Adaptation to hydrogen peroxide

Adaptation to hydrogen peroxide in Saccharomyces cerevisiae is profiled with expression arrays. Adaptation describes the process in which a mild dose of toxin (in this case, hydrogen peroxide) is able to protect against a later acute dose. Here, we study two adaptive protocols (0.1 mM H2O2 and 0.1 + 0.4 mM H2O2) and one acute protocol (0.4 mM H2O2) to identify processes uniquely involved in adaptation. Predictions from these studies are validated in expression profiling of deletion mutants of the transcription factors Yap1, Mga2, and Rox1. Three different treatment protocols were studied. Pretreatment - 0.1 mM H2O2 for 45 minutes. Adapted - 0.1 mM H2O2 for 45 minutes, followed by 0.4 mM H2O2 for 1 hour. Acute - 0.4 mM H2O2 for 1 hour. Each treatment protocol was examined with 4x biological replicates, with the dye orientation reversed in two of the replicates (no technical replicates). The effect of the pretreatment protocol (0.1 mM H2O2) was also studied in three transcription factor deletion mutants (Yap1, Mga2, and Rox1) with the same number/orientation of biological replicates.