title: Phage-inducible islands in the Gram-positive cocci.
abstract: The SaPIs are a cohesive subfamily of extremely common phage-inducible chromosomal islands (PICIs) that reside quiescently at specific att sites in the staphylococcal chromosome and are induced by helper phages to excise and replicate. They are usually packaged in small capsids composed of phage virion proteins, giving rise to very high transfer frequencies, which they enhance by interfering with helper phage reproduction. As the SaPIs represent a highly successful biological strategy, with many natural Staphylococcus aureus strains containing two or more, we assumed that similar elements would be widespread in the Gram-positive cocci. On the basis of resemblance to the paradigmatic SaPI genome, we have readily identified large cohesive families of similar elements in the lactococci and pneumococci/streptococci plus a few such elements in Enterococcus faecalis. Based on extensive ortholog analyses, we found that the PICI elements in the four different genera all represent distinct but parallel lineages, suggesting that they represent convergent evolution towards a highly successful lifestyle. We have characterized in depth the enterococcal element, EfCIV583, and have shown that it very closely resembles the SaPIs in functionality as well as in genome organization, setting the stage for expansion of the study of elements of this type. In summary, our findings greatly broaden the PICI family to include elements from at least three genera of cocci.
authors.affiliation: Departamento de Ciencias Biomédicas, Universidad CEU Cardenal Herrera, Moncada, Spain.
authors.forename: Roser
authors.initials: R
authors.lastname: Martínez-Rubio
authors.affiliation: Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
authors.forename: Nuria
authors.initials: N
authors.lastname: Quiles-Puchalt
authors.affiliation: Centro de Investigación y Tecnología Animal, Instituto Valenciano de Investigaciones Agrarias (CITA-IVIA), Castellón, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Martí
authors.affiliation: Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Humphrey
authors.affiliation: Skirball Institute Program in Molecular Pathogenesis and Departments of Microbiology and Medicine, Skirball Institute, New York University Medical Center, New York, NY, USA.
authors.forename: Geeta
authors.initials: G
authors.lastname: Ram
authors.affiliation: Skirball Institute Program in Molecular Pathogenesis and Departments of Microbiology and Medicine, Skirball Institute, New York University Medical Center, New York, NY, USA.
authors.forename: Davida
authors.initials: D
authors.lastname: Smyth
authors.affiliation: Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: John
authors.initials: J
authors.lastname: Chen
authors.affiliation: Skirball Institute Program in Molecular Pathogenesis and Departments of Microbiology and Medicine, Skirball Institute, New York University Medical Center, New York, NY, USA.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Novick
authors.affiliation: Departamento de Ciencias Biomédicas, Universidad CEU Cardenal Herrera, Moncada, Spain.|Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
authors.forename: José R
authors.initials: JR
authors.lastname: Penadés
mesh_terms: D001287:Attachment Sites, Microbiological; D001435:Bacteriophages / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D044404:Genomic Islands; D006095:Gram-Positive Cocci / Q000821:virology*