Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human immunodeficiency virus type 1 (HIV-1) is able to establish a latent infection during which the integrated provirus remains transcriptionally silent. In response to specific stimuli, the HIV-1 long terminal repeat (LTR) is highly activated, enhancing both transcriptional initiation and elongation. Here, we have identified a specific binding sequence of the nuclear NF-kappaB-repressing factor (NRF) within the HIV-1 LTR. The aim of this work was to define the role of NRF in regulating the LTR. Our data show that the endogenous NRF is required for transcriptional activation of the HIV-1 LTR in stimulated cells. In unstimulated cells, however, NRF inhibits HIV-1 LTR activity at the level of transcription elongation. Binding of NRF to the LTR in unstimulated cells prevents recruitment of elongation factor DRB sensitivity-inducing factor and formation of processive elongation complexes by hyperphosphorylated RNA polymerase II. Our data suggest that NRF interrupts the regulatory coupling of LTR binding factors and transcription elongation events. This inhibitory mechanism might contribute to transcriptional quiescence of integrated HIV-1 provirus.
Mol Cell Biol 2005 Sep
PMID:NF-kappaB-repressing factor inhibits elongation of human immunodeficiency virus type 1 transcription by DRB sensitivity-inducing factor. 1610 96

P54nrb is a protein implicated in multiple nuclear processes whose specific functions may correlate with its presence at different nuclear locations. Here we characterize paraspeckles, a subnuclear domain containing p54nrb and other RNA-binding proteins including PSP1, a protein with sequence similarity to p54nrb that acts as a marker for paraspeckles. We show that PSP1 interacts in vivo with a subset of the total cellular pool of p54nrb. We map the domain within PSP1 that is mediating this interaction and show it is required for the correct localization of PSP1 to paraspeckles. This interaction is necessary but not sufficient for paraspeckle targeting by PSP1, which also requires an RRM capable of RNA binding. Blocking the reinitiation of RNA Pol II transcription at the end of mitosis with DRB prevents paraspeckle formation, which recommences after removal of DRB, indicating that paraspeckle formation is dependent on RNA Polymerase II transcription. Thus paraspeckles are the sites where a subset of the total cellular pool of p54nrb is targeted in a RNA Polymerase II-dependent manner.
Mol Biol Cell 2005 Nov
PMID:P54nrb forms a heterodimer with PSP1 that localizes to paraspeckles in an RNA-dependent manner. 1614 43

To elucidate the structures of SLA-DR (swine leukocyte antigen DR) genes of three Chinese pig strains (Gz, Bm and Yn), the SLA-DRA and SLA-DRB cDNA were amplified by RT-PCR and subjected to determine the sequences. The whole structures of SLA-DRA alleles are identical among three strains, consisting of 759 nucleotides including an open reading frame (ORF), and are shared with those reported from NIH minipigs SLA-DRA(c) and SLA-DRA(d). The same length of the ORF-containing SLA-DRB genes of three Chinese pig strains was also identified. They are composed of 801 nucleotides encoding a xenogeneic antigen molecule of 266 amino acid residues. The nucleotide sequences of the SLA-DRB genes, however, are different when compared either among the three strains or with the published data of SLA-DRB sequences, which allowed our novel SLA-DRB alleles receiving their accession numbers AY102479, AY102480 and AY102481 from the GenBank. This study further reveals that the phylogenic homologies of MHC DR or DR-like genes in structures of nucleotides and deduced amino acids between Chinese pigs (SLA) and human (HLA-DRB1*0901) are better than those between pigs and mice (H-2(b)Ebeta). High similarities were also found for DRalpha-DRbeta heterodimers between Chinese pigs and human in terms of amino acids sequences critical for binding with human CD4 coreceptor molecule, which are better than those between SLA-DR and H-2 I-E molecules. A functional test indicated that, by cotransfection with Bm-DRA and Bm-DRB genes, the Bm-DR molecule-expressed L929 cells could stimulate human T cells quite well in a xenogeneic reaction in presence of human APCs.
Cell Mol Immunol 2004 Jun
PMID:Novel SLA-DR alleles of three Chinese pig strains and the related function in human T cell response. 1621 70

