Role of the hprT–ftsH locus in Staphylococcus aureus

Abstract

The roles of two adjacent genes in theStaphylococcus aureuschromosome with functions in starvation survival and the response to stressful conditions have been characterized. One of these,hprT, encoding a hypoxanthine–guanine phosphoribosyltransferase homologue, was initially identified in a transposon mutagenesis screen. Mutation ofhprTaffects starvation survival in amino-acid-limiting conditions and the ability ofS. aureusto grow in high-salt concentrations. Downstream ofhprTisftsH, which encodes a membrane-bound, ATP- and Zn2+-dependent ‘AAA’-type protease. Mutation offtsHinS. aureusleads to pleiotropic defects including slower growth, sensitivity to salt, acid, methyl viologen and potassium tellurite stresses, and reduced survival in amino-acid- or phosphate-limiting conditions. BothhprT–lacZandftsH–lacZgene fusions are expressed maximally in the post-exponential phase of growth. Although secretion of exoproteins is not affected, anftsHmutant is attenuated in a murine skin lesion model of pathogenicity.