gi|673408|emb|X82282.1|HSFas and/or FasLX4[673408]       X81338         H. sapiens  APT gene, exon 4       gi|537413|emb|X81338.1|HSAPT4[537413]       NM_000639         Homo sapiens  tumor necrosis factor (ligand) superfamily,       member 6 (TNFSF6), mRNA       gi|4557328|ref|NM_000639.1|[4557328]       X89102         H. sapiens  mRNA for fasligand       gi|887455|emb|X89102.1|HSFas and/or FasLLIGA[887455]       D38122       Human mRNA for Fas ligand, complete cds       gi|601892|dbj|D38122.1|HUMHPC[601892]       BC017502         Homo sapiens  tumor necrosis factor (ligand) superfamily,       member 6, mRNA (cDNA       clone MGC: 23109 IMAGE: 4849770), complete cds       gi|17028380|gb|BC017502.1|[17028380]       U08137       Human Fas ligand mRNA, complete cds       gi|624627|gb|U08137.1|HSU08137[624627]       Z96050       Human DNA sequence from clone RP1-105D12 on chromosome       1q24-25, complete       sequence       gi|2168138|emb|Z96050.1|HS105D12[2168138]       U11821       Human Fas ligand (FasL) mRNA, complete cds       gi|595430|gb|U11821.1|HSU11821[595430]       AY225406         Homo sapiens  Fas and/or FasL ligand (TNFSF6) mRNA, complete       cds       gi|28569613|gb|AY225406.1|[28569613]       AF344856         Macaca mulatta  clone RHCD95L Fas and/or FasL antigen CD95       mRNA, complete cds       gi|13650009|gb|AF344856.1|AF344856[13650009]       AF344847         Cercocebus torquatus  atys CD95L protein (CD95L) mRNA,       complete cds       gi|13655480|gb|AF344847.1|AF344847[13655480]       AB035138         Macaca fascicularis  Cm-FasL mRNA for Fas ligand, complete       cds       gi|6759342|dbj|AB035138.1|[6759342]       AB035139         Macaca mulatta  Rm-FasL mRNA for Fas ligand, complete cds       gi|6759344|dbj|AB035139.1|[6759344]       AB035140         Macaca nemestrina  Pt-FasL mRNA for Fas ligand, complete cds       gi|6759346|dbj|AB035140.1|[6759346]       AF288573         Homo sapiens  FasL isoform mRNA, complete cds       gi|12597288|gb|AF288573.1|AF288573[12597288]       AF530076         Macaca mulatta  Fas ligand CD178 mRNA, partial cds       gi|22324693|gb|AF530076.1|[22324693]       U97046         Homo sapiens  Fas ligand promoter, partial sequence       gi|2645410|gb|U97046.1|HSU97046[2645410]       AB013303         Homo sapiens  gene for Fas ligand, 5′-flanking region and       partial cds       gi|3492846|dbj|AB013303.1|[3492846]       AF044583         Homo sapiens  Fas ligand gene, promoter region and partial       cds       gi|3201667|gb|AF044583.1|AF044583[3201667]       AF035584         Homo sapiens  Fas ligand (FasL) gene, 5′ untranslated region       gi|2981185|gb|AF035584.1|AF035584[2981185]       AF027385         Homo sapiens  Fas ligand gene, promoter sequence       gi|2665472|gb|AF027385.1|AF027385[2665472]                  
 
     
       
         
           
               
             
               
                 TABLE II 
               
             
            
               
                   
               
               
                   
               
               
                 Fas and FasL siNA and Target Sequences 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                 Seq 
                   
                   
                 Seq 
                   
                   
                 Seq 
                   
               
               
                 Pos 
                 Seq 
                 ID 
                 UPos 
                 Upper seq 
                 ID 
                 LPos 
                 Lower seq 
                 ID 
               
               
                   
               
            
           
           
               
            
               
                 FAS NM_000043.3 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 3 
                 UACCCGCGCGCAGGCCAAG 
                 1 
                 3 
                 UACCCGCGCGCAGGCCAAG 
                 1 
                 21 
                 CUUGGCCUGCGCGCGGGUA 
                 151 
                   
               
               
                   
               
               
                 21 
                 GUUGCUGAAUCAAUGGAGC 
                 2 
                 21 
                 GUUGCUGAAUCAAUGGAGC 
                 2 
                 39 
                 GCUCCAUUGAUUCAGCAAC 
                 152 
               
               
                   
               
               
                 39 
                 CCCUCCCCAACCCGGGCGU 
                 3 
                 39 
                 CCCUCCCCAACCCGGGCGU 
                 3 
                 57 
                 ACGCCCGGGUUGGGGAGGG 
                 153 
               
               
                   
               
               
                 57 
                 UUCCCCAGCGAGGCUUCCU 
                 4 
                 57 
                 UUCCCCAGCGAGGCUUCCU 
                 4 
                 75 
                 AGGAAGCCUCGCUGGGGAA 
                 154 
               
               
                   
               
               
                 75 
                 UUCCCAUCCUCCUGACCAC 
                 5 
                 75 
                 UUCCCAUCCUCCUGACCAC 
                 5 
                 93 
                 GUGGUCAGGAGGAUGGGAA 
                 155 
               
               
                   
               
               
                 93 
                 CCGGGGCUUUUCGUGAGCU 
                 6 
                 93 
                 CCGGGGCUUUUCGUGAGCU 
                 6 
                 111 
                 AGCUCACGAAAAGCCCCGG 
                 156 
               
               
                   
               
               
                 111 
                 UCGUCUCUGAUCUCGCGCA 
                 7 
                 111 
                 UCGUCUCUGAUCUCGCGCA 
                 7 
                 129 
                 UGCGCGAGAUCAGAGACGA 
                 157 
               
               
                   
               
               
                 129 
                 AAGAGUGACACACAGGUGU 
                 8 
                 129 
                 AAGAGUGACACACAGGUGU 
                 8 
                 147 
                 ACACCUGUGUGUCACUCUU 
                 158 
               
               
                   
               
               
                 147 
                 UUCAAAGACGCUUCUGGGG 
                 9 
                 147 
                 UUCAAAGACGCUUCUGGGG 
                 9 
                 165 
                 CCCCAGAAGCGUCUUUGAA 
                 159 
               
               
                   
               
               
                 165 
                 GAGUGAGGGAAGCGGUUUA 
                 10 
                 165 
                 GAGUGAGGGAAGCGGUUUA 
                 10 
                 183 
                 UAAACCGCUUCCCUCACUC 
                 160 
               
               
                   
               
               
                 183 
                 ACGAGUGACUUGGCUGGAG 
                 11 
                 183 
                 ACGAGUGACUUGGCUGGAG 
                 11 
                 201 
                 CUCCAGCCAAGUCACUCGU 
                 161 
               
               
                   
               
               
                 201 
                 GCCUCAGGGGCGGGCACUG 
                 12 
                 201 
                 GCCUCAGGGGCGGGCACUG 
                 12 
                 219 
                 CAGUGCCCGCCCCUGAGGC 
                 162 
               
               
                   
               
               
                 219 
                 GGCACGGAACACACCCUGA 
                 13 
                 219 
                 GGCACGGAACACACCCUGA 
                 13 
                 237 
                 UCAGGGUGUGUUCCGUGCC 
                 163 
               
               
                   
               
               
                 237 
                 AGGCCAGCCCUGGCUGCCC 
                 14 
                 237 
                 AGGCCAGCCCUGGCUGCCC 
                 14 
                 255 
                 GGGCAGCCAGGGCUGGCCU 
                 164 
               
               
                   
               
               
                 255 
                 CAGGCGGAGCUGCCUCUUC 
                 15 
                 255 
                 CAGGCGGAGCUGCCUCUUC 
                 15 
                 273 
                 GAAGAGGCAGCUCCGCCUG 
                 165 
               
               
                   
               
               
                 273 
                 CUCCCGCGGGUUGGUGGAC 
                 16 
                 273 
                 CUCCCGCGGGUUGGUGGAC 
                 16 
                 291 
                 GUCCACCAACCCGCGGGAG 
                 166 
               
               
                   
               
               
                 291 
                 CCCGCUCAGUACGGAGUUG 
                 17 
                 291 
                 CCCGCUCAGUACGGAGUUG 
                 17 
                 309 
                 CAACUCCGUACUGAGCGGG 
                 167 
               
               
                   
               
               
                 309 
                 GGGGAAGCUCUUUCACUUC 
                 18 
                 309 
                 GGGGAAGCUCUUUCACUUC 
                 18 
                 327 
                 GAAGUGAAAGAGCUUCCCC 
                 168 
               
               
                   
               
               
                 327 
                 CGGAGGAUUGCUCAACAAC 
                 19 
                 327 
                 CGGAGGAUUGCUCAACAAC 
                 19 
                 345 
                 GUUGUUGAGCAAUCCUCCG 
                 169 
               
               
                   
               
               
                 345 
                 CCAUGCUGGGCAUCUGGAC 
                 20 
                 345 
                 CCAUGCUGGGCAUCUGGAC 
                 20 
                 363 
                 GUCCAGAUGCCCAGCAUGG 
                 170 
               
               
                   
               
               
                 363 
                 CCCUCCUACCUCUGGUUCU 
                 21 
                 363 
                 CCCUCCUACCUCUGGUUCU 
                 21 
                 381 
                 AGAACCAGAGGUAGGAGGG 
                 171 
               
               
                   
               
               
                 381 
                 UUACGUCUGUUGCUAGAUU 
                 22 
                 381 
                 UUACGUCUGUUGCUAGAUU 
                 22 
                 399 
                 AAUCUAGCAACAGACGUAA 
                 172 
               
               
                   
               
               
                 399 
                 UAUCGUCCAAAAGUGUUAA 
                 23 
                 399 
                 UAUCGUCCAAAAGUGUUAA 
                 23 
                 417 
                 UUAACACUUUUGGACGAUA 
                 173 
               
               
                   
               
               
                 417 
                 AUGCCCAAGUGACUGACAU 
                 24 
                 417 
                 AUGCCCAAGUGACUGACAU 
                 24 
                 435 
                 AUGUCAGUCACUUGGGCAU 
                 174 
               
               
                   
               
               
                 435 
                 UCAACUCCAAGGGAUUGGA 
                 25 
                 435 
                 UCAACUCCAAGGGAUUGGA 
                 25 
                 453 
                 UCCAAUCCCUUGGAGUUGA 
                 175 
               
               
                   
               
               
                 453 
                 AAUUGAGGAAGACUGUUAC 
                 26 
                 453 
                 AAUUGAGGAAGACUGUUAC 
                 26 
                 471 
                 GUAACAGUCUUCCUCAAUU 
                 176 
               
               
                   
               
               
                 471 
                 CUACAGUUGAGACUCAGAA 
                 27 
                 471 
                 CUACAGUUGAGACUCAGAA 
                 27 
                 489 
                 UUCUGAGUCUCAACUGUAG 
                 177 
               
               
                   
               
               
                 489 
                 ACUUGGAAGGCCUGCAUCA 
                 28 
                 489 
                 ACUUGGAAGGCCUGCAUCA 
                 28 
                 507 
                 UGAUGCAGGCCUUCCAAGU 
                 178 
               
               
                   
               
               
                 507 
                 AUGAUGGCCAAUUCUGCCA 
                 29 
                 507 
                 AUGAUGGCCAAUUCUGCCA 
                 29 
                 525 
                 UGGCAGAAUUGGCCAUCAU 
                 179 
               
               
                   
               
               
                 525 
                 AUAAGCCCUGUCCUCCAGG 
                 30 
                 525 
                 AUAAGCCCUGUCCUCCAGG 
                 30 
                 543 
                 CCUGGAGGACAGGGCUUAU 
                 180 
               
               
                   
               
               
                 543 
                 GUGAAAGGAAAGCUAGGGA 
                 31 
                 543 
                 GUGAAAGGAAAGCUAGGGA 
                 31 
                 561 
                 UCCCUAGCUUUCCUUUCAC 
                 181 
               
               
                   
               
               
                 561 
                 ACUGCACAGUCAAUGGGGA 
                 32 
                 561 
                 ACUGCACAGUCAAUGGGGA 
                 32 
                 579 
                 UCCCCAUUGACUGUGCAGU 
                 182 
               
               
                   
               
               
                 579 
                 AUGAACCAGACUGCGUGCC 
                 33 
                 579 
                 AUGAACCAGACUGCGUGCC 
                 33 
                 597 
                 GGCACGCAGUCUGGUUCAU 
                 183 
               
               
                   
               
               
                 597 
                 CCUGCCAAGAAGGGAAGGA 
                 34 
                 597 
                 CCUGCCAAGAAGGGAAGGA 
                 34 
                 615 
                 UCCUUCCCUUCUUGGCAGG 
                 184 
               
               
                   
               
               
                 615 
                 AGUACACAGACAAAGCCCA 
                 35 
                 615 
                 AGUACACAGACAAAGCCCA 
                 35 
                 633 
                 UGGGCUUUGUCUGUGUACU 
                 185 
               
