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)

A suppressor gene was identified, which in high copy number rescues a temperature-sensitive mutation in yeast TATA-binding protein (TBP). Suppression was allele specific because the suppressor did not rescue the temperature-sensitive phenotype of another TBP mutant. This suppressor gene encodes a 596-amino-acid protein of which the amino-terminal half is homologous to the Pol II-specific factor TFIIB. Disruption of this gene, termed BRF1, showed it to be essential for growth of yeast. Deletion of sequences at either the amino or carboxyl terminus of BRF1 gave both temperature- and cold-sensitive phenotypes. These temperature- and cold-sensitive strains were used to prepare extracts deficient in BRF1 activity and were tested for transcriptional activity by RNA polymerases I, II, and III in vitro. BRF1-deficient extracts are defective in Pol III transcription and can be reconstituted for Pol III transcription by the addition of recombinant BRF1. Western analysis shows that BRF1 is present in TFIIIB but not the TFIIIC fraction, suggesting that it is a component of TFIIIB. We propose that BRF1 plays a role in Pol III initiation analogous to the role played by TFIIB for Pol II in its interaction with TBP and polymerase. The identification of a Pol III-specific TFIIB-like factor extends the previously noted similarity of transcriptional initiation by the three nuclear polymerases.
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PMID:A yeast TFIIB-related factor involved in RNA polymerase III transcription. 139 71

The central RNA polymerase III (Pol III) transcription factor TFIIIB is composed of the TATA-binding protein (TBP), Brf, a protein related to TFIIB, and the product of the newly cloned TFC5 gene. TFIIIB assembles autonomously on the upstream promoter of the yeast U6 snRNA (SNR6) gene in vitro, through the interaction of its TBP subunit with a consensus TATA box located at base pair -30. As both the DNA-binding domain of TBP and the U6 TATA box are nearly twofold symmetrical, we have examined how the binding polarity of TFIIIB is determined. We find that TFIIIB can bind to the U6 promoter in both directions, that TBP is unable to discern the natural polarity of the TATA element and that, as a consequence, the U6 TATA box is functionally symmetrical. A modest preference for TFIIIB binding in the natural direction of the U6 promoter is instead dictated by flanking DNA. Because the assembly of TFIIIB on the yeast U6 gene in vivo occurs via a TFIIIC-dependent mechanism, we investigated the influence of TFIIIC on the binding polarity of TFIIIB. TFIIIC places TFIIIB on the promoter in one direction only; thus, it is TFIIIC that primarily specifies the direction of transcription. Experiments using TFIIIB reconstituted with the altered DNA specificity mutant TBPm3 demonstrate that in the TFIIIB-U6 promoter complex, the carboxy-terminal repeat of TBP contacts the upstream half of the TATA box. This orientation of yeast TBP in Pol III promoter-bound TFIIIB is the same as in Pol II promoter-bound TFIID and in TBP-DNA complexes that have been analyzed by X-ray crystallography.
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PMID:The symmetry of the yeast U6 RNA gene's TATA box and the orientation of the TATA-binding protein in yeast TFIIIB. 749 93

The human T-cell lymphotropic virus type 1 (HTLV-1) is the etiological agent for adult T-cell leukemia and tropical spastic paraparesis/HTLV-1-associated myelopathy. The HTLV-1 Tax1 gene product has been shown to transactivate transcription of viral and cellular promoters. To examine the biochemical mechanism of Tax1 transactivation, we have developed an in vitro transactivation assay in which wild-type Tax1 is able to specifically transactivate a polymerase II promoter through upstream Tax1-responsive elements. The in vitro system utilizes the HTLV-1 21-bp repeats cloned upstream of the ovalbumin promoter and G-free cassette. Purified Tax1 specifically transactivates this template 5- to 10-fold in a concentration-dependent manner. No transactivation of the ovalbumin promoter (pLovTATA) template control was observed. Tax1 transactivation was inhibited by low concentrations of alpha-amanitin and was effectively neutralized by anti-Tax1 but not control sera. Consistent with in vivo transactivating activity, Tax1 NF-kappa B mutant M22, but not cyclic AMP-responsive element-binding protein mutant M47, transactivated the template containing the tandem 21-bp repeat. In a reconstituted in vitro transcription assay, Tax1 transactivation was dependent upon basal transcription factors TFIIB, TFIIF, Pol II, TFIID, and TFIIA. TATA-binding protein did not functionally substitute for TFIID in the transactivation assay by Tax1 but was sufficient for basal transcription. Finally, we have used anti-TFIIA antibody (p55) to ask if Tax1 transactivation required TFIIA activity. Addition of TFIIA antibody to in vitro transcription reactions, as well as depletion of TFIIA by preclearing with antibody, showed that TFIIA was required for Tax1 transactivation. Only a slight (twofold) drop of basal transcription was observed. Tax1 transactivation was restored when purified HeLa TFIIA was added back into the reconstituted system. We propose that Tax1 utilizes a transactivation pathway involving the activator regulated basal transcription factors TFIID and TFIIA.
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PMID:Transactivation of the human T-cell lymphotropic virus type 1 Tax1-responsive 21-base-pair repeats requires Holo-TFIID and TFIIA. 760 77

