title: Contributions of chaperone/usher systems to cell binding, biofilm formation and Yersinia pestis virulence.
abstract: Yersinia pestis genome sequencing projects have revealed six intact uncharacterized chaperone/usher systems with the potential to play roles in plague pathogenesis. We cloned each locus and expressed them in the Δfim Escherichia coli strain AAEC185 to test the assembled Y. pestis surface structures for various activities. Expression of each chaperone/usher locus gave rise to specific novel fibrillar structures on the surface of E. coli. One locus, y0561-0563, was able to mediate attachment to human epithelial cells (HEp-2) and human macrophages (THP-1) but not mouse macrophages (RAW264.7), while several loci were able to facilitate E. coli biofilm formation. When each chaperone/usher locus was deleted in Y. pestis, only deletion of the previously described pH 6 antigen (Psa) chaperone/usher system resulted in decreased adhesion and biofilm formation. Quantitative RT-PCR (qRT-PCR) revealed low expression levels for each novel chaperone/usher system in vitro as well as in mouse tissues following intravenous infection. However, a Y. pestis mutant in the chaperone/usher locus y1858-1862 was attenuated for virulence in mice via the intravenous route of infection, suggesting that expression of this locus is, at some stage, sufficient to affect the outcome of a plague infection. qRT-PCR experiments also indicated that expression of the chaperone/usher-dependent capsule locus, caf1, was influenced by oxygen availability and that the well-described chaperone/usher-dependent pilus, Psa, was strongly induced in minimal medium even at 28 °C rather than 37 °C, a temperature previously believed to be required for Psa expression. These data indicate several potential roles for the novel chaperone/usher systems of Y. pestis in pathogenesis and infection-related functions such as cell adhesion and biofilm formation.
authors.affiliation: University of Michigan School of Dentistry, Department of Biologic and Materials Science, 1011 N. University, Dental Bldg 3209, Ann Arbor, MI 48109-1078, USA.
authors.forename: Suleyman
authors.initials: S
authors.lastname: Felek
authors.affiliation: University of Michigan School of Dentistry, Department of Biologic and Materials Science, 1011 N. University, Dental Bldg 3209, Ann Arbor, MI 48109-1078, USA.
authors.forename: Jenny J
authors.initials: JJ
authors.lastname: Jeong
authors.affiliation: New York Institute of Technology, Department of Life Sciences, NY, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Runco
authors.affiliation: University of Michigan School of Public Health, Department of Biostatistics, MI, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Murray
authors.affiliation: Stony Brook University, Department of Molecular Genetics and Microbiology, Center for Infectious Diseases, NY, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Thanassi
authors.affiliation: University of Michigan School of Medicine, Department of Microbiology and Immunology, MI, USA.|University of Michigan School of Dentistry, Department of Biologic and Materials Science, 1011 N. University, Dental Bldg 3209, Ann Arbor, MI 48109-1078, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Krukonis
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D002460:Cell Line; D004847:Epithelial Cells / Q000382:microbiology; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D010930:Plague / Q000382:microbiology; D014774:Virulence; D015010:Yersinia pestis / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D018832:Molecular Chaperones