bluuebunny/crossref_metadata_2025 huggingface dataset:
CREB binding protein is a required coactivator for Smad-dependent, transforming growth factor β transcriptional responses in endothelial cells
Authors: Topper James N. , DiChiara Maria R. , Brown Jonathan D. , Williams Amy J. , Falb Dean , Collins Tucker , Gimbrone Michael A.
Published: July 2002

The transforming growth factor-β (TGF-β) superfamily of growth factors and cytokines has been implicated in a variety of physiological and developmental processes within the cardiovascular system. Smad proteins are a recently described family of intracellular signaling proteins that transduce signals in response to TGF-β superfamily ligands. We demonstrate by both a mammalian two-hybrid and a biochemical approach that human Smad2 and Smad4, two essential Smad proteins involved in mediating TGF-β transcriptional responses in endothelial and other cell types, can functionally interact with the transcriptional coactivator CREB binding protein (CBP). This interaction is specific in that it requires ligand (TGF-β) activation and is mediated by the transcriptional activation domains of the Smad proteins. A closely related, but distinct endothelial-expressed Smad protein, Smad7, which does not activate transcription in endothelial cells, does not interact with CBP. Furthermore, Smad2,4–CBP interactions involve the COOH terminus of CBP, a region that interacts with other regulated transcription factors such as certain signal transduction and transcription proteins and nuclear receptors. Smad–CBP interactions are required for Smad-dependent TGF-β-induced transcriptional responses in endothelial cells, as evidenced by inhibition with overexpressed 12S E1A protein and reversal of this inhibition with exogenous CBP. This report demonstrates a functional interaction between Smad proteins and an essential component of the mammalian transcriptional apparatus (CBP) and extends our insight into how Smad proteins may regulate transcriptional responses in many cell types. Thus, functional Smad–coactivator interactions may be an important locus of signal integration in endothelial cells.
Defective insulin secretion and enhanced insulin action in K
ATP
channel-deficient mice
Authors: Miki Takashi , Nagashima Kazuaki , Tashiro Fumi , Kotake Kazumi , Yoshitomi Hideyuki , Tamamoto Atsuko , Gonoi Tohru , Iwanaga Toshihiko , Miyazaki Jun-ichi , Seino Susumu
Published: July 2002

ATP-sensitive K
+
(K
ATP
) channels regulate many cellular functions by linking cell metabolism to membrane potential. We have generated K
ATP
channel-deficient mice by genetic disruption of Kir6.2, which forms the K
+
ion-selective pore of the channel. The homozygous mice (Kir6.2
−/−
) lack K
ATP
channel activity. Although the resting membrane potential and basal intracellular calcium concentrations ([Ca
2+
]
i
) of pancreatic beta cells in Kir6.2
−/−
are significantly higher than those in control mice (Kir6.2
+/+
), neither glucose at high concentrations nor the sulfonylurea tolbutamide elicits a rise in [Ca
2+
]
i
, and no significant insulin secretion in response to either glucose or tolbutamide is found in Kir6.2
−/−
, as assessed by perifusion and batch incubation of pancreatic islets. Despite the defect in glucose-induced insulin secretion, Kir6.2
−/−
show only mild impairment in glucose tolerance. The glucose-lowering effect of insulin, as assessed by an insulin tolerance test, is increased significantly in Kir6.2
−/−
, which could protect Kir6.2
−/−
from developing hyperglycemia. Our data indicate that the K
ATP
channel in pancreatic beta cells is a key regulator of both glucose- and sulfonylurea-induced insulin secretion and suggest also that the K
ATP
channel in skeletal muscle might be involved in insulin action.
Complex behavior of self-propagating reaction waves in heterogeneous media
Authors: Varma Arvind , Rogachev Alexander S. , Mukasyan Alexander S. , Hwang Stephen
Published: July 2002

Self-propagating high temperature reaction waves, leading to the synthesis of advanced materials, are investigated in a variety of heterogeneous reaction systems by using a digital high-speed microscopic video recording technique. It is shown that, although on the macroscopic length and time scales, the reaction appears to move in a steady mode, on the microscopic level it has a complex character that is related to the reaction mechanism.
Very late DNA replication in the human cell cycle
Authors: Widrow R. J. , Hansen R. Scott , Kawame Hiroshi , Gartler Stanley M. , Laird Charles D.
Published: July 2002

G
2
was defined originally as the temporal gap between the termination of DNA replication and the beginning of mitosis. In human cells, the G
2
period was estimated to be 3–4 h. However, the absence of replicative DNA synthesis during this period designated G
2
has never been shown conclusively. In this report, we show that, at some autosomal and X linked loci, programmed DNA replication continues within 90 min of mitosis. Furthermore, the major accumulation of cyclin B1, a cell-cycle marker that is usually ascribed to G
2
, overlaps extensively with very late DNA replication. We conclude that the G
2
period is much shorter than previously thought and may, in some cells, be nonexistent.
Gene therapy in allergic encephalomyelitis using myelin basic protein-specific T cells engineered to express latent transforming growth factor-β1
Authors: Chen L. Z. , Hochwald G. M. , Huang C. , Dakin G. , Tao H. , Cheng C. , Simmons W. J. , Dranoff G. , Thorbecke G. J.
Published: July 2002

