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Role of thioredoxin reductase in the Yap1p‐dependent response to oxidative stress in Saccharomyces cerevisiae
Author(s) -
CarmelHarel Orna,
Stearman Robert,
Gasch Audrey P.,
Botstein David,
Brown Patrick O.,
Storz Gisela
Publication year - 2001
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2001.02255.x
Subject(s) - biology , saccharomyces cerevisiae , oxidative stress , thioredoxin reductase , thioredoxin , fight or flight response , oxidative phosphorylation , biochemistry , microbiology and biotechnology , yeast , gene
The Saccharomyces cerevisiae Yap1p transcription factor is required for the H 2 O 2 ‐dependent activation of many antioxidant genes including the TRX2 gene encoding thioredoxin 2. To identify factors that regulate Yap1p activity, we carried out a genetic screen for mutants that show elevated expression of a TRX2–HIS3 fusion in the absence of H 2 O 2 . Two independent mutants isolated in this screen carried mutations in the TRR1 gene encoding thioredoxin reductase. Northern blot and whole‐genome expression analysis revealed that the basal expression of most Yap1p targets and many other H 2 O 2 ‐inducible genes is elevated in Δ trr1 mutants in the absence of external stress. In Δ trr1 mutants treated with H 2 O 2 , the Yap1p targets, as well as genes comprising a general environmental stress response and genes encoding protein‐folding chaperones, are hyperinduced. However, despite the elevated expression of genes encoding antioxidant enzymes, Δ trr1 mutants are extremely sensitive to H 2 O 2 . The results suggest that cells lacking thioredoxin reductase have diminished capacity to detoxify oxidants and/or to repair oxidative stress‐induced damage and that the thioredoxin system is involved in the redox regulation of Yap1p transcriptional activity.