Signal-dependent requirement for the co-activator protein RcsA in transcription of the RcsB-regulated ugd gene

J Biol Chem. 2003 Dec 12;278(50):50588-95. doi: 10.1074/jbc.M309433200. Epub 2003 Sep 26.

Abstract

The RcsC/YojN/RcsB phosphorelay system controls gene expression in response to a variety of signals, including changes in temperature, osmolarity, and overproduction of membrane proteins. Transcription of certain RcsB-activated genes, such as the capsule synthesis cps operon, requires the co-activator protein RcsA, whereas expression of other RcsB-activated genes is RcsA-independent. We have established previously that a tolB mutation induces transcription of the Salmonella UDP-glucose dehydrogenase ugd gene in an RcsA- and RcsB-dependent manner. This induction is independent of the two-component systems PhoP/PhoQ and PmrA/PmrB, which are required for ugd expression in response to low Mg2+. We now report that the RcsC/YojN/RcsB system is activated in a pmrA mutant experiencing Fe3+ and low Mg2+, resulting in expression of both cps and ugd genes. However, whereas cps transcription remained RcsA-dependent, ugd transcription became RcsA-independent but dependent on the PhoP protein. S1 mapping experiments demonstrated that RcsA-dependent and -independent transcription of the ugd gene use the same promoter. DNase footprinting analysis identified a PhoP-binding site in the ugd promoter. Yet, PhoP-mediated ugd transcription required either the RcsC/YojN/RcsB or the PmrA/PmrB systems.

Publication types

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

MeSH terms

  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Binding Sites
  • Chromosomes / ultrastructure
  • Deoxyribonuclease I / metabolism
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism*
  • Gene Deletion
  • Iron / metabolism
  • Magnesium / metabolism
  • Models, Biological
  • Models, Genetic
  • Molecular Sequence Data
  • Mutation
  • Periplasmic Proteins / metabolism
  • Plasmids / metabolism
  • Promoter Regions, Genetic
  • Salmonella / metabolism*
  • Sequence Homology, Amino Acid
  • Single-Strand Specific DNA and RNA Endonucleases / metabolism
  • Temperature
  • Transcription Factors*
  • Transcription, Genetic
  • beta-Galactosidase / metabolism

Substances

  • Bacterial Proteins
  • Escherichia coli Proteins
  • Periplasmic Proteins
  • RcsB protein, E coli
  • Transcription Factors
  • tolB protein, E coli
  • RcsB protein, Bacteria
  • RcsA protein, E coli
  • Iron
  • Deoxyribonuclease I
  • Single-Strand Specific DNA and RNA Endonucleases
  • beta-Galactosidase
  • Magnesium