title: Tail and Kinase Modules Differently Regulate Core Mediator Recruitment and Function In Vivo.
abstract: Mediator is a highly conserved transcriptional coactivator organized into four modules, namely Tail, Middle, Head, and Kinase (CKM). Previous work suggests regulatory roles for Tail and CKM, but an integrated model for these activities is lacking. Here, we analyzed the genome-wide distribution of Mediator subunits in wild-type and mutant yeast cells in which RNA polymerase II promoter escape is blocked, allowing detection of transient Mediator forms. We found that although all modules are recruited to upstream activated regions (UAS), assembly of Mediator within the pre-initiation complex is accompanied by the release of CKM. Interestingly, our data show that CKM regulates Mediator-UAS interaction rather than Mediator-promoter association. In addition, although Tail is required for Mediator recruitment to UAS, Tailless Mediator nevertheless interacts with core promoters. Collectively, our data suggest that the essential function of Mediator is mediated by Head and Middle at core promoters, while Tail and CKM play regulatory roles.
authors: Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada.
authors: Célia
authors: C
authors: Jeronimo
authors: Département de Biochimie et Médecine Moléculaire, Faculté de Médecine, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada.
authors: Marie-France
authors: MF
authors: Langelier
authors: Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 456A North Frear Laboratory, University Park, PA 16802, USA.
authors: Alain R
authors: AR
authors: Bataille
authors: Département de Biochimie et Médecine Moléculaire, Faculté de Médecine, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada.
authors: John M
authors: JM
authors: Pascal
authors: Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 456A North Frear Laboratory, University Park, PA 16802, USA.
authors: B Franklin
authors: BF
authors: Pugh
authors: Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada; Département de Médecine, Faculté de Médecine, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada. Electronic address: francois.robert@ircm.qc.ca.
authors: François
authors: F
authors: Robert
mesh_terms: D001665:Binding Sites; D015966:Gene Expression Regulation, Fungal; D056892:Mediator Complex / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D000072757:Protein Conformation, beta-Strand; D054730:Protein Interaction Domains and Motifs; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012319:RNA Polymerase II / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D035581:Transcription Factor TFIIB / Q000235:genetics* / Q000378:metabolism; D061785:Transcription Initiation, Genetic; D015533:Transcriptional Activation
chemical_list: D056892:Mediator Complex; D021122:Protein Subunits; C073680:SUA7 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035581:Transcription Factor TFIIB; D012319:RNA Polymerase II
keywords: Cdk8/Srb10; TFIIH/Kin28; kinase module; mediator; tail module