Yeast TAF IIS in a multisubunit complex required for activated transcription

Reese, Joseph C.; Apone, Lynne; Walker, Scott S.; Griffin, Loree A.; Green, Michael R.

doi:10.1038/371523a0

Cited by 158 publications

(167 citation statements)

References 22 publications

Supporting

Mentioning

157

Contrasting

Order By: Relevance

“…In either case, the results imply that if an activator were imagined that could recruit TBP but could not remodel chromatin, the activator would fail to activate transcription, either because of its failure to bind to its own binding site or its inability to open chromatin to allow TBP binding to the TATA element following its recruitment. GAL4-TBP is likely to be associated with TAFs to form GAL4-TFIID in the cell, based on its ability to complement tbp Ϫ yeast cells and on the finding that a majority of TBP is associated with TAFs in yeast (62). Thus, our findings suggest that in spite of the histone acetyltransferase activity of yeast TAF II 130 (50), TFIID is considerably poorer at remodeling chromatin than are true activators.…”

Section: Discussionmentioning

confidence: 37%

“…1C), indicating that fusing TBP to the GAL4 DNA-binding domain does not appreciably impair TBP function. Since TFIID is probably required for transcription at most polymerase II promoters in yeast (41), this further implies that TAFs are normally associated with GAL4-TBP, as has been found for native yTBP (62).…”

Section: Retention Of Tbp Function In a Gal4-tbp Fusionmentioning

confidence: 90%

See 1 more Smart Citation

Artificially Recruited TATA-Binding Protein Fails To Remodel Chromatin and Does Not Activate Three Promoters That Require Chromatin Remodeling

Ryan

Stafford

et al. 2000

Molecular and Cellular Biology

View full text Add to dashboard Cite

Transcriptional activators are believed to work in part by recruiting general transcription factors, such as TATA-binding protein (TBP) and the RNA polymerase II holoenzyme. Activation domains also contribute to remodeling of chromatin in vivo. To determine whether these two activities represent distinct functions of activation domains, we have examined transcriptional activation and chromatin remodeling accompanying artificial recruitment of TBP in yeast (Saccharomyces cerevisiae). We measured transcription of reporter genes with defined chromatin structure by artificial recruitment of TBP and found that a reporter gene whose TATA element was relatively accessible could be activated by artificially recruited TBP, whereas two promoters, GAL10 and CHA1, that have accessible activator binding sites, but nucleosomal TATA elements, could not. A third reporter gene containing the HIS4 promoter could be activated by GAL4-TBP only when a RAP1 binding site was present, although RAP1 alone could not activate the reporter, suggesting that RAP1 was needed to open the chromatin structure to allow activation. Consistent with this interpretation, artificially recruited TBP was unable to perturb nucleosome positioning via a nucleosomal binding site, in contrast to a true activator such as GAL4, or to perturb the TATA-containing nucleosome at the CHA1 promoter. Finally, we show that activation of the GAL10 promoter by GAL4, which requires chromatin remodeling, can occur even in swi gcn5 yeast, implying that remodeling pathways independent of GCN5, the SWI-SNF complex, and TFIID can operate during transcriptional activation in vivo.Transcriptional activators are thought to stimulate transcription of TATA-containing promoters in part by recruiting TFIID, a multiprotein complex consisting of the TATA-binding protein (TBP) and TBP-associated factors (TAFs), to the TATA box (25,60). Several in vitro and in vivo studies support this model. For example, transcription initiated at a mutated TATA element by induced synthesis of TBP with altered specificity was enhanced in both rate and extent in the presence of an activator that could bind upstream of the relevant promoter, consistent with activator-mediated recruitment (40). Recruitment has also been inferred from the results of "activator bypass" experiments in which artificial recruitment of TBP to promoter sites near the TATA element resulted in transcriptional activation, implying that TBP recruitment is a rate-limiting step in transcriptional activation in vivo (10,39,79). Most convincingly, chromatin immunoprecipitation experiments revealed TBP to be physically associated with promoters of numerous genes under activated, but not nonactivated, conditions, implying that recruitment accompanies activation (43,46).A potential obstacle to recruitment of TBP in vivo is posed by chromatin. Binding of TBP to nucleosomal TATA elements is greatly impeded in vitro (23, 32). Transcription is also strongly repressed by chromatin, but this repression can be largely alleviated by binding of act...

