Role of rpoS in the regulation of glutathione oxidoreductase (gor) in Escherichia coli

Abstract

RpoS (sigma-38) is the major regulator of genes for survival of Escherichia coli in the stationary phase. OxyR is a transcriptional regulator that responds to H2O2 induced stress in exponential phase. Once considered to act independently of each other, they are now known to be integrally involved in the expression of several oxidative stress genes. While it is known that in the exponential phase, OxyR is the transcriptional regulator of gor, this study has shown that RpoS regulates gor in the stationary phase. beta-Galactosidase activity of a gor::lacZ promoter fusion showed no induction in a oxyR rpoS double mutant. Challenge of a gor mutant to several oxidants showed that the gene product was not functioning as a classic antioxidant.