The proximal sequence element (PSE), found in both RNA polymerase II (Pol II)- and RNA Pol III-transcribed small nuclear RNA (snRNA) genes, is specifically bound by the PSE-binding transcription factor (PTF). We have purified PTF to near homogeneity from HeLa cell extracts by using a combination of conventional and affinity chromatographic methods. Purified PTF is composed of four polypeptides with apparent molecular masses of 180, 55, 45, and 44 kDa. A combination of preparative electrophoretic mobility shift and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses has conclusively identified these four polypeptides as subunits of human PTF, while UV cross-linking experiments demonstrate that the largest subunit of PTF is in close contact with the PSE. The purified PTF activates transcription from promoters of both Pol II- and Pol III-transcribed snRNA genes in a PSE-dependent manner. In addition, we have investigated factor requirements in transcription of Pol III-dependent snRNA genes. We show that in extracts that have been depleted of TATA-binding protein (TBP) and associated factors, recombinant TBP restores transcription from U6 and 7SK promoters but not from the VAI promoter, whereas the highly purified TBP-TBP-associated factor complex TFIIIB restores transcription from the VAI but not the U6 or 7SK promoter. Furthermore, by complementation of heat-treated extracts lacking TFIIIC activity, we show that TFIIIC1 is required for transcription of both the 7SK and VAI genes, whereas TFIIIC2 is required only for transcription of the VAI gene. From these observations, we conclude (i) that PTF and TFIIIC2 function as gene-specific as gene-specific factors for PSE-and B-box-containing Pol III genes, respectively, (ii) that the form of TBP used by class III genes with upstream promoter elements differs from the from used by class III genes with internal promoters, and (iii) that TFIIIC1 is required for both internal and external Pol III promoters.
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PMID:Proximal sequence element-binding transcription factor (PTF) is a multisubunit complex required for transcription of both RNA polymerase II- and RNA polymerase III-dependent small nuclear RNA genes. 789 97

Although the TATA-binding protein (TBP) is highly conserved throughout the eukaryotic kingdom, human TBP cannot functionally replace yeast TBP for cell viability. To investigate the basis of this species specificity, we examine the in vivo transcriptional activity of human TBP at different classes of yeast promoters. Consistent with previous results, analysis of yeast/human hybrid TBPs indicates that growth defects are not correlated with the ability to promote TATA-dependent polymerase II (Pol II) transcription or to respond to acidic activator proteins. Human TBP partially complements the growth defects of a yeast TBP mutant with altered TATA element-binding specificity, suggesting that it carries out sufficient Pol II function to support viability. However, human TBP does not complement the defects of yeast TBP mutants that are specifically defective in transcription by RNA polymerase III. Three independently isolated derivatives of human TBP that permit yeast cell growth replace arginine 231 with lysine; the corresponding amino acid in yeast TBP (lysine 133) has been implicated in RNA polymerase III transcription. Transcriptional analysis indicates that human TBP functions poorly at promoters recognized by RNA polymerases I and III and at RNA Pol II promoters lacking a conventional TATA element. These observations suggest that species specificity of TBP primarily reflects evolutionarily diverged interactions with TBP-associated factors (TAFs) that are necessary for recruitment to promoters lacking TATA elements.
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PMID:Conserved and nonconserved functions of the yeast and human TATA-binding proteins. 792 34

Basic mechanisms of transcription initiation are conserved from yeast to man. However, in contrast to genes transcribed by RNA polymerases II and III, ribosomal gene transcription by RNA polymerase I (Pol I) is species-specific. Promoter selectivity is mediated by SL1/TIF-IB, a multiprotein complex containing the TATA-binding protein (TBP) and TBP-associated factors (TAFs) which bind to DNA and nucleate the assembly of initiation complexes. Using a human cell line that expresses epitope-tagged yeast TBP, we have isolated a chimeric complex consisting of yeast TBP and human TAFs which faithfully promotes human rDNA transcription in vitro. This result argues that specific interactions between TBP and Pol I-specific TAFs have been evolutionarily conserved between distant species. In addition, this finding also underscores the importance of TAFs in determining promoter selectivity of Pol I.
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PMID:Yeast TBP can replace its human homologue in the RNA polymerase I-specific multisubunit factor SL1. 796 4