A myelin basic protein (MBP)-specific BALB/c T helper 1 (Th1) clone was transduced with cDNA for murine latent transforming growth factor-β1 (TGF-β1) by coculture with fibroblasts producing a genetically engineered retrovirus. When SJL x BALB/c F1 mice, immunized 12–15 days earlier with proteolipid protein in complete Freund’s adjuvant, were injected with 3 × 106cells from MBP-activated untransduced cloned Th1 cells, the severity of experimental allergic encephalomyelitis (EAE) was slightly increased. In contrast, MBP-activated (but not resting) latent TGF-β1-transduced T cells significantly delayed and ameliorated EAE development. This protective effect was negated by simultaneously injected anti-TGF-β1. The transduced cells secreted 2–4 ng/ml of latent TGF-β1 into their culture medium, whereas control cells secreted barely detectable amounts. mRNA profiles for tumor necrosis factor, lymphotoxin, and interferon-γ were similar before and after transduction; interleukin-4 and -10 were absent. TGF-β1-transduced and antigen-activated BALB/c Th1 clones, specific for hemocyanin or ovalbumin, did not ameliorate EAE. Spinal cords from mice, taken 12 days after receiving TGF-β1-transduced, antigen-activated cells, contained detectable amounts of TGF-β1 cDNA. We conclude that latent TGF-β1-transduced, self-reactive T cell clones may be useful in the therapy of autoimmune diseases.
Sequence motifs in adenoviral DNA block immune activation by stimulatory CpG motifs
Authors: Krieg Arthur M. , Wu Tong , Weeratna Risini , Efler Susan M. , Love-Homan Laurie , Yang Lin , Yi Ae-Kyung , Short Dan , Davis Heather L.
Published: July 2002

Unmethylated CpG dinucleotides in particular base contexts (CpG-S motifs) are relatively common in bacterial DNA but are rare in vertebrate DNA. B cells and monocytes have the ability to detect such CpG-S motifs that trigger innate immune defenses with production of Th1-like cytokines. Despite comparable levels of unmethylated CpG dinucleotides, DNA from serotype 12 adenovirus is immune-stimulatory, but serotype 2 is nonstimulatory and can even inhibit activation by bacterial DNA. In type 12 genomes, the distribution of CpG-flanking bases is similar to that predicted by chance. However, in type 2 adenoviral DNA the immune stimulatory CpG-S motifs are outnumbered by a 15- to 30-fold excess of CpG dinucleotides in clusters of direct repeats or with a C on the 5′ side or a G on the 3′ side. Synthetic oligodeoxynucleotides containing these putative neutralizing (CpG-N) motifs block immune activation by CpG-S motifsin vitroandin vivo. Eliminating 52 of the 134 CpG-N motifs present in a DNA vaccine markedly enhanced its Th1-like functionin vivo, which was increased further by the addition of CpG-S motifs. Thus, depending on the CpG motif, prokaryotic DNA can be either immune-stimulatory or neutralizing. These results have important implications for understanding microbial pathogenesis and molecular evolution and for the clinical development of DNA vaccines and gene therapy vectors.
Hyers–Ulam stability of functional equations with a square-symmetric operation
Authors: Páles Zsolt , Volkmann Peter , Luce R. Duncan
Published: July 2002

The stability of the functional equation
f
(
x ○ y
) =
H
(
f
(
x
),
f
(
y
)) (
x
,
y ∈ S
) is investigated, where
H
is a homogeneous function and ○ is a square-symmetric operation on the set
S
. The results presented include and generalize the classical theorem of Hyers obtained in 1941 on the stability of the Cauchy functional equation.
The mutationally activated Met receptor mediates motility and metastasis
Authors: Jeffers Michael , Fiscella Michele , Webb Craig P. , Anver Miriam , Koochekpour Shahriar , Vande Woude George F.
Published: July 2002

Mutations in Met have been identified in human papillary renal carcinomas. We have shown previously that these mutations deregulate the enzymatic activity of Met and that NIH 3T3 cells expressing mutationally activated Met are transformed
in vitro
and are tumorigenic
in vivo
. In the present investigation, we find that mutant Met induces the motility of Madin-Darby canine kidney cells
in vitro
and experimental metastasis of NIH 3T3 cells
in vivo
, and that the Ras-Raf-MEK-ERK signaling pathway, which has been implicated previously in cellular motility and metastasis, is constitutively activated by the Met mutants. We also report that transgenic mice harboring mutationally activated Met develop metastatic mammary carcinoma. These data confirm the tumorigenic activity of mutant Met molecules and demonstrate their ability to induce the metastatic phenotype.
The
Vibrio cholerae
genome contains two unique circular chromosomes
Authors: Trucksis Michele , Michalski Jane , Deng Ying Kang , Kaper James B.
Published: July 2002

Vibrio cholerae
, the etiologic agent of the diarrheal disease cholera, is a Gram-negative bacterium that belongs to the γ subdivision of the family Proteobacteriaceae. The physical map of the genome has been reported, and the genome has been described as a single 3.2-Mb chromosome [Majumder, R.,
et al
. (1996)
J. Bacteriol
. 178, 1105–1112]. By using pulsed-field gel electrophoresis of genomic DNA immobilized in agarose plugs and digested with the restriction enzymes I-
Ceu
I,
Sfi
I, and
Not
I, we have also constructed the physical map of
V. cholerae
. Our analysis estimates the size of the genome at 4.0 Mb, 25% larger than the physical map reported by others. Our most notable finding is, however, that the
V. cholerae
chromosome appears to be not the single chromosome reported but two unique and separate circular megareplicons.
High-throughput genetic analysis using microfabricated 96-sample capillary array electrophoresis microplates
Authors: Simpson Peter C. , Roach David , Woolley Adam T. , Thorsen Todd , Johnston Rick , Sensabaugh George F. , Mathies Richard A.
Published: July 2002