               
                   
               
               
                 633 
                 AUUUUUCUUCCAAAUGCAG 
                 36 
                 633 
                 AUUUUUCUUCCAAAUGCAG 
                 36 
                 651 
                 CUGCAUUUGGAAGAAAAAU 
                 186 
               
               
                   
               
               
                 651 
                 GAAGAUGUAGAUUGUGUGA 
                 37 
                 651 
                 GAAGAUGUAGAUUGUGUGA 
                 37 
                 669 
                 UCACACAAUCUACAUCUUC 
                 187 
               
               
                   
               
               
                 669 
                 AUGAAGGACAUGGCUUAGA 
                 38 
                 669 
                 AUGAAGGACAUGGCUUAGA 
                 38 
                 687 
                 UCUAAGCCAUGUCCUUCAU 
                 188 
               
               
                   
               
               
                 687 
                 AAGUGGAAAUAAACUGCAC 
                 39 
                 687 
                 AAGUGGAAAUAAACUGCAC 
                 39 
                 705 
                 GUGCAGUUUAUUUCCACUU 
                 189 
               
               
                   
               
               
                 705 
                 CCCGGACCCAGAAUACCAA 
                 40 
                 705 
                 CCCGGACCCAGAAUACCAA 
                 40 
                 723 
                 UUGGUAUUCUGGGUCCGGG 
                 190 
               
               
                   
               
               
                 723 
                 AGUGCAGAUGUAAACCAAA 
                 41 
                 723 
                 AGUGCAGAUGUAAACCAAA 
                 41 
                 741 
                 UUUGGUUUACAUCUGCACU 
                 191 
               
               
                   
               
               
                 741 
                 ACUUUUUUUGUAACUCUAC 
                 42 
                 741 
                 ACUUUUUUUGUAACUCUAC 
                 42 
                 759 
                 GUAGAGUUACAAAAAAAGU 
                 192 
               
               
                   
               
               
                 759 
                 CUGUAUGUGAACACUGUGA 
                 43 
                 759 
                 CUGUAUGUGAACACUGUGA 
                 43 
                 777 
                 UCACAGUGUUCACAUACAG 
                 193 
               
               
                   
               
               
                 777 
                 ACCCUUGCACCAAAUGUGA 
                 44 
                 777 
                 ACCCUUGCACCAAAUGUGA 
                 44 
                 795 
                 UCACAUUUGGUGCAAGGGU 
                 194 
               
               
                   
               
               
                 795 
                 AACAUGGAAUCAUCAAGGA 
                 45 
                 795 
                 AACAUGGAAUCAUCAAGGA 
                 45 
                 813 
                 UCCUUGAUGAUUCCAUGUU 
                 195 
               
               
                   
               
               
                 813 
                 AAUGCACACUCACCAGCAA 
                 46 
                 813 
                 AAUGCACACUCACCAGCAA 
                 46 
                 831 
                 UUGCUGGUGAGUGUGCAUU 
                 196 
               
               
                   
               
               
                 831 
                 ACACCAAGUGCAAAGAGGA 
                 47 
                 831 
                 ACACCAAGUGCAAAGAGGA 
                 47 
                 849 
                 UCCUCUUUGCACUUGGUGU 
                 197 
               
               
                   
               
               
                 849 
                 AAGGAUCCAGAUCUAACUU 
                 48 
                 849 
                 AAGGAUCCAGAUCUAACUU 
                 48 
                 867 
                 AAGUUAGAUCUGGAUCCUU 
                 198 
               
               
                   
               
               
                 867 
                 UGGGGUGGCUUUGUCUUCU 
                 49 
                 867 
                 UGGGGUGGCUUUGUCUUCU 
                 49 
                 885 
                 AGAAGACAAAGCCACCCCA 
                 199 
               
               
                   
               
               
                 885 
                 UUCUUUUGCCAAUUCCACU 
                 50 
                 885 
                 UUCUUUUGCCAAUUCCACU 
                 50 
                 903 
                 AGUGGAAUUGGCAAAAGAA 
                 200 
               
               
                   
               
               
                 903 
                 UAAUUGUUUGGGUGAAGAG 
                 51 
                 903 
                 UAAUUGUUUGGGUGAAGAG 
                 51 
                 921 
                 CUCUUCACCCAAACAAUUA 
                 201 
               
               
                   
               
               
                 921 
                 GAAAGGAAGUACAGAAAAC 
                 52 
                 921 
                 GAAAGGAAGUACAGAAAAC 
                 52 
                 939 
                 GUUUUCUGUACUUCCUUUC 
                 202 
               
               
                   
               
               
                 939 
                 CAUGCAGAAAGCACAGPAA 
                 53 
                 939 
                 CAUGCAGAAAGCACAGAAA 
                 53 
                 957 
                 UUUCUGUGCUUUCUGCAUG 
                 203 
               
               
                   
               
               
                 957 
                 AGGAAAACCAAGGUUCUCA 
                 54 
                 957 
                 AGGAAAACCAAGGUUCUCA 
                 54 
                 975 
                 UGAGAACCUUGGUUUUCCU 
                 204 
               
               
                   
               
               
                 975 
                 AUGAAUCUCCAACCUUAAA 
                 55 
                 975 
                 AUGAAUCUCCAACCUUAAA 
                 55 
                 993 
                 UUUAAGGUUGGAGAUUCAU 
                 205 
               
               
                   
               
               
                 993 
                 AUCCUGAAACAGUGGCAAU 
                 56 
                 993 
                 AUCCUGAAACAGUGGCAAU 
                 56 
                 1011 
                 AUUGCCACUGUUUCAGGAU 
                 206 
               
               
                   
               
               
                 1011 
                 UAAAUUUAUCUGAUGUUGA 
                 57 
                 1011 
                 UAAAUUUAUCUGAUGUUGA 
                 57 
                 1029 
                 UCAACAUCAGAUAAAUUUA 
                 207 
               
               
                   
               
               
                 1029 
                 ACUUGAGUAAAUAUAUCAC 
                 58 
                 1029 
                 ACUUGAGUAAAUAUAUCAC 
                 58 
                 1047 
                 GUGAUAUAUUUACUCAAGU 
                 208 
               
               
                   
               
               
                 1047 
                 CCACUAUUGCUGGAGUCAU 
                 59 
                 1047 
                 CCACUAUUGCUGGAGUCAU 
                 59 
                 1065 
                 AUGACUCCAGCAAUAGUGG 
                 209 
               
               
                   
               
               
                 1065 
                 UGACACUAAGUCAAGUUAA 
                 60 
                 1065 
                 UGACACUAAGUCAAGUUAA 
                 60 
                 1083 
                 UUAACUUGACUUAGUGUCA 
                 210 
               
               
                   
               
               
                 1083 
                 AAGGCUUUGUUCGAAAGAA 
                 61 
                 1083 
                 AAGGCUUUGUUCGAAAGAA 
                 61 
                 1101 
                 UUCUUUCGAACAAAGCCUU 
                 211 
               
               
                   
               
               
                 1101 
                 AUGGUGUCAAUGAAGCCAA 
                 62 
                 1101 
                 AUGGUGUCAAUGAAGCCAA 
                 62 
                 1119 
                 UUGGCUUCAUUGACACCAU 
                 212 
               
               
                   
               
               
                 1119 
                 AAAUAGAUGAGAUCAAGAA 
                 63 
                 1119 
                 AAAUAGAUGAGAUCAAGAA 
                 63 
                 1137 
                 UUCUUGAUCUCAUCUAUUU 
                 213 
               
               
                   
               
               
                 1137 
                 AUGACAAUGUCCAAGACAC 
                 64 
                 1137 
                 AUGACAAUGUCCAAGACAC 
                 64 
                 1155 
                 GUGUCUUGGACAUUGUCAU 
                 214 
               
               
                   
               
               
                 1155 
                 CAGCAGAACAGAAAGUUCA 
                 65 
                 1155 
                 CAGCAGAACAGAAAGUUCA 
                 65 
                 1173 
                 UGAACUUUCUGUUCUGCUG 
                 215 
               
               
                   
               
               
                 1173 
                 AACUGCUUCGUAAUUGGCA 
                 66 
                 1173 
                 AACUGCUUCGUAAUUGGCA 
                 66 
                 1191 
                 UGCCAAUUACGAAGCAGUU 
                 216 
               
               
                   
               
               
                 1191 
                 AUCAACUUCAUGGAAAGAA 
                 67 
                 1191 
                 AUCAACUUCAUGGAAAGAA 
                 67 
                 1209 
                 UUCUUUCCAUGAAGUUGAU 
                 217 
               
               
                   
               
               
                 1209 
                 AAGAAGCGUAUGACACAUU 
                 68 
                 1209 
                 AAGAAGCGUAUGACACAUU 
                 68 
                 1227 
                 AAUGUGUCAUACGCUUCUU 
                 218 
               
               
                   
               
               
                 1227 
                 UGAUUAAAGAUCUCAAAAA 
                 69 
                 1227 
                 UGAUUAAAGAUCUCAAAAA 
                 69 
                 1245 
                 UUUUUGAGAUCUUUAAUCA 
                 219 
               
               
                   
               
               
                 1245 
                 AAGCCAAUCUUUGUACUCU 
                 70 
                 1245 
                 AAGCCAAUCUUUGUACUCU 
                 70 
                 1263 
                 AGAGUACAAAGAUUGGCUU 
                 220 
               
               
                   
               
               
                 1263 
                 UUGCAGAGAAAAUUCAGAC 
                 71 
                 1263 
                 UUGCAGAGAAAAUUCAGAC 
                 71 
                 1281 
                 GUCUGAAUUUUCUCUGCAA 
                 221 
               
               
                   
               
               
                 1281 
                 CUAUCAUCCUCAAGGACAU 
                 72 
                 1281 
                 CUAUCAUCCUCAAGGACAU 
                 72 
                 1299 
                 AUGUCCUUGAGGAUGAUAG 
                 222 
               
               
                   
               
               
                 1299 
                 UUACUAGUGACUCAGAAAA 
                 73 
                 1299 
                 UUACUAGUGACUCAGAAAA 
                 73 
                 1317 
                 UUUUCUGAGUCACUAGUAA 
                 223 
               
               
                   
               
               
                 1317 
                 AUUCAAACUUCAGAAAUGA 
                 74 
                 1317 
                 AUUCAAACUUCAGAAAUGA 
                 74 
                 1335 
                 UCAUUUCUGAAGUUUGAAU 
                 224 
               
               
                   
               
               
                 1335 
                 AAAUCCAAAGCUUGGUCUA 
                 75 
                 1335 
                 AAAUCCAAAGCUUGGUCUA 
                 75 
                 1353 
                 UAGACCAAGCUUUGGAUUU 
                 225 
               
               
                   
               
               
                 1353 
                 AGAGUGAAAAACAACAAAU 
                 76 
                 1353 
                 AGAGUGAAAAACAACAAAU 
                 76 
                 1371 
                 AUUUGUUGUUUUUCACUCU 
                 226 
               
               
                   
               
               
                 1371 
                 UUCAGUUCUGAGUAUAUGC 
                 77 
                 1371 
                 UUCAGUUCUGAGUAUAUGC 
                 77 
                 1389 
                 GCAUAUACUCAGAACUGAA 
                 227 
               
               
                   
               
               
                 1389 
                 CAAUUAGUGUUUGAAAAGA 
                 78 
                 1389 
                 CAAUUAGUGUUUGAAAAGA 
                 78 
                 1407 
                 UCUUUUCAAACACUAAUUG 
                 228 
               
               
                   
               
               
                 1407 
                 AUUCUUAAUAGCUGGCUGU 
                 79 
                 1407 
                 AUUCUUAAUAGCUGGCUGU 
                 79 
                 1425 
                 ACAGCCAGCUAUUAAGAAU 
                 229 
               
               
                   
               
               
                 1425 
                 UAAAUACUGCUUGGUUUUU 
                 80 
                 1425 
                 UAAAUACUGCUUGGUUUUU 
                 80 
                 1443 
                 AAAAACCAAGCAGUAUUUA 
                 230 
               
               
                   
               
               
                 1443 
                 UUACUGGGUACAUUUUAUC 
                 81 
                 1443 
                 UUACUGGGUACAUUUUAUC 
                 81 
                 1461 
                 GAUAAAAUGUACCCAGUAA 
                 231 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGA 
                 82 
                 1461 
                 CAUUUAUUAGCGCUGAAGA 
                 82 
                 1479 
                 UCUUCAGCGCUAAUAAAUG 
                 232 
               
               
                   
               
               
                 1479 
                 AGCCAACAUAUUUGUAGAU 
                 83 
                 1479 
                 AGCCAACAUAUUUGUAGAU 
                 83 
                 1497 
                 AUCUACAAAUAUGUUGGCU 
                 233 
               
               
                   
               
               
                 1497 
                 UUUUUAAUAUCUCAUGAUU 
                 84 
                 1497 
                 UUUUUAAUAUCUCAUGAUU 
                 84 
                 1515 
                 AAUCAUGAGAUAUUAAAAA 
                 234 
               
