scholarly journals The Stress-Responsive Alternative Sigma Factor SigB of Bacillus subtilis and Its Relatives: An Old Friend With New Functions

2020 ◽  
Vol 11 ◽  
Author(s):  
Facundo Rodriguez Ayala ◽  
Marco Bartolini ◽  
Roberto Grau
Keyword(s):  
Bacillus Subtilis ◽  
Sigma Factor ◽  
Alternative Sigma Factor

scholarly journals Role of autoregulation and relative synthesis of operon partners in alternative sigma factor networks

2015 ◽  
Author(s):  
Jatin Narula ◽  
Abhinav Tiwari ◽  
Oleg A. Igoshin
Keyword(s):  
Bacillus Subtilis ◽  
Stress Response ◽  
Negative Feedback ◽  
Sigma Factor ◽  
Critical Role ◽  
Sigma Factors ◽  
Alternative Sigma Factor ◽  
Negative Feedback Regulation ◽  
Alternative Sigma Factors

SummaryDespite the central role of alternative sigma factors in bacterial stress response and virulence their regulation remains incompletely understood. Here we investigate one of the best-studied examples of alternative sigma factors: the σBnetwork that controls the general stress response ofBacillus subtilisto uncover widely relevant general design principles that describe the structure-function relationship of alternative sigma factor regulatory networks. We show that the relative stoichiometry of the synthesis rates of σB, its anti-sigma factor RsbW and the anti-anti-sigma factor RsbV plays a critical role in shaping the network behavior by forcing the σBnetwork to function as an ultrasensitive negative feedback loop. We further demonstrate how this negative feedback regulation insulates alternative sigma factor activity from competition with the housekeeping sigma factor for RNA polymerase and allows multiple stress sigma factors to function simultaneously with little competitive interference.Major Subject Areas:Computational and systems biology, Microbiology & Infectious diseaseResearch Organism:Bacillus subtilis

scholarly journals Genetic Evidence for the Actin Homolog Gene mreBH and the Bacitracin Resistance Gene bcrC as Targets of the Alternative Sigma Factor SigI of Bacillus subtilis

2007 ◽  
Vol 190 (5) ◽  
pp. 1561-1567 ◽  
Author(s):  
Chi-Ling Tseng ◽  
Gwo-Chyuan Shaw
Keyword(s):  
Bacillus Subtilis ◽  
Heat Shock ◽  
Resistance Gene ◽  
Sigma Factor ◽  
Promoter Region ◽  
Consensus Sequence ◽  
Regulatory Region ◽  
Primer Extension ◽  
Vector System ◽  
Alternative Sigma Factor

ABSTRACT The Bacillus subtilis sigI gene, which is a member of the class VI heat shock genes of the B. subtilis heat shock stimulon, encodes an alternative sigma factor whose regulon is poorly defined. In this study, by using a binary vector system, we showed that B. subtilis SigI could drive expression of a transcriptional fusion between the sigI regulatory region from Bacillus licheniformis, Bacillus sp. strain NRRL B-14911, B. subtilis, or Bacillus thuringiensis and the xylE reporter gene in B. subtilis. The transcriptional initiation sites of these fusions in B. subtilis were mapped by primer extension analyses. A putative consensus promoter sequence probably recognized by the B. subtilis SigI was thus deduced. Using a consensus sequence-based search procedure, we found putative σI promoters preceding the actin homolog gene mreBH and the bacitracin resistance gene bcrC of B. subtilis. Overexpression of the B. subtilis sigI gene could specifically stimulate expression of both an mreBH promoter region-bgaB fusion and a bcrC promoter region-bgaB fusion. Expression of these two fusions at the amyE locus of the B. subtilis chromosome was heat inducible and SigI dependent as revealed by sigI gene disruption experiments. Primer extension analysis showed that the identified mreBH and bcrC transcriptional start sites were at appropriate distances from their σI promoter elements. This further supports the notion that SigI can directly regulate mreBH and bcrC expression. Taken together, these results strongly suggest that mreBH and bcrC are new members of the SigI regulon.

