bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Level Expression of Single-Chain Fv-Fc Fusion Protein in Serum and Egg White of Genetically Manipulated Chickens by Using a Retroviral Vector
Authors: Kamihira Masamichi , Ono Ken-ichiro , Esaka Kazuhisa , Nishijima Ken-ichi , Kigaku Ryoko , Komatsu Hiroyuki , Yamashita Takashi , Kyogoku Kenji , Iijima Shinji 
Published: August 2005

ABSTRACT
We report here the generation of transgenic chickens using a retroviral vector for the production of recombinant proteins. It was found that the transgene expression was suppressed when a Moloney murine leukemia virus-based retroviral vector was injected into chicken embryos at the blastodermal stage. When a concentrated viral solution was injected into the heart of developing embryos after 50 to 60 h of incubation, transgene expression was observed throughout the embryo, including the gonads. For practical production, a retroviral vector encoding an expression cassette of antiprion single-chain Fv fused with the Fc region of human immunoglobulin G1 (scFv-Fc) was injected into chicken embryos. The birds that hatched stably produced scFv-Fc in their serum and eggs at high levels (∼5.6 mg/ml). We obtained transgenic progeny from a transgenic chicken generated with this procedure. The transgene was stably integrated into the chromosomes of transgenic progeny. The transgenic progeny also expressed scFv-Fc in the serum and eggs.
Human Endogenous Retrovirus Expression Profiles in Samples from Brains of Patients with Schizophrenia and Bipolar Disorders
Authors: Frank Oliver , Giehl Michelle , Zheng Chun , Hehlmann Rüdiger , Leib-Mösch Christine , Seifarth Wolfgang 
Published: August 2005

ABSTRACTThe detection and identification of retroviral transcripts in brain samples, cerebrospinal fluid, and plasma of individuals with recent-onset schizophrenia and schizoaffective disorders suggest that activation or upregulation of distinct human endogenous retroviruses (HERVs) may play a role in the etiopathogenesis of neuropsychiatric diseases. To test this hypothesis, we performed a comprehensive microarray-based analysis of HERV transcriptional activity in human brains. We investigated 50 representative members of 20 HERV families in a total of 215 brain samples derived from individuals with schizophrenia or bipolar disorders and matched controls. A characteristic brain-specific retroviral activity profile was found that consists of members of the class I families HERV-E, HERV-F, and ERV9 and members of HERV-K taxa. In addition to these constitutively expressed HERVs, a number of differentially active HERV elements were identified in all brain samples independent of the disease pattern that may reflect differences in the genetic background of the tested individuals. Only a subgroup of the HML-2 family (HERV-K10) was significantly overrepresented in both bipolar-disorder- and schizophrenia-associated samples compared to healthy brains, suggesting a potential association with disease. Real-time PCR analysis of HERVenvtranscripts with coding capacity potentially involved in neuroinflammatory conditions revealed thatenvexpression of HERV-W, HERV-FRD, and HML-2 remains unaffected regardless of the clinical picture. Our data suggest that HERV transcription in brains is weakly correlated with schizophrenia and related diseases but may be influenced by the individual genetic background, brain-infiltrating immune cells, or medical treatment.
Identification of Domains in
Autographa californica
Multiple Nucleopolyhedrovirus Late Expression Factor 3 Required for Nuclear Transport of P143
Authors: Chen Zhilin , Carstens Eric B. 
Published: August 2005

ABSTRACT

Autographa californica multiple nucleopolyhedrovirus
(AcMNPV) late expression factor 3 (LEF-3) is an essential protein for DNA replication in transient assays. P143, a large DNA-binding protein with DNA-unwinding activity, is also essential for viral DNA replication in vivo. Both LEF-3 and P143 are found in the nucleus of AcMNPV-infected cells, but only LEF-3 localizes to the nucleus when expressed in transfected cells on its own from a plasmid expression vector. P143 requires LEF-3 as a transporter to enter the nucleus. To investigate the possibility that LEF-3 carries a nuclear localization signal domain, we constructed a series of LEF-3 deletion mutants and examined the intracellular localization of the products in plasmid-transfected cells. We discovered that the N-terminal 56 amino acid residues of LEF-3 were sufficient for nuclear localization and that this domain, when fused with either the green fluorescent protein reporter gene or P143, was able to direct these proteins to the nucleus. Transient DNA replication assays demonstrated that fusing the LEF-3 nuclear localization signal domain to P143 did not alter the function of P143 in supporting DNA replication but was not sufficient to substitute for whole LEF-3. These data show that although one role for LEF-3 during virus infection is to transport P143 to the nucleus, LEF-3 performs other essential replication functions once inside the nucleus.
Mutations of Epstein-Barr Virus gH That Are Differentially Able To Support Fusion with B Cells or Epithelial Cells
Authors: Wu Liguo , Borza Corina M. , Hutt-Fletcher Lindsey M. 
Published: August 2005

