Role of Escherichia coli rpoS and associated genes in defense against oxidative damage

Free Radic Biol Med. 1996;21(7):975-93. doi: 10.1016/s0891-5849(96)00154-2.


The first phenotype described for mutations in the Escherichia coli rpoS gene was hypersensitivity to near-ultraviolet radiation and to its oxidative photoproduct, hydrogen peroxide. Initially named nur, this gene is now known to code for a sigma factor, and has acquired new names such as katF and rpoS. The role of its protein product (sigma-38) is to regulate a battery of genes as cells enter and rest in stationary phase. Some of the gene products are involved in protection against oxidants (e.g., catalases) and repair of oxidative damage (e.g., exonuclease III). Sigma-38 may also modulate transcription of certain growth phase genes, including hydroperoxidase I and glutathione reductase. Sigma-38 activity is regulated at transcriptional, translational, and protein stabilization levels. This review describes the complex mechanisms whereby sigma-38 controls various genes, the interaction of sigma-38 with other regulators, and a possible role of sigma-38 in bacterial virulence.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • DNA-Binding Proteins / metabolism
  • Escherichia coli / genetics*
  • Gene Expression Regulation, Bacterial / genetics
  • Genes, Bacterial / genetics*
  • Nuclear Proteins / metabolism
  • Oxidative Stress / physiology
  • Phenotype
  • Reactive Oxygen Species / metabolism
  • Sigma Factor / genetics*
  • Sigma Factor / metabolism
  • Transcription, Genetic / genetics


  • Bacterial Proteins
  • DNA-Binding Proteins
  • H-NS protein, bacteria
  • Nuclear Proteins
  • Reactive Oxygen Species
  • Sigma Factor
  • sigma factor KatF protein, Bacteria