A Highly Unstable Transcript Makes CwlO D,L-Endopeptidase Expression Responsive to Growth Conditions in Bacillus subtilis

Abstract

bThe Bacillus subtilis cell wall is a dynamic structure, composed of peptidoglycan and teichoic acid, that is continually remodeled during growth. Remodeling is effected by the combined activities of penicillin binding proteins and autolysins that participate in the synthesis and turnover of peptidoglycan, respectively. It has been established that one or the other of the CwlO and LytE D,Lendopeptidase-type autolysins is essential for cell viability, a requirement that is fulfilled by coordinate control of their expression by WalRK and SigI RsgI. Here we report on the regulation of cwlO expression. The cwlO transcript is very unstable, with its degradation initiated by RNase Y cleavage within the 187-nucleotide leader sequence. An antisense cwlO transcript of heterogeneous length is expressed from a SigB promoter that has the potential to control cellular levels of cwlO RNA and protein under stress conditions. We discuss how a multiplicity of regulatory mechanisms makes CwlO expression and activity responsive to the prevailing growth conditions.

Regulatory RNAs in Bacillus subtilis: a Gram-Positive Perspective on Bacterial RNA-Mediated Regulation of Gene Expression

“…The sixth sense-antisense pair, cwlO-S1326 (80), was found to be strongly negatively correlated (Ϫ0.62) (15). CwlO is a D,L-endopeptidasetype autolysin encoded by a transcript that is highly unstable due to RNase Y-dependent cleavage in its S1327 leader region, as mentioned above in the section on 5=UTRs (80). Transcription of the S1326 asRNA was found to depend on the general stress sigma factor SigB, and absence of the respective promoter caused cells to enter exponential growth earlier than the parental strain.…”

“…CwlO is a D,Lendopeptidase-type autolysin involved in the highly regulated process of cell wall turnover. Noone et al reported that the cwlO transcript is highly unstable due to RNase Y-dependent cleavage in this leader region (80). It was proposed that this instability of the cwlO mRNA is of physiological relevance as it would give the transcriptional regulation via the WalRK two-component signal transduction system a more direct impact on the CwlO protein levels (80).…”

“…Transcription of the S1326 asRNA was found to depend on the general stress sigma factor SigB, and absence of the respective promoter caused cells to enter exponential growth earlier than the parental strain. Since this phenotype was rather weak, it was suggested that S1326 might play a more important role under specific environmental conditions (80). The conditions under which S1326 displays its highest expression suggest that this asRNA may be most important under conditions of swarming (Sw), biofilm formation (B60), and the late growth phase on minimal medium (M9-stat) (15).…”

“…The abnA mRNA has a long halflife that is possibly conferred by its UTR (49,79), but the underlying mechanism has not yet been reported. The fourth example concerns the 5= leader region of cwlO, S1327 (80). CwlO is a D,Lendopeptidase-type autolysin involved in the highly regulated process of cell wall turnover.…”

Expressions of alkaline phosphatase genes during phosphate starvation are under positive influences of multiple cell wall hydrolase genes in <i>Bacillus subtilis</i>

“…During phosphate starvation, the two-component system PhoPR of Bacillus subtilis activates transcription of APase genes (phoA, phoB, and phoD) to generate free phosphate groups for uptake and utilization (Allenby et al, 2005;Antelmann et al, 2000). Among the vegetatively expressed cell wall hydrolase genes lytC, lytD, lytE, lytF, cwlO, and cwlS of B. subtilis, only lytE and cwlO are not regulated by SigD (Chen et al, 2009;Huang et al, 2013;Noone et al, 2014;Tseng et al, 2011). It has been reported that LytE and CwlO are required for cell elongation and that cells lacking both enzymes exhibit a synthetic lethal phenotype (Bisicchia et al, 2007;Hashimoto et al, 2012).…”