Tup1p represses Mcm1p transcriptional activation and chromatin remodeling of an a-cell-specific gene.
In yeast, a number of regulatory proteins expressed only in specific cell types interact with general transcription factors in a combinatorial manner to control expression of cell-type-specific genes. We report a detailed analysis of activation and repression events that occur at the promoter of the a-cell-specific STE6 gene fused to a beta-galactosidase gene in a yeast minichromosome, as well as factors that control the chromatin structure of this promoter both in the minichromosome and in the genomic STE6 locus. Mcm1p results in chromatin remodeling and is responsible for all transcriptional activity from the STE6 promoter in both wild-type a and alpha cells. Matalpha2p cooperates with Tup1p to block both chromatin remodeling and Mcm1p-associated activation. While Matalpha2p represses only Mcm1p, the Tup1p-mediated repression involves both Mcm1p-dependent and -independent mechanisms. Swi/Snf and Gcn5p, required for full induction of the STE6 gene, do not contribute to chromatin remodeling. We suggest that Tup1p can contribute to repression by blocking transcriptional activators, in addition to interacting with transcription machinery and stabilizing chromatin.
Gavin
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IM
Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 308 Althouse Laboratory, University Park, PA 16802, USA.
Kladde
M P
MP
Simpson
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RT
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D001483:Base Sequence; D002843:Chromatin / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D006023:Glycoproteins; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D026341:Minichromosome Maintenance 1 Protein; D009687:Nuclear Proteins; D009875:Operator Regions, Genetic; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
D018528:ATP-Binding Cassette Transporters; C065455:CYC8 protein, S cerevisiae; D002843:Chromatin; D017931:DNA Primers; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D006023:Glycoproteins; D018398:Homeodomain Proteins; C062928:MATA2 protein, S cerevisiae; D026341:Minichromosome Maintenance 1 Protein; D009687:Nuclear Proteins; D012097:Repressor Proteins; C489241:STE12 protein, S cerevisiae; C489277:STE6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C066502:TUP1 protein, S cerevisiae; D014157:Transcription Factors