show abstract

Section: Discussionmentioning

confidence: 37%

Section: Retention Of Tbp Function In a Gal4-tbp Fusionmentioning

confidence: 90%

Artificially Recruited TATA-Binding Protein Fails To Remodel Chromatin and Does Not Activate Three Promoters That Require Chromatin Remodeling

Ryan

Stafford

et al. 2000

Molecular and Cellular Biology

View full text Add to dashboard Cite

show abstract

“…NGG1p and ADA2p may also function as components of non-ADA complexes. The finding of TBP in immunoprecipitates with NGG1p might suggest that one of the complexes is a TBP⅐TBP-associated factor complex; however, the sizes of proteins that coimmunoprecipitate with NGG1p do not resemble the sizes of the yeast TBP-associated factors (40,41). 2 The finding that ADA5p/SPT20p may associate with NGG1p/ADA3p (17) suggests that some of these complexes may contain the genetically related proteins SPT3, SPT7, and SPT8 (17,42).…”

Section: Stability Of Ngg1p and Ada2pmentioning

confidence: 90%

Identification of Native Complexes Containing the Yeast Coactivator/Repressor Proteins NGG1/ADA3 and ADA2

Saleh

Lang

Cook

et al. 1997

Journal of Biological Chemistry

109

119

View full text Add to dashboard Cite

NGG1p/ADA3p and ADA2p are dual function regulators that stimulate or inhibit a set of yeast transcriptional activator proteins. In vitro, NGG1p and ADA2p associate in a complex that also contains GCN5p (Horiuchi, J., Silverman, N., Marcus, G. A., and Guarente, L. (1995) Mol. Cell. Biol. 15, 1203-1209). We have found that NGG1p and ADA2p are coimmunoprecipitated from yeast whole cell extracts. In fact, <2% of cellular ADA2p was not associated with NGG1p. Also in agreement with their association in vivo, the stability of ADA2p and NGG1p depended on the presence of each other. In addition, three NGG1p-and ADA2p-containing peak fractions were resolved by Q-Sepharose Fast Flow ion-exchange chromatography of whole cell extract. The presence of another high molecular mass complex was supported by the separation of one of the NGG1p-and ADA2p-containing peak fractions by gel-filtration chromatography. Together, the combination of ion-exchange and gel-filtration chromatography suggests a total of four complexes, two with sizes of >2 MDa and single complexes of ϳ900 and 200 kDa. At least one of these complexes was found to associate with the TATA-binding protein (TBP) since TBP was present in immunoprecipitates with NGG1p. The association of TBP with the ADA proteins required amino acids 274 -307 of NGG1p, a region of NGG1p required for activity. This supports a role for NGG1p in the interaction with TBP and suggests that the interaction with TBP is functionally relevant.Activated transcription by RNA polymerase II requires the action of the basal transcriptional machinery, sequence-specific activator proteins, and coactivator or mediator proteins (1). Coactivators positively influence activator function either by providing a regulatory interface between the basal machinery and the activator protein or by enabling these components to contend with a DNA template in the form of chromatin. Coactivators have generally been found as components of regulatory complexes. The TBP 1 ⅐TBP-associated factor complex, the RNA polymerase II holoenzyme complex, and the Swi⅐Snf complex represent principal examples (reviewed in Refs. 2-4). The mechanisms and component structure of these complexes may overlap as suggested by the finding of Swi/Snf components (5) within the RNA polymerase II holoenzyme (6), the TBP-associated factor complex, and transcription factor IIF (7).Probably through related mechanisms, coactivator complexes can also be involved in repression. We initially discovered NGG1 based on its requirement for full inhibition of the GAL4 activator protein in glucose media (8). NGG1p likely acts as a more general repressor because transcriptional activation by the carboxyl-terminal activation domain of PDR1p is enhanced in a ngg1 background (9). Guarente and co-workers (10) independently isolated NGG1/ADA3 based on suppression of the toxicity of overexpression of VP16 in yeast. Mutations within four ADA genes, ADA2, NGG1/ADA3, GCN5/ADA4, and ADA5, suppress the toxicity of VP16 by inhibiting its ability to activate transcription (...

