Analysis of global transcriptional profiles of enterotoxigenic Escherichia coli isolate E24377A

Infect Immun. 2012 Mar;80(3):1232-42. doi: 10.1128/IAI.06138-11. Epub 2012 Jan 3.


Enterotoxigenic Escherichia coli (ETEC) is an important pathogenic variant (pathovar) of E. coli in developing countries from a human health perspective, causing significant morbidity and mortality. Previous studies have examined specific regulatory networks in ETEC, although little is known about the global effects of inter- and intrakingdom signaling on the expression of virulence and colonization factors in ETEC. In this study, an E. coli/Shigella pan-genome microarray, combined with quantitative reverse transcriptase PCR (qRT-PCR) and RNA sequencing (RNA-seq), was used to quantify the expression of ETEC virulence and colonization factors. Biologically relevant chemical signals were combined with ETEC isolate E24377A during growth in either Luria broth (LB) or Dulbecco's modified Eagle medium (DMEM), and transcription was examined during different phases of the growth cycle; chemical signals examined included glucose, bile salts, and preconditioned media from E. coli/Shigella isolates. The results demonstrate that the presence of bile salts, which are found in the intestine and thought to be bactericidal, upregulates the expression of many ETEC virulence factors, including heat-stable (estA) and heat-labile (eltA) enterotoxin genes. In contrast, the ETEC colonization factors CS1 and CS3 were downregulated in the presence of bile, consistent with findings in studies of other enteric pathogens. RNA-seq analysis demonstrated that one of the most differentially expressed genes in the presence of bile is a unique plasmid-encoded AraC-like transcriptional regulator (peaR); other previously unknown genetic elements were found as well. These results provide transcriptional targets and putative mechanisms that should help improve understanding of the global regulatory networks and virulence expression in this important human pathogen.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bile Acids and Salts / metabolism
  • Culture Media / chemistry
  • Enterotoxigenic Escherichia coli / genetics*
  • Enterotoxigenic Escherichia coli / growth & development
  • Escherichia coli
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial
  • Humans
  • Microarray Analysis
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, RNA
  • Signal Transduction
  • Stress, Physiological
  • Transcriptome*
  • Virulence Factors / genetics
  • Virulence Factors / metabolism


  • Bile Acids and Salts
  • Culture Media
  • Virulence Factors

Associated data

  • GEO/GSE31806