Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20226 (TATA-binding protein)
 1,297 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The retinoblastoma (RB) tumour suppressor protein negatively regulates cell proliferation by modulating transcription of growth-regulatory genes. Recruitment of Rb to promoters, by association with E2F complex or by fusion with heterologous DNA-binding domains, demonstrated that Rb represses directly transcription. Recent studies also suggest that the RB protein is able to repress gene transcription mediated by the RNA polymerase I and III. Since the TATA-binding protein (TBP) is an important component for transcription mediated by all three RNA polymerases, we have analysed the functional interaction between Rb and TBP in vivo in the context of RNA pol II-driven transcription. We demonstrated that in mammalian cells Rb tethered to promoter represses TBP-mediated activation in vivo, and Rb-mediated repression is reversed in the presence of the inhibition of histone deacetylase activity by trichostatin A (TSA).
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PMID:Retinoblastoma protein tethered to promoter DNA represses TBP-mediated transcription. 967 Dec 33

Using a genetic screen, we isolated three TATA-binding protein (TBP) mutants that increase transcription from promoters that are repressed by the Cyc8-Tup1 or Sin3-Rpd3 corepressors or that lack an enhancer element, but not from an equivalently weak promoter with a mutated TATA element. Increased transcription is observed when the TBP mutants are expressed at low levels in the presence of wild-type TBP. These TBP mutants are unable to support cell viability, and they are toxic in strains lacking Rpd3 histone deacetylase or when expressed at higher levels. Although these mutants do not detectably bind TATA elements in vitro, genetic and chromatin immunoprecipitation experiments indicate that they act directly at promoters and do not increase transcription by titration of a negative regulatory factor(s). The TBP mutants are mildly defective for associating with promoters responding to moderate or strong activators; in addition, they are severely defective for RNA polymerase (Pol) III but not Pol I transcription. These results suggest that, with respect to Pol II transcription, the TBP mutants specifically increase expression from core promoters. Biochemical analysis indicates that the TBP mutants are unaffected for TFIID complex formation, dimerization, and interactions with either the general negative regulator NC2 or the N-terminal inhibitory domain of TAF130. We speculate that these TBP mutants have an unusual structure that allows them to preferentially access TATA elements in chromatin templates. These TBP mutants define a criterion by which promoters repressed by Cyc8-Tup1 or Sin3-Rpd3 resemble enhancerless, but not TATA-defective, promoters; hence, they support the idea that these corepressors inhibit the function of activator proteins rather than the Pol II machinery.
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PMID:TATA-binding protein mutants that increase transcription from enhancerless and repressed promoters in vivo. 1066 25

Elucidation of the mechanism of transcriptional silencing of human immunodeficiency virus type 1 (HIV-1) provirus in latently infected cells is crucial to understand the pathophysiology of HIV-1 infection and to develop novel therapies. Here we demonstrate that AP-4 is responsible for the transcriptional repression of HIV-1. We found that AP-4 site within the viral long terminal repeat (LTR) is well conserved in the majority of HIV-1 subtypes and that AP-4 represses HIV-1 gene expression by recruiting histone deacetylase (HDAC) 1 as well as by masking TATA-binding protein to TATA box. AP-4-mediated transcriptional repression was inhibited by an HDAC inhibitor, tricostatin A, and could be exerted even at distant locations from the TATA box. In addition, AP-4 interacted with HDAC1 both in vivo and in vitro. Moreover, chromatin immunoprecipitation assays have revealed that AP-4 and HDAC1 are present in the HIV-1 LTR promoter in latently infected ACH2 and U1 cells, and they are dissociated from the promoter concomitantly with the association of acetylated histone H3, TBP, and RNA polymerase II upon TNF-alpha stimulation of HIV-1 replication. Furthermore, when AP-4 is knocked down by siRNA, HIV-1 production was greatly augmented in cells transfected with a full-length HIV-1 clone. These results suggest that AP-4 may be responsible for transcriptional quiescence of latent HIV-1 provirus and give a molecular basis to the reported efficacy of combination therapy of conventional anti-HIV drugs with an HDAC inhibitor in accelerating the clearance of HIV-1 from individuals infected with the virus.
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PMID:Transcriptional repression of human immunodeficiency virus type 1 by AP-4. 1654 Apr 71

