F9 fimbriae of uropathogenic Escherichia coli are expressed at low temperature and recognise Galβ1-3GlcNAc-containing glycans

PLoS One. 2014 Mar 26;9(3):e93177. doi: 10.1371/journal.pone.0093177. eCollection 2014.

Abstract

Uropathogenic Escherichia coli (UPEC) is the leading causative agent of urinary tract infections (UTI) in the developed world. Among the major virulence factors of UPEC, surface expressed adhesins mediate attachment and tissue tropism. UPEC strains typically possess a range of adhesins, with type 1 fimbriae and P fimbriae of the chaperone-usher class the best characterised. We previously identified and characterised F9 as a new chaperone-usher fimbrial type that mediates biofilm formation. However, the regulation and specific role of F9 fimbriae remained to be determined in the context of wild-type clinical UPEC strains. In this study we have assessed the distribution and genetic context of the f9 operon among diverse E. coli lineages and pathotypes and demonstrated that f9 genes are significantly more conserved in a UPEC strain collection in comparison to the well-defined E. coli reference (ECOR) collection. In the prototypic UPEC strain CFT073, the global regulator protein H-NS was identified as a transcriptional repressor of f9 gene expression at 37°C through its ability to bind directly to the f9 promoter region. F9 fimbriae expression was demonstrated at 20°C, representing the first evidence of functional F9 fimbriae expression by wild-type E. coli. Finally, glycan array analysis demonstrated that F9 fimbriae recognise and bind to terminal Galβ1-3GlcNAc structures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylglucosamine / metabolism
  • Adhesins, Bacterial / genetics
  • Adhesins, Bacterial / metabolism
  • Amino Acid Sequence
  • Bacterial Adhesion
  • Base Sequence
  • Biofilms
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Evolution, Molecular
  • Fimbriae, Bacterial / genetics*
  • Fimbriae, Bacterial / metabolism
  • Galactose / metabolism
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Molecular Sequence Data
  • Operon
  • Phylogeny
  • Polysaccharides / metabolism*
  • Transcription, Genetic
  • Uropathogenic Escherichia coli / genetics*
  • Uropathogenic Escherichia coli / metabolism

Substances

  • Adhesins, Bacterial
  • Escherichia coli Proteins
  • Polysaccharides
  • Acetylglucosamine
  • Galactose

Grants and funding

This work was supported by grants from the Australian National Health and Medical Research Council (631654 and APP1012076). MAS and GCU are supported by Australian Research Council (ARC) Future Fellowships (FT100100662 and FT110101048). MT is supported by an ARC Discovery Early Career Researcher Award (DE130101169). MPJ is supported by a NHMRC Program Grant 565526 and a Smart Futures Fund Research Partnerships Program Grant. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.