ABSTRACT
The core fusion machinery of all herpesviruses consists of three conserved glycoproteins, gB and gHgL, suggesting a common mechanism for virus cell fusion, but fusion of Epstein-Barr virus (EBV) with B cells and epithelial cells is initiated differently. Fusion with B cells requires a fourth protein, gp42, which complexes with gHgL and interacts with HLA class II, the B-cell coreceptor. Fusion with an epithelial cell does not require gp42 but requires interaction of gHgL with a novel epithelial cell coreceptor. Epithelial cell fusion can be inhibited by gp42 binding to gHgL and by antibodies to gH that fail to block B-cell fusion. This suggests that regions of gHgL initiating fusion with each cell are separable from each other and from regions involved in fusion itself. To address this possibility we mapped the region of gH recognized by a monoclonal antibody to gH that blocks EBV fusion with epithelial cells but not B cells by making a series of chimeras with the gH homolog of rhesus lymphocryptovirus. Proteins with mutations engineered within this region included those that preferentially mediate fusion with B cells, those that preferentially mediate fusion with epithelial cells, and those that mediate fusion with neither cell type. These results support the hypothesis that the core fusion function of gH is the same for B cells and epithelial cells and that it differs only in the way in which it is triggered into a functionally active state.
Structural Determinants of Tissue Tropism and In Vivo Pathogenicity for the Parvovirus Minute Virus of Mice
Authors: Kontou Maria , Govindasamy Lakshmanan , Nam Hyun-Joo , Bryant Nathan , Llamas-Saiz Antonio L. , Foces-Foces Concepción , Hernando Eva , Rubio Mari-Paz , McKenna Robert , Almendral José M. , Agbandje-McKenna Mavis 
Published: August 2005

ABSTRACT

Two strains of the parvovirus minute virus of mice (MVM), the immunosuppressive (MVMi) and the prototype (MVMp) strains, display disparate in vitro tropism and in vivo pathogenicity. We report the crystal structures of MVMp virus-like particles (MVMp
b
) and native wild-type (wt) empty capsids (MVMp
e
), determined and refined to 3.25 and 3.75 Å resolution, respectively, and their comparison to the structure of MVMi, also refined to 3.5 Å resolution in this study. A comparison of the MVMp
b
and MVMp
e
capsids showed their structures to be the same, providing structural verification that some heterologously expressed parvovirus capsids are indistinguishable from wt capsids produced in host cells. The structures of MVMi and MVMp capsids were almost identical, but local surface conformational differences clustered from symmetry-related capsid proteins at three specific domains: (i) the icosahedral fivefold axis, (ii) the “shoulder” of the protrusion at the icosahedral threefold axis, and (iii) the area surrounding the depression at the icosahedral twofold axis. The latter two domains contain important determinants of MVM in vitro tropism (residues 317 and 321) and forward mutation residues (residues 399, 460, 553, and 558) conferring fibrotropism on MVMi. Furthermore, these structural differences between the MVM strains colocalize with tropism and pathogenicity determinants mapped for other autonomous parvovirus capsids, highlighting the importance of common parvovirus capsid regions in the control of virus-host interactions.
The Cotton Rat (
Sigmodon hispidus
) Is a Permissive Small Animal Model of Human Metapneumovirus Infection, Pathogenesis, and Protective Immunity
Authors: Williams John V. , Tollefson Sharon J. , Johnson Joyce E. , Crowe James E. 
Published: August 2005

