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The Ssn6–Tup1 repressor complex of Saccharomyces cerevisiae is involved in the osmotic induction of HOG‐dependent and ‐independent genes
Author(s) -
Márquez José A.,
PascualAhuir Amparo,
Proft Markus,
Serrano Ramón
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.9.2543
Subject(s) - repressor , biology , saccharomyces cerevisiae , psychological repression , mutant , transcriptional regulation , transcription factor , osmotic shock , gene , microbiology and biotechnology , regulation of gene expression , gene expression , genetics
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 (URS HAL1 ) 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 URS HAL1 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.