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Query: UNIPROT:P20226 (TATA-binding protein)
 1,297 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

TFIID, the TATA-binding protein, was found to stimulate transcription from the adenovirus IVa2 promoter, a promoter considered to lack the TATA motif. Remarkably, a TATA-like sequence element located downstream of the transcription start site binds TFIID and is required for TFIID-dependent transcription from the IVa2 promoter. Transcription from the IVa2 and the adjacent adenovirus major late promoter (Ad-MLP) is divergent, and the cap sites are separated by 212 nucleotides. Nevertheless, the TATA motifs of the IVa2 promoter and Ad-MLP were found to be oriented in the same direction. An initiator motif around the transcription start site is located in the IVa2 promoter, and in contrast to the TATA motifs, the IVa2-initiator is in the opposite orientation with respect to the initiator of the Ad-MLP. A model is presented in which the polar nature of the initiator governs the direction of transcription. We propose that RNA polymerase II and accessory factors recognize the initiator in an orientation-dependent fashion. The recognition of the IVa2 initiator by RNA polymerase is enhanced by the binding of TFIID to the downstream TATA motif.
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PMID:A TATA-like sequence located downstream of the transcription initiation site is required for expression of an RNA polymerase II transcribed gene. 225 81

GAL4 is a transcriptional activator found in yeast. Two distinct functions of the protein are required for its activity: one directs sequence-specific DNA binding, and another interacts with some other component of the transcriptional machinery, for example, RNA polymerase II or a TATA-binding protein. Two short regions of GAL4 function as 'activating sequences' when attached to the DNA-binding portion of GAL4 and these regions can be replaced by a large number of peptides encoded by Escherichia coli genomic DNA fragments or by a synthetic peptide designed to form an amphiphilic alpha-helix. All of these activating sequences, like that found in another yeast activator, GCN4 bear an excess negative charge. GAL4 and its derivatives that are active in yeast stimulate transcription in mammalian cells when GAL4 binding sites are introduced upstream of a mammalian gene; similarly, GAL4 activates transcription in Drosophila cells. Here we show that GAL4 derivatives stimulate gene expression in plant cells.
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PMID:Yeast activators stimulate plant gene expression. 316 94

The yeast transcriptional activator GAL4 binds specific sites on DNA to activate transcription of adjacent genes. The distinct activating regions of GAL4 are rich in acidic residues and it has been suggested that these regions interact with another protein component of the transcriptional machinery (such as the TATA-binding protein or RNA polymerase II) while the DNA-binding region serves to position the activating region near the gene. Here we show that various GAL4 derivatives, when expressed at high levels in yeast, inhibit transcription of certain genes lacking GAL4 binding sites, that more efficient activators inhibit more strongly and that inhibition does not depend on the DNA-binding domain. We suggest that this inhibition, which we call squelching, reflects titration of a transcription factor by the activating region of GAL4.
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PMID:Negative effect of the transcriptional activator GAL4. 341 49

Most proteins that activate RNA polymerase II-mediated transcription in eukaryotic cells contain sequence-specific DNA-binding domains and "activation" regions. The latter bind general transcription factors and/or coactivators and are required for high-level transcription. Their function in vivo is unknown. Since several activation domains bind the TATA-binding protein (TBP), TBP-associated factors, or other general factors in vitro, one role of the activation domain may be to facilitate promoter occupancy by supporting cooperative binding of the activator and general transcription factors. Using the GAL4 system of yeast, we have tested this model in vivo. It is demonstrated that the presence of a TATA box (the TBP binding site) facilitates binding of GAL4 protein to low- and moderate-affinity sites and that the activation domain modulates these effects. These results support the cooperative binding model for activation domain function in vivo.
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PMID:The activation domain of GAL4 protein mediates cooperative promoter binding with general transcription factors in vivo. 747 65

The human T-lymphotropic virus type I (HTLV-I) promoter contains the structural features of a typical RNA polymerase II (pol II) template. The promoter contains a TATA box 30 bp upstream of the transcription initiation site and binding sites for several pol II transcription factors, and long poly(A)+ RNA is synthesized from the integrated HTLV-I proviral DNA in vivo. Consistent with these characteristics, HTLV-I transcription activity was reconstituted in vitro by using TATA-binding protein, TFIIA, recombinant TFIIB, TFIIE, and TFIIF, TFIIH, and pol II. Transcription of the HTLV-I promoter in the reconstituted system requires RNA pol II. In HeLa whole cell extracts, however, the HTLV-I long terminal repeat also contains an overlapping transcription unit (OTU). HTLV-I OTU transcription is initiated at the same nucleotide site as the RNA isolated from the HTLV-I-infected cell line MT-2 but was not inhibited by the presence of alpha-amanitin at concentrations which inhibited the adenovirus major late pol II promoter (6 micrograms/ml). HTLV-I transcription was inhibited when higher concentrations of alpha-amanitin (60 micrograms/ml) were used, in the range of a typical pol III promoter (VA-I). Neutralization and depletion experiments with three distinct pol II antibodies demonstrate that RNA pol II is not required for HTLV-I OTU transcription. Antibodies to basal transcription factors TATA-binding protein and TFIIB, but not TFIIIC, inhibited HTLV-I OTU transcription. These observations suggest that the HTLV-I long terminal repeat contains overlapping promoters, a typical pol II promoter and a unique pol III promoter which requires a distinct set of transcription factors.
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PMID:Transcription of the human T-cell lymphotropic virus type I promoter by an alpha-amanitin-resistant polymerase. 752 15

