The tib adherence locus of enterotoxigenic Escherichia coli is regulated by cyclic AMP receptor protein

Shirley M. Espert, Eric A. Elsinghorst, George Munson

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Enterotoxigenic Escherichia coli (ETEC) is a Gram-negative enteric pathogen that causes profuse watery diarrhea through the elaboration of heat-labile and/or heat-stable toxins. Virulence is also dependent upon the expression of adhesive pili and afimbrial adhesins that allow the pathogen to adhere to the intestinal epithelium or mucosa. Both types of enterotoxins are regulated at the level of transcription by cyclic AMP (cAMP) receptor protein (CRP). To further our understanding of virulence gene regulation, an in silico approach was used to identify putative CRP binding sites in the genome of H10407 (O78:H11), an ETEC strain that was originally isolated from the stool of a Bangledeshi patient with cholera-like symptoms circa 1971. One of the predicted binding sites was located within an intergenic region upstream of tibDBCA. TibA is an autotransporter and afimbrial adhesin that is glycosylated by TibC. Expression of the TibA glycoprotein was abolished in an H10407 crp mutant and restored when crp was provided in trans. TibA-dependent aggregation was also abolished in a cyaA::kan strain and restored by addition of exogenous cAMP to the growth medium. DNase I footprinting confirmed that the predicted site upstream of tibDBCA is bound by CRP. Point mutations within the CRP binding site were found to abolish or significantly impair CRP-dependent activation of the tibDB promoter. Thus, these studies demonstrate that CRP positively regulates the expression of the glycosylated afimbrial adhesin TibA through occupancy of a binding site within tibDBp.

Original languageEnglish
Pages (from-to)1369-1376
Number of pages8
JournalJournal of Bacteriology
Volume193
Issue number6
DOIs
StatePublished - Mar 1 2011

Fingerprint

Cyclic AMP Receptor Protein
Enterotoxigenic Escherichia coli
Binding Sites
Intestinal Mucosa
Protein Binding
Virulence
Hot Temperature
Intergenic DNA
Cholera
Enterotoxins
Deoxyribonuclease I
Point Mutation
Adhesives
Computer Simulation
Cyclic AMP
Diarrhea
Glycoproteins
Genome
Growth
Genes

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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The tib adherence locus of enterotoxigenic Escherichia coli is regulated by cyclic AMP receptor protein. / Espert, Shirley M.; Elsinghorst, Eric A.; Munson, George.

In: Journal of Bacteriology, Vol. 193, No. 6, 01.03.2011, p. 1369-1376.

Research output: Contribution to journalArticle

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