title: Comparative proteomic analysis of extracellular proteins of enterohemorrhagic and enteropathogenic Escherichia coli strains and their ihf and ler mutants.
abstract: Enterohemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC, respectively) strains are closely related human pathogens that are responsible for food-borne epidemics in many countries. Integration host factor (IHF) and the locus of enterocyte effacement-encoded regulator (Ler) are needed for the expression of virulence genes in EHEC and EPEC, including the elicitation of actin rearrangements for attaching and effacing lesions. We applied a proteomic approach, using two-dimensional polyacrylamide gel electrophoresis in combination with matrix-assisted laser desorption ionization-time of flight mass spectrometry and a protein database search, to analyze the extracellular protein profiles of EHEC EDL933, EPEC E2348/69, and their ihf and ler mutants. Fifty-nine major protein spots from the extracellular proteomes were identified, including six proteins of unknown function. Twenty-six of them were conserved between EHEC EDL933 and EPEC E2348/69, while some of them were strain-specific proteins. Four common extracellular proteins (EspA, EspB, EspD, and Tir) were regulated by both IHF and Ler in EHEC EDL933 and EPEC E2348/69. TagA in EHEC EDL933 and EspC and EspF in EPEC E2348/69 were present in the wild-type strains but absent from their respective ler and ihf mutants, while FliC was overexpressed in the ihf mutant of EPEC E2348/69. Two dominant forms of EspB were found in EHEC EDL933 and EPEC E2348/69, but the significance of this is unknown. These results show that proteomics is a powerful platform technology for accelerating the understanding of EPEC and EHEC pathogenesis and identifying markers for laboratory diagnoses of these pathogens.
authors.affiliation: Department of Biological Sciences, Faculty of Science, National University of Singapore, Science Dr. 4, Singapore 117543.
authors.forename: M
authors.initials: M
authors.lastname: Li
authors.forename: I
authors.initials: I
authors.lastname: Rosenshine
authors.forename: S L
authors.initials: SL
authors.lastname: Tung
authors.forename: X H
authors.initials: XH
authors.lastname: Wang
authors.forename: D
authors.initials: D
authors.lastname: Friedberg
authors.forename: C L
authors.initials: CL
authors.lastname: Hew
authors.forename: K Y
authors.initials: KY
authors.lastname: Leung
mesh_terms: D004926:Escherichia coli / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000235:genetics*; D020543:Proteome / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; D020543:Proteome