title: Expression of enteropathogenic Escherichia coli map is significantly different than that of other type III secreted effectors in vivo.
abstract: The enteropathogenic Escherichia coli (EPEC) locus of enterocyte effacement (LEE)-encoded effectors EspF and Map are multifunctional and have an impact on the tight junction barrier while the non-LEE-encoded proteins NleH1 and NleH2 possess significant anti-inflammatory activity. In order to address the temporal expression of these important genes in vivo, their promoters were cloned upstream of the luxCDABE operon, and luciferase expression was measured in EPEC-infected mice by bioluminescence using an in vivo imaging system (IVIS). Bioluminescent images of living mice, of excised whole intestines, and of whole intestines longitudinally opened and washed were assessed. The majority of bioluminescent bacteria localized in the cecum by 3 h postinfection, indicating that the cecum is not only a major colonization site of EPEC but also a site of EPEC effector gene expression in mice. espF, nleH1, and nleH2 were abundantly expressed over the course of infection. In contrast, map expression was suppressed at 2 days postinfection, and at 4 days postinfection it was totally abolished. After 2 to 4 days postinfection, when map is suppressed, EPEC colonization is significantly reduced, indicating that map may be one of the factors required to maintain EPEC colonization. This was confirmed in a competitive colonization study and in two models of chronic infection, repeated exposure to ketamine and Citrobacter rodentium infection. Our data suggest that map expression contributes to the maintenance of EPEC colonization.
authors.affiliation: Departments of Medicine, Microbiology/Immunology, Division of Gastroenterology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois, USA.
authors.forename: Mai
authors.initials: M
authors.lastname: Nguyen
authors.affiliation: Jefferson Medical College, Philadelphia, Pennsylvania, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Rizvi
authors.affiliation: Departments of Medicine, Microbiology/Immunology, Division of Gastroenterology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois, USA Hines VA Medical Center, Hines, Illinois, USA ghecht@lumc.edu.
authors.forename: Gail
authors.initials: G
authors.lastname: Hecht
mesh_terms: D000818:Animals; D019677:Artificial Gene Fusion; D004195:Disease Models, Animal; D004751:Enteritis / Q000382:microbiology*; D054308:Enteropathogenic Escherichia coli / Q000235:genetics / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000096:biosynthesis*; D020869:Gene Expression Profiling; D017930:Genes, Reporter; D007422:Intestines / Q000382:microbiology; D008156:Luciferases / Q000032:analysis / Q000235:genetics; D008163:Luminescent Measurements; D008297:Male; D008810:Mice, Inbred C57BL; D013997:Time Factors
chemical_list: D029968:Escherichia coli Proteins; C512346:Map protein, E coli; D008156:Luciferases