Matching of the HLA antigens for donor-recipient in transplantation, disease predisposition or protection, population studies, and forensic testing requires accurate but simple typing methods. Here, we describe a DNA-based tissue-typing assay that determines the haplotype of the DRB1/3/4/5 loci in hy-bridization of oligonucleotide array after sample amplification. Using this multianalyte DNA hybridization system, we analyzed seven regions of exon 2 of DRB loci that have single-base discrimination. Thirty-six oligonucleotide probes complementary to the alleles of interest were immobilized on each microslide. The efficiency and specificity of identifying DRB genotypes using the oligonucleotide arrays was evaluated by blinded analysis of 147 samples from reference standards and subjects. The established method provides a rapid and inexpensive DRB "low-resolution" typing tool for prescreening a large number of samples.
J Mol Diagn 2005 Nov
PMID:Simultaneous genotyping of DRB1/3/4/5 loci by oligonucleotide microarray. 1625 57

Major histocompatibility complex (MHC) genes, coding molecules which play an important role in immune response, are the most polymorphic genes known in vertebrates. However, MHC polymorphism in some species is limited. MHC monomorphism at several MHC class I and II loci was previously reported for two neighbouring northern European populations of the Eurasian beaver (Castor fiber) and reduced selection for polymorphism has been hypothesized. Here, we analysed a partial sequence of the second exon of the MHC II DRB locus from seven relict European and Asian beaver populations. We detected 10 unique alleles among 76 beavers analysed. Only a western Siberian population was polymorphic, with four alleles detected in 10 individuals. Each of the remaining populations was fixed for a different allele. Sequences showed considerable divergence, suggesting the long persistence of allelic lineages. A significant excess of nonsynonymous substitutions was detected at the antigen binding sites, indicating that sequence evolution of beaver DRB was driven by positive selection. Current MHC monomorphism in the majority of populations may be the result of the superimposition of the recent bottleneck on pre-existing genetic structure resulting from population subdivision and differential pathogen pressure.
Mol Ecol 2005 Dec
PMID:Sequence diversity of the MHC DRB gene in the Eurasian beaver (Castor fiber). 1631 90

We have determined the early effects of camptothecin and alpha-amanitin on genomic DNA-binding sites of RNA polymerase II (RNAPII), TATA-binding protein (TBP), DNA topoisomerase I (Top1), and histone components in human transcribed loci by chromatin-immunoprecipitation (ChIP). The two agents caused notably different alterations in active chromatin. Camptothecin induced a specific reduction of RNAPII density at promoter pause sites and histone modifications suggesting an increased chromatin accessibility. alpha-Amanitin caused an accumulation of RNAPII at transcribed genes, a reduction of TBP bound to chromatin and a less accessible chromatin structure. Interestingly, RNAPII reduction at promoter pause sites occurred within 5-10min of camptothecin treatment, and was not a response to replication-dependent DNA breaks. ChIP analyses of RNAPII along transcribed genes indicated that RNAPII levels were transiently increased at internal exons, and that camptothecin effects could be fully reversed by DRB, a cdk inhibitor. Top1 was found to be enriched in active chromatin, therefore suggesting that Top1 inhibition at the transcribed template and/or adjacent regulating regions immediately affects RNAPII at active genes. The findings are novel in vivo evidence of camptothecin effects on RNAPII bound to transcribing genomic regions, and are consistent with the hypothesis that Top1 activity can be involved in transcription regulation at the level of promoter clearance.
J Mol Biol 2006 Mar 17
PMID:Early effects of topoisomerase I inhibition on RNA polymerase II along transcribed genes in human cells. 1642 78

Major histocompatibility complex (MHC) class II DRB genotypes were examined in two geographically isolated populations of California sea lions (Zalophus californianus) (Gulf of California and California coastal Pacific Ocean). Genomic DNA from 227 California sea lions was examined using eight sequence-specific primer (SSP) pairs flanking the putative peptide-binding site. A total of 40 different Zaca-DRB genotype configurations were identified among the 227 individuals. Using SSP-PCR, significant differences were found between coastal California and Gulf of California Zalophus populations in numbers of DRB sequences per individual and configuration of sequences within individuals. Additionally, unique local patterns of MHC diversity were identified among the Midriff Island animals. These population differences are consistent with either ecologically distinct patterns of selection pressures and/or geographical isolation. The consequences of these partitioned MHC configurations at the population level are as yet unknown; however, the worldwide increase in emerging marine diseases lends urgency to their examination.
Mol Ecol 2006 Feb
PMID:MHC gene configuration variation in geographically disparate populations of California sea lions (Zalophus californianus). 1644 18