Transcription factor IIB (TFIIB) plays a central role in the assembly of the RNA polymerase II initiation complex. Monoclonal antibodies (mAbs) that react with human TFIIB were prepared and used as probes to identify portions of TFIIB that are accessible when the factor is in solution and when it is contained in a complex with DNA. Seven mAbs were examined and were mapped to three regions of the TFIIB molecule. Only the mAbs that mapped to residues 52-105 inhibited transcription, immunoprecipitated recombinant TFIIB and TFIIB from HeLa cell nuclear extract (NE), and supershifted a complex containing TFIIB, the TATA-binding protein, and DNA. The mAbs that mapped to residues 1-51 and the mAb that mapped to residues 106-316 did not show activity in the functional assays, with the exception of the far N-terminal mAbs (residues 1-51), which immunoprecipitated recombinant TFIIB, but not TFIIB from HeLa cell NE. These data indicate that the region containing residues 52-105 is exposed in solution and when TFIIB is part of the preinitiation complex and that some far N-terminal epitopes are accessible on the purified protein, but become blocked when TFIIB is in HeLa cell NE or in the preinitiation complex.
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PMID:Accessibility of epitopes on human transcription factor IIB in the native protein and in a complex with DNA. 753 65

The TATA-binding protein (TBP) contains a concave surface that interacts specifically with TATA promoter elements and a convex surface that mediates protein-protein interactions with general and gene-specific transcription factors. Biochemical experiments suggest that interactions between activator proteins and TBP are important in stimulating transcription by the RNA polymerase II machinery. To gain insight into the role of TBP in mediating transcriptional activation in vivo, we implemented a genetic strategy in Saccharomyces cerevisiae that involved the use of a TBP derivative with altered specificity for TATA elements. By genetically screening a set of TBP mutant libraries that were biased to the convex surface that mediates protein-protein interactions, we identified TBP derivatives that are impaired in the response to three acidic activators (Gcn4, Gal4, and Ace1) but appear normal for constitutive polymerase II transcription. A genetic complementation assay indicates that the activation-defective phenotypes reflect specific functional properties of the TBP derivatives rather than an indirect effect on transcription. Surprisingly, three of the four activation-defective mutants affect residues that directly contact DNA. Moreover, all four mutants are defective for TATA element binding, but they interact normally with an acidic activation domain and TFIIB. In addition, we show that a subset of TBP derivatives with mutations on the DNA-binding surface of TBP are also compromised in their responses to acidic activators in vivo. These observations suggest that interactions at the TBP-TATA element interface can specifically affect the response to acidic activator proteins in vivo.
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PMID:Mutations on the DNA-binding surface of TATA-binding protein can specifically impair the response to acidic activators in vivo. 756 97

The binding of TATA-binding protein (TBP) to the TATA element is the first step in the initiation of RNA polymerase II transcription from many promoters in vitro. It has been proposed that upstream activator proteins stimulate transcription by recruiting TBP to the promoter, thus facilitating the assembly of a transcription complex. However, the role of activator proteins acting at this step to stimulate transcription in vivo remains largely speculative. To test whether recruitment of TBP to the promoter is sufficient for transcriptional activation in vivo, we constructed a hybrid protein containing TBP of the yeast Saccharomyces cerevisiae fused to the DNA-binding domain of GAL4. Our results show that TBP recruited by the GAL4 DNA-binding domain to promoters bearing a GAL4-binding site can interact with the TATA element and direct high levels of transcription. This finding indicates that binding of TBP to promoters in S. cerevisiae is a major rate-limiting step accelerated by upstream activator proteins.
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PMID:Recruiting TATA-binding protein to a promoter: transcriptional activation without an upstream activator. 756 28

The promoter of vertebrate U6 small nuclear RNA genes consists of a TATA box and a snRNA proximal sequence element (PSE), and the combination of these two elements directs RNA polymerase III transcription. We detected RNA polymerase II transcription as well as pol III transcription from the human U6 promoter in a HeLa nuclear extract. The pol II-specific transcription was independent of the PSE and dependent on the presence of the TATA box. Both pol III- and pol II-specific transcription were stimulated by addition of recombinant TATA-binding protein (TBP). We conclude that both pol III and pol II preinitiation complexes can assemble on the U6 promoter in vitro and could compete during the bona fide process in the cell.
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PMID:Both RNA polymerase III and RNA polymerase II accurately initiate transcription from a human U6 promoter in vitro. 757 66

Transcription factor TFIIB is essential for the formation of RNA polymerase II initiation complexes where it binds to the TATA-binding protein (TBP) complex with DNA and recruits RNA polymerase II. TFIIB is probably a target for various activators. Several models have been proposed for the position of TFIIB in the TFIIB-TBP-DNA complex. Here we examine the structure of this complex using gel mobility-shift assays and hydroxyl-radical footprinting. TFIIB requires at least seven base pairs of DNA on either side of the TATA box to form a stable TFIIB-TBP-DNA complex. The sugar residues protected from hydroxyl-radical cleavage by the TFIIB-TBP complex were mapped on the crystal-structure model of the TBP-DNA complex. This analysis suggests that TFIIB binds beneath the concave surface of TBP, contacting DNA both upstream and downstream of the TATA box. Our model predicts that TFIIB binds close to the C-terminal stirrup of TBP and provides one explanation for why TBP needs to bend DNA.
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PMID:Model for binding of transcription factor TFIIB to the TBP-DNA complex. 763 13


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