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. 2019 Feb 27;89(3-4):243–266. doi: 10.3184/003685006783238290

Deciphering a Complex Genetic Regulatory Network: The Bacillus Subtilis σW Protein and Intrinsic Resistance to Antimicrobial Compounds

John D Helmann 1,✉
PMCID: PMC10368348  PMID: 17338440

Abstract

Bacillus subtilis, a spore-forming soil bacterium, is the preeminent model system for the analysis of gene regulation in Gram-positive bacteria. Early genetic analyses established that this organism uses alternative sigma (σ) subunits to reprogram RNA polymerase to activate genes required for growth phase transitions, motility, general stress response, and sporulation. Unexpectedly, the genome sequence predicts the presence of an additional seven a subunits: all members of the extracytoplasmic function (ECF) a subfamily of regulators that typically respond to cell envelope stresses. Here, we review our current understanding of one of these a factors, a with an emphasis on experimental strategies and approaches. Exposure to cell envelope active antibiotics and toxic peptides triggers a signaling cascade that releases σW from its cognate anti-σ thereby allowing transcription of ∼60 σW-dependent genes. These genes encode proteins that inactivate, sequester, or eliminate toxic compounds from the cell.

Keywords: gene regulation, transcription, RNA polymerase, sigma, cell wall, antibiotic, bacteriocin, genomics, microarray

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