title: Identification of Tup1 and Cyc8 mutations defective in the responses to osmotic stress.
abstract: In the yeast Saccharomyces cerevisiae, Tup1, in association with Cyc8 (Ssn6), functions as a general transcriptional corepressor. This repression is mediated by recruitment of the Tup1-Cyc8 complex to target promoters through sequence-specific DNA-binding proteins such as Sko1, which mediates the HOG pathway-dependent regulation. We identified tup1 and cyc8 mutant alleles as the suppressor of osmo-sensitivity of the hog1Delta strain. In these mutants, although the expression of the genes under the control of DNA-binding proteins other than Sko1 was apparently normal, the Sko1-regulated genes GRE2 and AHP1 were derepressed under non-stress conditions, suggesting that the Tup1 and Cyc8 mutant proteins were specifically defective in the repression of the Sko1-dependent genes. Chromatin immunoprecipitation analyses of the GRE2 promoter in the mutants demonstrated that the Sko1-Tup1-Cyc8 complex was localized to the promoter, together with Gcn5/SAGA, suggesting that the erroneous recruitment of SAGA to the promoter led to the derepression.
authors.affiliation: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Tomomi
authors.initials: T
authors.lastname: Inai
authors.forename: Masaki
authors.initials: M
authors.lastname: Mizunuma
authors.forename: Ichitaro
authors.initials: I
authors.lastname: Okada
authors.forename: Atsunori
authors.initials: A
authors.lastname: Shitamukai
authors.forename: Dai
authors.initials: D
authors.lastname: Hirata
authors.forename: Tokichi
authors.initials: T
authors.lastname: Miyakawa
mesh_terms: D000483:Alleles; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D051548:Histone Acetyltransferases / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009997:Osmotic Pressure; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D012680:Sensitivity and Specificity; D000099224:p300-CBP-Associated Factor
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D002118:Calcium; D004268:DNA-Binding Proteins; D051548:Histone Acetyltransferases; D020928:Mitogen-Activated Protein Kinases; D009687:Nuclear Proteins; D010088:Oxidoreductases; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C065455:CYC8 protein, S cerevisiae; C077832:SKO1 protein, S cerevisiae; C066502:TUP1 protein, S cerevisiae; C432953:GRE2 protein, S cerevisiae; C501392:GCN5 protein, S cerevisiae; D000099224:p300-CBP-Associated Factor; C088589:HOG1 protein, S cerevisiae