               
                   
               
               
                 1515 
                 UCUGCCUCCAAGGAUGUUU 
                 85 
                 1515 
                 UCUGCCUCCAAGGAUGUUU 
                 85 
                 1533 
                 AAACAUCCUUGGAGGCAGA 
                 235 
               
               
                   
               
               
                 1533 
                 UAAAAUCUAGUUGGGAAAA 
                 86 
                 1533 
                 UAAAAUCUAGUUGGGAAAA 
                 86 
                 1551 
                 UUUUCCCAACUAGAUUUUA 
                 236 
               
               
                   
               
               
                 1551 
                 ACAAACUUCAUCAAGAGUA 
                 87 
                 1551 
                 ACAAACUUCAUCAAGAGUA 
                 87 
                 1569 
                 UACUCUUGAUGAAGUUUGU 
                 237 
               
               
                   
               
               
                 1569 
                 AAAUGCAGUGGCAUGCUAA 
                 88 
                 1569 
                 AAAUGCAGUGGCAUGCUAA 
                 88 
                 1587 
                 UUAGCAUGCCACUGCAUUU 
                 238 
               
               
                   
               
               
                 1587 
                 AGUACCCAAAUAGGAGUGU 
                 89 
                 1587 
                 AGUACCCAAAUAGGAGUGU 
                 89 
                 1605 
                 ACACUCCUAUUUGGGUACU 
                 239 
               
               
                   
               
               
                 1605 
                 UAUGCAGAGGAUGAAAGAU 
                 90 
                 1605 
                 UAUGCAGAGGAUGAAAGAU 
                 90 
                 1623 
                 AUCUUUCAUCCUCUGCAUA 
                 240 
               
               
                   
               
               
                 1623 
                 UUAAGAUUAUGCUCUGGCA 
                 91 
                 1623 
                 UUAAGAUUAUGCUCUGGCA 
                 91 
                 1641 
                 UGCCAGAGCAUAAUCUUAA 
                 241 
               
               
                   
               
               
                 1641 
                 AUCUAACAUAUGAUUCUGU 
                 92 
                 1641 
                 AUCUAACAUAUGAUUCUGU 
                 92 
                 1659 
                 ACAGAAUCAUAUGUUAGAU 
                 242 
               
               
                   
               
               
                 1659 
                 UAGUAUGAAUGUAAUCAGU 
                 93 
                 1659 
                 UAGUAUGAAUGUAAUCAGU 
                 93 
                 1677 
                 ACUGAUUACAUUCAUACUA 
                 243 
               
               
                   
               
               
                 1677 
                 UGUAUGUUAGUACAAAUGU 
                 94 
                 1677 
                 UGUAUGUUAGUACAAAUGU 
                 94 
                 1695 
                 ACAUUUGUACUAACAUACA 
                 244 
               
               
                   
               
               
                 1695 
                 UCUAUCCACAGGCUAACCC 
                 95 
                 1695 
                 UCUAUCCACAGGCUAACCC 
                 95 
                 1713 
                 GGGUUAGCCUGUGGAUAGA 
                 245 
               
               
                   
               
               
                 1713 
                 CCACUCUAUGAAUCAAUAG 
                 96 
                 1713 
                 CCACUCUAUGAAUCAAUAG 
                 96 
                 1731 
                 CUAUUGAUUCAUAGAGUGG 
                 246 
               
               
                   
               
               
                 1731 
                 GAAGAAGCUAUGACCUUUU 
                 97 
                 1731 
                 GAAGAAGCUAUGACCUUUU 
                 97 
                 1749 
                 AAAAGGUCAUAGCUUCUUC 
                 247 
               
               
                   
               
               
                 1749 
                 UGCUGAAAUAUCAGUUACU 
                 98 
                 1749 
                 UGCUGAAAUAUCAGUUACU 
                 98 
                 1767 
                 AGUAACUGAUAUUUCAGCA 
                 248 
               
               
                   
               
               
                 1767 
                 UGAACAGGCAGGCCACUUU 
                 99 
                 1767 
                 UGAACAGGCAGGCCACUUU 
                 99 
                 1785 
                 AAAGUGGCCUGCCUGUUCA 
                 249 
               
               
                   
               
               
                 1785 
                 UGCCUCUAAAUUACCUCUG 
                 100 
                 1785 
                 UGCCUCUAAAUUACCUCUG 
                 100 
                 1803 
                 CAGAGGUAAUUUAGAGGCA 
                 250 
               
               
                   
               
               
                 1803 
                 GAUAAUUCUAGAGAUUUUA 
                 101 
                 1803 
                 GAUAAUUCUAGAGAUUUUA 
                 101 
                 1821 
                 UAAAAUCUCUAGAAUUAUC 
                 251 
               
               
                   
               
               
                 1821 
                 ACCAUAUUUCUAAACUUUG 
                 102 
                 1821 
                 ACCAUAUUUCUAAACUUUG 
                 102 
                 1839 
                 CAAAGUUUAGAAAUAUGGU 
                 252 
               
               
                   
               
               
                 1839 
                 GUUUAUAACUCUGAGAAGA 
                 103 
                 1839 
                 GUUUAUAACUCUGAGAAGA 
                 103 
                 1857 
                 UCUUCUCAGAGUUAUAAAC 
                 253 
               
               
                   
               
               
                 1857 
                 AUCAUAUUUAUGUAAAGUA 
                 104 
                 1857 
                 AUCAUAUUUAUGUAAAGUA 
                 104 
                 1875 
                 UACUUUACAUAAAUAUGAU 
                 254 
               
               
                   
               
               
                 1875 
                 AUAUGUAUUUGAGUGCAGA 
                 105 
                 1875 
                 AUAUGUAUUUGAGUGCAGA 
                 105 
                 1893 
                 UCUGCACUCAAAUACAUAU 
                 255 
               
               
                   
               
               
                 1893 
                 AAUUUAAAUAAGGCUCUAC 
                 106 
                 1893 
                 AAUUUAAAUAAGGCUCUAC 
                 106 
                 1911 
                 GUAGAGCCUUAUUUAAAUU 
                 256 
               
               
                   
               
               
                 1911 
                 CCUCAAAGACCUUUGCACA 
                 107 
                 1911 
                 CCUCAAAGACCUUUGCACA 
                 107 
                 1929 
                 UGUGCAAAGGUCUUUGAGG 
                 257 
               
               
                   
               
               
                 1929 
                 AGUUUAUUGGUGUCAUAUU 
                 108 
                 1929 
                 AGUUUAUUGGUGUCAUAUU 
                 108 
                 1947 
                 AAUAUGACACCAAUAAACU 
                 258 
               
               
                   
               
               
                 1947 
                 UAUACAAUAUUUCAAUUGU 
                 109 
                 1947 
                 UAUACAAUAUUUCAAUUGU 
                 109 
                 1965 
                 ACAAUUGAAAUAUUGUAUA 
                 259 
               
               
                   
               
               
                 1965 
                 UGAAUUCACAUAGAAAACA 
                 110 
                 1965 
                 UGAAUUCACAUAGAAAACA 
                 110 
                 1983 
                 UGUUUUCUAUGUGAAUUCA 
                 260 
               
               
                   
               
               
                 1983 
                 AUUAAAUUAUAAUGUUUGA 
                 111 
                 1983 
                 AUUAAAUUAUAAUGUUUGA 
                 111 
                 2001 
                 UCAAACAUUAUAAUUUAAU 
                 261 
               
               
                   
               
               
                 2001 
                 ACUAUUAUAUAUGUGUAUG 
                 112 
                 2001 
                 ACUAUUAUAUAUGUGUAUG 
                 112 
                 2019 
                 CAUACACAUAUAUAAUAGU 
                 262 
               
               
                   
               
               
                 2019 
                 GCAUUUUACUGGCUCAAAA 
                 113 
                 2019 
                 GCAUUUUACUGGCUCAAAA 
                 113 
                 2037 
                 UUUUGAGCCAGUAAAAUGC 
                 263 
               
               
                   
               
               
                 2037 
                 ACUACCUACUUCUUUCUCA 
                 114 
                 2037 
                 ACUACCUACUUCUUUCUCA 
                 114 
                 2055 
                 UGAGAAAGAAGUAGGUAGU 
                 264 
               
               
                   
               
               
                 2055 
                 AGGCAUCAAAAGCAUUUUG 
                 115 
                 2055 
                 AGGCAUCAAAAGCAUUUUG 
                 115 
                 2073 
                 CAAAAUGCUUUUGAUGCCU 
                 265 
               
               
                   
               
               
                 2073 
                 GAGCAGGAGAGUAUUACUA 
                 116 
                 2073 
                 GAGCAGGAGAGUAUUACUA 
                 116 
                 2091 
                 UAGUAAUACUCUCCUGCUC 
                 266 
               
               
                   
               
               
                 2091 
                 AGAGCUUUGCCACCUCUCC 
                 117 
                 2091 
                 AGAGCUUUGCCACCUCUCC 
                 117 
                 2109 
                 GGAGAGGUGGCAAAGCUCU 
                 267 
               
               
                   
               
               
                 2109 
                 CAUUUUUGCCUUGGUGCUC 
                 118 
                 2109 
                 CAUUUUUGCCUUGGUGCUC 
                 118 
                 2127 
                 GAGCACCAAGGCAAAAAUG 
                 268 
               
               
                   
               
               
                 2127 
                 CAUCUUAAUGGCCUAAUGC 
                 119 
                 2127 
                 CAUCUUAAUGGCCUAAUGC 
                 119 
                 2145 
                 GCAUUAGGCCAUUAAGAUG 
                 269 
               
               
                   
               
               
                 2145 
                 CACCCCCAAACAUGGAAAU 
                 120 
                 2145 
                 CACCCCCAAACAUGGAAAU 
                 120 
                 2163 
                 AUUUCCAUGUUUGGGGGUG 
                 270 
               
               
                   
               
               
                 2163 
                 UAUCACCAAAAAAUACUUA 
                 121 
                 2163 
                 UAUCACCAAAAAAUACUUA 
                 121 
                 2181 
                 UAAGUAUUUUUUGGUGAUA 
                 271 
               
               
                   
               
               
                 2181 
                 AAUAGUCCACCAAAAGGCA 
                 122 
                 2181 
                 AAUAGUCCACCAAAAGGCA 
                 122 
                 2199 
                 UGCCUUUUGGUGGACUAUU 
                 272 
               
               
                   
               
               
                 2199 
                 AAGACUGCCCUUAGAAAUU 
                 123 
                 2199 
                 AAGACUGCCCUUAGAAAUU 
                 123 
                 2217 
                 AAUUUCUAAGGGCAGUCUU 
                 273 
               
               
                   
               
               
                 2217 
                 UCUAGCCUGGUUUGGAGAU 
                 124 
                 2217 
                 UCUAGCCUGGUUUGGAGAU 
                 124 
                 2235 
                 AUCUCCAAACCAGGCUAGA 
                 274 
               
               
                   
               
               
                 2235 
                 UACUAACUGCUCUCAGAGA 
                 125 
                 2235 
                 UACUAACUGCUCUCAGAGA 
                 125 
                 2253 
                 UCUCUGAGAGCAGUUAGUA 
                 275 
               
               
                   
               
               
                 2253 
                 AAAGUAGCUUUGUGACAUG 
                 126 
                 2253 
                 AAAGUAGCUUUGUGACAUG 
                 126 
                 2271 
                 CAUGUCACAAAGCUACUUU 
                 276 
               
               
                   
               
               
                 2271 
                 GUCAUGAACCCAUGUUUGC 
                 127 
                 2271 
                 GUCAUGAACCCAUGUUUGC 
                 127 
                 2289 
                 GCAAACAUGGGUUCAUGAC 
                 277 
               
               
                   
               
               
                 2289 
                 CAAUCAAAGAUGAUAAAAU 
                 128 
                 2289 
                 CAAUCAAAGAUGAUAAAAU 
                 128 
                 2307 
                 AUUUUAUCAUCUUUGAUUG 
                 278 
               
               
                   
               
               
                 2307 
                 UAGAUUCUUAUUUUUCCCC 
                 129 
                 2307 
                 UAGAUUCUUAUUUUUCCCC 
                 129 
                 2325 
                 GGGGAAAAAUAAGAAUCUA 
                 279 
               
               
                   
               
               
                 2325 
                 CCACCCCCGAAAAUGUUCA 
                 130 
                 2325 
                 CCACCCCCGAAAAUGUUCA 
                 130 
                 2343 
                 UGAACAUUUUCGGGGGUGG 
                 280 
               
               
                   
               
               
                 2343 
                 AAUAAUGUCCCAUGUAAAA 
                 131 
                 2343 
                 AAUAAUGUCCCAUGUAAAA 
                 131 
                 2361 
                 UUUUACAUGGGACAUUAUU 
                 281 
               
               
                   
               
               