The histone deacetylase (HDAC) inhibitor trichostatin A (TSA) and hexamethylene bisacetamide (HMBA), which lacks HDAC inhibitory activity, both possess the capacity to induce leukemia cell differentiation and to enhance the expression of a wide range of transiently transfected reporter genes in 3T3 Swiss cells. In addition, known inducers of leukemia cell differentiation, including hypoxanthine, diazepam, 6-thioguanine and phorbol 12-myristate 13-acetate, also exhibited the ability to enhance reporter gene expression, while randomly chosen compounds that did not induce leukemia cell differentiation did not enhance reporter gene expression. The activity of TSA in the transfection system was modified by co-expression of histone acetyltransferase p300 and HDAC1; whereas, that of HMBA was enhanced by co-expression of the TATA-binding protein TBP. The stimulatory effects of diverse chemical inducers on transiently transfected genes suggest the existence of multiple exploitable targets for the selection of novel inducers of differentiation that function as modulators of gene activity.
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PMID:Relationship between the induction of leukemia cell differentiation and the enhancement of reporter gene expression in 3T3 Swiss cells. 1762 56

Histone acetyltransferases and histone deacetylases (HDACs) are important epigenetic coregulators. It has been thought that HDACs associate with corepressor complexes and repress gene transcription; however, in this study, we have found that PU.1-a key master regulator for hematopoietic self-renewal and lineage specification-requires HDAC activity for gene activation. Deregulated PU.1 gene expression is linked to dysregulated hematopoiesis and the development of leukemia. In this study, we used erythroid differentiation as a model to analyze how the PU.1 gene is regulated. We found that active HDAC1 is directly recruited to active PU.1 promoter in progenitor cells, whereas acetylated HDAC1, which is inactive, is on the silenced PU.1 promoter in differentiated erythroid cells. We then studied the mechanism of HDAC1-mediated activation. We discovered that HDAC1 activates PU.1 gene transcription via deacetylation of TATA-binding protein-associated factor 9 (TAF9), a component in the transcription factor IID (TFIID) complex. Treatment with HDAC inhibitor results in an increase in TAF9 acetylation. Acetylated TAF9 does not bind to the PU.1 gene promoter and subsequently leads to the disassociation of the TFIID complex and transcription repression. Thus, these results demonstrate a key role for HDAC1 in PU.1 gene transcription and, more importantly, uncover a novel mechanism of TFIID recruitment and gene activation.-Jian, W., Yan, B., Huang, S., Qiu, Y. Histone deacetylase 1 activates PU.1 gene transcription through regulating TAF9 deacetylation and transcription factor IID assembly.
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PMID:Histone deacetylase 1 activates PU.1 gene transcription through regulating TAF9 deacetylation and transcription factor IID assembly. 2857 46

Gene silencing for plasmid-based vectors and the underlying mechanism are critical factors for development of effective gene therapy. The objective of this study is to explore the role of epigenetic regulation for transgene expression. Two reporter genes, mouse interleukin 10 and human secreted alkaline phosphatase under the control of human cytomegalovirus immediate early promoter for expression, were delivered to mouse liver by hrodydynamics-based procedure and reporter gene expression was monitored. Reporter gene expression reached its peak level one day after gene delivery and declined progressively thereafter, reaching the minimal level in about 3 weeks. Intra-peritoneal injection of vorinostat, valproic acid or sodium butyrate, the known histone deacetylase inhibitors, resulted in a dose-dependent reactivation of reporter gene expression. Repeated administration of histone deacetylase inhibitors blocked gene silencing and maintained reporter gene expression. Mechanistic studies reveal that reactivation of reporter genes is corelated with hyperacetylation of histones H3 and H4, and elevated binding of TATA-box binding protein to the promoter region. These results suggest that epigenetic regulation plays a critical role in controlling transgene expression in vivo and demonstrate that enzymes involved in epigenetic regulation such as histone deacetylase could serve as a target to achieve controlled transgene expression for gene therapy.
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PMID:Histone deacetylase inhibitors reactivate silenced transgene in vivo. 3053 7