title: Functional analysis of antigen 43 in uropathogenic Escherichia coli reveals a role in long-term persistence in the urinary tract.
abstract: Escherichia coli is the primary cause of urinary tract infection (UTI) in the developed world. The major factors associated with the virulence of uropathogenic E. coli (UPEC) are fimbrial adhesins, which mediate specific attachment to host receptors and trigger innate host responses. Another group of adhesins is represented by the autotransporter subgroup of proteins. The best characterized of these proteins, antigen 43 (Ag43), is a self-recognizing adhesin that is associated with cell aggregation and biofilm formation in E. coli K-12. The sequenced genome of prototype UPEC strain CFT073 contains two variant Ag43-encoding genes located on pathogenicity islands. The biological significance of both of these genes and their role in UPEC pathogenesis have not been investigated previously. Here we performed a detailed molecular characterization analysis of Ag43a (c3655) and Ag43b (c1273) from UPEC CFT073. Expression of Ag43a and Ag43b in a K-12 background revealed that they possess different functional properties. Ag43a produced a strong aggregation phenotype and promoted significant biofilm growth. Deletion mutants and strains constitutively expressing Ag43a and Ag43b were also constructed using CFT073. When these mutants were analyzed in a mouse model of UTI, Ag43a (but not Ag43b) promoted long-term persistence in the urinary bladder. Our findings demonstrate that Ag43a contributes to UPEC disease pathogenesis and reveal that there are pathogenicity-adapted variants of Ag43 with distinct virulence-related functions.
authors.affiliation: School of Molecular and Microbial Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
authors.forename: Glen C
authors.initials: GC
authors.lastname: Ulett
authors.forename: Jaione
authors.initials: J
authors.lastname: Valle
authors.forename: Christophe
authors.initials: C
authors.lastname: Beloin
authors.forename: Orla
authors.initials: O
authors.lastname: Sherlock
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Ghigo
authors.forename: Mark A
authors.initials: MA
authors.lastname: Schembri
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D018830:Adhesins, Escherichia coli; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology; D048168:Escherichia coli K12 / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D017353:Gene Deletion; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D013997:Time Factors; D001743:Urinary Bladder / Q000382:microbiology*; D014552:Urinary Tract Infections / Q000382:microbiology*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D018830:Adhesins, Escherichia coli; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D037521:Virulence Factors; C118376:antigen 43, E coli