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

Regulatory factors must contend with chromatin structure to function. Although nucleosome structure and position on promoters can be important in determining factor access, the intrinsic ability of factors to bind to nucleosomal DNA might also play an essential regulatory role. We have used templates where nucleosomes were either randomly positioned or rotationally phased to demonstrate that two transcription factors, heat shock factor (HSF) and GAL4, differ significantly in their ability to bind to nucleosomes. GAL4 was able to bind to nucleosomal templates. Surprisingly, in contrast to its behavior on naked DNA, GAL4 bound better to multiple GAL4 sites than to a single GAL4 site on these templates. HSF alone was not able to bind to nucleosomal templates. HSF was able to bind to nucleosomal templates, however, when the TATA-binding factor TFIID was present. Consequently, binding to nucleosomal templates could be facilitated by adjacent binding of the same protein in the case of GAL4 but required binding of a second protein in the case of HSF. Taken together, these data demonstrate that regulatory factors differ in their inherent ability to bind to nucleosomal templates. These differences are likely to be important to the function of these factors in vivo.
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PMID:Facilitated binding of GAL4 and heat shock factor to nucleosomal templates: differential function of DNA-binding domains. 206 77

We have analyzed the DNA sequence requirements for TATA element function by assaying the transcriptional activities of 25 promoters, including those representing each of the 18 single-point mutants of the consensus sequence TATAAA, in a reconstituted in vitro system that depends on the TATA element-binding factor TFIID. Interestingly, yeast TFIID and HeLa cell TFIID were virtually identical in terms of their relative activities on this set of promoters. Of the mutated elements, only two had undetectable activity; the rest had activities ranging from 2 to 75% of the activity of the consensus element, which was the most active. In addition, mutations of the nucleotide following the TATAAA core strongly influenced transcriptional activity, although with somewhat different effects on yeast and HeLa TFIID. The activities of all these promoters depended upon TFIID, and the level of TFIID-dependent transcription in vitro correlated strongly with their activities in yeast cells. This suggests that the in vivo activities of these elements reflect their ability to functionally interact with a single TATA-binding factor. However, some elements with similar activities in vitro supported very different levels of transcriptional activation by GAL4 protein in vivo. These results extend the degree of evolutionary conservation between yeast and mammalian TFIID and are useful for predicting the level of TATA element function from the primary sequence.
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PMID:Yeast and human TATA-binding proteins have nearly identical DNA sequence requirements for transcription in vitro. 219 37

In the gal-his3 hybrid promoter his3-GG1, the yeast upstream activator protein GCN4 stimulates transcription when bound at the position normally occupied by the TATA element. This TATA-independent activation by GCN4 requires two additional elements in the gal enhancer region that are distinct from those involved in normal galactose induction. Both additional elements appear to be functionally distinct from a classical TATA element because they cannot be replaced by the TFIID-binding sequence TATAAA. One of these elements, termed Q, is essential for GCN4-activated transcription and contains the sequence GTCAC CCG, which overlaps (but is distinct from) a GAL4 binding site. Surprisingly, relatively small increases in the distance between Q and the GCN4 binding site significantly reduce the level of transcription. The Q element specifically interacts with a yeast protein (Q-binding protein [QBP]) that may be equivalent to Y, a protein that binds at a sequence that forms a constraint to nucleosome positioning. Analysis of various deletion mutants indicates that the sequence requirements for binding by QBP in vitro are indistinguishable from those necessary for Q activity in vivo, strongly suggesting that QBP is required for the function of this TATA-independent promoter. These results support the view that transcriptional activation can occur by an alternative mechanism in which the TATA-binding factor TFIID either is not required or is not directly bound to DNA. In addition, they suggest a potential role of nucleosome positioning for the activity of a promoter.
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PMID:A nucleosome-positioning sequence is required for GCN4 to activate transcription in the absence of a TATA element. 219 50

