Transcription and translation products of the cytolysin gene psm-mec on the mobile genetic element SCCmec regulate Staphylococcus aureus virulence.

• Main Authors: Chikara Kaito, Yuki Saito, Gentaro Nagano, Mariko Ikuo, Yosuke Omae, Yuichi Hanada, Xiao Han, Kyoko Kuwahara-Arai, Tomomi Hishinuma, Tadashi Baba, Teruyo Ito, Keiichi Hiramatsu, Kazuhisa Sekimizu
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2011-02-01
• Series: PLoS Pathogens
• Online Access: https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21304931/pdf/?tool=EBI
• ISSN: 1553-7366; 1553-7374

The F region downstream of the mecI gene in the SCCmec element in hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) contains two bidirectionally overlapping open reading frames (ORFs), the fudoh ORF and the psm-mec ORF. The psm-mec ORF encodes a cytolysin, phenol-soluble modulin (PSM)-mec. Transformation of the F region into the Newman strain, which is a methicillin-sensitive S. aureus (MSSA) strain, or into the MW2 (USA400) and FRP3757 (USA300) strains, which are community-acquired MRSA (CA-MRSA) strains that lack the F region, attenuated their virulence in a mouse systemic infection model. Introducing the F region to these strains suppressed colony-spreading activity and PSMα production, and promoted biofilm formation. By producing mutations into the psm-mec ORF, we revealed that (i) both the transcription and translation products of the psm-mec ORF suppressed colony-spreading activity and promoted biofilm formation; and (ii) the transcription product of the psm-mec ORF, but not its translation product, decreased PSMα production. These findings suggest that both the psm-mec transcript, acting as a regulatory RNA, and the PSM-mec protein encoded by the gene on the mobile genetic element SCCmec regulate the virulence of Staphylococcus aureus.