The CpxRA two-component system represses gene expression of the heat-labile toxin of enterotoxigenic Escherichia coli

J Med Microbiol. 2023 Apr;72(4). doi: 10.1099/jmm.0.001682.

Abstract

Enterotoxigenic Escherichia coli (ETEC) strains produce at least one of two types of enterotoxins: the heat-labile (LT) and heat-stable (ST) toxins, which are responsible for the watery secretory diarrhoea that is a hallmark of the human ETEC infection. One regulatory system that controls the transcription of virulence genes in pathogenic bacteria is the CpxRA two-component system (TCS). We reported that the eltAB bicistronic operon, which encodes for the A and B subunits of LT, was repressed for the CpxRA TCS by direct binding of CpxR-P from -12 to +6 bp with respect to the transcription start site of eltAB. Moreover, the Cpx-response activation down-regulated the transcription of eltAB genes, and this negative effect was CpxRA-dependent. Our data show that CpxRA TCS is a negative regulator of the LT, one of the main virulence determinants of ETEC.

Keywords: CpxRA; ETEC; eltAB; heat-labile toxin.

MeSH terms

  • Bacterial Toxins* / genetics
  • Bacterial Toxins* / metabolism
  • Diarrhea / microbiology
  • Enterotoxigenic Escherichia coli* / genetics
  • Enterotoxigenic Escherichia coli* / metabolism
  • Enterotoxins / genetics
  • Enterotoxins / metabolism
  • Escherichia coli Infections* / microbiology
  • Escherichia coli Proteins* / genetics
  • Escherichia coli Proteins* / metabolism
  • Gene Expression
  • Hot Temperature
  • Humans

Substances

  • Bacterial Toxins
  • Escherichia coli Proteins
  • Enterotoxins