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 SAGA complex of Saccharomyces cerevisiae is required for the transcription of many RNA polymerase II-dependent genes. Previous studies have demonstrated that SAGA possesses histone acetyltransferase activity, catalyzed by the SAGA component Gcn5. However, the transcription of many genes, although SAGA dependent, is Gcn5 independent, suggesting the existence of distinct SAGA activities. We have studied the in vivo role of two other SAGA components, Spt3 and Spt20, at the well-characterized GAL1 promoter. Our results demonstrate that both Spt3 and Spt20 are required for the binding of TATA-binding protein but not of the activator Gal4 and that this role is Gcn5 independent. These results suggest a coactivator role for Spt3 and Spt20 in the recruitment of TBP.
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PMID:The Spt components of SAGA facilitate TBP binding to a promoter at a post-activator-binding step in vivo. 1058 1

Previous studies demonstrated that the SAGA (Spt-Ada-Gcn5-Acetyltransferase) complex facilitates the binding of TATA-binding protein (TBP) during transcriptional activation of the GAL1 gene of Saccharomyces cerevisiae. TBP binding was shown to require the SAGA components Spt3 and Spt20/Ada5, but not the SAGA component Gcn5. We have now examined whether SAGA is directly required as a coactivator in vivo by using chromatin immunoprecipitation analysis. Our results demonstrate that SAGA is physically recruited in vivo to the upstream activation sequence (UAS) regions of the galactose-inducible GAL genes. This recruitment is dependent on both induction by galactose and the Gal4 activation domain. Furthermore, we demonstrate that another well-characterized activator, Gal4-VP16, also recruits SAGA in vivo. Finally, we provide evidence that a specific interaction between Spt3 and TBP in vivo is important for Gal4 transcriptional activation at a step after SAGA recruitment. These results, taken together with previous studies, demonstrate a dependent pathway for the recruitment of TBP to GAL gene promoters consisting of the recruitment of SAGA by Gal4 and the subsequent recruitment of TBP by SAGA.
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PMID:The S. cerevisiae SAGA complex functions in vivo as a coactivator for transcriptional activation by Gal4. 1148 89

Evolutionarily conserved variant histone H2A.Z has been recently shown to regulate gene transcription in Saccharomyces cerevisiae. Here we show that loss of H2A.Z in this organism negatively affects the induction of GAL genes. Importantly, fusion of the H2A.Z C-terminal region to S phase H2A without its corresponding C-terminal region can mediate the variant histone's specialized function in GAL1-10 gene induction, and it restores the slow-growth phenotype of cells with a deletion of HTZ1. Furthermore, we show that the C-terminal region of H2A.Z can interact with some components of the transcriptional apparatus. In cells lacking H2A.Z, recruitment of RNA polymerase II and TATA-binding protein to the GAL1-10 promoters is significantly diminished under inducing conditions. Unexpectedly, we also find that H2A.Z is required to globally maintain chromatin integrity under GAL gene-inducing conditions. We hypothesize that H2A.Z can positively regulate gene transcription, at least in part, by modulating interactions with RNA polymerase II-associated factors at certain genes under specific cell growth conditions.
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PMID:H2A.Z is required for global chromatin integrity and for recruitment of RNA polymerase II under specific conditions. 1150 69

Transcriptional activation of the yeast HO gene involves the sequential action of DNA-binding and chromatin-modifying factors. Here we examine the role of the SAGA complex and the Nhp6 architectural transcription factor in HO regulation. Our data suggest that these factors regulate binding of the TATA-binding protein (TBP) to the promoter. A gcn5 mutation, eliminating the histone acetyltransferase present in SAGA, reduces the transcription of HO, but expression is restored in a gcn5 spt3 double mutant. We conclude that the major role of Gcn5 in HO activation is to overcome repression by Spt3. Spt3 is also part of SAGA, and thus two proteins in the same regulatory complex can have opposing roles in transcriptional regulation. Chromatin immunoprecipitation experiments show that TBP binding to HO is very weak in wild-type cells but markedly increased in an spt3 mutant, indicating that Spt3 reduces HO expression by inhibiting TBP binding. In contrast, it has been shown previously that Spt3 stimulates TBP binding to the GAL1 promoter as well as GAL1 expression, and thus, Spt3 regulates these promoters differently. We also find genetic interactions between TBP and either Gcn5 or the high-mobility-group protein Nhp6, including multicopy suppression and synthetic lethality. These results suggest that, while Spt3 acts to inhibit TBP interaction with the HO promoter, Gcn5 and Nhp6 act to promote TBP binding. The result of these interactions is to limit TBP binding and HO expression to a short period within the cell cycle. Furthermore, the synthetic lethality resulting from combining a gcn5 mutation with specific TBP point mutations can be suppressed by the overexpression of transcription factor IIA (TFIIA), suggesting that histone acetylation by Gcn5 can stimulate transcription by promoting the formation of a TBP/TFIIA complex.
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PMID:Regulation of TATA-binding protein binding by the SAGA complex and the Nhp6 high-mobility group protein. 1261 66

