SUMMARY
Bacteria, yeast and cells of higher eukaryotes specifically induce the expression of genes encoding antioxidant defenses when exposed to reactive oxygen species. Recent studies have also suggested that reactive oxygen intermediates play a role as second messengers in signal transduction pathways. Therefore, cells must possess regulators that sense oxidant signals and transduce the signals into changes in gene expression. This review provides an overview of the transcription factors in Escherichia coli, Saccharomyces cerevisiae and mammalian cells that govern the response to oxidative stress. Some of the regulators function primarily as regulators of antioxidant genes while other regulators of the oxidative stress response also regulate genes important for metal homeostasis or cell metabolism during aerobic or anaerobic growth.