                 2361 
                 ACCUGCUACAAAUGGCAGC 
                 132 
                 2361 
                 ACCUGCUACAAAUGGCAGC 
                 132 
                 2379 
                 GCUGCCAUUUGUAGCAGGU 
                 282 
               
               
                   
               
               
                 2379 
                 CUUAUACAUAGCAAUGGUA 
                 133 
                 2379 
                 CUUAUACAUAGCAAUGGUA 
                 133 
                 2397 
                 UACCAUUGCUAUGUAUAAG 
                 283 
               
               
                   
               
               
                 2397 
                 AAAAUCAUCAUCUGGAUUU 
                 134 
                 2397 
                 AAAAUCAUCAUCUGGAUUU 
                 134 
                 2415 
                 AAAUCCAGAUGAUGAUUUU 
                 284 
               
               
                   
               
               
                 2415 
                 UAGGAAUUGCUCUUGUCAU 
                 135 
                 2415 
                 UAGGAAUUGCUCUUGUCAU 
                 135 
                 2433 
                 AUGACAAGAGCAAUUCCUA 
                 285 
               
               
                   
               
               
                 2433 
                 UACCCCCAAGUUUCUAAGA 
                 136 
                 2433 
                 UACCCCCAAGUUUCUAAGA 
                 136 
                 2451 
                 UCUUAGAAACUUGGGGGUA 
                 286 
               
               
                   
               
               
                 2451 
                 AUUUAAGAUUCUCCUUACU 
                 137 
                 2451 
                 AUUUAAGAUUCUCCUUACU 
                 137 
                 2469 
                 AGUAAGGAGAAUCUUAAAU 
                 287 
               
               
                   
               
               
                 2469 
                 UACUAUCCUACGUUUAAAU 
                 138 
                 2469 
                 UACUAUCCUACGUUUAAAU 
                 138 
                 2487 
                 AUUUAAACGUAGGAUAGUA 
                 288 
               
               
                   
               
               
                 2487 
                 UAUCUUUGAAAGUUUGUAU 
                 139 
                 2487 
                 UAUCUUUGAAAGUUUGUAU 
                 139 
                 2505 
                 AUACAAACUUUCAAAGAUA 
                 289 
               
               
                   
               
               
                 2505 
                 UUAAAUGUGAAUUUUAAGA 
                 140 
                 2505 
                 UUAAAUGUGAAUUUUAAGA 
                 140 
                 2523 
                 UCUUAAAAUUCACAUUUAA 
                 290 
               
               
                   
               
               
                 2523 
                 AAAUAAUAUUUAUAUUUCU 
                 141 
                 2523 
                 AAAUAAUAUUUAUAUUUCU 
                 141 
                 2541 
                 AGAAAUAUAAAUAUUAUUU 
                 291 
               
               
                   
               
               
                 2541 
                 UGUAAAUGUAAACUGUGAA 
                 142 
                 2541 
                 UGUAAAUGUAAACUGUGAA 
                 142 
                 2559 
                 UUCACAGUUUACAUUUACA 
                 292 
               
               
                   
               
               
                 2559 
                 AGAUAGUUAUAAACUGAAG 
                 143 
                 2559 
                 AGAUAGUUAUAAACUGAAG 
                 143 
                 2577 
                 CUUCAGUUUAUAACUAUCU 
                 293 
               
               
                   
               
               
                 2577 
                 GCAGAUACCUGGAACCACC 
                 144 
                 2577 
                 GCAGAUACCUGGAACCACC 
                 144 
                 2595 
                 GGUGGUUCCAGGUAUCUGC 
                 294 
               
               
                   
               
               
                 2595 
                 CUAAAGAACUUCCAUUUAU 
                 145 
                 2595 
                 CUAAAGAACUUCCAUUUAU 
                 145 
                 2613 
                 AUAAAUGGAAGUUCUUUAG 
                 295 
               
               
                   
               
               
                 2613 
                 UGGAGGAUUUUUUUGCCCC 
                 146 
                 2613 
                 UGGAGGAUUUUUUUGCCCC 
                 146 
                 2631 
                 GGGGCAAAAAAAUCCUCCA 
                 296 
               
               
                   
               
               
                 2631 
                 CUUGUGUUUGGAAUUAUAA 
                 147 
                 2631 
                 CUUGUGUUUGGAAUUAUAA 
                 147 
                 2649 
                 UUAUAAUUCCAAACACAAG 
                 297 
               
               
                   
               
               
                 2649 
                 AAAUAUAGGUAAAAGUACG 
                 148 
                 2649 
                 AAAUAUAGGUAAAAGUACG 
                 148 
                 2667 
                 CGUACUUUUACCUAUAUUU 
                 298 
               
               
                   
               
               
                 2667 
                 GUAAUUAAAUAAUGUUUUU 
                 149 
                 2667 
                 GUAAUUAAAUAAUGUUUUU 
                 149 
                 2685 
                 AAAAACAUUAUUUAAUUAC 
                 299 
               
               
                   
               
               
                 2685 
                 UGGUAAAAAAAAAAAAAAA 
                 150 
                 2685 
                 UGGUAAAAAAAAAAAAAAA 
                 150 
                 2703 
                 UUUUUUUUUUUUUUUACCA 
                 300 
               
               
                   
               
            
           
           
               
            
               
                 FasL TNFSF6 NM_000639 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 3 
                 GGUGUUUCCCUUAGCUAUG 
                 301 
                 3 
                 GGUGUUUCCCUUAGCUAUG 
                 301 
                 21 
                 CAUAGCUAAGGGAAACACC 
                 405 
                   
               
               
                   
               
               
                 21 
                 GGAAACUCUAUAAGAGAGA 
                 302 
                 21 
                 GGAAACUCUAUAAGAGAGA 
                 302 
                 39 
                 UCUCUCUUAUAGAGUUUCC 
                 406 
               
               
                   
               
               
                 39 
                 AUCCAGCUUGCCUCCUCUU 
                 303 
                 39 
                 AUCCAGCUUGCCUCCUCUU 
                 303 
                 57 
                 AAGAGGAGGCAAGCUGGAU 
                 407 
               
               
                   
               
               
                 57 
                 UGAGCAGUCAGCAACAGGG 
                 304 
                 57 
                 UGAGCAGUCAGCAACAGGG 
                 304 
                 75 
                 CCCUGUUGCUGACUGCUCA 
                 408 
               
               
                   
               
               
                 75 
                 GUCCCGUCCUUGACACCUC 
                 305 
                 75 
                 GUCCCGUCCUUGACACCUC 
                 305 
                 93 
                 GAGGUGUCAAGGACGGGAC 
                 409 
               
               
                   
               
               
                 93 
                 CAGCCUCUACAGGACUGAG 
                 306 
                 93 
                 CAGCCUCUACAGGACUGAG 
                 306 
                 111 
                 CUCAGUCCUGUAGAGGCUG 
                 410 
               
               
                   
               
               
                 111 
                 GAAGAAGUAAAACCGUUUG 
                 307 
                 111 
                 GAAGAAGUAAAACCGUUUG 
                 307 
                 129 
                 CAAACGGUUUUACUUCUUC 
                 411 
               
               
                   
               
               
                 129 
                 GCUGGGGCUGGCCUGACUC 
                 308 
                 129 
                 GCUGGGGCUGGCCUGACUC 
                 308 
                 147 
                 GAGUCAGGCCAGCCCCAGC 
                 412 
               
               
                   
               
               
                 147 
                 CACCAGCUGCCAUGCAGCA 
                 309 
                 147 
                 CACCAGCUGCCAUGCAGCA 
                 309 
                 165 
                 UGCUGCAUGGCAGCUGGUG 
                 413 
               
               
                   
               
               
                 165 
                 AGCCCUUCAAUUACCCAUA 
                 310 
                 165 
                 AGCCCUUCAAUUACCCAUA 
                 310 
                 183 
                 UAUGGGUAAUUGAAGGGCU 
                 414 
               
               
                   
               
               
                 183 
                 AUCCCCAGAUCUACUGGGU 
                 311 
                 183 
                 AUCCCCAGAUCUACUGGGU 
                 311 
                 201 
                 ACCCAGUAGAUCUGGGGAU 
                 415 
               
               
                   
               
               
                 201 
                 UGGACAGCAGUGCCAGCUC 
                 312 
                 201 
                 UGGACAGCAGUGCCAGCUC 
                 312 
                 219 
                 GAGGUGGCACUGGUGUCCA 
                 416 
               
               
                   
               
               
                 219 
                 CUCCCUGGGCCCCUCCAGG 
                 313 
                 219 
                 CUCCCUGGGCCCCUCCAGG 
                 313 
                 237 
                 CCUGGAGGGGCCCAGGGAG 
                 417 
               
               
                   
               
               
                 237 
                 GCACAGUUCUUCCCUGUCC 
                 314 
                 237 
                 GCACAGUUCUUCCCUGUCC 
                 314 
                 255 
                 GGACAGGGAAGAACUGUGC 
                 418 
               
               
                   
               
               
                 255 
                 CAACCUCUGUGCCCAGAAG 
                 315 
                 255 
                 CAACCUCUGUGCCCAGAAG 
                 315 
                 273 
                 CUUCUGGGCACAGAGGUUG 
                 419 
               
               
                   
               
               
                 273 
                 GGCCUGGUCAAAGGAGGCC 
                 316 
                 273 
                 GGCCUGGUCAAAGGAGGCC 
                 316 
                 291 
                 GGCCUCCUUUGACCAGGCC 
                 420 
               
               
                   
               
               
                 291 
                 CACCACCACCACCGCCACC 
                 317 
                 291 
                 CACCACCACCACCGCCACC 
                 317 
                 309 
                 GGUGGCGGUGGUGGUGGUG 
                 421 
               
               
                   
               
               
                 309 
                 CGCCACCACUACCACCUCC 
                 318 
                 309 
                 CGCCACCACUACCACCUCC 
                 318 
                 327 
                 GGAGGUGGUAGUGGUGGCG 
                 422 
               
               
                   
               
               
                 327 
                 CGCCGCCGCCGCCACCACU 
                 319 
                 327 
                 CGCCGCCGCCGCCACCACU 
                 319 
                 345 
                 AGUGGUGGCGGCGGCGGCG 
                 423 
               
               
                   
               
               
                 345 
                 UGCCUCCACUACCGCUGCC 
                 320 
                 345 
                 UGCCUCCACUACCGCUGCC 
                 320 
                 363 
                 GGCAGCGGUAGUGGAGGCA 
                 424 
               
               
                   
               
               
                 363 
                 CACCCCUGAAGAAGAGAGG 
                 321 
                 363 
                 CACCCCUGAAGAAGAGAGG 
                 321 
                 381 
                 CCUCUCUUCUUCAGGGGUG 
                 425 
               
               
                   
               
               
                 381 
                 GGAACCACAGCACAGGCCU 
                 322 
                 381 
                 GGAACCACAGCACAGGCCU 
                 322 
                 399 
                 AGGCCUGUGCUGUGGUUCC 
                 426 
               
               
                   
               
               
                 399 
                 UGUGUCUCCUUGUGAUGUU 
                 323 
                 399 
                 UGUGUCUCCUUGUGAUGUU 
                 323 
                 417 
                 AACAUCACAAGGAGACACA 
                 427 
               
               
                   
               
               
                 417 
                 UUUUCAUGGUUCUGGUUGC 
                 324 
                 417 
                 UUUUCAUGGUUCUGGUUGC 
                 324 
                 435 
                 GCAACCAGAACCAUGAAAA 
                 428 
               
               
                   
               
               
                 435 
                 CCUUGGUAGGAUUGGGCCU 
                 325 
                 435 
                 CCUUGGUAGGAUUGGGCCU 
                 325 
                 453 
                 AGGCCCAAUCCUACCAAGG 
                 429 
               
               
                   
               
               
                 453 
                 UGGGGAUGUUUCAGCUCUU 
                 326 
                 453 
                 UGGGGAUGUUUCAGCUCUU 
                 326 
                 471 
                 AAGAGCUGAAACAUCCCCA 
                 430 
               
               
                   
               
               
                 471 
                 UCCACCUACAGAAGGAGCU 
                 327 
                 471 
                 UCCACCUACAGAAGGAGCU 
                 327 
                 489 
                 AGCUCCUUCUGUAGGUGGA 
                 431 
               
               
                   
               
               
                 489 
                 UGGCAGAACUCCGAGAGUC 
                 328 
                 489 
                 UGGCAGAACUCCGAGAGUC 
                 328 
                 507 
                 GACUCUCGGAGUUCUGCCA 
                 432 
               
               
                   
               
               
                 507 
                 CUACCAGCCAGAUGCACAC 
                 329 
                 507 
                 CUACCAGCCAGAUGCACAC 
                 329 
                 525 
                 GUGUGCAUCUGGCUGGUAG 
                 433 
               
               
                   
               
               
                 525 
                 CAGCAUCAUCUUUGGAGAA 
                 330 
                 525 
                 CAGCAUCAUCUUUGGAGAA 
                 330 
                 543 
                 UUCUCCAAAGAUGAUGCUG 
                 434 
               