We have investigated the requirements for nucleosome remodeling upon transcriptional induction of the GAL1 promoter. We found that remodeling was dependent on two SAGA complex components, Gcn5 and Spt3. The involvement of the latter was surprising as its function has been suggested to be directly involved in TATA-binding protein (TBP) recruitment. We demonstrated that this novel function was in fact independent of TBP recruitment and this was further validated using a Gal4-driven synthetic promoter. Most importantly, we showed that the involvement of Spt3 in chromatin remodeling was independent of transcription, as it was also observed for a nonpromoter nucleosome located next to an activator-binding site. In an effort to explore how the Spt3 function was elicited, we found that Mot1, an ATPase of the Snf2 family that genetically interacts with Spt3, was also required for nucleosome remodeling independently of TBP recruitment. Interestingly enough, Spt3 and Mot1 were recruited on the GAL1 promoter as well as on the nonpromoter site in an interdependent manner. These findings show that the two proteins cooperate in nucleosomal transactions.
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PMID:Spt3 and Mot1 cooperate in nucleosome remodeling independently of TBP recruitment. 1505 69

Drug resistance as a result of overexpression of drug transporter genes presents a major obstacle in the treatment of cancers and infections. The molecular mechanisms underlying transcriptional up-regulation of drug transporter genes remains elusive. Employing Saccharomyces cerevisiae as a model, we analyzed here transcriptional regulation of the drug transporter gene PDR5 in a drug-resistant pdr1-3 strain. This mutant bears a gain-of-function mutation in PDR1, which encodes a transcriptional activator for PDR5. Similar to the well studied model gene GAL1, we provide evidence showing that PDR5 belongs to a group of genes whose transcription requires the Spt-Ada-Gcn5 acetyltransferase (SAGA) complex. We also show that the drugindependent PDR5 transcription is associated with enhanced promoter occupancy of coactivator complexes, including SAGA, Mediator, chromatin remodeling SWI/SNF complex, and TATA-binding protein. Analyzed by chromatin immunoprecipitations, loss of contacts between histones and DNA occurs at both promoter and coding sequences of PDR5. Consistently, micrococcal nuclease susceptibility analysis revealed altered chromatin structure at the promoter and coding sequences of PDR5. Our data provide molecular description of the changes associated with constitutive PDR5 transcription, and reveal the molecular mechanism underlying drug-independent transcriptional up-regulation of PDR5.
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PMID:On the mechanism of constitutive Pdr1 activator-mediated PDR5 transcription in Saccharomyces cerevisiae: evidence for enhanced recruitment of coactivators and altered nucleosome structures. 1529 7

The Saccharomyces cerevisiae SAGA (Spt-Ada-Gcn5-acetyltransferase) complex functions as a coactivator during Gal4-activated transcription. A functional interaction between the SAGA component Spt3 and TATA-binding protein (TBP) is important for TBP binding at Gal4-activated promoters. To better understand the role of SAGA and other factors in Gal4-activated transcription, we selected for suppressors that bypass the requirement for SAGA. We obtained eight complementation groups and identified the genes corresponding to three of the groups as NHP10, HDA1, and SRB9. In contrast to the srb9 suppressor mutation that we identified, an srb9Delta mutation causes a strong defect in Gal4-activated transcription. Our studies have focused on this requirement for Srb9. Srb9 is part of the Srb8-Srb11 complex, associated with the Mediator coactivator. Srb8-Srb11 contains the Srb10 kinase, whose activity is important for GAL1 transcription. Our data suggest that Srb8-Srb11, including Srb10 kinase activity, is directly involved in Gal4 activation. By chromatin immunoprecipitation studies, Srb9 is present at the GAL1 promoter upon induction and facilitates the recruitment or stable association of TBP. Furthermore, the association of Srb9 with the GAL1 upstream activation sequence requires SAGA and specifically Spt3. Finally, Srb9 association also requires TBP. These results suggest that Srb8-Srb11 associates with the GAL1 promoter subsequent to SAGA binding, and that the binding of TBP and Srb8-Srb11 is interdependent.
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PMID:The Saccharomyces cerevisiae Srb8-Srb11 complex functions with the SAGA complex during Gal4-activated transcription. 1560 35

