Molecular Variation among Type IV Pilin ( <i>bfpA</i> ) Genes from Diverse Enteropathogenic <i>Escherichia coli</i> Strains

DOI Web Site 被引用文献4件
  • T. Eric Blank
    <!--label omitted: 1-->Division of Infectious Diseases, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201,1 and
  • Hailang Zhong
    <!--label omitted: 1-->Division of Infectious Diseases, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201,1 and
  • Alison L. Bell
    <!--label omitted: 2-->Institute of Molecular Evolutionary Genetics and Department of Biology, Pennsylvania State University, University Park, Pennsylvania 168022
  • Thomas S. Whittam
    <!--label omitted: 2-->Institute of Molecular Evolutionary Genetics and Department of Biology, Pennsylvania State University, University Park, Pennsylvania 168022
  • Michael S. Donnenberg
    <!--label omitted: 1-->Division of Infectious Diseases, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201,1 and
  • A. D. O'Brien
    editor

抄録

<jats:title>ABSTRACT</jats:title> <jats:p> Typical enteropathogenic <jats:italic>Escherichia coli</jats:italic> (EPEC) strains produce bundle-forming pili (BFP), type IVB fimbriae that have been implicated in EPEC virulence, antigenicity, autoaggregation, and localized adherence to epithelial cells (LA). BFP are polymers of bundlin, a pilin protein that is encoded by the <jats:italic>bfpA</jats:italic> gene found on a large EPEC plasmid. Striking sequence variation has previously been observed among type IV pilin genes of other gram-negative bacterial pathogens (e.g., <jats:italic>Pseudomonas</jats:italic> and <jats:italic>Neisseria</jats:italic> spp.). In contrast, the established sequences of <jats:italic>bfpA</jats:italic> genes from two distantly related prototype EPEC strains vary by only a single base pair. To determine whether bundlin sequences vary more extensively, we used PCR to amplify the <jats:italic>bfpA</jats:italic> genes from 19 EPEC strains chosen for their various serotypes and sites and years of isolation. Eight different <jats:italic>bfpA</jats:italic> alleles were identified by sequencing of the PCR products. These alleles can be classified into two major groups. The α group contains three alleles derived from strains carrying O55, O86, O111, O119, O127, or O128 somatic antigens. The β group contains five alleles derived from strains carrying O55, O110, O128ab, O142, or nontypeable antigens. Sequence comparisons show that bundlin has highly conserved and variable regions, with most of the variation occurring in the C-terminal two-thirds of the protein. The results of multilocus enzyme electrophoresis support the hypothesis that <jats:italic>bfpA</jats:italic> sequences have spread horizontally across distantly related clonal lineages. Strains with divergent bundlin sequences express bundlin protein, produce BFP, and carry out autoaggregation and LA. However, four strains lack most or all of these phenotypes despite having an intact <jats:italic>bfpA</jats:italic> gene. These results have important implications for our understanding of bundlin structure, transmission of the <jats:italic>bfp</jats:italic> gene cluster among EPEC strains, and the role of bundlin variation in the evasion of host immune system responses. </jats:p>

収録刊行物

被引用文献 (4)*注記

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