               
                   
               
               
                 543 
                 AGCAAAUAGGCCACCCCAG 
                 331 
                 543 
                 AGCAAAUAGGCCACCCCAG 
                 331 
                 561 
                 CUGGGGUGGCCUAUUUGCU 
                 435 
               
               
                   
               
               
                 561 
                 GUCCACCCCCUGAAAAAAA 
                 332 
                 561 
                 GUCCACCCCCUGAAAAAAA 
                 332 
                 579 
                 UUUUUUUCAGGGGGUGGAC 
                 436 
               
               
                   
               
               
                 579 
                 AGGAGCUGAGGAAAGUGGC 
                 333 
                 579 
                 AGGAGCUGAGGAAAGUGGC 
                 333 
                 597 
                 GCCACUUUCCUCAGCUCCU 
                 437 
               
               
                   
               
               
                 597 
                 CCCAUUUAACAGGCAAGUC 
                 334 
                 597 
                 CCCAUUUAACAGGCAAGUC 
                 334 
                 615 
                 GACUUGCCUGUUAAAUGGG 
                 438 
               
               
                   
               
               
                 615 
                 CCAACUCAAGGUCCAUGCC 
                 335 
                 615 
                 CCAACUCAAGGUCCAUGCC 
                 335 
                 633 
                 GGCAUGGACCUUGAGUUGG 
                 439 
               
               
                   
               
               
                 633 
                 CUCUGGAAUGGGAAGACAC 
                 336 
                 633 
                 CUCUGGAAUGGGAAGACAC 
                 336 
                 651 
                 GUGUCUUCCCAUUCCAGAG 
                 440 
               
               
                   
               
               
                 651 
                 CCUAUGGAAUUGUCCUGCU 
                 337 
                 651 
                 CCUAUGGAAUUGUCCUGCU 
                 337 
                 669 
                 AGCAGGACAAUUCCAUAGG 
                 441 
               
               
                   
               
               
                 669 
                 UUUCUGGAGUGAAGUAUAA 
                 338 
                 669 
                 UUUCUGGAGUGAAGUAUAA 
                 338 
                 687 
                 UUAUACUUCACUCCAGAAA 
                 442 
               
               
                   
               
               
                 687 
                 AGAAGGGUGGCCUUGUGAU 
                 339 
                 687 
                 AGAAGGGUGGCCUUGUGAU 
                 339 
                 705 
                 AUCACAAGGCCACCCUUCU 
                 443 
               
               
                   
               
               
                 705 
                 UCAAUGAAACUGGGCUGUA 
                 340 
                 705 
                 UCAAUGAAACUGGGCUGUA 
                 340 
                 723 
                 UACAGCCCAGUUUCAUUGA 
                 444 
               
               
                   
               
               
                 723 
                 ACUUUGUAUAUUCCAAAGU 
                 341 
                 723 
                 ACUUUGUAUAUUCCAAAGU 
                 341 
                 741 
                 ACUUUGGAAUAUACAAAGU 
                 445 
               
               
                   
               
               
                 741 
                 UAUACUUCCGGGGUCAAUC 
                 342 
                 741 
                 UAUACUUCCGGGGUCAAUC 
                 342 
                 759 
                 GAUUGACCCCGGAAGUAUA 
                 446 
               
               
                   
               
               
                 759 
                 CUUGCAACAACCUGCCCCU 
                 343 
                 759 
                 CUUGCAACAACCUGCCCCU 
                 343 
                 777 
                 AGGGGCAGGUUGUUGCAAG 
                 447 
               
               
                   
               
               
                 777 
                 UGAGCCACAAGGUCUACAU 
                 344 
                 777 
                 UGAGCCACAAGGUCUACAU 
                 344 
                 795 
                 AUGUAGACCUUGUGGCUCA 
                 448 
               
               
                   
               
               
                 795 
                 UGAGGAACUCUAAGUAUCC 
                 345 
                 795 
                 UGAGGAACUCUAAGUAUCC 
                 345 
                 813 
                 GGAUACUUAGAGUUCCUCA 
                 449 
               
               
                   
               
               
                 813 
                 CCCAGGAUCUGGUGAUGAU 
                 346 
                 813 
                 CCCAGGAUCUGGUGAUGAU 
                 346 
                 831 
                 AUCAUCACCAGAUCCUGGG 
                 450 
               
               
                   
               
               
                 831 
                 UGGAGGGGAAGAUGAUGAG 
                 347 
                 831 
                 UGGAGGGGAAGAUGAUGAG 
                 347 
                 849 
                 CUCAUCAUCUUCCCCUCCA 
                 451 
               
               
                   
               
               
                 849 
                 GCUACUGCACUACUGGGCA 
                 348 
                 849 
                 GCUACUGCACUACUGGGCA 
                 348 
                 867 
                 UGCCCAGUAGUGCAGUAGC 
                 452 
               
               
                   
               
               
                 867 
                 AGAUGUGGGCCCGCAGCAG 
                 349 
                 867 
                 AGAUGUGGGCCCGCAGCAG 
                 349 
                 885 
                 CUGCUGCGGGCCCACAUCU 
                 453 
               
               
                   
               
               
                 885 
                 GCUACCUGGGGGCAGUGUU 
                 350 
                 885 
                 GCUACCUGGGGGCAGUGUU 
                 350 
                 903 
                 AACACUGCCCCCAGGUAGC 
                 454 
               
               
                   
               
               
                 903 
                 UCAAUCUUACCAGUGCUGA 
                 351 
                 903 
                 UCAAUCUUACCAGUGCUGA 
                 351 
                 921 
                 UCAGCACUGGUAAGAUUGA 
                 455 
               
               
                   
               
               
                 921 
                 AUCAUUUAUAUGUCAACGU 
                 352 
                 921 
                 AUCAUUUAUAUGUCAACGU 
                 352 
                 939 
                 ACGUUGACAUAUAAAUGAU 
                 456 
               
               
                   
               
               
                 939 
                 UAUCUGAGCUCUCUCUGGU 
                 353 
                 939 
                 UAUCUGAGCUCUCUCUGGU 
                 353 
                 957 
                 ACCAGAGAGAGCUCAGAUA 
                 457 
               
               
                   
               
               
                 957 
                 UCAAUUUUGAGGAAUCUCA 
                 354 
                 957 
                 UCAAUUUUGAGGAAUCUCA 
                 354 
                 975 
                 UGAGAUUCCUCAAAAUUGA 
                 458 
               
               
                   
               
               
                 975 
                 AGACGUUUUUCGGCUUAUA 
                 355 
                 975 
                 AGACGUUUUUCGGCUUAUA 
                 355 
                 993 
                 UAUAAGCCGAAAAACGUCU 
                 459 
               
               
                   
               
               
                 993 
                 AUAAGCUCUAAGAGAAGCA 
                 356 
                 993 
                 AUAAGCUCUAAGAGAAGCA 
                 356 
                 1011 
                 UGCUUCUCUUAGAGCUUAU 
                 460 
               
               
                   
               
               
                 1011 
                 ACUUUGGGAUUCUUUCCAU 
                 357 
                 1011 
                 ACUUUGGGAUUCUUUCCAU 
                 357 
                 1029 
                 AUGGAAAGAAUCCCAAAGU 
                 461 
               
               
                   
               
               
                 1029 
                 UUAUGAUUCUUUGUUACAG 
                 358 
                 1029 
                 UUAUGAUUCUUUGUUACAG 
                 358 
                 1047 
                 CUGUAACAAAGAAUCAUAA 
                 462 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAU 
                 359 
                 1047 
                 GGCACCGAGAAUGUUGUAU 
                 359 
                 1065 
                 AUACAACAUUCUCGGUGCC 
                 463 
               
               
                   
               
               
                 1065 
                 UUCAGUGAGGGUCUUCUUA 
                 360 
                 1065 
                 UUCAGUGAGGGUCUUCUUA 
                 360 
                 1083 
                 UAAGAAGACCCUCACUGAA 
                 464 
               
               
                   
               
               
                 1083 
                 ACAUGCAUUUGAGGUCAAG 
                 361 
                 1083 
                 ACAUGCAUUUGAGGUCAAG 
                 361 
                 1101 
                 CUUGACCUCAAAUGCAUGU 
                 465 
               
               
                   
               
               
                 1101 
                 GUAAGAAGACAUGAACCAA 
                 362 
                 1101 
                 GUAAGAAGACAUGAACCAA 
                 362 
                 1119 
                 UUGGUUCAUGUCUUCUUAC 
                 466 
               
               
                   
               
               
                 1119 
                 AGUGGACCUUGAGACCACA 
                 363 
                 1119 
                 AGUGGACCUUGAGACCACA 
                 363 
                 1137 
                 UGUGGUCUCAAGGUCCACU 
                 467 
               
               
                   
               
               
                 1137 
                 AGGGUUCAAAAUGUCUGUA 
                 364 
                 1137 
                 AGGGUUCAAAAUGUCUGUA 
                 364 
                 1155 
                 UACAGACAUUUUGAACCCU 
                 468 
               
               
                   
               
               
                 1155 
                 AGCUCCUCAACUCACCUAA 
                 365 
                 1155 
                 AGCUCCUCAACUCACCUAA 
                 365 
                 1173 
                 UUAGGUGAGUUGAGGAGCU 
                 469 
               
               
                   
               
               
                 1173 
                 AUGUUUAUGAGCCAGACAA 
                 366 
                 1173 
                 AUGUUUAUGAGCCAGACAA 
                 366 
                 1191 
                 UUGUCUGGCUCAUAAACAU 
                 470 
               
               
                   
               
               
                 1191 
                 AAUGGAGGAAUAUGACGGA 
                 367 
                 1191 
                 AAUGGAGGAAUAUGACGGA 
                 367 
                 1209 
                 UCCGUCAUAUUCCUCCAUU 
                 471 
               
               
                   
               
               
                 1209 
                 AAGAACAUAGAACUCUGGG 
                 368 
                 1209 
                 AAGAACAUAGAACUCUGGG 
                 368 
                 1227 
                 CCCAGAGUUCUAUGUUCUU 
                 472 
               
               
                   
               
               
                 1227 
                 GCUGCCAUGUGAAGAGGGA 
                 369 
                 1227 
                 GCUGCCAUGUGAAGAGGGA 
                 369 
                 1245 
                 UCCCUCUUCACAUGGCAGC 
                 473 
               
               
                   
               
               
                 1245 
                 AGAAGCAUGAAAAAGCAGC 
                 370 
                 1245 
                 AGAAGCAUGAAAAAGCAGC 
                 370 
                 1263 
                 GCUGCUUUUUCAUGCUUCU 
                 474 
               
               
                   
               
               
                 1263 
                 CUACCAGGUGUUCUACACU 
                 371 
                 1263 
                 CUACCAGGUGUUCUACACU 
                 371 
                 1281 
                 AGUGUAGAACACCUGGUAG 
                 475 
               
               
                   
               
               
                 1281 
                 UCAUCUUAGUGCCUGAGAG 
                 372 
                 1281 
                 UCAUCUUAGUGCCUGAGAG 
                 372 
                 1299 
                 CUCUCAGGCACUAAGAUGA 
                 476 
               
               
                   
               
               
                 1299 
                 GUAUUUAGGCAGAUUGAAA 
                 373 
                 1299 
                 GUAUUUAGGCAGAUUGAAA 
                 373 
                 1317 
                 UUUCAAUCUGCCUAAAUAC 
                 477 
               
               
                   
               
               
                 1317 
                 AAGGACACCUUUUAACUCA 
                 374 
                 1317 
                 AAGGACACCUUUUAACUCA 
                 374 
                 1335 
                 UGAGUUAAAAGGUGUCCUU 
                 478 
               
               
                   
               
               
                 1335 
                 ACCUCUCAAGGUGGGCCUU 
                 375 
                 1335 
                 ACCUCUCAAGGUGGGCCUU 
                 375 
                 1353 
                 AAGGCCCACCUUGAGAGGU 
                 479 
               
               
                   
               
               
                 1353 
                 UGCUACCUCAAGGGGGACU 
                 376 
                 1353 
                 UGCUACCUCAAGGGGGACU 
                 376 
                 1371 
                 AGUCCCCCUUGAGGUAGCA 
                 480 
               
               
                   
               
               
                 1371 
                 UGUCUUUCAGAUACAUGGU 
                 377 
                 1371 
                 UGUCUUUCAGAUACAUGGU 
                 377 
                 1389 
                 ACCAUGUAUCUGAAAGACA 
                 481 
               
               
                   
               
               
                 1389 
                 UUGUGACCUGAGGAUUUAA 
                 378 
                 1389 
                 UUGUGACCUGAGGAUUUAA 
                 378 
                 1407 
                 UUAAAUCCUCAGGUCACAA 
                 482 
               
               
                   
               
               
                 1407 
                 AGGGAUGGAAAAGGAAGAC 
                 379 
                 1407 
                 AGGGAUGGAAAAGGAAGAC 
                 379 
                 1425 
                 GUCUUCCUUUUCCAUCCCU 
                 483 
               
