H-NS: a modulator of environmentally regulated gene expression

Mol Microbiol. 1997 Apr;24(1):7-17. doi: 10.1046/j.1365-2958.1997.3151679.x.

Abstract

H-NS is a small chromatin-associated protein found in enterobacteria. H-NS has affinity for all types of nucleic acids but binds preferentially to intrinsically curved DNA. The major role of H-NS is to modulate the expression of a large number of genes, mostly by negatively affecting transcription. Many of the H-NS-modulated genes are regulated by environmental signals, and expression of most of these genes is positively regulated by specific transcription factors. Therefore one of the purposes of H-NS could be to repress expression of some genes under conditions characteristic of a non-intestinal environment, but allow expression of specific genes in response to certain stimuli in the intestinal environment. The hns gene is autoregulated. In vivo the H-NS to DNA ratio is fairly constant except during cold shock, when it increases three- to fourfold. In this review we propose that only the preferential binding to intrinsically curved DNA plays a role under normal growth conditions, and we discuss the different mechanisms by which H-NS might affect gene expression and how H-NS could be involved in the response to different stress situations. Finally, we summarize the evolutionary and functional relationship between H-NS and the homologous StpA.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Cold Temperature
  • DNA / metabolism
  • DNA, Bacterial
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial*
  • Homeostasis
  • Molecular Chaperones*
  • Molecular Sequence Data
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Sigma Factor / genetics
  • Temperature
  • Trans-Activators / antagonists & inhibitors
  • Water-Electrolyte Balance

Substances

  • Bacterial Proteins
  • DNA, Bacterial
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • H-NS protein, bacteria
  • Molecular Chaperones
  • Nuclear Proteins
  • Sigma Factor
  • StpA protein, E coli
  • Trans-Activators
  • sigma factor KatF protein, Bacteria
  • DNA

Associated data

  • GENBANK/L10328
  • GENBANK/U14003
  • GENBANK/U18997
  • GENBANK/U32832