title: The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K(-): H6) is related to Pap pili but exhibits a truncated regulatory region.
abstract: Adhesins provide a major advantage for uropathogenic Escherichia coli in establishing urinary tract infections (UTIs). A novel gene cluster responsible for the expression of a filamentous adhesin of the pyelonephritogenic E. coli strain X2194 has been identified, molecularly cloned, and characterized. The 'pix operon' contains eight open reading frames which exhibit significant sequence homology to corresponding genes in the pap operon encoding P pili, the prevalent E. coli adhesins in non-obstructive acute pyelonephritis in humans. Although a pixB gene corresponding to the PapB regulator was identified, a papI homologue could not be found in the pix operon. Instead, a fragment of the R6 gene of the highly uropathogenic E. coli strain CFT073 was identified upstream of pixB. The R6 gene is located in a pathogenicity island containing several pilus-encoding sequences and shows homology to a transposase of Chelatobacter heintzii. In a pixA-lacZ fusion system it was demonstrated that the expression of Pix pili is regulated at the transcriptional level by the R6 gene sequence. A significantly reduced transcription was observed by deleting this fragment and by lowering the growth temperature from 37 to 26 degrees C. In contrast to other filamentous adhesin systems, Pix pili are mainly expressed in the steady state growth phase and were not repressed by the addition of glucose.
authors.affiliation: Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Lügering
authors.affiliation: Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
authors.forename: Inga
authors.initials: I
authors.lastname: Benz
authors.affiliation: Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Knochenhauer
authors.affiliation: Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Ruffing
authors.affiliation: Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von Esmarch Strasse 56, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany.
authors.forename: M Alexander
authors.initials: MA
authors.lastname: Schmidt
mesh_terms: D018830:Adhesins, Escherichia coli / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology / Q000648:ultrastructure; D004927:Escherichia coli Infections / Q000209:etiology; D036781:Fimbriae Proteins / Q000235:genetics* / Q000502:physiology; D010861:Fimbriae, Bacterial / Q000502:physiology* / Q000648:ultrastructure; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D006367:HeLa Cells; D006801:Humans; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D005810:Multigene Family; D009876:Operon; D011704:Pyelonephritis / Q000209:etiology; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D014774:Virulence / Q000235:genetics
chemical_list: D018830:Adhesins, Escherichia coli; D004269:DNA, Bacterial; D036781:Fimbriae Proteins