ABSTRACT

Human metapneumovirus (hMPV) is a newly described paramyxovirus that is an important cause of acute respiratory tract disease. We undertook to develop a small animal model of hMPV infection, pathogenesis, and protection. Hamsters, guinea pigs, cotton rats, and nine inbred strains of mice were inoculated intranasally with hMPV. The animals were sacrificed, and nasal and lung tissue virus yields were determined by plaque titration. None of the animals exhibited respiratory symptoms. The quantity of virus present in the nasal tissue ranged from 4.6 × 10
2
PFU/gram tissue (C3H mice) to greater than 10
5
PFU/gram (hamster). The amount of virus in the lungs was considerably less than in nasal tissue in each species tested, ranging from undetectable (<5 PFU/g; guinea pigs) to 1.8 × 10
5
PFU/gram (cotton rat). The peak virus titer in cotton rat lungs occurred on day 4 postinfection. hMPV-infected cotton rat lungs examined on day 4 postinfection exhibited histopathological changes consisting of peribronchial inflammatory infiltrates. Immunohistochemical staining detected virus only at the luminal surfaces of respiratory epithelial cells throughout the respiratory tract. hMPV-infected cotton rats mounted virus-neutralizing antibody responses and were partially protected against virus shedding and lung pathology on subsequent rechallenge with hMPV. Viral antigen was undetectable in the lungs on challenge of previously infected animals. This study demonstrates that the cotton rat is a permissive small animal model of hMPV infection that exhibits lung histopathology associated with infection and that primary infection protected animals against subsequent infection. This model will allow further in vivo studies of hMPV pathogenesis and evaluation of vaccine candidates.
Hepatitis A Virus Suppresses RIG-I-Mediated IRF-3 Activation To Block Induction of Beta Interferon
Authors: Fensterl Volker , Grotheer Dajana , Berk Iris , Schlemminger Stefanie , Vallbracht Angelika , Dotzauer Andreas 
Published: August 2005

ABSTRACT
Hepatitis A virus (HAV) antagonizes the innate immune response by inhibition of double-stranded RNA (dsRNA)-induced beta interferon (IFN-β) gene expression. In this report, we show that this is due to an interaction of HAV with the intracellular dsRNA-induced retinoic acid-inducible gene I (RIG-I)-mediated signaling pathway upstream of the kinases responsible for interferon regulatory factor 3 (IRF-3) phosphorylation (TBK1 and IKKε). In consequence, IRF-3 is not activated for nuclear translocation and gene induction. In addition, we found that HAV reduces TRIF (TIR domain-containing adaptor inducing IFN-β)-mediated IRF-3 activation, which is part of the Toll-like receptor 3 signaling pathway. As IRF-3 is necessary for IFN-β transcription, inhibition of this factor results in efficient suppression of IFN-β synthesis. This ability of HAV seems to be of considerable importance for HAV replication, as HAV is not resistant to IFN-β, and it may allow the virus to establish infection and preserve the sites of virus production in later stages of the infection.
Human Immunodeficiency Virus Type 1 Vpr Induces the Degradation of the UNG and SMUG Uracil-DNA Glycosylases
Authors: Schröfelbauer Bärbel , Yu Qin , Zeitlin Samantha G. , Landau Nathaniel R. 
Published: August 2005

ABSTRACT

The human immunodeficiency virus type 1 (HIV-1) accessory protein Vpr has previously been shown to bind to the cellular uracil DNA glycosylase UNG. We show here that the binding of Vpr to UNG and to the related enzyme SMUG induces their proteasomal degradation. UNG and SMUG were found to be encapsidated in Δ
vpr
HIV-1 virions but were significantly less abundant in
vpr

+

virions. Δ
vpr
virions contained readily detectable uracil-DNA glycosylase enzymatic activity, while the activity was reduced to undetectable levels in
vpr

+

virions. Consistent with proteasomal degradation, complexes that contained Vpr and the E3 ubiquitin ligase components Cul1 and Cul4 were detected in cell lysates. We hypothesized that the interaction of Vpr might be a means for the virus to reduce the frequency of abasic sites in viral reverse transcripts at uracil residues caused by APOBEC3-catalyzed deamination of cytosine residues. Although APOBEC3 is largely neutralized by the Vif accessory protein, residual enzyme could remain in virions that would generate uracils. In support of this, Δ
vif vpr