Capillary array electrophoresis (CAE) microplates that can analyze 96 samples in less than 8 min have been produced by bonding 10-cm-diameter micromachined glass wafers to form a glass sandwich structure. The microplate has 96 sample wells and 48 separation channels with an injection unit that permits the serial analysis of two different samples on each capillary. An elastomer sheet with an 8 by 12 array of holes is placed on top of the glass sandwich structure to define the sample wells. Samples are addressed with an electrode array that makes up the third layer of the assembly. Detection of all lanes with high temporal resolution was achieved by using a laser-excited confocal fluorescence scanner. To demonstrate the functionality of these microplates, electrophoretic separation and fluorescence detection of a restriction fragment marker for the diagnosis of hereditary hemochromatosis were performed. CAE microplates will facilitate all types of high-throughput genetic analysis because their high assay speed provides a throughput that is 50 to 100 times greater than that of conventional slab gels.
E2F-6, a member of the E2F family that can behave as a transcriptional repressor
Authors: Trimarchi Jeffrey M. , Fairchild Brian , Verona Raluca , Moberg Ken , Andon Nancy , Lees Jacqueline A.
Published: July 2002

The E2F family of proteins is required to establish the correct cell-cycle-dependent transcription of genes that direct the process of cell division. All previously identified E2F proteins can act in a similar manner; depending on whether or not they are associated with the cell cycle inhibitors the retinoblastoma protein (pRB), p107, or p130, they can either repress or activate the transcription of E2F-responsive genes. We now report the cloning and characterization of another E2F family member, E2F-6, whose structure is reminiscent of the dominant inhibitors of other transcription factor families. The dimerization and DNA binding properties of E2F-6 are similar to those of the other E2F family members. However, it is not regulated by pRB, p107, or p130, and it is unable to activate transcription. Instead, it can act to repress the transcription of E2F responsive genes by countering the activity of the other E2F complexes via a pRB-, p107-, or p130-independent mechanism.
Creatine kinase: Essential arginine residues at the nucleotide binding site identified by chemical modification and high-resolution tandem mass spectrometry
Authors: Wood Troy D. , Guan Ziqiang , Borders Charles L. , Chen Lorenzo H. , Kenyon George L. , McLafferty Fred W.
Published: July 2002

Phenylglyoxal is an arginine-specific reagent that inactivates creatine kinase (CK). Previous results suggest that modification of the dimeric enzyme at a single arginine residue per subunit causes complete inactivation accompanied by the loss of nucleotide binding; the actual site of modification was not identified. Here, high-resolution tandem mass spectrometry (MS/MS) was used to identify three phenylglyoxal-modified Arg residues in monomeric rabbit muscle CK. Electrospray ionizaton Fourier-transform MS of the phenylglyoxal-modified CK that had lost ≈80% activity identified three species: unmodified, once-modified (+116 Da), and twice-modified (+232 Da) enzyme in a ratio of approximately 1:4:1. MS/MS restricts the derivatized sites to P122-P212 and P283-V332, whereas MS of Lys-C digestions revealed two modified peptides, A266-K297 and G116-K137. The only Arg in A266-K297 is Arg-291 (invariant), whereas MS/MS of modified G116-K137 shows that two of the three sites Arg-129, Arg-131, or Arg-134 (all invariant) can contain the modification. The recently reported x-ray crystal structure for the octameric chicken mitochondrial CK indicates that its nucleotide triphosphate-binding site indeed contains the equivalent of R291, R129, and R131 reported here to be at the active site of rabbit muscle CK.
A quantitative analysis of signal transduction from activin receptor to nucleus and its relevance to morphogen gradient interpretation
Authors: Shimizu Kazuya , Gurdon J. B.
Published: July 2002

Previous work has shown that
Xenopus
blastula cells sense activin concentration by assessing the absolute number of occupied receptors per cell (100 and 300 molecules of bound activin activate
Xbra
and
Xgsc
transcription, respectively; a difference of only 3-fold). We now ask how quantitative differences in the absolute number of occupied receptors lead to the qualitatively distinct gene responses in the nucleus through SMAD2, a transducer of concentration-dependent gene responses to activin. We show that the injection of 0.2 or 0.6 ng of
Smad2
mRNA activates
Xbra
or
Xgsc
transcription, respectively, involving, again, only a 3-fold difference. Furthermore,
Xbra
transcription is down-regulated by overexpression of SMAD2 as it is after activin signaling. We have developed a method to isolate nuclei from animal cap cells and subsequently have quantified the amount of nuclear SMAD2 protein. We find that the injection of 0.2 or 0.6 ng of
Smad2
mRNA into an egg leads to only a 3-fold difference in the amount of SMAD2 protein in the nuclei of the blastula cells that express
Xbra
or
Xgsc
. We conclude that a 3-fold difference in the absolute number of occupied activin receptors can be maintained only as a 3-fold difference in the level of nuclear SMAD2 protein. Therefore, in this example of morphogen action, there appears to be no amplification of a key cytoplasmic transduction response, and a small but developmentally important change in extracellular signal concentration is relayed directly to the nucleus.
Structure of the subunit c oligomer in the F
1
F
o
ATP synthase: Model derived from solution structure of the monomer and cross-linking in the native enzyme
Authors: Dmitriev Oleg Y. , Jones Phil C. , Fillingame Robert H.
Published: July 2002

