The Bacillus subtilis σ^M regulon and its contribution to cell envelope stress responses

Abstract

The Bacillus subtilis extracytoplasmic function (ECF) σ M factor is activated by cell envelope stress elicited by antibiotics, and by acid, heat, ethanol, and superoxide stresses. Here, we have used several complementary approaches to identify genes controlled by σ M . In many cases, expression is only partially dependent on σ M due to both overlapping promoter recognition with other ECF σ factors and the presence of additional promoter elements. Genes regulated by σ M have a characteristic pattern of induction in response to cell envelope-acting antibiotics as evidenced by hierarchical clustering analysis. σ M also contributes to the expression of the Spx transcription factor and thereby indirectly regulates genes of the Spx regulon. Cell envelope stress responses also include regulons controlled by σ W , σ B , and several two-component regulatory systems (e.g. LiaRS, YycFG, BceRS). Activation of the σ M regulon increases expression of proteins functioning in transcriptional control, cell wall synthesis and shape determination, cell division, DNA damage monitoring, recombinational repair, and detoxification.

A Comprehensive Proteomics and Transcriptomics Analysis ofBacillus subtilisSalt Stress Adaptation

“…, and X regulons using the DBTBS database (55) and additional data from genome-wide studies (8,12,33,51,52).…”

MurJ and a novel lipid II flippase are required for cell wall biogenesis inBacillus subtilis

“…Thus, both sigM and ydaH appear to be conditionally essential in the absence of the four putative MurJ paralogs. SigM (σ M ) is an extracytoplasmic function sigma factor that activates the expression of many genes involved in cell wall synthesis in response to cell envelope stress (17)(18)(19). Intriguingly, the ydaH gene is among the most strongly induced genes expressed under σ M control (18,19), and it is predicted to encode a polytopic membrane protein with six transmembrane segments.…”

Regulation of bacterial virulence gene expression by cell envelope stress responses

“…They include at least 4 ECF s factors in B. subtilis (s M , s W , s X and s V ) that respond to antibiotics and CAMPs to control numerous target genes. [136][137][138][139][140] However, relatively little is known about ECF s factors in other Gram-positive bacteria. Other members of this category include 2 component regulatory systems.…”