Selective repression by Fis and H-NS at the Escherichia coli dps promoter

Mol Microbiol. 2008 Jun;68(6):1366-77. doi: 10.1111/j.1365-2958.2008.06253.x. Epub 2008 Apr 28.

Abstract

Dps is a nucleoid-associated protein that plays a major role in condensation of the Escherichia coli chromosome in stationary phase. Here we show that two other nucleoid-associated proteins, Fis and H-NS, can bind at the dps gene promoter and downregulate its activity. Both Fis and H-NS selectively repress the dps promoter, preventing transcription initiation by RNA polymerase containing sigma(70), the housekeeping sigma factor, but not by RNA polymerase containing sigma(38), the stationary-phase sigma factor. Fis represses by trapping RNA polymerase containing sigma(70) at the promoter. In contrast, H-NS functions by displacing RNA polymerase containing sigma(70), but not RNA polymerase containing sigma(38). Dps levels are known to be very low in exponentially growing cells and rise sharply as cells enter stationary phase. Conversely, Fis levels are high in growing cells but fall to nearly zero in stationary-phase cells. Our data suggest a simple model to explain how the Dps-dependent super-compaction of the folded chromosome is triggered as cell growth ceases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Outer Membrane Proteins / genetics*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • DNA-Directed RNA Polymerases / metabolism
  • Down-Regulation*
  • Escherichia coli / genetics*
  • Escherichia coli / growth & development
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / genetics*
  • Escherichia coli Proteins / metabolism*
  • Factor For Inversion Stimulation Protein / genetics
  • Factor For Inversion Stimulation Protein / metabolism*
  • Gene Expression Regulation, Bacterial*
  • Molecular Sequence Data
  • Promoter Regions, Genetic*
  • Salmonella typhimurium / genetics
  • Sequence Alignment
  • Sequence Deletion
  • Sigma Factor / metabolism

Substances

  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • Factor For Inversion Stimulation Protein
  • Fis protein, E coli
  • H-NS protein, bacteria
  • Sigma Factor
  • dps protein, E coli
  • sigma factor KatF protein, Bacteria
  • DNA-Directed RNA Polymerases