title: Moonlighting bacteriophage proteins derepress staphylococcal pathogenicity islands.
abstract: Staphylococcal superantigen-carrying pathogenicity islands (SaPIs) are discrete, chromosomally integrated units of approximately 15 kilobases that are induced by helper phages to excise and replicate. SaPI DNA is then efficiently encapsidated in phage-like infectious particles, leading to extremely high frequencies of intra- as well as intergeneric transfer. In the absence of helper phage lytic growth, the island is maintained in a quiescent prophage-like state by a global repressor, Stl, which controls expression of most of the SaPI genes. Here we show that SaPI derepression is effected by a specific, non-essential phage protein that binds to Stl, disrupting the Stl-DNA complex and thereby initiating the excision-replication-packaging cycle of the island. Because SaPIs require phage proteins to be packaged, this strategy assures that SaPIs will be transferred once induced. Several different SaPIs are induced by helper phage 80alpha and, in each case, the SaPI commandeers a different non-essential phage protein for its derepression. The highly specific interactions between different SaPI repressors and helper-phage-encoded antirepressors represent a remarkable evolutionary adaptation involved in pathogenicity island mobilization.
authors.affiliation: Centro de Investigación y Tecnología Animal, Instituto Valenciano de Investigaciones Agrarias (CITA-IVIA), Apdo. 187, Segorbe, Castellón 12400, Spain.
authors.forename: María Angeles
authors.initials: MA
authors.lastname: Tormo-Más
authors.forename: Ignacio
authors.initials: I
authors.lastname: Mir
authors.forename: Archana
authors.initials: A
authors.lastname: Shrestha
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Tallent
authors.forename: Susana
authors.initials: S
authors.lastname: Campoy
authors.forename: Iñigo
authors.initials: I
authors.lastname: Lasa
authors.forename: Jordi
authors.initials: J
authors.lastname: Barbé
authors.forename: Richard P
authors.initials: RP
authors.lastname: Novick
authors.forename: Gail E
authors.initials: GE
authors.lastname: Christie
authors.forename: José R
authors.initials: JR
authors.lastname: Penadés
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D004261:DNA Replication; D044404:Genomic Islands / Q000235:genetics*; D006378:Helper Viruses / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008242:Lysogeny / Q000502:physiology; D008969:Molecular Sequence Data; D039002:Prophages / Q000378:metabolism / Q000502:physiology; D011755:Pyrophosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic / Q000235:genetics; D012097:Repressor Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D012772:Shock, Septic; D013204:Staphylococcus Phages / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D013211:Staphylococcus aureus / Q000235:genetics* / Q000472:pathogenicity / Q000821:virology; D018089:Superantigens / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D012097:Repressor Proteins; D018089:Superantigens; D014764:Viral Proteins; D004247:DNA; D011755:Pyrophosphatases; C020020:dUTP pyrophosphatase
references.citation: Appl Environ Microbiol. 2004 Oct;70(10):6076-85
references.pmid: 15466553
references.citation: J Bacteriol. 2007 Oct;189(20):7520-4
references.pmid: 17693489
references.citation: Nat Rev Microbiol. 2010 Aug;8(8):541-51
references.pmid: 20634809
references.citation: Mol Microbiol. 2008 Feb;67(3):493-503
references.pmid: 18086210
references.citation: Mol Microbiol. 1998 Jul;29(2):527-43
references.pmid: 9720870
references.citation: J Bacteriol. 2008 Apr;190(7):2434-40
references.pmid: 18223072
references.citation: Science. 1997 Jun 27;276(5321):2027-30
references.pmid: 9197262
references.citation: Mol Microbiol. 2005 May;56(3):836-44
references.pmid: 15819636
references.citation: Nat Biotechnol. 2004 Feb;22(2):185-91
references.pmid: 14716317
references.citation: J Mol Biol. 2004 Aug 6;341(2):503-17
references.pmid: 15276840
references.citation: Mol Microbiol. 2007 Jul;65(1):41-50
references.pmid: 17581119
references.citation: Science. 2009 Jan 2;323(5910):139-41
references.pmid: 19119236
references.citation: Appl Environ Microbiol. 2004 Nov;70(11):6887-91
references.pmid: 15528558
references.citation: Biochem Biophys Res Commun. 2008 Aug 15;373(1):8-13
references.pmid: 18519027