title: Yeast 14-3-3 protein functions as a comodulator of transcription by inhibiting coactivator functions.
abstract: In eukaryotes combinatorial activation of transcription is an important component of gene regulation. In the budding yeast Saccharomyces cerevisiae, Adr1-Cat8 and Adr1-Oaf1/Pip2 are pairs of activators that act together to regulate two diverse sets of genes. Transcription activation of both sets is regulated positively by the yeast AMP-activated protein kinase homolog, Snf1, in response to low glucose or the presence of a non-fermentable carbon source and negatively by two redundant 14-3-3 isoforms, Bmh1 and Bmh2. Bmh regulates the function of these pairs at a post-promoter binding step by direct binding to Adr1. However, how Bmh regulates transcription after activator binding remains unknown. In the present study we analyzed Bmh-mediated regulation of two sets of genes activated independently by these pairs of activators. We report that Bmh inhibits mRNA synthesis when the second activator is absent. Using gene fusions we show that Bmh binding to the Adr1 regulatory domain inhibits an Adr1 activation domain but not a heterologous activation domain or artificially recruited Mediator, consistent with Bmh acting at a step in transcription downstream of activator binding. Bmh inhibits the assembly and the function of a preinitiation complex (PIC). Gene expression studies suggest that Bmh regulates Adr1 activity through the coactivators Mediator and Swi/Snf. Mediator recruitment appeared to occur normally, but PIC formation and function were defective, suggesting that Bmh inhibits a step between Mediator recruitment and PIC activation.
authors.affiliation: From the Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350.
authors.forename: Pabitra K
authors.initials: PK
authors.lastname: Parua
authors.affiliation: From the Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350.
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Dombek
authors.affiliation: From the Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350 ety@uw.edu.
authors.forename: Elton T
authors.initials: ET
authors.lastname: Young
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics* / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D007700:Kinetics; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D048948:14-3-3 Proteins; C074682:ADR1 protein, S cerevisiae; C075852:BMH1 protein, S cerevisiae; C097164:BMH2 protein, S cerevisiae; C092600:CAT8 protein, S cerevisiae; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C120764:OAF1 protein, S cerevisiae; C100530:PIP2 protein, S cerevisiae; D012333:RNA, Messenger; C078562:SWI1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases
keywords: 14-3-3 Protein; Adr1; Cat8; Combinatorial Regulation; Gene Regulation; Gene Transcription; Oaf1/Pip2; RNA Polymerase II; Transcription Coactivator