title: Enterococcus faecalis pCF10-encoded surface proteins PrgA, PrgB (aggregation substance) and PrgC contribute to plasmid transfer, biofilm formation and virulence.
abstract: Enterococcus faecalis pCF10 transfers at high frequencies upon pheromone induction of the prgQ transfer operon. This operon codes for three cell wall-anchored proteins - PrgA, PrgB (aggregation substance) and PrgC - and a type IV secretion system through which the plasmid is delivered to recipient cells. Here, we defined the contributions of the Prg surface proteins to plasmid transfer, biofilm formation and virulence using the Caenorhabditis elegans infection model. We report that a combination of PrgB and extracellular DNA (eDNA), but not PrgA or PrgC, was required for extensive cellular aggregation and pCF10 transfer at wild-type frequencies. In addition to PrgB and eDNA, production of PrgA was necessary for extensive binding of enterococci to abiotic surfaces and development of robust biofilms. However, although PrgB is a known virulence factor in mammalian infection models, we determined that PrgA and PrgC, but not PrgB, were required for efficient killing in the worm infection model. We propose that the pheromone-responsive, conjugative plasmids of E. faecalis have retained Prg-like surface functions over evolutionary time for attachment, colonization and robust biofilm development. In natural settings, these biofilms are polymicrobial in composition and constitute optimal environments for signal exchange, mating pair formation and widespread lateral gene transfer.
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX, 77030, USA.
authors.forename: Minny
authors.initials: M
authors.lastname: Bhatty
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Cruz
authors.forename: Kristi L
authors.initials: KL
authors.lastname: Frank
authors.forename: Jenny A Laverde
authors.initials: JA
authors.lastname: Gomez
authors.forename: Fernando
authors.initials: F
authors.lastname: Andrade
authors.forename: Danielle A
authors.initials: DA
authors.lastname: Garsin
authors.forename: Gary M
authors.initials: GM
authors.lastname: Dunny
authors.forename: Heidi B
authors.initials: HB
authors.lastname: Kaplan
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Christie
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D017173:Caenorhabditis elegans / Q000382:microbiology*; D003227:Conjugation, Genetic; D013293:Enterococcus faecalis / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D014158:Transcription, Genetic; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D037521:Virulence Factors