Antibiotics that inhibit cell wall biosynthesis induce expression of the Bacillus subtilis σW and σM regulons

Abstract

Bacillus subtilis encodes seven extracytoplasmic function (ECF) sigma factors. ThesW regulon includes functions involved in detoxification and protection against antimicrobials, whereas sM is essential for growth at high salt concentrations. We now report that antibiotics that inhibit cell wall biosynthesis induce bothsW andsM regulons as monitored using DNA microarrays. Induction of selectedsW-dependent genes was confirmed usinglacZ reporter fusions and Northern blot analysis. The ability of vancomycin to induce thesW regulon is dependent on bothsW and the cognate anti-s, RsiW, but is independent of the transition state regulator AbrB. These results suggest that the membrane-localized RsiW anti-sW factor mediates the transcriptional response to cell wall stress. Our findings are consistent with the idea that one function of ECF s factors is to coordinate antibiosis stress responses and cell envelope homeostasis.