Interaction of Bacillus subtilis extracytoplasmic function (ECF) sigma factors with the N-terminal regions of their potential anti-sigma factors

Abstract

Extracytoplasmic function (ECF) sigma factors constitute a diverse family of proteins, within the class of the sigma 70 subunit of RNA polymerase. Most members of the family studied to date are known to regulate gene expression in response to stress conditions. The Bacillus subtilis genome encodes at least 17 distinct sigma factors, seven of which are members of the ECF subfamily. Among these, five sigma factors, namely SigV, SigW, SigX, SigY and SigM, are encoded by the first genes of the cognate sigma operons. Disruption or repressed expression of the downstream gene(s) resulted in transcriptional activation of the cognate sigma operon. Moreover, in vivo protein-protein interaction analyses by yeast two-hybrid experiments indicated that these immediate downstream gene products bind the cognate ECF sigma factor, suggesting that they function as anti-sigma factors by capturing sigma factor on the inner surface of the cytoplasmic membrane. Interaction with other sigma factors was not observed. The results presented here also show that these anti-sigma factors interact with ECF sigma factors through their N-terminal region, implying that the N-terminal domain resides inside the cytoplasmic membrane.

Group 3 sigma factors in the marine cyanobacterium Synechococcus sp. strain PCC 7002 are required for growth at low temperature

“…strain PCC 7002. This result is apparently similar to previous reports that the mutation of the yhdL gene encoding anti-sigma factor against SigM or the mutation of the yxlC gene encoding anti-sigma factor against SigY are lethal in B. subtilis (Horsburgh and Moir, 1999;Yoshimura et al, 2004).…”

NblR Is a Novel One-Component Response Regulator in the CyanobacteriumSynechococcus elongatusPCC 7942

“…18,19) Full-length (primers, nblR-Eco-F and nblR-Sal-R) and the REC domain (primers, nblR-Eco-F and nblR-REC-Sal-R) were PCR-amplified and cloned into pGBTK, a GAL4 DNA-binding domain fusion vector. 20) Similarly, the other fragments used in this analysis were amplified using the primers listed in Table 1.…”

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

“…amj is regulated by the stress-response sigma factor σ M . σ M is held inactive by the two integral membrane proteins YhdL and YhdK, and inhibition is relieved in response to an unknown signal that is thought to be generated by cell wall stress (21)(22)(23). Expression profiling experiments indicate that σ M -controlled genes are transcribed at low levels under normal growth conditions and are induced twoto fivefold in response to acute exposure to cell wall synthesis inhibitors (19,24).…”