The structure of the subunit c oligomer of the H
+
-transporting ATP synthase of
Escherichia coli
has been modeled by molecular dynamics and energy minimization calculations from the solution structure of monomeric subunit c and 21 intersubunit distance constraints derived from cross-linking of subunits. Subunit c folds in a hairpin-like structure with two transmembrane helices. In the c
12
oligomer model, the subunits pack to form a compact hollow cylinder with an outer diameter of 55–60 Å and an inner space with a minimal diameter of 11–12 Å. Phospholipids are presumed to pack in the inner space in the native membrane. The transmembrane helices pack in two concentric rings with helix 1 inside and helix 2 outside. The calculations strongly favor this structure versus a model with helix 2 inside and helix 1 outside. Asp-61, the H
+
-transporting residue, packs toward the center of the four transmembrane helices of two interacting subunits. From this position at the front face of one subunit, the Asp-61 carboxylate lies proximal to side chains of Ala-24, Ile-28, and Ala-62, projecting from the back face of a second subunit. These interactions were predicted from previous mutational analyses. The packing supports the suggestion that a c–c dimer is the functional unit. The positioning of the Asp-61 carboxyl in the center of the interacting transmembrane helices, rather than at the periphery of the cylinder, has important implications regarding possible mechanisms of H
+
-transport-driven rotation of the c oligomer during ATP synthesis.
Antigen-specific modulation of experimental myasthenia gravis: Nasal tolerization with recombinant fragments of the human acetylcholine receptor α-subunit
Authors: Barchan Dora , Souroujon Miriam C. , Im Sin-Hyeog , Antozzi Carlo , Fuchs Sara
Published: July 2002

Myasthenia gravis (MG) and experimental autoimmune myasthenia gravis (EAMG) are antibody-mediated autoimmune diseases in which the nicotinic acetylcholine receptor (AcChoR) is the major autoantigen. The immune response in these diseases is heterogeneous and is directed to a wide variety of T and B cell epitopes of AcChoR. Candidate molecules for specific immunotherapy of MG should, therefore, have a broad specificity. We used recombinant fragments of the human AcChoR, encompassing the extracellular domain of the α-subunit, or shorter fragments derived from it, in experiments to modulate EAMG. We have demonstrated that intranasal administration of these recombinant fragments, which represent a major portion of epitopes involved in MG, prevents the induction of EAMG in rats and immunosuppresses an ongoing disease, as assessed by clinical symptoms, weight loss, and muscle AcChoR content. These effects on EAMG were accompanied by a marked reduction in the proliferative T-cell response and IL-2 production in response to AcChoR, in reduced anti-self AcChoR antibody titers and in an isotype switch of AcChoR-specific antibodies, from IgG2 to IgG1. We conclude that nasal tolerance induced by appropriate recombinant fragments of human AcChoR is effective in suppressing EAMG and might possibly be considered as a therapeutic modality for MG.
The 3D NOESY-[
1
H,
15
N,
1
H]-ZQ-TROSY NMR experiment with diagonal peak suppression
Authors: Pervushin Konstantin V. , Wider Gerhard , Riek Roland , Wüthrich Kurt
Published: July 2002

In our 3D NOESY-[
1
H,
15
N,
1
H]-ZQ-TROSY experiment, the TROSY principle (transverse relaxation-optimized spectroscopy) is used in three-dimensional (3D)
15
N-resolved nuclear Overhauser enhancement spectroscopy (NOESY), which enables resonance assignments by sequential nuclear Overhauser effects and the collection of structural constraints in large
15
N- or
2
H,
15
N-labeled proteins. Our experiment affords optimization of the transverse relaxation in all three frequency dimensions, provides suppression of the strong diagonal autorelaxation peaks, which otherwise tend to interfere with the analysis of nearby informative crosspeaks, and yields improved resolution for the entire spectrum when compared with conventional 3D
15
N-resolved-[
1
H,
1
H]-NOESY, because of the narrower lineshapes along both proton dimensions. The key element of this experiment is an approach for correlating the
15
N and
1
H chemical shifts with two-dimensional ZQ-[
15
N,
1
H]-TROSY, where zero-quantum (ZQ) coherence is generated and the remote cross-correlation between the
1
H and
15
N chemical shift anisotropy interactions is used to reduce transverse relaxation during
15
N evolution. Practical applications are illustrated with spectra of a protein with a molecular mass of 110,000 Da.
The Med1 subunit of the yeast mediator complex is involved in both transcriptional activation and repression
Authors: Balciunas Darius , Gälman Cecilia , Ronne Hans , Björklund Stefan
Published: July 2002

The mediator complex is essential for regulated transcription
in vitro
.
In the yeast
Saccharomyces cerevisiae
, mediator comprises >15 subunits and interacts with the C-terminal domain of the largest subunit of RNA polymerase II, thus forming an RNA polymerase II holoenzyme. Here we describe the molecular cloning of the
MED1
cDNA encoding the 70-kDa subunit of the mediator complex. Yeast cells lacking the
MED1
gene are viable but show a complex phenotype including partial defects in both repression and induction of the
GAL
genes. Together with results on other mediator subunits, this implies that the mediator is involved in both transcriptional activation and repression. Similar to mutations in the
SRB10
and
SRB11
genes encoding cyclin C and the cyclin C-dependent kinase, a disruption of the
MED1
gene can partially suppress loss of the Snf1 protein kinase. We further found that a lexA-Med1 fusion protein is a strong activator in
srb11
cells, which suggests a functional link between Med1 and the Srb10/11 complex. Finally, we show that the Med2 protein is lost from the mediator on purification from Med1-deficient cells, indicating a physical interaction between Med1 and Med2.
Evidence for the recent horizontal transfer of long terminal repeat retrotransposon
Authors: Jordan I. King , Matyunina Lilya V. , McDonald John F.
Published: July 2002