Although the yeast his3 promoter region contains two functional TATA elements, TR and TC, the GCN4 and GAL4 upstream activator proteins stimulate transcription only through TR. In combination with GAL4, an oligonucleotide containing the sequence TATAAA is fully sufficient for TR function, whereas almost all single-base-pair substitutions of this sequence abolish the ability of this element to activate transcription. Further analysis of these and other mutations of the TR element led to the following conclusions. First, sequences downstream of the TATAAA sequence are important for TR function. Second, a double mutant, TATTTA, can serve as a TR element even though the corresponding single mutation, TATTAA, is unable to do so. Third, three mutations have the novel property of being able to activate transcription in combination with GCN4 but not with GAL4; this finding suggests that activation by GCN4 and by GAL4 may not occur by identical mechanisms. From these observations, we address the question of whether there is a single TATA-binding factor required for the transcription of all genes.
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PMID:Functional distinctions between yeast TATA elements. 268 58

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 expression of the 7B2 protein, secreted from a variety of neural and endocrine tissues, increases dramatically in specific neuroendocrine tumors. We have recently shown that human 7B2 can act as a molecular chaperone in the deaggregation of proteins in vitro. In order to identify polypeptides which might bind 7B2 in vivo, the yeast two-hybrid system was employed. Surprisingly, mere covalent linkage of 7B2 to the DNA-binding domains of two yeast transcription activators, Ace1 and Gal4, activates transcription from the ACE1 and GAL4 operon. 7B2's ability to activate nuclear transcription surpasses that of Ace1 and compares favourably with the strong activation domain of the tumor suppressor protein, p53. Our results suggest that 7B2 must possess an activating sequence, a domain which defines all transcriptional activator proteins. Like the acidic activation domains of some transcriptional activators, 7B2 also binds the yeast TATA-box binding protein, an essential polypeptide in the basic transcription machinery. Deletion analysis of the gene encoding 7B2 reveals two independent transcriptional activating sequences in the 185 amino acid protein. It is therefore conceivable that 7B2 not only has a functional role in the secretory pathway but also in the nucleus. Moreover, these findings raise an intriguing question regarding the activation domains of 7B2 and their possible link to 7B2's oncogenic potential.
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PMID:The neuroendocrine protein 7B2 contains unusually potent transcriptional activating sequences. 748 73

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 ubiquitous human POU domain protein, Oct-1, and the related B-cell protein, Oct-2, regulate transcription from a variety of eukaryotic genes by binding to a common cis-acting octamer element, 5'-ATTTGCAT-3'. The binding of Oct-1 and Oct-2 to the functionally important lipoprotein lipase (LPL) promoter octamer site was stimulated by the general transcription factor, TFIIB. Comparative analysis of the LPL, histone H2B (H2B), and herpes simplex virus ICPO gene promoter octamer sites revealed that nucleotide sequences within and flanking the octamer sequence determined the degree of TFIIB-mediated stimulation of Oct-1 DNA binding. TFIIB was found to decrease the rate of dissociation of Oct-1 from the LPL octamer site, whereas it increased the rate of association, as well as decreased the rate of dissociation, of Oct-1 from the H2B octamer site. A monoclonal antibody against TFIIB immunoprecipitated a ternary complex containing TFIIB, Oct-1, and the LPL and H2B octamer binding sites. TFIIB did not alter the DNase I footprints generated by Oct-1 on the LPL and H2B promoters. However, Oct-1 on the TATA-binding protein and TFIIB from footprinting the perfect TATA box sequence located 5' of the LPL, NF-Y binding site. In transfection experiments, transcription from the reporters containing the LPL octamer, and either the SV40 or the yeast transcription factor GAL4-dependent enhancers, initiated at a precise position within the octamer sequence. Transcription from reporters containing the H2B octamer and the SV40 enhancer initiated at several positions within and flanking the octamer site, whereas transcription initiated at a precise position within the octamer from reporters with both the H2B octamer and the GAL4-dependent enhancer. These results suggest that octamers and their flanking sequences play an important role in positioning the site of transcription initiation, and that this could be a function of the interaction of Oct-1 with TFIIB.
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PMID:Interaction of Oct-1 with TFIIB. Implications for a novel response elicited through the proximal octamer site of the lipoprotein lipase promoter. 764 49


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