Histone phosphorylation influences transcription, chromosome condensation, DNA repair and apoptosis. Previously, we showed that histone H3 Ser10 phosphorylation (pSer10) by the yeast Snf1 kinase regulates INO1 gene activation in part via Gcn5/SAGA complex-mediated Lys14 acetylation (acLys14). How such chromatin modification patterns develop is largely unexplored. Here we examine the mechanisms surrounding pSer10 at INO1, and at GAL1, which herein is identified as a new regulatory target of Snf1/pSer10. Snf1 behaves as a classic coactivator in its recruitment by DNA-bound activators, and in its role in modifying histones and recruiting TATA-binding protein (TBP). However, one important difference in Snf1 function in vivo at these promoters is that SAGA recruitment at INO1 requires histone phosphorylation via Snf1, whereas at GAL1, SAGA recruitment is independent of histone phosphorylation. In addition, the GAL1 activator physically interacts with both Snf1 and SAGA, whereas the INO1 activator interacts only with Snf1. Thus, at INO1, pSer10's role in recruiting SAGA may substitute for recruitment by DNA-bound activator. Our results emphasize that histone modifications share general functions between promoters, but also acquire distinct roles tailored for promoter-specific requirements.
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PMID:Histone H3 phosphorylation can promote TBP recruitment through distinct promoter-specific mechanisms. 1571 21

TFIIS is a transcription elongation factor that has been extensively studied biochemically. Although the in vitro mechanisms by which TFIIS stimulates RNA transcript cleavage and polymerase read-through have been well characterized, its in vivo roles remain unclear. To better understand TFIIS function in vivo, we have examined its role during Gal4-mediated activation of the Saccharomyces cerevisiae GAL1 gene. Surprisingly, TFIIS is strongly associated with the GAL1 upstream activating sequence. In addition, TFIIS recruitment to Gal4-binding sites is dependent on Gal4, SAGA, and Mediator but not on RNA polymerase II (Pol II). The association of TFIIS is also necessary for the optimal recruitment of TATA-binding protein and Pol II to the GAL1 promoter. These results provide strong evidence that TFIIS plays an important role in the initiation of transcription at GAL1 in addition to its well-characterized roles in transcription elongation.
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PMID:Evidence that the elongation factor TFIIS plays a role in transcription initiation at GAL1 in Saccharomyces cerevisiae. 1576 71

Tbp1, the TATA-binding protein, is essential for transcriptional activation, and Gal4 and Gcn4 are unable to fully activate transcription in a Saccharomyces cerevisiae TBP1E86D mutant strain. In the present study we have shown that the Tbp1E186D mutant protein is proteolytically instable, and we have isolated intragenic and extragenic suppressors of the transcription defects of the TBP1E186D mutant strain. The TBP1R6S mutation stabilizes the Tbp1E186D mutant protein and suppresses the defects of the TBP1E186D mutant strain. Furthermore, we found that the overexpression of the de-ubiquitinating enzyme Ubp3 (ubiquitin-specific protease 3) also stabilizes the Tbp1E186D mutant protein and suppresses of the defects of the TBP1E186D mutant strain. Importantly, the deletion of UBP3 and its cofactor BRE5 lead to increased degradation of wild-type Tbp1 protein and to defects in transcriptional activation by Gal4 and Gcn4. Purified GST (glutathione transferase)-Ubp3 reversed Tbp1 ubiquitination, and the deletion of UBP3 lead to the accumulation of poly-ubiquitinated species of Tbp1 in a proteaseome-deficient genetic background, demonstrating that Ubp3 reverses ubiquitination of Tbp1 in vitro and in vivo. Chromatin immunoprecipitation showed that Ubp3 was recruited to the GAL1 and HIS3 promoters upon the induction of the respective gene, indicating that protection of promoter-bound Tbp1 by Ubp3 is required for transcriptional activation.
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PMID:Transcriptional activation requires protection of the TATA-binding protein Tbp1 by the ubiquitin-specific protease Ubp3. 2073 57


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