The evolutionary dynamics existing between transposable elements (TEs) and their host genomes have been likened to an “arms race.” The selfish drive of TEs to replicate, in turn, elicits the evolution of host-mediated regulatory mechanisms aimed at repressing transpositional activity. It has been postulated that horizontal (cross-species) transfer may be one effective strategy by which TEs and other selfish genes can escape host-mediated silencing mechanisms over evolutionary time; however, to date, the most definitive evidence that TEs horizontally transfer between species has been limited to class II or DNA-type elements. Evidence that the more numerous and widely distributed retroelements may also be horizontally transferred between species has been more ambiguous. In this paper, we report definitive evidence for a recent horizontal transfer of the
copia
long terminal repeat retrotransposon between
Drosophila melanogaster
and
Drosophila willistoni
.
Residual delay maps unveil global patterns of atmospheric nonlinearity and produce improved local forecasts
Authors: Sugihara George , Casdagli Martin , Habjan Edward , Hess Dale , Dixon Paul , Holland Greg
Published: July 2002

We use residual-delay maps of observational field data for barometric pressure to demonstrate the structure of latitudinal gradients in nonlinearity in the atmosphere. Nonlinearity is weak and largely lacking in tropical and subtropical sites and increases rapidly into the temperate regions where the time series also appear to be much noisier. The degree of nonlinearity closely follows the meridional variation of midlatitude storm track frequency. We extract the specific functional form of this nonlinearity, a V shape in the lagged residuals that appears to be a basic feature of midlatitude synoptic weather systems associated with frontal passages. We present evidence that this form arises from the relative time scales of high-pressure versus low-pressure events. Finally, we show that this nonlinear feature is weaker in a well regarded numerical forecast model (European Centre for Medium-Range Forecasts) because small-scale temporal and spatial variation is smoothed out in the grided inputs. This is significant, in that it allows us to demonstrate how application of statistical corrections based on the residual-delay map may provide marked increases in local forecast accuracy, especially for severe weather systems.
Xenopus laevis
sperm receptor gp69/64 glycoprotein is a homolog of the mammalian sperm receptor ZP2
Authors: Tian Jingdong , Gong Hui , Lennarz William J.
Published: July 2002

Little is known about sperm-binding proteins in the egg envelope of nonmammalian vertebrate species. We report here the molecular cloning and characterization of a recently identified sperm receptor (gp69/64) in the
Xenopus laevis
egg vitelline envelope. Our data indicate that the gp69 and gp64 glycoproteins are two glycoforms of the receptor and have the same number of N-linked oligosaccharide chains but differ in the extent of O
-
glycosylation. The amino acid sequence of the receptor is closely related to that of the mouse zona pellucida protein ZP2. Most of the sequence conservation, including a ZP domain, a potential furin cleavage site, and a putative transmembrane domain are located in the C-terminal half of the receptor. Proteolytic cleavage of the gp69/64 protein by a cortical granule protease during fertilization removes 27 amino acid residues from the N terminus of gp69/64 and results in loss of sperm binding to the activated eggs. Similarly, we find that treatment of eggs with type I collagenase removes 31 residues from the N terminus of gp69/64 and has the same effect on sperm binding. The isolated and purified N terminus-truncated receptor protein is inactive as an inhibitor of sperm–egg binding. Earlier studies on the effect of Pronase digestion on receptor activity suggest that this N-terminal peptide may contain an O-linked glycan that is involved in the binding process. Based on these results and the findings on the primary structure of the receptor, a pathway for the maturation and secretion of gp69/64, as well as its inactivation following fertilization, is proposed.
U1 small nuclear RNA and spliceosomal introns in
Euglena
gracilis
Authors: Breckenridge David G. , Watanabe Yoh-ichi , Greenwood Spencer J. , Gray Michael W. , Schnare Murray N.
Published: July 2002

In the flagellated protozoon
Euglena gracilis
, characterized nuclear genes harbor atypical introns that usually are flanked by short repeats, adopt complex secondary structures in pre-mRNA, and do not obey the GT-AG rule of conventional cis-spliced introns. In the nuclear fibrillarin gene of
E. gracilis
, we have identified three spliceosomal-type introns that have GT-AG consensus borders. Furthermore, we have isolated a small RNA from
E. gracilis
and propose, on the basis of primary and secondary structure comparisons, that it is a homolog of U1 small nuclear RNA, an essential component of the cis-spliceosome in higher eukaryotes. Conserved sequences at the 5′ splice sites of the fibrillarin introns can potentially base pair with
Euglena
U1 small nuclear RNA. Our observations demonstrate that spliceosomal GT-AG cis-splicing occurs in
Euglena
, in addition to the nonconventional cis-splicing and spliced leader trans-splicing previously recognized in this early diverging unicellular eukaryote.
T cell receptor gene deletion circles identify recent thymic emigrants in the peripheral T cell pool
Authors: Kong Fan-kun , Chen Chen-lo H. , Six Adrien , Hockett Richard D. , Cooper Max D.
Published: July 2002

