Staphylococcus aureus svrA: a gene required for virulence and expression of the agr locus.

A Staphylococcus aureus gene originally identified by signature-tagged mutagenesis as being required for virulence was cloned, sequenced and named svrA. Hydropathy profiles revealed that SvrA is likely to be membrane associated, having two regions with six membrane-spanning domains, the regions separated by an extended hydrophilic loop. When compared with the wild-type strain, an svrA mutant expressed greatly reduced amounts of alpha-, beta- and delta-toxins and an increased amount of protein A.