Abstract
In the presence of oxidative stress, cellular defense systems that can detoxify reactive oxygen species are activated through multiple signaling cascades and transcriptional reprogramming. The budding yeast Saccharomyces cerevisiae has served as an excellent model for genetically-identifying factors important for the response to oxidative stress. Here, we describe two assays for testing yeast gene deletion strains or strains overexpressing a gene of interest for viability following oxidative stress induced by hydrogen peroxide treatment. These include a plate-based spot assay for visualizing cell growth and a quantitative colony counting assay. As stress response assays can be highly variable depending on cell growth conditions, these protocols have been optimized for obtaining highly-reproducible results between experiments. We demonstrate the use of these protocols for genetic tests of a putative chromatin regulator implicated in regulating the transcriptional response to oxidative stress.