Progenitor cells undergo T cell receptor (TCR) gene rearrangements during their intrathymic differentiation to become T cells. Rearrangements of the variable (V), diversity (D), and joining (J) segments of the TCR genes result in deletion of the intervening chromosomal DNA and the formation of circular episomes as a byproduct. Detection of these extrachromosomal excision circles in T cells located in the peripheral lymphoid tissues has been viewed as evidence for the existence of extrathymic T cell generation. Because all of the T cells in chickens apparently are generated in the thymus, we have employed this avian model to determine the fate of the V(D)J deletion circles. In normal animals we identified TCR Vγ-Jγ and Vβ-Dβ deletion circles in the blood, spleen, and intestines, as well as in the thymus. Thymectomy resulted in the gradual loss of these DNA deletion circles in all of the peripheral lymphoid tissues. A quantitative PCR analysis of Vγ1-Jγ1 and Vβ1-Dβ deletion circles in splenic γδ and Vβ1+αβ T cells indicated that their numbers progressively decline after thymectomy with a half-life of approximately 2 weeks. Although TCR deletion circles therefore cannot be regarded as reliable indicators ofin situV(D)J rearrangement, measuring their levels in peripheral T cell samples can provide a valuable index of newly generated T cells entering the T cell pool.
Coalescent estimates of HIV-1 generation timein vivo
Authors: Rodrigo Allen G. , Shpaer Eugene G. , Delwart Eric L. , Iversen Astrid K. N. , Gallo Michael V. , Brojatsch Jürgen , Hirsch Martin S. , Walker Bruce D. , Mullins James I.
Published: July 2002

The generation time of HIV Type 1 (HIV-1)in vivohas previously been estimated using a mathematical model of viral dynamics and was found to be on the order of one to two days per generation. Here, we describe a new method based on coalescence theory that allows the estimate of generation times to be derived by using nucleotide sequence data and a reconstructed genealogy of sequences obtained over time. The method is applied to sequences obtained from a long-term nonprogressing individual at five sampling occasions. The estimate of viral generation time using the coalescent method is 1.2 days per generation and is close to that obtained by mathematical modeling (1.8 days per generation), thus strengthening confidence in estimates of a short viral generation time. Apart from the estimation of relevant parameters relating to viral dynamics, coalescent modeling also allows us to simulate the evolutionary behavior of samples of sequences obtained over time.
3′ poly(A) is dispensable for translation
Authors: Searfoss Anjanette M. , Wickner Reed B.
Published: July 2002

In wild-type cells, the 3′ poly(A) structure is necessary for translation of mRNA and for mRNA stability. The
superkiller 2 (ski2), ski3, ski6, ski7
, and
ski8
mutations enhance the expression of the poly(A)
−
mRNAs of yeast RNA viruses. Ski2p is a DEVH-box RNA helicase and Slh1p resembles Ski2p. Both repress L-A double-stranded RNA (dsRNA) virus copy number, further suggesting that their functions may overlap. We find that
slh1
Δ
ski2
Δ double mutants are healthy (in the absence of viruses) and show normal rates of turnover of several cellular mRNAs. The
slh1
Δ
ski2
Δ strains translate electroporated nonpoly(A) mRNA with the same kinetics as polyA
+
mRNA. Thus, the translation apparatus is inherently capable of efficiently using nonpoly(A) mRNA even in the presence of normal amounts of competing poly(A)
+
mRNA, but is normally prevented from doing so by the combined action of the nonessential proteins Ski2p and Slh1p.
Coordinate control of translation and localization of Vg1 mRNA in
Xenopus
oocytes
Authors: Wilhelm James E. , Vale Ronald D. , Hegde Ramanujan S.
Published: July 2002

Vg1, a member of the transforming growth factor-β family involved
in mesoderm induction, is translated subsequent to the localization of
its mRNA to the vegetal pole of
Xenopus
oocytes. Whereas
the localization of Vg1 mRNA is known to be directed by the 3′
untranslated region (UTR), the basis of its translational regulation is
unknown. We show here that the 3′ UTR of Vg1 causes translational
repression of two different reporter mRNAs in
Xenopus
oocytes. A 350-nucleotide region of the 3′ UTR, which is distinct from
the localization element, is necessary and sufficient for mediating
translational repression and specifically binds to a 38-kDa
polypeptide. The translational repression activity is found throughout
the oocyte and at all stages of oogenesis. These results suggest that
factors colocalized with Vg1 mRNA at the vegetal pole relieve
translational repression to allow expression of Vg1 protein.
Genetic restriction of HIV-1 pathogenesis to AIDS by promoter alleles of IL10
Authors: Shin Hyoung Doo , Winkler Cheryl , Stephens J. Claiborne , Bream Jay , Young Howard , Goedert James J. , O'Brien Thomas R. , Vlahov David , Buchbinder Susan , Giorgi Janis , Rinaldo Charles , Donfield Sharyne , Willoughby Anne , O'Brien Stephen J. , Smith Michael W.
Published: July 2002

