title: Gene cluster for assembly of pilus colonization factor antigen III of enterotoxigenic Escherichia coli.
abstract: The assembly of pilus colonization factor antigen III (CFA/III) of enterotoxigenic Escherichia coli (ETEC) requires the processing of CFA/III major pilin (CofA) by a prepilin peptidase (CofP), similar to other type IV pilus formation systems. CofA is produced initially as a 26.5-kDa preform pilin (prepilin) and then processed to a 20.5-kDa mature pilin by CofP which is predicted to be localized in the inner membrane. In the present experiment, we determined the nucleotide sequence of the whole region for CFA/III formation and identified a cluster of 14 genes, including cofA and cofP. Several proteins encoded by cof genes were similar to previously described proteins, such as the toxin-coregulated pili of Vibrio cholerae and the bundle-forming pili of enteropathogenic E. coli. The G+C content of the cof gene cluster was 37%, which was significantly lower than the average for the E. coli genome (50%). The introduction of a recombinant plasmid containing the cof gene cluster into the E. coli K-12 strain conferred CFA/III biogenesis and the ability of adhesion to the human colon carcinoma cell line Caco-2. This is the first report of a complete nucleotide sequence of the type IV pili found in human ETEC, and our results provide a useful model for studying the molecular mechanism of CFA/III biogenesis and the role of CFA/III in ETEC infection.
authors.affiliation: Department of Microbiology, Nagoya City University Medical School, Nagoya, Aichi 467-8601, Japan. taniguti@med.nagoya-cu.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Akeda
authors.forename: A
authors.initials: A
authors.lastname: Haba
authors.forename: Y
authors.initials: Y
authors.lastname: Yasuda
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Honda
authors.forename: K
authors.initials: K
authors.lastname: Tochikubo
mesh_terms: D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D018938:Caco-2 Cells; D004768:Enterotoxins / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D036781:Fimbriae Proteins; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004768:Enterotoxins; C022924:colonization factor antigens; D036781:Fimbriae Proteins