               
                   
               
               
                 1425 
                 CUAGAGGCUUGCAUAAUAA 
                 380 
                 1425 
                 CUAGAGGCUUGCAUAAUAA 
                 380 
                 1443 
                 UUAUUAUGCAAGCCUCUAG 
                 484 
               
               
                   
               
               
                 1443 
                 AGCUAAAGAGGCUGAAAGA 
                 381 
                 1443 
                 AGCUAAAGAGGCUGAAAGA 
                 381 
                 1461 
                 UCUUUCAGCCUCUUUAGCU 
                 485 
               
               
                   
               
               
                 1461 
                 AGGCCAAUGCCCCACUGGC 
                 382 
                 1461 
                 AGGCCAAUGCCCCACUGGC 
                 382 
                 1479 
                 GCCAGUGGGGCAUUGGCCU 
                 486 
               
               
                   
               
               
                 1479 
                 CAGCAUCUUCACUUCUAAA 
                 383 
                 1479 
                 CAGCAUCUUCACUUCUAAA 
                 383 
                 1497 
                 UUUAGAAGUGAAGAUGCUG 
                 487 
               
               
                   
               
               
                 1497 
                 AUGCAUAUCCUGAGCCAUC 
                 384 
                 1497 
                 AUGCAUAUCCUGAGCCAUC 
                 384 
                 1515 
                 GAUGGCUCAGGAUAUGCAU 
                 488 
               
               
                   
               
               
                 1515 
                 CGGUGAAACUAACAGAUAA 
                 385 
                 1515 
                 CGGUGAAACUAACAGAUAA 
                 385 
                 1533 
                 UUAUCUGUUAGUUUCACCG 
                 489 
               
               
                   
               
               
                 1533 
                 AGCAAGAGAGAUGUUUUGG 
                 386 
                 1533 
                 AGCAAGAGAGAUGUUUUGG 
                 386 
                 1551 
                 CCAAAACAUCUCUCUUGCU 
                 490 
               
               
                   
               
               
                 1551 
                 GGGACUCAUUUCAUUCCUA 
                 387 
                 1551 
                 GGGACUCAUUUCAUUCCUA 
                 387 
                 1569 
                 UAGGAAUGAAAUGAGUCCC 
                 491 
               
               
                   
               
               
                 1569 
                 AACACAGCAUGUGUAUUUC 
                 388 
                 1569 
                 AACACAGCAUGUGUAUUUC 
                 388 
                 1587 
                 GAAAUACACAUGCUGUGUU 
                 492 
               
               
                   
               
               
                 1587 
                 CCAGUGCAAUUGUAGGGGU 
                 389 
                 1587 
                 CCAGUGCAAUUGUAGGGGU 
                 389 
                 1605 
                 ACCCCUACAAUUGCACUGG 
                 493 
               
               
                   
               
               
                 1605 
                 UGUGUGUGUGUGUGUGUGU 
                 390 
                 1605 
                 UGUGUGUGUGUGUGUGUGU 
                 390 
                 1623 
                 ACACACACACACACACACA 
                 494 
               
               
                   
               
               
                 1623 
                 UGUGUGUGUGUGUAUGACU 
                 391 
                 1623 
                 UGUGUGUGUGUGUAUGACU 
                 391 
                 1641 
                 AGUCAUACACACACACACA 
                 495 
               
               
                   
               
               
                 1641 
                 UAAAGAGAGAAUGUAGAUA 
                 392 
                 1641 
                 UAAAGAGAGAAUGUAGAUA 
                 392 
                 1659 
                 UAUCUACAUUCUCUCUUUA 
                 496 
               
               
                   
               
               
                 1659 
                 AUUGUGAAGUACAUAUUAG 
                 393 
                 1659 
                 AUUGUGAAGUACAUAUUAG 
                 393 
                 1677 
                 CUAAUAUGUACUUCACAAU 
                 497 
               
               
                   
               
               
                 1677 
                 GGAAAAUAUGGGUUGCAUU 
                 394 
                 1677 
                 GGAAAAUAUGGGUUGCAUU 
                 394 
                 1695 
                 AAUGCAACCCAUAUUUUCC 
                 498 
               
               
                   
               
               
                 1695 
                 UUGGUCAAGAUUUUGAAUG 
                 395 
                 1695 
                 UUGGUCAAGAUUUUGAAUG 
                 395 
                 1713 
                 CAUUCAAAAUCUUGACCAA 
                 499 
               
               
                   
               
               
                 1713 
                 GCUUCCUGACAAUCAACUC 
                 396 
                 1713 
                 GCUUCCUGACAAUCAACUC 
                 396 
                 1731 
                 GAGUUGAUUGUCAGGAAGC 
                 500 
               
               
                   
               
               
                 1731 
                 CUAAUAGUGCUUAAAAAUC 
                 397 
                 1731 
                 CUAAUAGUGCUUAAAAAUC 
                 397 
                 1749 
                 GAUUUUUAAGCACUAUUAG 
                 501 
               
               
                   
               
               
                 1749 
                 CAUUGAUUGUCAGCUACUA 
                 398 
                 1749 
                 CAUUGAUUGUCAGCUACUA 
                 398 
                 1767 
                 UAGUAGCUGACAAUCAAUG 
                 502 
               
               
                   
               
               
                 1767 
                 AAUGAUGUUUUCCUAUAAU 
                 399 
                 1767 
                 AAUGAUGUUUUCCUAUAAU 
                 399 
                 1785 
                 AUUAUAGGAAAACAUCAUU 
                 503 
               
               
                   
               
               
                 1785 
                 UAUAAUAAAUAUUUAUGUA 
                 400 
                 1785 
                 UAUAAUAAAUAUUUAUGUA 
                 400 
                 1803 
                 UACAUAAAUAUUUAUUAUA 
                 504 
               
               
                   
               
               
                 1803 
                 AGAUGUGCAUUUUUGUGAA 
                 401 
                 1803 
                 AGAUGUGCAUUUUUGUGAA 
                 401 
                 1821 
                 UUCACAAAAAUGCACAUCU 
                 505 
               
               
                   
               
               
                 1821 
                 AAUGAAAACAUGUAAUAAA 
                 402 
                 1821 
                 AAUGAAAACAUGUAAUAAA 
                 402 
                 1839 
                 UUUAUUACAUGUUUUCAUU 
                 506 
               
               
                   
               
               
                 1839 
                 AAAGUAUAUGUUAGGAUAC 
                 403 
                 1839 
                 AAAGUAUAUGUUAGGAUAC 
                 403 
                 1857 
                 GUAUCCUAACAUAUACUUU 
                 507 
               
               
                   
               
               
                 1854 
                 AUACAAAAAAAAAAAAAAA 
                 404 
                 1854 
                 AUACAAAAAAAAAAAAAAA 
                 404 
                 1872 
                 UUUUUUUUUUUUUUUGUAU 
                 508 
               
               
                   
               
               
                   The 3′-ends of the Upper sequence and the Lower sequence of the siNA construct can include an overhang sequence, for example about 1, 2, 3, or 4 nucleotides in length, preferably 2 nucleotides in length, wherein the overhanging sequence of the lower sequence is optionally complementary to a portion of the target sequence. The upper sequence is also referred to as the sense strand, whereas the lower sequence is also referred to as the antisense strand. The upper and lower    
               
               
                 # sequences in the Table can further comprise a chemical modification having Formulae I-VII or any combination thereof.  
               
            
           
         
       
     
     
       
         
           
               
               
               
             
               
                 TABLE III 
               
             
            
               
                   
               
               
                   
               
               
                 Fas and FasL Synthetic Modified siNA constructs 
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Target 
                   
                 Seq 
                 Com- 
                   
                   
                 Seq 
                   
                   
               
               
                 Pos 
                 Target 
                 ID 
                 pound# 
                 Aliases 
                 Sequence 
                 ID 
               
               
                   
               
            
           
           
               
               
               
            
               
                 FAS 
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:422U21 siRNA 
                 CAAGUGACUGACAUCAACUTT 
                 525 
                   
                   
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:427U21 siRNA 
                 GACUGACAUCAACUCCAAGTT 
                 526 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:550U21 siRNA 
                 GAAAGCUAGGGACUGCACATT 
                 527 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1096U21 siRNA 
                 AAAGAAUGGUGUCAAUGAATT 
                 528 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1100U21 siRNA 
                 AAUGGUGUCAAUGAAGCCATT 
                 529 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1463U21 siRNA 
                 UUUAUUAGCGCUGAAGAGCTT 
                 530 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1906U21 siRNA 
                 CUCUACCUCAAAGACCUUUTT 
                 531 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2576U21 siRNA 
                 AGCAGAUACCUGGAACCACTT 
                 532 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:440L21 siRNA (422C) 
                 AGUUGAUGUCAGUCACUUGTT 
                 533 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:445L21 siRNA (427C) 
                 CUUGGAGUUGAUGUCAGUCTT 
                 534 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:568L21 siRNA (550C) 
                 UGUGCAGUCCCUAGCUUUCTT 
                 535 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1114L21 siRNA (1096C) 
                 UUCAUUGACACCAUUCUUUTT 
                 536 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1118L21 siRNA (1100C) 
                 UGGCUUCAUUGACACCAUUTT 
                 537 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1481L21 siRNA (1463C) 
                 GCUCUUCAGCGCUAAUAAATT 
                 538 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1924L21 siRNA (1906C) 
                 AAAGGUCUUUGAGGUAGAGTT 
                 539 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2594L21 siRNA (2576C) 
                 GUGGUUCCAGGUAUCUGCUU 
                 540 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:422U21 siRNA stab04 
                 B cAAGuGAcuGAcAucAAcuTT B 
                 541 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:427U21 siRNA stab04 
                 B GAcuGAcAucAAcuccAAGTT B 
                 542 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:550U21 siRNA stab04 
                 B GAAAGcuAGGGAcuGcAcATT B 
                 543 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1096U21 siRNA stab04 
                 B AAAGAAuGGuGucAAuGAATT B 
                 544 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1100U21 siRNA stab04 
                 B AAuGGuGucAAuGAAGccATT B 
                 545 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1463U21 siRNA stab04 
                 B uuuAuuAGcGcuGAAGAGcTT B 
                 546 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1906U21 siRNA stab04 
                 B cucuAccucAAAGAccuuuTT B 
                 547 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2576U21 siRNA stab04 
                 B AGcAGAuAccuGGAAccAcTT B 
                 548 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:440L21 siRNA (422C) stab05 
                 AGuuGAuGucAGucAcuuGTsT 
                 549 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:445L21 siRNA (427C) stab05 
                 cuuGGAGuuGAuGucAGucTsT 
                 550 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:568L21 siRNA (550C) stab05 
                 uGuGcAGucccuAGcuuucTsT 
                 551 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1114L21 siRNA (1096C) 
                 uucAuuGAcAccAuucuuuTsT 
                 552 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1118L21 siRNA (1100C) 
                 uGGcuucAuuGAcAccAuuTsT 
                 553 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1481L21 siRNA (1463C) 
                 GcucuucAGcGcuAAuAAATsT 
                 554 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1924L21 siRNA (1906C) 
                 AAAGGucuuuGAGGuAGAGTsT 
                 555 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2594L21 siRNA (2576C) 
                 GuGGuuccAGGuAucuGcuTsT 
                 556 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:422U21 siRNA stab07 
                 B c AAG u GA cu GA c A uc AA cuTT B 
                 557 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:427U21 siRNA stab07 
                 B  GA cu GA c A uc AA cucc AAG TT B 
                 558 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:550U21 siRNA stab07 
                 B  GAAAG cu AGGGA cu G c A c A TT B 
                 559 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1096U21 siRNA stab07 
                 B  AAAGAA u GG u G uc AA u GAA TT B 
                 560 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1100U21 siRNA stab07 
                 B  AA u GG u G uc AA u GAAG cc A TT B 
                 561 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1463U21 siRNA stab07 
                 B uuu A uu AG c G cu GAAGAG cTT B 
                 562 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1906U21 siRNA stab07 
                 B cucu A ccuc AAAGA ccuuuTT B 
                 563 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2576U21 siRNA stab07 
                 B  AG c AGA u A ccu GGAA cc A cTT B 
                 564 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:440L21 siRNA (422C) stab11 
                   AG uu GA u G uc AG uc A cuu G TsT 
                 565 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:445L21 siRNA (427C) stab11 
                 cuu GGAG uu GA u G uc AG ucTsT 
                 566 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:568L21 siRNA (550C) stab11 
                 u G u G c AG ucccu AG cuuucTsT 
                 567 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1114L21 siRNA (1096C) 
                 uuc A uu GA c A cc A uucuuuTsT 
                 568 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1118L21 siRNA (1100C) 
                 u GG cuuc A uu GA c A cc A uuTsT 
                 569 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1481L21 siRNA (1463C) 
                   G cucuuc AG c G cu AA u AAA TsT 
                 570 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1924L21 siRNA (1906C) 
                   AAAGG ucuuu GAGG u AGAG TsT 
                 571 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2594L21 siRNA (2576C) 
                   G u GG uucc AGG u A ucu G cuTsT 
                 572 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:422U21 siRNA stab18 
                 B c AAG u GA cu GA c A uc AA cuTT B 
                 573 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:427U21 siRNA stab18 
                 B  GA cu GA c A uc AA cucc AAG TT B 
                 574 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:550U21 siRNA stab18 
                 B  GAAAG cu AGGGA cu G c A c A TT B 
                 575 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1096U21 siRNA stab18 
                 B  AAAGAA u GG u G uc AA u GAA TT B 
                 576 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1100U21 siRNA stab18 
                 B  AA u GG u G uc AA u GAAG cc A TT B 
                 577 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1463U21 siRNA stab18 
                 B uuu A uu AG c G cu GAAGAG cTT B 
                 578 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1906U21 siRNA stab18 
                 B cucu A ccuc AAAGA ccuuuTT B 
                 579 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2576U21 siRNA stab18 
                 B  AG c AGA u A ccu GGAA cc A cTT B 
                 580 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:440L21 siRNA (422C) stab08 
                   AG uu GA u G uc AG uc A cuu G TsT 
                 581 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:445L21 siRNA (427C) stab08 
                 cuu GGAG uu GA u G uc AG ucTsT 
                 582 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:568L21 siRNA (550C) stab08 
                 u G u G c AG ucccu AG cuuucTsT 
                 583 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1114L21 siRNA (1096C) 
                 uuc A uu GA c A cc A uucuuuTsT 
                 584 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1118L21 siRNA (1100C) 
                 u GG cuuc A uu GA c A cc A uuTsT 
                 585 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1481L21 siRNA (1463C) 
                   G cucuuc AG c G cu AA u AAA TsT 
                 586 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1924L21 siRNA (1906C) 
                   AAAGG ucuuu GAGG u AGAG TsT 
                 587 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2594L21 siRNA (2576C) 
                   G u GG uucc AGG u A ucu G cuTsT 
                 588 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:422U21 siRNA stab09 
                 B CAAGUGACUGACAUCAACUTT B 
                 589 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:427U21 siRNA stab09 
                 B GACUGACAUCAACUCCAAGTT B 
                 590 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:550U21 siRNA stab09 
                 B GAAAGCUAGGGACUGCACATT B 
                 591 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1096U21 siRNA stab09 
                 B AAAGAAUGGUGUCAAUGAATT B 
                 592 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1100U21 siRNA stab09 
                 B AAUGGUGUCAAUGAAGCCATT B 
                 593 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1463U21 siRNA stab09 
                 B UUUAUUAGCGCUGAAGAGCTT B 
                 594 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1906U21 siRNA stab09 
                 B CUCUACCUCAAAGACCUUUTT B 
                 595 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2576U21 siRNA stab09 
                 B AGCAGAUACCUGGAACCACTT B 
                 596 
               
