Interplay Between Global Regulators of Escherichia Coli: Effect of RpoS, Lrp and H-NS on Transcription of the Gene osmC

Mol Microbiol. 1998 Jun;28(5):971-80. doi: 10.1046/j.1365-2958.1998.00855.x.


The transcription of the osmC gene of Escherichia coli is regulated as a function of the phase of growth. It is induced during the decelerating phase, before entry into stationary phase. osmC expression is directed by two overlapping promoters, osmCp1 and osmCp2. osmCp2 is mainly transcribed by E-sigma(s), the RNA polymerase using the sigma(s) (RpoS) sigma factor, and is responsible for the growth phase regulation. Transcription from osmCp1 is independent of sigma(s). The leucine-responsive protein (Lrp) has been shown to bind the osmC promoter region in band shift experiments. In vivo analysis using osmC-lacZ transcriptional fusions demonstrated that Lrp affects the expression of both promoters. It represses the transcription of osmCp1 and activates the transcription of osmCp2 by E-sigma(s). An absence of Lrp results in an increase in the amount of RpoS during exponential growth in minimal medium. The nucleoid-associated protein H-NS also represses osmC transcription from both promoters. However, this happens through different mechanisms. The effect on osmCp2 is probably mediated by the increase in sigma(s) concentration in the cytoplasm of hns- mutants, while the effect on osmCp1 is independent of sigma(s). No binding of H-NS to the promoter region DNA could be detected, indicating that the effect on osmCp1 could also be indirect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Artificial Gene Fusion
  • Bacterial Proteins / genetics*
  • Base Sequence
  • Culture Media
  • DNA, Bacterial
  • DNA-Binding Proteins / metabolism*
  • Drosophila Proteins*
  • Escherichia coli / metabolism
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial*
  • Low Density Lipoprotein Receptor-Related Protein-1
  • Molecular Sequence Data
  • Mutagenesis
  • Nerve Tissue Proteins / metabolism*
  • Nuclear Proteins / metabolism*
  • Promoter Regions, Genetic
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / metabolism*
  • Transcription Factors*
  • Transcription, Genetic*


  • Bacterial Proteins
  • Culture Media
  • DNA, Bacterial
  • DNA-Binding Proteins
  • Drosophila Proteins
  • Escherichia coli Proteins
  • H-NS protein, bacteria
  • Low Density Lipoprotein Receptor-Related Protein-1
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • Receptors, Immunologic
  • Transcription Factors
  • osmC protein, E coli
  • pros protein, Drosophila