Thioredoxin peroxidase is required for the transcriptional response to oxidative stress in budding yeast

A genetic screen was performed in Saccharomyces cerevisiae to identify mech anisms important for the transcriptional activation of genes encoding antio xidant proteins. Thioredoxin peroxidase, Tsa1p, of the thioredoxin system, was found to be essential for the transcriptional induction of other compon ents of the thioredoxin system, TRX2 (thioredoxin) and TRR1 (thioredoxin re ductase), in response to H2O2. The expression of TRX2 and TRR1 is known to be regulated by the transcription factors Yap1p and Skn7p in response to H2 O2, and the Tsa1p-dependent regulation of TRX2 requires the Yap1p/Skn7p pat hway. The data suggest that expression of components of the thioredoxin sys tem is dependent on the activity of Tsa1p in response to H2O2 in a Yap1p/Sk n7p-dependent pathway.