title: Mediator independently orchestrates multiple steps of preinitiation complex assembly in vivo.
abstract: Mediator is a large multiprotein complex conserved in all eukaryotes, which has a crucial coregulator function in transcription by RNA polymerase II (Pol II). However, the molecular mechanisms of its action in vivo remain to be understood. Med17 is an essential and central component of the Mediator head module. In this work, we utilised our large collection of conditional temperature-sensitive med17 mutants to investigate Mediator's role in coordinating preinitiation complex (PIC) formation in vivo at the genome level after a transfer to a non-permissive temperature for 45 minutes. The effect of a yeast mutation proposed to be equivalent to the human Med17-L371P responsible for infantile cerebral atrophy was also analyzed. The ChIP-seq results demonstrate that med17 mutations differentially affected the global presence of several PIC components including Mediator, TBP, TFIIH modules and Pol II. Our data show that Mediator stabilizes TFIIK kinase and TFIIH core modules independently, suggesting that the recruitment or the stability of TFIIH modules is regulated independently on yeast genome. We demonstrate that Mediator selectively contributes to TBP recruitment or stabilization to chromatin. This study provides an extensive genome-wide view of Mediator's role in PIC formation, suggesting that Mediator coordinates multiple steps of a PIC assembly pathway.
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA, CNRS, Université Paris Sud, F-91191 Gif-sur-Yvette cedex, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Eyboulet
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA, CNRS, Université Paris Sud, F-91191 Gif-sur-Yvette cedex, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Wydau-Dematteis
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA, CNRS, Université Paris Sud, F-91191 Gif-sur-Yvette cedex, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eychenne
authors.affiliation: CEA, iRCM, LEFG, Genopole G2, F-91057 Evry cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Alibert
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA, CNRS, Université Paris Sud, F-91191 Gif-sur-Yvette cedex, France.
authors.forename: Helen
authors.initials: H
authors.lastname: Neil
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA, CNRS, Université Paris Sud, F-91191 Gif-sur-Yvette cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Boschiero
authors.affiliation: CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, F-91191 Gif sur Yvette cedex, France.
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Nevers
authors.affiliation: CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, F-91191 Gif sur Yvette cedex, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Volland
authors.affiliation: CNRS, Centre de Recherche de Gif, SICaPS, F-91198 Gif-sur-Yvette cedex, France.
authors.forename: David
authors.initials: D
authors.lastname: Cornu
authors.affiliation: CNRS, Centre de Recherche de Gif, SICaPS, F-91198 Gif-sur-Yvette cedex, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Redeker
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA, CNRS, Université Paris Sud, F-91191 Gif-sur-Yvette cedex, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Werner
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), Institut de Biologie et de Technologies de Saclay (iBiTec-S), CEA, CNRS, Université Paris Sud, F-91191 Gif-sur-Yvette cedex, France julie.soutourina@cea.fr.
authors.forename: Julie
authors.initials: J
authors.lastname: Soutourina
mesh_terms: D002843:Chromatin / Q000378:metabolism; D005686:Galactokinase / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D016681:Genome, Fungal; D056892:Mediator Complex / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D035181:TATA-Box Binding Protein / Q000378:metabolism; D051758:Transcription Factor TFIIH / Q000378:metabolism; D061785:Transcription Initiation, Genetic
chemical_list: D002843:Chromatin; D056892:Mediator Complex; D012333:RNA, Messenger; C082148:SRB4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D051758:Transcription Factor TFIIH; C524219:GAL1 protein, S cerevisiae; D005686:Galactokinase; D012319:RNA Polymerase II