In Saccharomyces cerevisiae, two components of the RNA polymerase III (Pol III) general transcription factor TFIIIB are the TATA-binding protein (TBP) and the B-related factor (BRF), so called because its amino-terminal half is homologous to the Pol II transcription factor IIB (TFIIB). We have cloned BRF genes from the yeasts Kluyveromyces lactis and Candida albicans. Despite the large evolutionary distance between these species and S. cerevisiae, the BRF proteins are conserved highly. Although the homology is most pronounced in the amino-terminal half, conserved regions also exist in the carboxy-terminal half that is unique to BRF. By assaying for interactions between BRF and other Pol III transcription factors, we show that it is able to bind to the 135-kD subunit of TFIIIC and also to TBP. Surprisingly, in addition to binding the TFIIB-homologous amino-terminal portion of BRF, TBP also interacts strongly with the carboxy-terminal half. Deleting two conserved regions in the BRF carboxy-terminal region abrogates this interaction. Furthermore, TBP mutations that selectively inhibit Pol III transcription in vivo impair interactions between TBP and the BRF carboxy-terminal domain. Finally, we demonstrate that BRF but not TFIIB binds the Pol III subunit C34 and we define a region of C34 necessary for this interaction. These observations provide insights into the roles performed by BRF in Pol III transcription complex assembly.
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PMID:Conserved functional domains of the RNA polymerase III general transcription factor BRF. 799 25

The TATA-binding protein (TBP) is required for transcription by all three nuclear RNA polymerases. TBP was subjected to regional codon randomization, a codon-based mutagenesis method that generates complex yet compact protein libraries. Analysis of 186 temperature-sensitive TBP mutants yielded 65 specifically defective in transcription by RNA polymerase III (Pol III). These mutants map to a limited TBP surface that may interact with Tds4, a component of the Pol III transcription factor TFIIIB. Strains that contain the Pol III-defective derivatives have increased amounts of messenger RNA, which suggests that competition among TBP-interacting factors for limiting quantities of TBP determines the ratio of Pol II and Pol III transcription in vivo.
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PMID:Regional codon randomization: defining a TATA-binding protein surface required for RNA polymerase III transcription. 821 Nov 43

Host cell RNA polymerase II (Pol II)-mediated transcription is inhibited by poliovirus infection. This inhibition is correlated to a specific decrease in the activity of a chromatographic fraction which contains the transcription factor TFIID. To investigate the mechanism by which poliovirus infection results in a decrease of TFIID activity, we have analyzed a component of TFIID, the TATA-binding protein (TBP). Using Western immunoblot analysis, we show that TBP is cleaved in poliovirus-infected cells at the same time postinfection as when Pol II transcription is inhibited. Further, we show that one of the cleaved forms of TBP can be reproduced in vitro by incubating TBP with cloned, purified poliovirus encoded protease 3C. Protease 3C is a poliovirus-encoded protease that specifically cleaves glutamine-glycine bonds in the viral polyprotein. The cleavage of TBP by protease 3C occurs directly. Finally, incubation of an uninfected cell-derived TBP-containing fraction (TFIID) with protease 3C results in significant inhibition of Pol II-mediated transcription in vitro. These results demonstrate that a cellular transcription factor can be directly cleaved both in vitro and in vivo by a viral protease and suggest a role of the poliovirus proteinase 3C in host cell Pol II-mediated transcription shutoff.
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PMID:Direct cleavage of human TATA-binding protein by poliovirus protease 3C in vivo and in vitro. 838 Aug 94

TIF-IB is a transcription factor which interacts with the mouse ribosomal gene promoter and nucleates the formation of an initiation complex containing RNA polymerase I (Pol I). We have purified this factor to near homogeneity and demonstrate that TIF-IB is a large complex (< 200 kDa) which contains several polypeptides. One of the subunits present in this protein complex is the TATA-binding protein (TBP) as revealed by copurification of TIF-IB activity and TBP over different chromatographic steps including immunoaffinity purification. In addition to TBP, three tightly associated proteins (TAFs-I) with apparent molecular weights of 95, 68, and 48 kDa are contained in this multimeric complex. This subunit composition is similar--but not identical--to the analogous human factor SL1. Depletion of TBP from TIF-IB-containing fractions by immunoprecipitation eliminates TIF-IB activity. Neither TBP alone nor fractions containing other TBP complexes are capable of substituting for TIF-IB activity. Therefore, TIF-IB is a unique complex with Pol I-specific TAFs distinct from other TBP-containing complexes. The identification of TBP as an integral part of the murine rDNA promoter-specific transcription initiation factor extends the previously noted similarity of transcriptional initiation by the three nuclear RNA polymerases and underscores the importance of TAFs in determining promoter specificity.
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PMID:A TBP-containing multiprotein complex (TIF-IB) mediates transcription specificity of murine RNA polymerase I. 841 71


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