The confounding effects of population structure complicate efforts to identify regions of the genome under the influence of selection in natural populations. Here we test for evidence of selection in three genes involved in vertebrate immune function - the major histocompatibility complex (MHC), interferon gamma (IFNG) and natural resistance associated macrophage polymorphism (NRAMP) - in highly structured populations of wild thinhorn sheep (Ovis dalli). We examined patterns of variation at microsatellite loci linked to these gene regions and at the DNA sequence level. Simple Watterson's tests indicated balancing selection at all three gene regions. However, evidence for selection was confounded by population structure, as the Watterson's test statistics from linked markers were not outside of the range of values from unlinked and presumably neutral microsatellites. The translated coding sequences of thinhorn IFNG and NRAMP are fixed and identical to those of domestic sheep (Ovis aries). In contrast, the thinhorn MHC DRB locus shows significant evidence of overdominance through both an excess of nonsynonymous substitution and trans-species polymorphism. The failure to detect balancing selection at microsatellite loci linked to the MHC is likely the result of recombination between the markers and expressed gene regions.
Mol Ecol 2006 Mar
PMID:Detecting the signature of selection on immune genes in highly structured populations of wild sheep (Ovis dalli). 1649 90

Varying the concentration of selected factors alters the induction properties of steroid receptors by changing the position of the dose-response curve (or the value for half-maximal induction=EC(50)) and the amount of partial agonist activity of antisteroids. We now describe a rudimentary mathematical model that predicts a simple Michaelis-Menten curve for the multi-step process of steroid-regulated gene induction. This model suggests that steps far downstream from receptor binding to steroid can influence the EC(50) of agonist-complexes and partial agonist activity of antagonist-complexes. We therefore asked whether inhibitors of three possible downstream steps can reverse the effects of increased concentrations of two factors: glucocorticoid receptors (GRs) and Ubc9. The downstream steps (with inhibitors in parentheses) are protein deacetylation (TSA and VPA), DNA unwinding (CPT), and CTD phosphorylation of RNA polymerase II (DRB and H8). None of the inhibitors mimic or prevent the effects of added GRs. However, inhibitors of DNA unwinding and CTD phosphorylation do reverse the effects of Ubc9 with high GR concentrations. These results support our earlier conclusion that different rate-limiting steps operate at low and high GR concentrations versus high GR with Ubc9. The present data also suggest that downstream steps can modulate the EC(50) of GR-mediated induction, thus both supporting the utility of our mathematical model and widening the field of biochemical processes that can modify the EC(50).
J Steroid Biochem Mol Biol 2006 Jul
PMID:Effects of acetylation, polymerase phosphorylation, and DNA unwinding in glucocorticoid receptor transactivation. 1672 22

Habitat destruction and human activity have greatly impacted the natural history of the giant panda (Ailuropoda melanoleuca). Although the genetic diversity of neutral markers has been examined in this endangered species, no previous work has examined adaptive molecular polymorphisms in the giant panda. Here, the major histocompatibility complex (MHC) class II DRB locus was investigated in the giant panda, using single-strand conformation polymorphism (SSCP) and sequence analysis. Comparisons of DNA samples extracted from faecal and blood samples from the same individual revealed that the two materials yielded similar quantities and qualities of DNA, as well as identical SSCP patterns and allelic sequences, demonstrating the reliability of DNA isolation from panda faeces. Analysis of faecal samples from 60 giant pandas revealed relatively low number of alleles: seven alleles. However, the alleles were quite divergent, varying from each other by a range of 7-47 nucleotide substitutions (4-25 amino acid substitutions). Construction of a neighbour-joining tree and comparisons among DRB alleles from other species revealed that both similar and highly divergent alleles survived in the bottlenecked panda populations. Despite species-specific primers used and excellent faecal DNA isolated, a lower level of heterozygosity than expected was still observed due to inbreeding. There were three types of evidence supporting the presence of balancing selection in the giant panda: (i) an obvious excess of nonsynonymous substitutions over synonymous at the antigen-binding positions; (ii) trans-species evolution of two alleles between the giant panda and other felids; and (iii) a more even distribution of alleles than expected from neutrality.
Mol Ecol 2006 Aug
PMID:Major histocompatibility complex class II variation in the giant panda (Ailuropoda melanoleuca). 1684 18


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