               
                   
               
               
                 420 
                 CCCAAGUGACUGACAUCAACUCC 
                 509 
                   
                 FAS:440L21 siRNA (422C) stab10 
                 AGUUGAUGUCAGUCACUUGTsT 
                 597 
               
               
                   
               
               
                 425 
                 GUGACUGACAUCAACUCCAAGGG 
                 510 
                   
                 FAS:445L21 siRNA (427C) stab10 
                 CUUGGAGUUGAUGUCAGUCTsT 
                 598 
               
               
                   
               
               
                 548 
                 AGGAAAGCUAGGGACUGCACAGU 
                 511 
                   
                 FAS:568L21 siRNA (550C) stab10 
                 UGUGCAGUCCCUAGCUUUCTsT 
                 599 
               
               
                   
               
               
                 1094 
                 CGAAAGAAUGGUGUCAAUGAAGC 
                 512 
                   
                 FAS:1114L21 siRNA (1096C) 
                 UUCAUUGACACCAUUCUUUTsT 
                 600 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
               
                 1098 
                 AGAAUGGUGUCAAUGAAGCCAAA 
                 513 
                   
                 FAS:1118L21 siRNA (1100C) 
                 UGGCUUCAUUGACACCAUUTsT 
                 601 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
               
                 1461 
                 CAUUUAUUAGCGCUGAAGAGCCA 
                 514 
                   
                 FAS:1481L21 siRNA (1463C) 
                 GCUCUUCAGCGCUAAUAAATsT 
                 602 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
               
                 1904 
                 GGCUCUACCUCAAAGACCUUUGC 
                 515 
                   
                 FAS:1924L21 siRNA (1906C) 
                 AAAGGUCUUUGAGGUAGAGTsT 
                 603 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
               
                 2574 
                 GAAGCAGAUACCUGGAACCACCU 
                 516 
                   
                 FAS:2594L21 siRNA (2576C) 
                 GUGGUUCCAGGUAUCUGCUTsT 
                 604 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
            
           
           
               
               
               
            
               
                 FasL 
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 85 
                 UGACACCUCAGGCUCUACAGGAC 
                 517 
                   
                 FasL:87U21 siRNA 
                 ACACCUCAGCCUCUACAGGTT 
                 605 
                   
                   
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:241U21 siRNA 
                 AGUUCUUCCCUGUCCAACCTT 
                 606 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:244U21 siRNA 
                 UCUUCCCUGUCCAACCUCUTT 
                 607 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:468U21 siRNA 
                 UCUUCCACCUACAGAAGGATT 
                 608 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1040U21 siRNA 
                 UGUUACAGGCACCGAGAAUTT 
                 609 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1041U21 siRNA 
                 GUUACAGGCACCGAGAAUGTT 
                 610 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1049U21 siRNA 
                 CACCGAGAAUGUUGUAUUCTT 
                 611 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1547U21 siRNA 
                 UUUGGGGACUCAUUUCAUUTT 
                 612 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:105L21 siRNA (87C) 
                 CCUGUAGAGGCUGAGGUGUTT 
                 613 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:259L21 siRNA (241C) 
                 GGUUGGACAGGGAAGAACUTT 
                 614 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:262L21 siRNA (244C) 
                 AGAGGUUGGACAGGGAAGATT 
                 615 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:486L21 siRNA (468C) 
                 UCCUUCUGUAGGUGGAAGATT 
                 616 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1058L21 siRNA (1040C) 
                 AUUCUCGGUGCCUGUAACATT 
                 617 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1059L21 siRNA (1041C) 
                 CAUUCUCGGUGCCUGUAACTT 
                 618 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1067L21 siRNA (1049C) 
                 GAAUACAACAUUCUCGGUGTT 
                 619 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1565L21 siRNA (1547C) 
                 AAUGAAAUGAGUCCCCAAATT 
                 620 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:87U21 siRNA stab04 
                 B AcAccucAGccucuAcAGGTT B 
                 621 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:241U21 siRNA stab04 
                 B AGuucuucccuGuccAAccTT B 
                 622 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:244U21 siRNA stab04 
                 B ucuucccuGuccAAccucuTT B 
                 623 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:468U21 siRNA stab04 
                 B ucuuccAccuAcAGAAGGATT B 
                 624 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1040U21 siRNA stab04 
                 B uGuuAcAGGcAccGAGAAuTT B 
                 625 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1041U21 siRNA stab04 
                 B GuuAcAGGcAccGAGAAuGTT B 
                 626 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1049U21 siRNA stab04 
                 B cAccGAGAAuGuuGuAuucTT B 
                 627 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1547U21 siRNA stab04 
                 B uuuGGGGAcucAuuucAuuTT B 
                 628 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:105L21 siRNA (87C) stab05 
                 ccuGuAGAGGcuGAGGuGuTsT 
                 629 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:259L21 siRNA (241C) stab05 
                 GGuuGGAcAGGGAAGAAcuTsT 
                 630 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:262L21 siRNA (244C) stab05 
                 AGAGGuuGGAcAGGGAAGATsT 
                 631 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:486L21 siRNA (468C) stab05 
                 uccuucuGuAGGuGGAAGATsT 
                 632 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1058L21 siRNA (1040C) 
                 AuucucGGuGccuGuAAcATsT 
                 633 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1059L21 siRNA (1041C) 
                 cAuucucGGuGccuGuAAcTsT 
                 634 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1067L21 siRNA (1049C) 
                 GAAuAcAAcAuucucGGuGTsT 
                 635 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1565L21 siRNA (1547C) 
                 AAuGAAAuGAGuccccAAATsT 
                 636 
               
               
                   
                   
                   
                   
                 stab05 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:87U21 siRNA stab07 
                 B  A c A ccuc AG ccucu A c AGG TT B 
                 637 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:241U21 siRNA stab07 
                 B  AG uucuucccu G ucc AA ccTT B 
                 638 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:244U21 siRNA stab07 
                 B ucuucccu G ucc AA ccucuTT B 
                 639 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:468U21 siRNA stab07 
                 B ucuucc A ccu A c AGAAGGA TT B 
                 640 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1040U21 siRNA stab07 
                 B u G uu A c AGG c A cc GAGAA uTT B 
                 641 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1041U21 siRNA stab07 
                 B  G uu A c AGG c A cc GAGAA u G TT B 
                 642 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1049U21 siRNA stab07 
                 B c A cc GAGAA u G uu G u A uucTT B 
                 643 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1547U21 siRNA stab07 
                 B uuu GGGGA cuc A uuuc A uuTT B 
                 644 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:105L21 siRNA (87C) stab11 
                 ccu G u AGAGG cu GAGG u G uTsT 
                 645 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:259L21 siRNA (241C) stab11 
                   GG uu GGA c AGGGAAGAA cuTsT 
                 646 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:262L21 siRNA (244C) stab11 
                   AGAGG uu GGA c AGGGAAGA TsT 
                 647 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:486L21 siRNA (468C) stab11 
                 uccuucu G u AGG u GGAAGA TsT 
                 648 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1058L21 siRNA (1040C) 
                   A uucuc GG u G ccu G u AA c A TsT 
                 649 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1059L21 siRNA (1041C) 
                 c A uucuc GG u G ccu G u AA cTsT 
                 650 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1067L21 siRNA (1049C) 
                   GAA u A c AA c A uucuc GG u G TsT 
                 651 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1565L21 siRNA (1547C) 
                   AA u GAAA u GAG ucccc AAA TsT 
                 652 
               
               
                   
                   
                   
                   
                 stab11 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:87U21 siRNA stab18 
                 B  A c A ccuc AG ccucu A c AGG TT B 
                 653 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:241U21 siRNA stab18 
                 B  AG uucuucccu G ucc AA ccTT B 
                 654 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:244U21 siRNA stab18 
                 B ucuucccu G ucc AA ccucuTT B 
                 655 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:468U21 siRNA stab18 
                 B ucuucc A ccu A c AGAAGGA TT B 
                 656 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1040U21 siRNA stab18 
                 B u G uu A c AGG c A cc GAGAA uTT B 
                 657 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1041U21 siRNA stab18 
                 B  G uu A c AGG c A cc GAGAA u G TT B 
                 658 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1049U21 siRNA stab18 
                 B c A cc GAGAA u G uu G u A uucTT B 
                 659 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1547U21 siRNA stab18 
                 B uuu GGGGA cuc A uuuc A uuTT B 
                 660 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:105L21 siRNA (87C) stab08 
                 ccu G u AGAGG cu GAGG u G uTsT 
                 661 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:259L21 siRNA (241C) stab08 
                   GG uu GGA c AGGGAAGAA cuTsT 
                 662 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:262L21 siRNA (244C) stab08 
                   AGAGG uu GGA c AGGGAAGA TsT 
                 663 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:486L21 siRNA (468C) stab08 
                 uccuucu G u AGG u GGAAGA TsT 
                 664 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1058L21 siRNA (1040C) 
                   A uucuc GG u G ccu G u AA c A TsT 
                 665 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1059L21 siRNA (1041C) 
                 c A uucuc GG u G ccu G u AA cTsT 
                 666 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1067L21 siRNA (1049C) 
                   GAA u A c AA c A uucuc GG u G TsT 
                 667 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1565L21 siRNA (1547C) 
                   AA u GAAA u GAG ucccc AAA TsT 
                 668 
               
               
                   
                   
                   
                   
                 stab08 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:87U21 siRNA stab09 
                 B ACACCUCAGCCUCUACAGGTT B 
                 669 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:241U21 siRNA stab09 
                 B AGUUCUUCCCUGUCCAACCTT B 
                 670 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:244U21 siRNA stab09 
                 B UCUUCCCUGUCCAACCUCUTT B 
                 671 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:468U21 siRNA stab09 
                 B UCUUCCACCUACAGAAGGATT B 
                 672 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1040U21 siRNA stab09 
                 B UGUUACAGGCACCGAGAAUTT B 
                 673 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1041U21 siRNA stab09 
                 B GUUACAGGCACCGAGAAUGTT B 
                 674 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1049U21 siRNA stab09 
                 B CACCGAGAAUGUUGUAUUCTT B 
                 675 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1547U21 siRNA stab09 
                 B UUUGGGGACUCAUUUCAUUTT B 
                 676 
               
