title: Expression of YAP4 in Saccharomyces cerevisiae under osmotic stress.
abstract: YAP4, a member of the yeast activator protein ( YAP ) gene family, is induced in response to osmotic shock in the yeast Saccharomyces cerevisiae. The null mutant displays mild and moderate growth sensitivity at 0.4 M and 0.8 M NaCl respectively, a fact that led us to analyse YAP4 mRNA levels in the hog1 (high osmolarity glycerol) mutant. The data obtained show a complete abolition of YAP4 gene expression in this mutant, placing YAP4 under the HOG response pathway. YAP4 overexpression not only suppresses the osmosensitivity phenotype of the yap4 mutant but also relieves that of the hog1 mutant. Induction, under the conditions tested so far, requires the presence of the transcription factor Msn2p, but not of Msn4p, as YAP4 mRNA levels are depleted by at least 75% in the msn2 mutant. This result was further substantiated by the fact that full YAP4 induction requires the two more proximal stress response elements. Furthermore we find that GCY1, encoding a putative glycerol dehydrogenase, GPP2, encoding a NAD-dependent glycerol-3-phosphate phosphatase, and DCS2, a homologue to a decapping enzyme, have decreased mRNA levels in the yap4 -deleted strain. Our data point to a possible, as yet not entirely understood, role of the YAP4 in osmotic stress response.
authors.affiliation: Stress and Genomics Laboratory, Institute of Chemical and Biological Technology, Av. da República, Apt. 127, 2781-901 Oeiras, Portugal.
authors.forename: Tracy
authors.initials: T
authors.lastname: Nevitt
authors.forename: Jorge
authors.initials: J
authors.lastname: Pereira
authors.forename: Dulce
authors.initials: D
authors.lastname: Azevedo
authors.forename: Paulo
authors.initials: P
authors.lastname: Guerreiro
authors.forename: Claudina
authors.initials: C
authors.lastname: Rodrigues-Pousada
mesh_terms: D004268:DNA-Binding Proteins / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D005990:Glycerol / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D009154:Mutation; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D009997:Osmotic Pressure; D010641:Phenotype; D020218:Response Elements; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology
chemical_list: C422266:Cin5 protein, S cerevisiae; D004268:DNA-Binding Proteins; C081935:MSN2 protein, S cerevisiae; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D005990:Glycerol