show abstract

“…TATA box-binding protein (TBP) affinity chromatography was performed as described (38) starting with 1.2 kg of cell pellet. Approximately 60% of the total cellular amount of each NC2 subunit was eluted in 1 M KOAc.…”

Section: Methodsmentioning

confidence: 99%

Functional antagonism between RNA polymerase II holoenzyme and global negative regulator NC2 in vivo

Gadbois

Chao

Reese

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

Activation of eukaryotic class II gene expression involves the formation of a transcription initiation complex that includes RNA polymerase II, general transcription factors, and SRB components of the holoenzyme. Negative regulators of transcription have been described, but it is not clear whether any are general repressors of class II genes in vivo. We reasoned that defects in truly global negative regulators should compensate for deficiencies in SRB4 because SRB4 plays a positive role in holoenzyme function. Genetic experiments reveal that this is indeed the case: a defect in the yeast homologue of the human negative regulator NC2 (Dr1⅐DRAP1) suppresses a mutation in SRB4. Global defects in mRNA synthesis caused by the defective yeast holoenzyme are alleviated by the NC2 suppressing mutation in vivo, indicating that yeast NC2 is a global negative regulator of class II transcription. These results imply that relief from repression at class II promoters is a general feature of gene activation in vivo.Activation of class II gene transcription in eukaryotes involves the recruitment of a transcription initiation complex that includes the RNA polymerase II holoenzyme (1-6). The yeast RNA polymerase II holoenzyme is a large multisubunit complex containing RNA polymerase II, a subset of the general transcription factors, and SRB regulatory proteins (7-11). Mammalian RNA polymerase II holoenzymes have also been purified, and an SRB7 homologue has been identified as a component of those complexes (12)(13)(14).For some class II genes, regulation appears to involve both positive and negative transcriptional regulators. The negative regulators that have been described include proteins purified for their ability to inhibit transcription in vitro (15-21) and genes identified because their products repress transcription from a subset of class II genes in vivo (21-29). For example, the human proteins NC1 (15, 16), NC2 or Dr1⅐DRAP1 (16,17,20), and DNA topoisomerase I (18, 19) repress basal transcription in vitro. The products of the yeast genes MOT1 (21-24), NOT1-4 (25-27), and SIN4 (28-29) negatively regulate at least a subset of yeast genes in vivo. Whether any of these negative regulators are generally employed for class II gene regulation in vivo is not yet clear.The RNA polymerase II C-terminal domain and the associated SRB complex have been implicated in the response to transcriptional activators (7-9, 30, 31). Two holoenzyme components, SRB4 and SRB6, have been shown to play essential and positive roles in transcription at the majority of class II genes in Saccharomyces cerevisiae (32). We reasoned that a defect in SRB4 might be alleviated by defects in general negative regulators and that knowledge of such regulators could contribute to our understanding of the mechanisms involved in gene regulation in vivo. Here we show that a deficiency in yeast NC2 can compensate for the global transcriptional defects caused by mutations in the SRB4 and SRB6 subunits of the RNA polymerase II holoenzyme and that NC2 is a globa...

show abstract

Yeast TAF IIS in a multisubunit complex required for activated transcription

Cited by 158 publications

References 22 publications

Artificially Recruited TATA-Binding Protein Fails To Remodel Chromatin and Does Not Activate Three Promoters That Require Chromatin Remodeling

Artificially Recruited TATA-Binding Protein Fails To Remodel Chromatin and Does Not Activate Three Promoters That Require Chromatin Remodeling

Identification of Native Complexes Containing the Yeast Coactivator/Repressor Proteins NGG1/ADA3 and ADA2

Functional antagonism between RNA polymerase II holoenzyme and global negative regulator NC2 in vivo

Contact Info

Product

Resources

About