title: Regulators of oxidative stress response genes in Escherichia coli and their functional conservation in bacteria.
abstract: Oxidative stress, through the production of reactive oxygen species, is a natural consequence of aerobic metabolism. Escherichia coli has several major regulators activated during oxidative stress, including OxyR, SoxRS, and RpoS. OxyR and SoxR undergo conformation changes when oxidized in the presence of hydrogen peroxide and superoxide radicals, respectively, and subsequently control the expression of cognate genes. In contrast, the RpoS regulon is induced by an increase in RpoS levels. Current knowledge regarding the activation and function of these regulators and their dependent genes in E. coli during oxidative stress forms the scope of this review. Despite the enormous genomic diversity of bacteria, oxidative stress response regulators in E. coli are functionally conserved in a wide range of bacterial groups, possibly reflecting positive selection of these regulators. SoxRS and RpoS homologs are present and respond to oxidative stress in Proteobacteria, and OxyR homologs are present and function in H(2)O(2) resistance in a range of bacteria, from gammaproteobacteria to Actinobacteria. Bacteria have developed complex, adapted gene regulatory responses to oxidative stress, perhaps due to the prevalence of reactive oxygen species produced endogenously through metabolism or due to the necessity of aerotolerance mechanisms in anaerobic bacteria exposed to oxygen.
authors.affiliation: Department of Biology, McMaster University, 1280 Main St. West, Life Sciences Building, Hamilton, ON, Canada L8S 4K1.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Chiang
authors.forename: Herb E
authors.initials: HE
authors.lastname: Schellhorn
mesh_terms: D018407:Bacterial Physiological Phenomena; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006861:Hydrogen Peroxide; D008954:Models, Biological; D008956:Models, Chemical; D008957:Models, Genetic; D018384:Oxidative Stress; D011487:Protein Conformation; D017382:Reactive Oxygen Species; D018085:Regulon; D012097:Repressor Proteins / Q000378:metabolism; D013045:Species Specificity; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D017382:Reactive Oxygen Species; D012097:Repressor Proteins; C499299:oxyR protein, E coli; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase