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Critical Reviews™ in Eukaryotic Gene Expression
インパクトファクター: 1.841 5年インパクトファクター: 1.927 SJR: 0.649 SNIP: 0.516 CiteScore™: 1.96

ISSN 印刷: 1045-4403
ISSN オンライン: 2162-6502

Critical Reviews™ in Eukaryotic Gene Expression

DOI: 10.1615/CritRevEukarGeneExpr.v6.i4.30
pages 377-389

Two-Stage Gene Regulation of the Superoxide Stress Response soxRS System in Escherichia Coli

Tatsuo Nunoshiba
Department of Molecular and Cellular Biology, Biological Institute, Graduate School of Science, Tohoku University, Sendai 980-77, Japan

要約

All organisms have adapted to environmental changes by acquiring various functions controlled by gene regulation. In bacteria, a number of specific responses have been found to confer cell survival in various nutrient-limited conditions, and under physiological stresses such as high or low temperature, extreme pH, radiation, and oxidation (for review, see Neidhardt et al., 1987). In this article, I introduce an Escherichia coli (E. coli) global response induced by superoxide stress, the soxRS regulon. The functions controlled by this system consist of a wide variety of enzymes such as manganese-containing SOD (Mn-SOD), glucose 6-phosphate dehydrogenase (G6PD), the DNA repair enzyme endonuclease IV, fumarase C, NADPH:ferredoxin oxidoreductase, and aconitase. This response is positively regulated by a two-stage control system in which SoxR iron-sulfur protein senses exposure to superoxide and nitric oxide, and then activates transcription of the soxS gene, whose product stimulates the expression of the regulon genes. Our recent finding indicates that soxS transcription is initiated in a manner dependent on the rpoS gene encoding RNA polymerase sigma factor,σs, in response to entering the stationary phase of growth. With this information, mechanisms for prokaryotic coordinating gene expression in response to superoxide stress and in stationary phase are discussed.