title: Role of Gal11, a component of the RNA polymerase II mediator in stress-induced hyperphosphorylation of Msn2 in Saccharomyces cerevisiae.
abstract: In the yeast Saccharomyces cerevisiae, the Msn2 transcription factor is a key element in mediating the environmental stress response (ESR), leading to the induction of 100-200 genes through the cis-acting Stress Response Element (STRE) in response to various physico-chemical stresses and nutritional variations. This activation is accompanied by a stress-induced hyperphosphorylation of Msn2. By a systematic screening we identified two proteins essential in this process: (i) the cyclin-dependent Ssn3/Srb10 protein kinase, part of a module of the RNA polymerase II mediator, which has already been shown to be involved in hyperphosphorylation and degradation of Msn2 upon stress, and (ii) Gal11, a component of the mediator. In a gal11 mutant, stress-induced hyperphosphorylation of Msn2 is abolished, stress-induced transcription of Msn2-dependent genes is decreased and Msn2 degradation is impaired. Rgr1, another component of the mediator, is also critical for this hyperphosphorylation, indicating that the integrity of the mediator is required for this process. Moreover the transactivating region of Msn2 interacts in vitro with the N-terminal domain of Gal11. These results point out the role of the mediator, especially its Gal11 subunit, in the hyperphosphorylation and degradation of Msn2 during stress response.
authors.affiliation: Laboratoire Polarité cellulaire, Traffic membranaire & Signalisation, UMR 6061 CNRS, Université Rennes 1, Faculté de Médecine, 2 Avenue du Pr Léon Bernard, CS 34317, 35043 Rennes Cedex, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Lallet
authors.forename: Hervé
authors.initials: H
authors.lastname: Garreau
authors.forename: Cecilia
authors.initials: C
authors.lastname: Garmendia-Torres
authors.forename: Dagmara
authors.initials: D
authors.lastname: Szestakowska
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Boy-Marcotte
authors.forename: Sophie
authors.initials: S
authors.lastname: Quevillon-Chéruel
authors.forename: Michel
authors.initials: M
authors.lastname: Jacquet
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D006358:Hot Temperature; D006868:Hydrolysis; D015151:Immunoblotting; D056892:Mediator Complex; D008954:Models, Biological; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation; D012319:RNA Polymerase II / Q000378:metabolism*; 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 / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; C058337:GAL11 protein, S cerevisiae; C081935:MSN2 protein, S cerevisiae; D056892:Mediator Complex; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D012319:RNA Polymerase II