title: Components of the SAGA histone acetyltransferase complex are required for repressed transcription of ARG1 in rich medium.
abstract: Transcriptional regulation of the Saccharomyces cerevisiae ARG1 gene is controlled by positive and negative elements. The transactivator Gcn4p is required for activation in minimal medium, while arginine repression requires the ArgR/Mcm1 regulatory complex, which binds to two upstream arginine control elements. We have found that the coordinated regulation of ARG1 requires components of the SAGA chromatin-remodeling complex. Using gcn5 deletion strains and a Gcn5 protein carrying the E173Q mutation in the histone acetyltransferase (HAT) region, we show that the HAT activity of Gcn5p is required for repression of ARG1 in rich medium. Similar increases in expression were seen upon deletion of other SAGA components but not upon deletion of the ADA-specific component, Ahc1p. Chromatin immunoprecipitations using antibodies to acetylated H3 confirmed that a decrease in the level of acetylated histones at the ARG1 promoter correlated with increased ARG1 expression. Up-regulation of ARG1 in the absence of Gcn5p also correlated with increased binding of TATA-binding protein to the promoter. The analysis of promoter deletions showed that Gcn5/Ada repression of ARG1 was mediated through the action of the ArgR/Mcm1 regulatory complex. In addition, studies with minimal medium demonstrated a requirement for the Ada proteins in activation of ARG1. This suggests that SAGA has a dual role at ARG1, acting to repress transcription in rich medium and activate transcription in minimal medium.
authors.affiliation: Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada.
authors.forename: Andrea R
authors.initials: AR
authors.lastname: Ricci
authors.forename: Julie
authors.initials: J
authors.lastname: Genereaux
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Brandl
mesh_terms: D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D001124:Argininosuccinate Synthase / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D003470:Culture Media; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D051548:Histone Acetyltransferases; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000378:metabolism; D026341:Minichromosome Maintenance 1 Protein / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D035181:TATA-Box Binding Protein; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D000099224:p300-CBP-Associated Factor
chemical_list: D000123:Acetyltransferases; D001124:Argininosuccinate Synthase; D001426:Bacterial Proteins; D003470:Culture Media; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D051548:Histone Acetyltransferases; D006655:Histone Deacetylases; D006657:Histones; D026341:Minichromosome Maintenance 1 Protein; D011494:Protein Kinases; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; C087018:ArgR protein, Bacteria; C118425:SAGA protein, Emericella nidulans; C071731:SIN3 protein, S cerevisiae; C501392:GCN5 protein, S cerevisiae; D000099224:p300-CBP-Associated Factor; C071665:RPD3 protein, S cerevisiae