Independent recruitment of mediator and SAGA by the activator Met4.
Mediator is a key RNA polymerase II (Pol II) cofactor in the regulation of eukaryotic gene expression. It is believed to function as a coactivator linking gene-specific activators to the basal Pol II initiation machinery. In support of this model, we provide evidence that Mediator serves in vivo as a coactivator for the yeast activator Met4, which controls the gene network responsible for the biosynthesis of sulfur-containing amino acids and S-adenosylmethionine. In addition, we show that SAGA (Spt-Ada-Gcn5-acetyltransferase) is also recruited to Met4 target promoters, where it participates in the recruitment of Pol II by a mechanism involving histone acetylation. Interestingly, we find that SAGA is not required for Mediator recruitment by Met4 and vice versa. Our results provide a novel example of functional interplay between Mediator and coactivators involved in histone modification.
Leroy
Christophe
C
Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France.
Cormier
Laëtitia
L
Kuras
Laurent
L
D000107:Acetylation; D050976:Basic-Leucine Zipper Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D006657:Histones / Q000378:metabolism; D008957:Models, Genetic; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D006657:Histones; C073675:MET4 protein, S cerevisiae; D012333:RNA, Messenger; C507785:SAGA complex, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D012319:RNA Polymerase II