The Ssn6-Tup1 repressor complex of Saccharomyces cerevisiae is involved in the osmotic induction of HOG-dependent and -independent genes.
The response of yeast to osmotic stress has been proposed to rely on the HOG-MAP kinase signalling pathway and on transcriptional activation mediated by STRE promoter elements. However, the osmotic induction of HAL1, an important determinant of salt tolerance, is HOG independent and occurs through the release of transcriptional repression. We have identified an upstream repressing sequence in HAL1 promoter (URSHAL1) located between -231 and -156. This promoter region was able to repress transcription from a heterologous promoter and to bind proteins in non-stressed cells, but not in salt-treated cells. The repression conferred by URSHAL1 is mediated through the Ssn6-Tup1 protein complex and is abolished in the presence of osmotic stress. The Ssn6-Tup1 co-repressor is also involved in the regulation of HOG-dependent genes such as GPD1, CTT1, ALD2, ENA1 and SIP18, and its deletion can suppress the osmotic sensitivity of hog1 mutants. We propose that the Ssn6-Tup1 repressor complex might be a general component in the regulation of osmostress responses at the transcriptional level of both HOG-dependent and -independent genes.
Márquez
J A
JA
Instituto de Biología Molecular y Celular de Plantas, Universidad politécnica de Valencia-CSIC, Camino de vera s/n, 46022 Valencia, Spain.
Pascual-Ahuir
A
A
Proft
M
M
Serrano
R
R
D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D009994:Osmolar Concentration; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000096:biosynthesis
C065455:CYC8 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C076232:HAL1 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C066502:TUP1 protein, S cerevisiae; D017868:Cyclic AMP-Dependent Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D001616:beta-Galactosidase