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 general transcription initiation factor TFIID contains the TATA-binding protein (TBP) and TBP-associated factors (TAFs) implicated in the function of gene-specific activators. Previous studies have indicated that a hamster cell line (ts13) with a point mutation in the TAF(II)250/CCG1 (TAF(II)250) gene shows temperature-sensitive expression of a subset of genes and arrests in late G1 at 39.5 degrees C. Here, we report the identification of cell cycle-specific (G1-specific) genes that appear to be regulated directly through TAF(II)250 both in vivo and in vitro. Transcription rates of several cell cycle-regulatory genes were determined by run-on assays in nuclei from ts13 cells grown at permissive (33 degrees C) and nonpermissive (39.5 degrees C) temperatures. Temperature-dependent differences in transcription rates were observed for cyclin A, D1, and D3 genes. In transient-transfection assays, the human cyclin D1 promoter fused to a luciferase reporter showed a temperature-dependent reduction in activity in ts13 cells but not in parental BHK cells. In in vitro assays, upstream sequence-dependent transcription from the human cyclin D1 promoter was significantly reduced in ts13 nuclear extracts preincubated at 30 degrees C but not in similarly treated BHK nuclear extracts, and transcription in the ts13 extract was restored by addition of an affinity-purified human TFIID. Preincubation of the ts13 nuclear extracts did not affect the function of several GAL4-activation domain fusion proteins (GAL4-VP16, GAL4-p65, and GAL4-p53) on either the adenovirus major late or cyclin D1 core promoter bearing GAL4 sites, further indicating that the effect of the TAF(II)250 mutation is both core promoter and activator specific.
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PMID:The ts13 mutation in the TAF(II)250 subunit (CCG1) of TFIID directly affects transcription of D-type cyclin genes in cells arrested in G1 at the nonpermissive temperature. 915 27

Numerous studies have demonstrated that the hepatitis B virus HBx protein stimulates signal transduction pathways and may bind to certain transcription factors, particularly the cyclic AMP response element binding protein, CREB. HBx has also been shown to promote early cell cycle progression, possibly by functionally replacing the TATA-binding protein-associated factor 250 (TAF(II)250), a transcriptional coactivator, and/or by stimulating cytoplasmic signal transduction pathways. To understand the basis for early cell cycle progression mediated by HBx, we characterized the molecular mechanism by which HBx promotes deregulation of the G0 and G1 cell cycle checkpoints in growth-arrested cells. We demonstrate that TAF(II)250 is absolutely required for HBx activation of the cyclin A promoter and for promotion of early cell cycle transit from G0 through G1. Thus, HBx does not functionally replace TAF(II)250 for transcriptional activity or for cell cycle progression, in contrast to a previous report. Instead, HBx is shown to activate the cyclin A promoter, induce cyclin A-cyclin-dependent kinase 2 complexes, and promote cycling of growth-arrested cells into G1 through a pathway involving activation of Src tyrosine kinases. HBx stimulation of Src kinases and cyclin gene expression was found to force growth-arrested cells to transit through G1 but to stall at the junction with S phase, which may be important for viral replication.
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PMID:Hepatitis B virus HBx protein activation of cyclin A-cyclin-dependent kinase 2 complexes and G1 transit via a Src kinase pathway. 1128 74