Mechanism of Agr-dependent regulation of <i>psm-mec</i>.

<p>Expression of <i>psm-mec</i> on the protein (A) and transcript (B) levels was analyzed in the <i>psm-mec</i>-positive, Agr-dysfunctional MRSA strains N315 (SCC<i>mec</i> type II), BK1406<i>agr</i> (SCC<i>mec</i> type III), and BK23684<i>agr</i> (SCC<i>mec</i> type VIII), in which the <i>agrA</i> gene or RNAIII were constitutively over-expressed using plasmid pTXΔ (in strain N315) or expressed using induction with 0.5% xylose in a pKX background (in the other 2 strains). Control, containing the empty plasmid pTXΔ16 or pKX16, respectively. (A) Protein level analysis. (B) Transcript level analysis. Relative expression of the <i>psm-mec</i> transcript is shown, relative to expression of the housekeeping gene <i>gyrB</i>. N.S., not significant; ***, p<0.0001; One-way analysis of variance with Dunnett post tests compared to the control sample.