+

HIV-1 produced in the presence of limited amounts of APOBEC3G was significantly more infectious than Δ
vif
Δ
vpr
virus. In Addition,
vpr
+
HIV-1 replicated more efficiently than
vpr
−
virus in cells that expressed limited amounts of APOBEC3G. The findings highlight the importance of cytidine deamination in the virus replication cycle and present a novel function for Vpr.
The Product of the Vaccinia Virus L5R Gene Is a Fourth Membrane Protein Encoded by All Poxviruses That Is Required for Cell Entry and Cell-Cell Fusion
Authors: Townsley Alan C. , Senkevich Tatiana G. , Moss Bernard 
Published: August 2005

ABSTRACT

The L5R gene of vaccinia virus is conserved among all sequenced members of the
Poxviridae
but has no predicted function or recognized nonpoxvirus homolog. Here we provide the initial characterization of the L5 protein. L5 is expressed following DNA replication with kinetics typical of a viral late protein, contains a single intramolecular disulfide bond formed by the virus-encoded cytoplasmic redox pathway, and is incorporated into intracellular mature virus particles, where it is exposed on the membrane surface. To determine whether L5 is essential for virus replication, we constructed a mutant that synthesizes L5 only in the presence of an inducer. The mutant exhibited a conditional-lethal phenotype, as cell-to-cell virus spread and formation of infectious progeny were dependent on the inducer. Nevertheless, all stages of replication occurred in the absence of inducer and intracellular and extracellular progeny virions appeared morphologically normal. Noninfectious virions lacking L5 could bind to cells, but the cores did not enter the cytoplasm. In addition, virions lacking L5 were unable to mediate low-pH-triggered cell-cell fusion from within or without. The phenotype of the L5R conditional lethal mutant is identical to that of recently described mutants in which expression of the A21, A28, and H2 genes is repressed. Thus, L5 is the fourth component of the poxvirus cell entry/fusion apparatus that is required for entry of both the intracellular and extracellular infectious forms of vaccinia virus.
Multiple Gene Segments Control the Temperature Sensitivity and Attenuation Phenotypes of
ca
B/Ann Arbor/1/66
Authors: Hoffmann Erich , Mahmood Kutubuddin , Chen Zhongying , Yang Chin-Fen , Spaete Joshua , Greenberg Harry B. , Herlocher M. Louise , Jin Hong , Kemble George 
Published: August 2005

ABSTRACT

Cold-adapted (
ca
) B/Ann Arbor/1/66 is the influenza B virus strain master donor virus for FluMist, a live, attenuated, influenza virus vaccine licensed in 2003 in the United States. Each FluMist vaccine strain contains six gene segments of the master donor virus; these master donor gene segments control the vaccine's replication and attenuation. These gene segments also express characteristic biological traits in model systems. Unlike most virulent wild-type (wt) influenza B viruses,
ca
B/Ann Arbor/1/66 is temperature sensitive (
ts
) at 37°C and attenuated (
att
) in the ferret model. In order to define the minimal genetic components of these phenotypes, the amino acid sequences of the internal genes of
ca
B/Ann Arbor/1/66 were aligned to those of other influenza B viruses. These analyses revealed eight unique amino acids in three proteins: two in the polymerase subunit PA, two in the M1 matrix protein, and four in the nucleoprotein (NP). Using reverse genetics, these eight wt amino acids were engineered into a plasmid-derived recombinant of
ca
B/Ann Arbor/1/66, and these changes reverted both the
ts
and the
att
phenotypes. A detailed mutational analysis revealed that a combination of two sites in NP (A114 and H410) and one in PA (M431) controlled expression of
ts
, whereas these same changes plus two additional residues in M1 (Q159 and V183) controlled the
att
phenotype. Transferring this genetic signature to the divergent wt B/Yamanashi/166/98 strain conferred both the
ts
and the
att
phenotypes on the recombinant, demonstrating that this small, complex, genetic signature encoded the essential elements for these traits.
Characterization of an Antisense Transcript Spanning the UL81-82 Locus of Human Cytomegalovirus
Authors: Bego Mariana , Maciejewski J. , Khaiboullina S. , Pari G. , St. Jeor S. 
Published: August 2005