scholarly journals One of Two OsmC Homologs in Bacillus subtilis Is Part of the ςB-Dependent General Stress Regulon

1998 ◽  
Vol 180 (16) ◽  
pp. 4212-4218 ◽  
Author(s):  
Uwe Völker ◽  
Kasper Krogh Andersen ◽  
Haike Antelmann ◽  
Kevin M. Devine ◽  
Michael Hecker
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Expression Pattern ◽  
Sigma Factor ◽  
Minimal Medium ◽  
Alternative Sigma Factor ◽  
Rich Medium ◽  
E Coli ◽  
Complex Expression

ABSTRACT In this report we present the identification and analysis of twoBacillus subtilis genes, yklA andykzA, which are homologous to the partially RpoS-controlledosmC gene from Escherichia coli. TheyklA gene is expressed at higher levels in minimal medium than in rich medium and is driven by a putative vegetative promoter. Expression of ykzA is not medium dependent but increases dramatically when cells are exposed to stress and starvation. This stress-induced increase in ykzA expression is absolutely dependent on the alternative sigma factor ςB, which controls a large stationary-phase and stress regulon. ykzAis therefore another example of a gene common to the RpoS and ςB stress regulons of E. coli andB. subtilis, respectively. The composite complex expression pattern of the two B. subtilis genes is very similar to the expression profile of osmC in E. coli.

scholarly journals The Listeria monocytogenes σB Regulon and Its Virulence-Associated Functions Are Inhibited by a Small Molecule

mBio ◽  
2011 ◽  
Vol 2 (6) ◽  
Author(s):  
M. Elizabeth Palmer ◽  
Soraya Chaturongakul ◽  
Martin Wiedmann ◽  
Kathryn J. Boor
Keyword(s):  
Bacillus Subtilis ◽  
Listeria Monocytogenes ◽  
Small Molecule ◽  
Sigma Factor ◽  
Pathogen Transmission ◽  
Bile Salt Hydrolase ◽  
Alternative Sigma Factor ◽  
Bacterial Survival ◽  
Gram Positive ◽  
Content Type

ABSTRACTThe stress-responsive alternative sigma factor σBis conserved across diverse Gram-positive bacterial genera. InListeria monocytogenes, σBregulates transcription of >150 genes, including genes contributing to virulence and to bacterial survival under host-associated stress conditions, such as those encountered in the human gastrointestinal lumen. An inhibitor ofL. monocytogenesσBactivity was identified by screening ~57,000 natural and synthesized small molecules using a high-throughput cell-based assay. The compound fluoro-phenyl-styrene-sulfonamide (FPSS) (IC50= 3.5 µM) downregulated the majority of genes previously identified as members of the σBregulon inL. monocytogenes10403S, thus generating a transcriptional profile comparable to that of a 10403S ΔsigBstrain. Specifically, of the 208 genes downregulated by FPSS, 75% had been identified previously as positively regulated by σB. Downregulated genes included key virulence and stress response genes, such asinlA,inlB,bsh,hfq,opuC, andbilE. From a functional perspective, FPSS also inhibitedL. monocytogenesinvasion of human intestinal epithelial cells and bile salt hydrolase activity. The ability of FPSS to inhibit σBactivity in bothL. monocytogenesandBacillus subtilisindicates its utility as a specific inhibitor of σBacross multiple Gram-positive genera.IMPORTANCEThe σBtranscription factor regulates expression of genes responsible for bacterial survival under changing environmental conditions and for virulence; therefore, this alternative sigma factor is important for transmission ofL. monocytogenesand other Gram-positive bacteria. Regulation of σBactivity is complex and tightly controlled, reflecting the key role of this factor in bacterial metabolism. We present multiple lines of evidence indicating that fluoro-phenyl-styrene-sulfonamide (FPSS) specifically inhibits activity of σBacross Gram-positive bacterial genera, i.e., in bothListeria monocytogenesandBacillus subtilis. Therefore, FPSS is an important new tool that will enable novel approaches for exploring complex regulatory networks inL. monocytogenesand other Gram-positive pathogens and for investigating small-molecule applications for controlling pathogen transmission.

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