Remodeling of yeast genome expression in response to environmental changes

We used genome-wide expression analysis to explore how gene expression in S accharomyces cerevisiae is remodeled in response to various changes in extr acellular environment, including changes in temperature, oxidation, nutrien ts, pH, and osmolarity. The results demonstrate that more than half of the genome is involved in various responses to environmental change and identif y the global set of genes induced and repressed by each condition. These da ta implicate a substantial number of previously uncharacterized genes in th ese responses and reveal a signature common to environmental responses that involves similar to 10% of yeast genes. The results of expression analysis with MSN2/MSN4 mutants support the model that the Msn2/Msn4 activators ind uce the common response to environmental change. These results provide a gl obal description of the transcriptional response to environmental change an d extend our understanding of the role of activators in effecting this resp onse.