IL10 is a powerful TH-2 cell cytokine produced by lymphoid cells that limits HIV-1 replicationin vivo, ostensibly by inhibiting macrophage/monocyte and T-cell lymphocyte replication and secretion of inflammatory cytokines (IL1, TNFα, IL6, IL8, and IL12). A genetic epidemiological scan of patients enrolled in AIDS cohorts for candidate gene-linked short tandem repeat polymorphisms revealed significant genotype associations for HIV-1 infection and progression to AIDS with markers adjacent to and tracking (by linkage disequilibrium) common single nucleotide polymorphic variants in theIL10promoter region. Individuals carrying theIL10-5′−592A(IL10-5′A) promoter allele possibly were at increased risk for HIV-1 infection, and once infected they progressed to AIDS more rapidly than homozygotes for the alternativeIL10-5′−592 C/C(IL10-+/+) genotype, particularly in the later stages of HIV-1 infection. An estimated 25–30% of long-term nonprogressors (who avoid clinical AIDS for 10 or more years after HIV-1 infection) can be attributed to theirIL10-+/+ promoter genotype. AlternativeIL10promoter alleles are functionally distinct in relative IL10 production, in retention of an avian erythroblastosis virus transcription factor recognition sequence and in binding to specific putative nuclear transcription factors, suggesting a potential mechanism wherebyIL10-5′Adown-regulation of inhibitory IL10 facilitates HIV-1 replicationin vivo, accelerating the onset of AIDS.
Genetic remodeling of protein glycosylation
in vivo
induces autoimmune disease
Authors: Chui Daniel , Sellakumar Gayathri , Green Ryan S. , Sutton-Smith Mark , McQuistan Tammie , Marek Kurt W. , Morris Howard R. , Dell Anne , Marth Jamey D.
Published: July 2002

Autoimmune diseases are among the most prevalent of
afflictions, yet the genetic factors responsible are largely undefined.
Protein glycosylation in the Golgi apparatus produces structural
variation at the cell surface and contributes to immune
self-recognition. Altered protein glycosylation and antibodies that
recognize endogenous glycans have been associated with
various autoimmune syndromes, with the possibility that such
abnormalities may reflect genetic defects in glycan formation. We show
that mutation of a single gene, encoding α-mannosidase II, which
regulates the hybrid to complex branching pattern of extracellular
asparagine (N)-linked oligosaccharide chains
(
N
-glycans), results in a systemic autoimmune disease
similar to human systemic lupus erythematosus. α-Mannosidase
II-deficient autoimmune disease is due to an incomplete overlap of two
conjoined pathways in complex-type
N
-glycan production.
Lymphocyte development, abundance, and activation parameters are
normal; however, serum immunoglobulins are increased and kidney
function progressively falters as a disorder consistent with lupus
nephritis develops. Autoantibody reactivity and circulating immune
complexes are induced, and anti-nuclear antibodies exhibit reactivity
toward histone, Sm antigen, and DNA. These findings reveal a genetic
cause of autoimmune disease provoked by a defect in the pathway of
protein
N
-glycosylation.
Human Nature and World Politics: Cognition, Identity, and Influence
Authors: Tetlock Philip E. , Goldgeier James M.
Published: July 2002

Many psychologists deem it self‐evident that psychology can make fundamental contributions to our understanding of world politics. Many social scientists, however, argue that policymakers are tightly constrained by macro political and economic forces. This article will advance a systemic approach to world politics that challenges: (a) psychologists by highlighting ways in which macro social structures may transform the character of “basic” intrapsychic processes; (b) anti‐psychological theorists by showing that even the most sweepingly deterministic macro claims—for example, claims about the power of free trade to promote peace—rest on controversial assumptions about human nature. Systemic approaches to world politics are far more consistent with how seasoned diplomats—from Dag Hammarskjöld to Henry Kissinger—have historically approached geopolitical problems than are the traditional but increasingly obsolete micro and macro dualities that have dominated academic analyses.
Ideological Beliefs About Family Practices: Contemporary Perspectives Among North Indian Families
Authors: Suppal Preeti G. , Roopnarine Jaipaul L. , Buesig Trace , Bennett Alan
Published: July 2002

Ninety‐two dual‐wage and 103 single‐wage Indian families with a preschool‐age child residing in extended and nuclear households provided assessments regarding their beliefs about the division of household chores, financial responsibilities, childcare, and filial obligations. Analysis focused on possible differences in belief structures that may be attributed to the gender of the parent, family structural living arrangement, and maternal employment outside of the home. Husbands and wives did not differ in ideological beliefs on any of the components assessed, but differences did emerge as a function of family structural arrangements and whether or not the wife worked outside of the home. Data are discussed in terms of possible changes in ideological beliefs about family functions and practices and the broader socio‐cultural factors operating within Indian society.
Unrealistic Optimism and Positive‐Negative Asymmetry: A Conceptual and Cross‐cultural Study of Interrelationships between Optimism, Pessimism, and Realism
Authors: Peeters Guido , Cammaert Marie‐France , Czapinski Janusz
Published: July 2002

Using a variant of Weinstein's (1980) technique for the measurement of unrealistic optimism, subjects were classified as optimistic, realistic, or pessimistic about their chances of being confronted in the future with problems such as divorce, nervous breakdown, etc. On the basis of previous theory and research on cognition and affect, it was hypothesized that, across problems, subjects would alternate optimism with realism rather than with pessimism. Cross‐cultural data obtained from 19 samples of Belgian, Moroccan, and Polish subjects not only confirmed the hypothesis but also showed high agreement about the nature of the problems that were selectively associated with optimism, realism and pessimism.
Estimating the Capacity of Phonological Short‐term Memory
Authors: Gathercole Susan E. , Pickering Susan J.
Published: July 2002

