An Array of Coactivators Is Required for Optimal Recruitment of TATA Binding Protein and RNA Polymerase II by Promoter-Bound Gcn4p

Qiu, Hongfang; Hu, Cuihua; Yoon, Sungpil; Natarajan, Krishnamurthy; Swanson, Mark J.; Hinnebusch, Alan G.

doi:10.1128/mcb.24.10.4104-4117.2004

Cited by 85 publications

(119 citation statements)

References 70 publications

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“…This notion was further supported by recent findings that Mediator can also stimulate basal transcription in vitro (21). Consistent with these findings, Mediator is recruited to the promoters of many inducible genes in both yeast and higher eukaryotes (18,29,40,41). However, it remained possible that Mediator does not function directly at all genes, and that transcriptional defects caused by loss of Mediator could be the result of indirect effects at many genes.…”

Section: Discussionsupporting

confidence: 73%

“…In vivo, Mediator appears to be a direct target of activators and is recruited to gene promoters at the preinitiation stage of transcription (11)(12)(13)(14)(15)(16). Mediator in turn facilitates recruitment of the preinitiation complex (PIC) to promoters (17,18). Recruitment of pol II is probably achieved in part by direct contacts between the carboxyl-terminal domain (CTD) of the Rpb1 subunit and the head and middle modules of Mediator (19,20).…”

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confidence: 99%

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Mediator complex association with constitutively transcribed genes in yeast

Ansari

Morse

2009

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

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Mediator is a large, multisubunit complex that is essential for transcription of mRNA by RNA Pol II in eukaryotes and is believed to bridge transcriptional activators and the general transcription machinery. However, several recent studies suggest that the requirement for Mediator during transcriptional activation is not universal, but rather activator dependent, and may be indirect for some genes. Here we have investigated Mediator association with several constitutively transcribed genes in yeast by comparing a yeast strain that harbors a temperature-sensitive mutation in an essential Mediator subunit, Srb4, with its wild-type (WT) counterpart. We find modest association of Mediator with constitutively active genes and show that this association is strongly decreased in srb4 ts yeast, whereas association with a nontranscribed region or repressed gene promoters is lower and unaffected in the mutant yeast. The tail module of Mediator remains associated with ribosomal protein (RP) gene promoters in srb4 ts yeast, while subunits from the head and middle modules are lost. Tail module association at Rap1-dependent gene promoters is lost in rap1 ts yeast, indicating that Rap1 is required for Mediator recruitment at these gene promoters and that its recruitment occurs via the tail module. Pol II association is also rapidly and severely affected in srb4 ts yeast, indicating that Mediator is directly required for pol II association at constitutively transcribed genes. Our results are consistent with Mediator functioning as a general transcription factor in yeast. Rap1 ͉ transcription

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Section: Discussionsupporting

confidence: 73%

mentioning

confidence: 99%

Mediator complex association with constitutively transcribed genes in yeast

Ansari

Morse

2009

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

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“…ChIP assays were conducted as described (14) by using the same primers utilized to amplify the ARG1 upstream activation sequence (UAS) (13), SNZ1 UAS (14), or ARG4 UAS (15). Western analysis of WCEs from cells treated with trichloroacetic acid was conducted as described (14).…”

Section: Methodsmentioning

confidence: 99%

“…1 B and C). Transcription of SNZ1, ARG4, and ARG1 is induced by Gcn4p (2), and Gcn4p binds to the promoters of all three of these genes in vivo (15). However, ARG4 lacks ARC elements and is not repressed by the ArgR͞Mcm1p complex (1), and SNZ1 does not encode an arginine biosynthetic enzyme.…”

Section: Gcn4p Recruits the Entire Argr͞mcm1p Complex To Arg1 In Argimentioning

confidence: 99%

Recruitment of the ArgR/Mcm1p repressor is stimulated by the activator Gcn4p: A self-checking activation mechanism

Yoon

Govind

Qiu

et al. 2004

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

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Transcription of the arginine biosynthetic gene ARG1 is repressed by the ArgR͞Mcm1p complex in arginine-replete cells and activated by Gcn4p, a transcription factor induced by starvation for any amino acid. We show that all four subunits of the arginine repressor are recruited to ARG1 by Gcn4p in cells replete with arginine but starved for isoleucine͞valine. None of these proteins is recruited to the Gcn4p target genes ARG4 and SNZ1, which are not regulated by ArgR͞Mcm1p. Mcm1p and Arg80p were found in a soluble complex lacking Arg81p and Arg82p, and both Mcm1p and Arg80p were efficiently recruited to ARG1 in wild-type cells in the presence or absence of exogenous arginine, and also in arg81⌬ cells. By contrast, the recruitment of Arg81p and Arg82p was stimulated by exogenous arginine. These findings suggest that Gcn4p constitutively recruits an Mcm1p͞Arg80p heterodimer and that efficient assembly of a functional repressor also containing Arg81p and Arg82p occurs only in arginine excess. By recruiting an arginineregulated repressor, Gcn4p can precisely modulate its activation function at ARG1 according to the availability of arginine.

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“…Mediator promotes both basal and activated transcription in vitro (13) and is critical for transcription of most genes in vivo (14). It stimulates preinitiation complex assembly at promoters in vivo by facilitating recruitment of chromatin-modifying complexes (11,12,15,16), TATA-binding protein, and pol II (12,(17)(18)(19). Mediator interacts with transcription factors TFIIE and TFIIH and the C-terminal domain (CTD) of pol II, and it stimulates CTD phosphorylation by the Kin28 subunit of TFIIH (3).…”

mentioning

confidence: 99%

Activator Gcn4 Employs Multiple Segments of Med15/Gal11, Including the KIX Domain, to Recruit Mediator to Target Genes in Vivo

Jedidi

Zhang

Qiu

et al. 2010

Journal of Biological Chemistry

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Mediator is a multisubunit coactivator required for initiation by RNA polymerase II. The Mediator tail subdomain, containing Med15/Gal11, is a target of the activator Gcn4 in vivo, critical for recruitment of native Mediator or the Mediator tail subdomain present in sin4⌬ cells. Although several Gal11 segments were previously shown to bind Gcn4 in vitro, the importance of these interactions for recruitment of Mediator and transcriptional activation by Gcn4 in cells was unknown. We show that interaction of Gcn4 with the Mediator tail in vitro and recruitment of this subcomplex and intact Mediator to the ARG1 promoter in vivo involve additive contributions from three different segments in the N terminus of Gal11. These include the KIX domain, which is a critical target of other activators, and a region that shares a conserved motif (B-box) with mammalian coactivator SRC-1, and we establish that B-box is a critical determinant of Mediator recruitment by Gcn4. We further demonstrate that Gcn4 binds to the Gal11 KIX domain directly and, by NMR chemical shift analysis combined with mutational studies, we identify the likely binding site for Gcn4 on the KIX surface. Gcn4 is distinctive in relying on comparable contributions from multiple segments of Gal11 for efficient recruitment of Mediator in vivo.

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An Array of Coactivators Is Required for Optimal Recruitment of TATA Binding Protein and RNA Polymerase II by Promoter-Bound Gcn4p

Cited by 85 publications

References 70 publications

Mediator complex association with constitutively transcribed genes in yeast

Mediator complex association with constitutively transcribed genes in yeast

Recruitment of the ArgR/Mcm1p repressor is stimulated by the activator Gcn4p: A self-checking activation mechanism

Activator Gcn4 Employs Multiple Segments of Med15/Gal11, Including the KIX Domain, to Recruit Mediator to Target Genes in Vivo

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