               
                   
               
               
                 85 
                 UGACACCUCAGCCUCUACAGGAC 
                 517 
                   
                 FasL:105L21 siRNA (87C) stab10 
                 CCUGUAGAGGCUGAGGUGUTsT 
                 677 
               
               
                   
               
               
                 239 
                 ACAGUUCUUCCCUGUCCAACCUC 
                 518 
                   
                 FasL:259L21 siRNA (241C) stab10 
                 GGUUGGACAGGGAAGAACUTsT 
                 678 
               
               
                   
               
               
                 242 
                 GUUCUUCCCUGUCCAACCUCUGU 
                 519 
                   
                 FasL:262L21 siRNA (244C) stab10 
                 AGAGGUUGGACAGGGAAGATsT 
                 679 
               
               
                   
               
               
                 466 
                 GCUCUUCCACCUACAGAAGGAGC 
                 520 
                   
                 FasL:486L21 siRNA (468C) stab10 
                 UCCUUCUGUAGGUGGAAGATsT 
                 680 
               
               
                   
               
               
                 1038 
                 UUUGUUACAGGCACCGAGAAUGU 
                 521 
                   
                 FasL:1058L21 siRNA (1040C) 
                 AUUCUCGGUGCCUGUAACATsT 
                 681 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
               
                 1039 
                 UUGUUACAGGCACCGAGAAUGUU 
                 522 
                   
                 FasL:1059L21 siRNA (1041C) 
                 CAUUCUCGGUGCCUGUAACTsT 
                 682 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
               
                 1047 
                 GGCACCGAGAAUGUUGUAUUCAG 
                 523 
                   
                 FasL:1067L21 siRNA (1049C) 
                 GAAUACAACAUUCUCGGUGTsT 
                 683 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
               
                 1545 
                 GUUUUGGGGACUCAUUUCAUUCC 
                 524 
                   
                 FasL:1565L21 siRNA (1547C) 
                 AAUGAAAUGAGUCCCCAAATsT 
                 684 
               
               
                   
                   
                   
                   
                 stab10 
               
               
                   
               
               
                   Uppercase = ribonucleotide    
               
               
                   u,c = 2′-deoxy-2′-fluoro U,C    
               
               
                   T = thymidine    
               
               
                   B = inverted deoxy abasic    
               
               
                   s = phosphorothioate linkage    
               
               
                     A  = deoxy Adenosine    
               
               
                     G  = deoxy Guanosine    
               
               
                     G  = 2′-O-methyl Guanosine    
               
               
                     A  = 2′-O-methyl Adenosine    
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE IV 
               
             
            
               
                   
               
               
                   
               
               
                 Non-limiting examples of Stabilization Chemistries for chemically 
               
               
                 modified siNA constructs 
               
            
           
           
               
               
               
               
               
               
            
               
                 Chemistry 
                 pyrimidine 
                 Purine 
                 cap 
                 p = S 
                 Strand 
               
               
                   
               
               
                 “Stab 00” 
                 Ribo 
                 Ribo 
                 TT at 
                   
                 S/AS 
               
               
                   
                   
                   
                 3′-ends 
               
               
                 “Stab 1” 
                 Ribo 
                 Ribo 
                 — 
                 5 at 5′-end 
                 S/AS 
               
               
                   
                   
                   
                   
                 1 at 3′-end 
               
               
                 “Stab 2” 
                 Ribo 
                 Ribo 
                 — 
                 All 
                 Usually AS 
               
               
                   
                   
                   
                   
                 linkages 
               
               
                 “Stab 3” 
                 2′-fluoro 
                 Ribo 
                 — 
                 4 at 5′-end 
                 Usually S 
               
               
                   
                   
                   
                   
                 4 at 3′-end 
               
               
                 “Stab 4” 
                 2′-fluoro 
                 Ribo 
                 5′ and 
                 — 
                 Usually S 
               
               
                   
                   
                   
                 3′-ends 
               
               
                 “Stab 5” 
                 2′-fluoro 
                 Ribo 
                 — 
                 1 at 3′-end 
                 Usually AS 
               
               
                 “Stab 6” 
                 2′-O-Methyl 
                 Ribo 
                 5′ and 
                 — 
                 Usually S 
               
               
                   
                   
                   
                 3′-ends 
               
               
                 “Stab 7” 
                 2′-fluoro 
                 2′-deoxy 
                 5′ and 
                 — 
                 Usually S 
               
               
                   
                   
                   
                 3′-ends 
               
               
                 “Stab 8” 
                 2′-fluoro 
                 2′-O- 
                 — 
                 1 at 3′-end 
                 Usually AS 
               
               
                   
                   
                 Methyl 
               
               
                 “Stab 9” 
                 Ribo 
                 Ribo 
                 5′ and 
                 — 
                 Usually S 
               
               
                   
                   
                   
                 3′-ends 
               
               
                 “Stab 10” 
                 Ribo 
                 Ribo 
                 — 
                 1 at 3′-end 
                 Usually AS 
               
               
                 “Stab 11” 
                 2′-fluoro 
                 2′-deoxy 
                 — 
                 1 at 3′-end 
                 Usually AS 
               
               
                 “Stab 12” 
                 2′-fluoro 
                 LNA 
                 5′ and 
                   
                 Usually S 
               
               
                   
                   
                   
                 3′-ends 
               
               
                 “Stab 13” 
                 2′-fluoro 
                 LNA 
                   
                 1 at 3′-end 
                 Usually AS 
               
               
                 “Stab 14” 
                 2′-fluoro 
                 2′-deoxy 
                   
                 2 at 5′-end 
                 Usually AS 
               
               
                   
                   
                   
                   
                 1 at 3′-end 
               
               
                 “Stab 15” 
                 2′-deoxy 
                 2′-deoxy 
                   
                 2 at 5′-end 
                 Usually AS 
               
               
                   
                   
                   
                   
                 1 at 3′-end 
               
               
                 “Stab 16 
                 Ribo 
                 2′-O- 
                 5′ and 
                   
                 Usually S 
               
               
                   
                   
                 Methyl 
                 3′-ends 
               
               
                 “Stab 17” 
                 2′-O-Methyl 
                 2′-O- 
                 5′ and 
                   
                 Usually S 
               
               
                   
                   
                 Methyl 
                 3′-ends 
               
               
                 “Stab 18” 
                 2′-fluoro 
                 2′-O- 
                 5′ and 
                 1 at 3′-end 
                 Usually S 
               
               
                   
                   
                 Methyl 
                 3′-ends 
               
               
                 “Stab 19” 
                 2′-fluoro 
                 2′-O- 
                 3′-end 
                   
                 Usually AS 
               
               
                   
                   
                 Methyl 
               
               
                 “Stab 20” 
                 2′-fluoro 
                 2′-deoxy 
                 3′-end 
                   
                 Usually AS 
               
               
                 “Stab 21” 
                 2′-fluoro 
                 Ribo 
                 3′-end 
                   
                 Usually AS 
               
               
                 “Stab 22” 
                 Ribo 
                 Ribo 
                 3′-end - 
                   
                 Usually AS 
               
               
                 “Stab 23” 
                 2′-fluoro* 
                 2′-deoxy* 
                 5′ and 
                   
                 Usually S 
               
               
                   
                   
                   
                 3′-ends 
               
               
                 “Stab 24” 
                 2′-fluoro* 
                 2′-O- 
                 — 
                 1 at 3′-end 
                 Usually AS 
               
               
                   
                   
                 Methyl* 
               
               
                 “Stab 25” 
                 2′-fluoro* 
                 2′-O- 
                 — 
                 1 at 3′-end 
                 Usually AS 
               
               
                   
                   
                 Methyl* 
               
               
                   
               
               
                   CAP = any terminal cap, see for example  FIG. 10 .    
               
               
                   All Stab 1-25 chemistries can comprise 3′-terminal thymidine (TT) residues    
               
               
                   All Stab 1-25 chemistries typically comprise about 21 nucleotides, but can vary as described herein.    
               
               
                   S = sense strand    
               
               
                   AS = antisense strand    
               
               
                   *Stab 23 has single ribonucleotide adjacent to 3′-CAP    
               
               
                   *Stab 24 has single ribonucleotide at 5′-terminus    
               
               
                   *Stab 25 has three ribonucleotides at 5′-terminus    
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE V 
               
               
                   
               
               
                   
               
             
            
               
                 A. 2.5 μmol Synthesis Cycle ABI 394 Instrument 
               
            
           
           
               
               
               
               
               
               
            
               
                 Reagent 
                 Equivalents 
                 Amount 
                 Wait Time* DNA 
                 Wait Time* 2′-O-methyl 
                 Wait Time* RNA 
               
               
                   
               
               
                 Phosphoramidites 
                 6.5 
                  163 μL 
                  45 sec 
                  2.5 min 
                  7.5 min 
               
               
                 S-Ethyl Tetrazole 
                 23.8 
                  238 μL 
                  45 sec 
                  2.5 min 
                  7.5 min 
               
               
                 Acetic Anhydride 
                 100 
                  233 μL 
                  5 sec 
                  5 sec 
                  5 sec 
               
               
                 N-Methyl 
                 186 
                  233 μL 
                  5 sec 
                  5 sec 
                  5 sec 
               
               
                 Imidazole 
               
               
                 TCA 
                 176 
                  2.3 mL 
                  21 sec 
                  21 sec 
                  21 sec 
               
               
                 Iodine 
                 11.2 
                  1.7 mL 
                  45 sec 
                  45 sec 
                  45 sec 
               
               
                 Beaucage 
                 12.9 
                  645 μL 
                 100 sec 
                 300 sec 
                 300 sec 
               
               
                 Acetonitrile 
                 NA 
                 6.67 mL 
                 NA 
                 NA 
                 NA 
               
               
                   
               
            
           
           
               
            
               
                 B. 0.2 μmol Synthesis Cycle ABI 394 Instrument 
               
            
           
           
               
               
               
               
               
               
            
               
                 Reagent 
                 Equivalents 
                 Amount 
                 Wait Time* DNA 
                 Wait Time* 2′-O-methyl 
                 Wait Time* RNA 
               
               
                   
               
               
                 Phosphoramidites 
                 15 
                   31 μL 
                  45 sec 
                 233 sec 
                 465 sec 
               
               
                 S-Ethyl Tetrazole 
                 38.7 
                   31 μL 
                  45 sec 
                 233 min 
                 465 sec 
               
               
                 Acetic Anhydride 
                 655 
                  124 μL 
                  5 sec 
                  5 sec 
                  5 sec 
               
               
                 N-Methyl 
                 1245 
                  124 μL 
                  5 sec 
                  5 sec 
                  5 sec 
               
               
                 Imidazole 
               
               
                 TCA 
                 700 
                  732 μL 
                  10 sec 
                  10 sec 
                  10 sec 
               
               
                 Iodine 
                 20.6 
                  244 μL 
                  15 sec 
                  15 sec 
                  15 sec 
               
               
                 Beaucage 
                 7.7 
                  232 μL 
                 100 sec 
                 300 sec 
                 300 sec 
               
               
                 Acetonitrile 
                 NA 
                 2.64 mL 
                 NA 
                 NA 
                 NA 
               
               
                   
               
            
           
           
               
            
               
                 C. 0.2 μmol Synthesis Cycle 96 well Instrument 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Equivalents: DNA/ 
                 Amount: DNA/2′-O- 
                   
                 Wait Time* 2′-O- 
                   
               
               
                 Reagent 
                 2′-O-methyl/Ribo 
                 methyl/Ribo 
                 Wait Time* DNA 
                 methyl 
                 Wait Time* Ribo 
               
               
                   
               
               
                 Phosphoramidites 
                  22/33/66 
                  40/60/120 μL 
                  60 sec 
                 180 sec 
                 360 sec 
               
               
                 S-Ethyl Tetrazole 
                  70/105/210 
                  40/60/120 μL 
                  60 sec 
                 180 min 
                 360 sec 
               
               
                 Acetic Anhydride 
                 265/265/265 
                   50/50/50 μL 
                  10 sec 
                  10 sec 
                  10 sec 
               
               
                 N-Methyl 
                 502/502/502 
                   50/50/50 μL 
                  10 sec 
                  10 sec 
                  10 sec 
               
               
                 Imidazole 
               
               
                 TCA 
                 238/475/475 
                 250/500/500 μL 
                  15 sec 
                  15 sec 
                  15 sec 
               
               
                 Iodine 
                  6.8/6.8/6.8 
                   80/80/80 μL 
                  30 sec 
                  30 sec 
                  30 sec 
               
               
                 Beaucage 
                  34/51/51 
                 80/120/120 
                 100 sec 
                 200 sec 
                 200 sec 
               
               
                 Acetonitrile 
                 NA 
                 1150/1150/1150 μL   
                 NA 
                 NA 
                 NA 
               
               
                   
               
               
                   Wait time does not include contact time during delivery.    
               
               
                   Tandem synthesis utilizes double coupling of linker molecule