Staphylococcal pathogenicity island DNA packaging system involving cos-site packaging and phage-encoded HNH endonucleases

Quiles-Puchalt, N., Carpena, N. , Alonso, J. C., Novick, R. P., Marina, A. and Penades, J. R. (2014) Staphylococcal pathogenicity island DNA packaging system involving cos-site packaging and phage-encoded HNH endonucleases. Proceedings of the National Academy of Sciences of the United States of America, 111(16), pp. 6016-6021. (doi: 10.1073/pnas.1320538111) (PMID:24711396) (PMCID:PMC4000808)

Abstract

Staphylococcal pathogenicity islands (SaPIs) are the prototypical members of a widespread family of chromosomally located mobile genetic elements that contribute substantially to intra- and interspecies gene transfer, host adaptation, and virulence. The key feature of their mobility is the induction of SaPI excision and replication by certain helper phages and their efficient encapsidation into phage-like infectious particles. Most SaPIs use the headful packaging mechanism and encode small terminase subunit (TerS) homologs that recognize the SaPI-specific <i>pac</i> site and determine SaPI packaging specificity. Several of the known SaPIs do not encode a recognizable TerS homolog but are nevertheless packaged efficiently by helper phages and transferred at high frequencies. In this report, we have characterized one of the non–<i>ter</i>S-coding SaPIs, SaPIbov5, and found that it uses two different, undescribed packaging strategies. SaPIbov5 is packaged in full-sized phage-like particles either by typical pac-type helper phages, or by <i>cos</i>-type phages—i.e., it has both <i>pac</i> and <i>cos</i> sites—a configuration that has not hitherto been described for any mobile element, phages included—and uses the two different phage-coded TerSs. To our knowledge, this is the first example of SaPI packaging by a <i>cos</i> phage, and in this, it resembles the P4 plasmid of <i>Escherichia coli.Cos</i>-site packaging in <i>Staphylococcus aureus</i> is additionally unique in that it requires the HNH nuclease, carried only by <i>cos</i> phages, in addition to the large terminase subunit, for <i>cos</i>-site cleavage and melting.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Penades, Prof Jose R and Carpena Garcia, Miss Nuria and Duplicate Quiles, Miss Duplicate Nuria
• Authors: Quiles-Puchalt, N., Carpena, N., Alonso, J. C., Novick, R. P., Marina, A., and Penades, J. R.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Proceedings of the National Academy of Sciences of the United States of America
• Publisher: National Academy of Sciences
• ISSN: 0027-8424
• ISSN (Online): 1091-6490