ABSTRACT

In this study we present the characterization of a novel transcript,
UL81-82ast
, UL81-82 antisense transcript, and its protein product. The transcript was initially found in a cDNA library of monocytes from a seropositive donor. mRNA was obtained from monocytes isolated from a healthy donor with a high antibody titer against human cytomegalovirus (HCMV). The mRNAs were cloned into a lambda phage-derived vector to create the cDNA library. Using PCR,
UL81-82ast
was amplified from the library. The library was tested for the presence of numerous HCMV genes. Neither structural genes nor immediate-early genes were found.
UL81-82ast
was detected in five bone marrow samples from healthy antibody-positive donors. This same transcript was also found in in vitro-infected human fibroblasts early after infection but disappears at the same time that UL82 transcription begins. Not only was the transcript amplified using reverse transcription-PCR and sequenced but its protein product (UL82as protein) was detected by both Western blot and immunofluorescence. Phylogenetic studies using UL82as protein were conducted, showing a high degree of conservation in clinical isolates, laboratory strains of HCMV, and even in chimpanzee CMV. The transcript could be involved in the posttranscriptional regulation of the UL82 gene, affecting its mRNA stability or translation. Since the UL82 product, pp71, functions as an immediate-early transactivator, its posttranscriptional control could have some effect over latency reactivation and lytic replication.
The Expression Strategy of Goose Parvovirus Exhibits Features of both the
Dependovirus
and
Parvovirus
Genera
Authors: Qiu Jianming , Cheng Fang , Yoto Yuko , Zádori Zoltán , Pintel David 
Published: August 2005

ABSTRACT

The RNA transcription profile of the goose parvovirus (GPV) was determined, and it is a surprising hybrid of features of the
Parvovirus
and
Dependovirus
genera of the
Parvovirinae
subfamily of the
Parvoviridae
. Similar to the
Dependovirus
adeno-associated virus type 5, RNAs transcribed from the GPV upstream P9 promoter, which encode the viral nonstructural proteins, were polyadenylated at a high efficiency at a polyadenylation site [(pA)p] located within an intron in the center of the genome. Efficient usage of (pA)p required a downstream element that overlaps with the polypyrimidine tract of the A2 3′ splice site of the central intron. An upstream element required for efficient use of (pA)p was also identified. RNAs transcribed from the P42 promoter, presumed to encode the viral capsid proteins, primarily extended through (pA)p and were polyadenylated at a site, (pA)d, located at the right end of the genome and ultimately spliced at a high efficiency. No promoter analogous to the
Dependovirus
P19 promoter was detected; however, similar to minute virus of mice and other members of the
Parvovirus
genus, a significant portion of pre-mRNAs generated from the P9 promoter were additionally spliced within the putative GPV Rep1 coding region and likely encode an additional, smaller, nonstructural protein. Also similar to members of the
Parvovirus
genus, detectable activity of the GPV P42 promoter was highly dependent on transactivation by the GPV Rep1 protein in a manner dependent on binding to a
cis
-element located in the P42 promoter.
Alpha/Beta Interferon Differentially Modulates the Clearance of Cytoplasmic Encapsidated Replication Intermediates and Nuclear Covalently Closed Circular Hepatitis B Virus (HBV) DNA from the Livers of Hepatocyte Nuclear Factor 1α-Null HBV Transgenic Mice
Authors: Anderson Aimee L. , Banks Krista E. , Pontoglio Marco , Yaniv Moshe , McLachlan Alan 
Published: August 2005

ABSTRACT
Treatment with alpha interferon is a standard therapy for patients with chronic hepatitis B virus (HBV) infections. This treatment can reduce virus load and ameliorate disease symptoms. However, in the majority of cases, alpha interferon therapy fails to resolve the chronic HBV infection. The reason alpha interferon therapy is inefficient at resolving chronic HBV infections is assumed to be because it fails to eliminate covalently closed circular (CCC) HBV DNA from the nuclei of infected hepatocytes. In an attempt to address this issue, the stability of HBV CCC DNA in response to alpha/beta interferon induction was examined in HNF1α-null HBV transgenic mice. Alpha/beta interferon induction by polyinosinic-polycytidylic acid [poly(I-C)] treatment efficiently eliminated encapsidated cytoplasmic HBV replication intermediates while only modestly reducing nuclear HBV CCC DNA. These observations indicate that nuclear HBV CCC DNA is more stable than cytoplasmic replication intermediates in response to alpha/beta interferon induction. Consequently it appears that for therapies to resolve chronic HBV infection efficiently, they will have to target the elimination of the most stable HBV replication intermediate, nuclear HBV CCC DNA.