Two methods of assessing the capacity of phonological short‐term memory that minimize support from long‐term memory were compared in a sample of 7‐ and 8‐year‐old children. The children were tested on immediate serial recall of words and nonwords, and on the serial recognition of sequences composed of words and nonwords. Serial recognition scores were found to be highly related to children's accuracy of recall of nonwords composed of low‐probability phonotactic combinations, but were independent of the long‐term memory contributions to recall estimated in the serial recall experiment. Children with high vocabulary knowledge performed significantly better than low vocabulary children on both the recall and recognition measures. It is argued that the convergence of the two techniques lends substantial validity to their use as assessments of phonological storage capacity relatively free of long‐term memory influence, and that the crucial difference between children varying in vocabulary knowledge lies in this storage capacity rather than the differential availability and use of long‐term knowledge.
National Self-Determination: A Theoretical Discussion
Authors: Neuberger Benyamin
Published: July 2002

The principle of national self-determination has been haunting the world since the French Revolution. In Eastern Europe and the former Soviet Union alone 20 new “nation-states” were created in the 1990s—200 years after the French Revolution. They were all established on the basis of the principle of national self-determination. There may be no other term in modern political discourse which is used with more emotion and passion. Recent history has known many wars fueled by conflicting interpretations of self-determination. Woodrow Wilson thought that implementation of the principle of self-determination would lead to a better world, a world without wars and “safe for democracy.” His secretary of state, Robert Lansing, had doubts. He suspected the concept of self-determination to be “loaded with dynamite” and capable of causing even more bloodshed because it “will raise hopes which can never be realized.”
On the Borders of the Nation: Jews and the German–Polish National Conflict in Poznania, 1886–1914
Authors: Drummond Elizabeth A.
Published: July 2002

National identity is everywhere constructed through a process of negotiation with other categories of identity—local, regional, class, confessional, and gender. In borderlands, however, there is another element in this negotiation process—the sharing of public space with another national group, an element that further complicates identity formation. Here categories can change and/or function differently than in the interior of a country. In many respects, the construction of Germanness in the province of Poznania [German:Posen; Polish:Poznań] proceeded along similar lines as in the rest of the German Empire. German nationalists, both in the eastern provinces and in the rest of the Reich, produced publications and organized lectures about and celebrations of German history and German culture in an effort to mobilize national loyalties in support of policies that would consolidate Germandom both within and without. However, the presence of a Polish challenge in Poznania—the defining problem of the province—complicated constructions of German national identity.
Towards a typology of standard negation
Authors: Miestamo Matti
Published: July 2002

Standard negation is the basic sentential negation in a language. This article proposes a typology of standard negation that takes into account the whole negative construction and allows explanation of different negation types by different semantico-pragmatic background phenomena. There is semantic and pragmatic asymmetry between affirmation and negation, and this asymmetry is manifested in different ways in the morphosyntax of negative constructions. The primary division in the classification is between symmetric and asymmetric negation. The asymmetric type can be divided into subtypes according to which aspects of the semantico-pragmatic asymmetry are grammaticalized in the negative constructions. Symmetric and asymmetric negative constructions are analogous to the affirmative structure and to the background semantics and pragmatics of negation, respectively.
Substance Use Disorders in High‐Risk Adolescent Offspring
Authors: Milberger Sharon , Faraone Stephen V. , Biederman Joseph , Chu Monica P. , Feighner Jennifer A.
Published: July 2002

Objective: To examine the risk for substance use disorders (SUD) in offspring of SUD parents who were not selected due to referral to SUD treatment centers. Method: The original sample was ascertained through two groups of index children: 140 ADHD probands and 120 non‐ADHD comparison probands. These groups had 1 74 and 129 biological siblings and 279 and 240 parents, respectively. Results: We found that: 1) parental SUD was associated with SUD and all SUD subtypes in the offspring; 2) parental alcohol use disorders were associated with alcohol use disorders in the offspring as well as co‐occurring alcohol and drug use disorders but not drug use disorders alone in the offspring; and 3) drug use disorders in the parents were associated with drug use disorders but not alcohol use disorders in the offspring. Conclusions: These findings suggest that alcoholism and drug abuse may breed true from parents to their offspring, but further work with larger samples is needed to confirm this idea. Our findings also suggest a possible common diathesis that is expressed as comorbid alcohol and drug use in the offspring of alcoholic parents. If confirmed, these findings may be useful for the development of preventive and early intervention strategies for adolescents at high risk for SUD based on parental history of SUD.
Italian neopatriotism: Debating national identity in the 1990s
Authors: Patriarca Silvana
Published: July 2002

This article discusses some of the distinguishing features of the debate over national identity that took place in Italy in the 1990s. Reacting against the threats of the Lega Nord and in response to the new ideological and political landscape of the post-Cold War order, a number of Italian intellectuals rediscovered the value of patriotism. Searching for the origins of the Italians' allegedly weak sense of national identity, some questioned the Resistance and the party system that originated from it. While this historical revisionism has been the object of well-deserved criticism, there is another type of thematization of identity which has received less attention: it deploys the old notion of an ‘Italian character’, which appears frequently in the press and the media. The article shows that this discourse, too, is a way of articulating patriotism, and then reflects on the meaning that this reconfiguration of ideologies and identities acquires in the new context, both domestic and international.