Dataset Information

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

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.

SUBMITTER: Espert SM

PROVIDER: S-EPMC3067628 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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

Espert Shirley M SM Elsinghorst Eric A EA Munson George P GP

Journal of bacteriology 20110107 6

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 ge ...[more]

PMID: 21216994

Similar Datasets

Project description:Enterotoxigenic Escherichia coli (ETEC) shares with other diarrheal pathogens the capacity to invade epithelial cell lines originating from the human ileum or colon, although the role of invasion in ETEC pathogenesis remains undefined. Two distinct loci (tia and tib) that direct noninvasive E. coli to adhere to and invade intestinal epithelial cell lines have previously been isolated from cosmid libraries of the classical ETEC strain H10407. Here, we report the molecular characterization of the tia locus. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of cellular fractions of E. coli DH5alpha carrying the tia-positive cosmids and recombinant plasmid subclones revealed that this locus directs the production of a 25-kDa protein (the Tia protein) that is localized to the outer membrane. The tia locus was subcloned to a maximum of 2 kb and mutagenized with bacteriophage Mud. Synthesis of this protein was directly correlated with the ability of subclones and Mud transposon mutants to adhere to and invade epithelial cells. Sequencing of the tia locus identified a 756-bp open reading frame. All transposon insertions resulting in an invasion-negative phenotype mapped to this open reading frame. The open reading frame was amplified and directionally cloned behind the lac promoter of pHG165. This construct directed DHalpha to express a 25-kDa protein and to adhere to and invade epithelial cells. The role of the tia gene in directing epithelial adherence and invasion was further assessed by the construction of chromosomal tia deletion derivatives of the parent ETEC strain, H10407. These tia deletion strains were noninvasive and lacked the ability to adhere to human ileocecal cells. The tia gene shares limited homology with the Yersinia ail locus and significant homology with the hra1 agglutinin gene cloned from a porcine ETEC strain. Additionally, tia probes hybridized to geographically diverse ETEC strains, as well as some enteropathogenic E. coli, enteroaggregative E. coli, and Shigella sonnei strains.

Dataset Information

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

Publications

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

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets