title: PinR mediates the generation of reversible population diversity in Streptococcus zooepidemicus.
abstract: Opportunistic pathogens must adapt to and survive in a wide range of complex ecosystems. Streptococcus zooepidemicus is an opportunistic pathogen of horses and many other animals, including humans. The assembly of different surface architecture phenotypes from one genotype is likely to be crucial to the successful exploitation of such an opportunistic lifestyle. Construction of a series of mutants revealed that a serine recombinase, PinR, inverts 114 bp of the promoter of SZO_08560, which is bordered by GTAGACTTTA and TAAAGTCTAC inverted repeats. Inversion acts as a switch, controlling the transcription of this sortase-processed protein, which may enhance the attachment of S. zooepidemicus to equine trachea. The genome of a recently sequenced strain of S. zooepidemicus, 2329 (Sz2329), was found to contain a disruptive internal inversion of 7 kb of the FimIV pilus locus, which is bordered by TAGAAA and TTTCTA inverted repeats. This strain lacks pinR and this inversion may have become irreversible following the loss of this recombinase. Active inversion of FimIV was detected in three strains of S. zooepidemicus, 1770 (Sz1770), B260863 (SzB260863) and H050840501 (SzH050840501), all of which encoded pinR. A deletion mutant of Sz1770 that lacked pinR was no longer capable of inverting its internal region of FimIV. The data highlight redundancy in the PinR sequence recognition motif around a short TAGA consensus and suggest that PinR can reversibly influence the wider surface architecture of S. zooepidemicus, providing this organism with a bet-hedging solution to survival in fluctuating environments.
authors.affiliation: Animal Health Trust, Kentford, Newmarket CB8 7UU, UK.
authors.forename: Karen F
authors.initials: KF
authors.lastname: Steward
authors.affiliation: Animal Health Trust, Kentford, Newmarket CB8 7UU, UK.
authors.forename: Tihana
authors.initials: T
authors.lastname: Harrison
authors.affiliation: Animal Health Trust, Kentford, Newmarket CB8 7UU, UK.
authors.forename: Carl
authors.initials: C
authors.lastname: Robinson
authors.affiliation: Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK.
authors.forename: Josh
authors.initials: J
authors.lastname: Slater
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK.
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Maskell
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK.
authors.forename: Simon R
authors.initials: SR
authors.lastname: Harris
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK.
authors.forename: Matthew T G
authors.initials: MTG
authors.lastname: Holden
authors.affiliation: Animal Health Trust, Kentford, Newmarket CB8 7UU, UK.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Waller
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D017353:Gene Deletion; D023061:Gene Order; D056426:Genetic Loci; D006736:Horses; D009154:Mutation; D011401:Promoter Regions, Genetic; D057345:Sequence Inversion; D018502:Streptococcus equi / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins