The nucleoid-associated DNA-binding protein H-NS is required for the efficient adaptation of Escherichia coli K-12 to a cold environment

Mol Gen Genet. 1994 Oct 28;245(2):255-9. doi: 10.1007/BF00283274.

Abstract

The hns gene is a member of the cold-shock regulon, indicating that the nucleoid-associated, DNA-binding protein H-NS plays an important role in the adaptation of Escherichia coli to low temperatures. We show here that the ability to cope efficiently with a cold environment (12 degrees C and 25 degrees C) is strongly impaired in E. coli strains carrying hns mutations. Growth inhibition is much more pronounced in strains carrying the hns-206 allele (an ampicillin resistance cassette inserted after codon 37) than in those carrying the hns-205 mutation (a Tn10 insertion located in codon 93). A protein fragment (H-NS*) is synthesized in strains carrying the hns-205::Tn10 mutation, suggesting that this truncated polypeptide is partially functional in the cold adaptation process. Analysis of the growth properties of strains harbouring four different low-copy-number plasmid-encoded hns' genes that result in the production of C-terminally truncated H-NS proteins supports this proposal. H-NS* proteins composed of 133, 117 or 94 amino-terminal amino acids partially complemented the severe cold-sensitive growth phenotype of the hns-206 mutant. In contrast, synthesis of a truncated H-NS protein with only 75 amino-terminal amino acids was insufficient to restore growth at low temperature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological / genetics*
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / physiology*
  • Bacterial Proteins*
  • Cold Temperature*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Escherichia coli / genetics
  • Escherichia coli / growth & development
  • Escherichia coli / physiology*
  • Genetic Complementation Test
  • Mutagenesis, Insertional
  • Regulon
  • Sequence Deletion

Substances

  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • DNA-Binding Proteins
  • H-NS protein, bacteria