FlgM is a primary regulator of sigmaD activity, and its absence restores motility to a sinR mutant

Fredrick, Kurt; Helmann, John D.

doi:10.1128/jb.178.23.7010-7013.1996

Cited by 48 publications

(43 citation statements)

References 30 publications

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“…Hpr would appear to be a checkpoint for the commitment to sporulation. If insufficient levels of Spo0AϳP are present, Hpr repression will downregulate sinI transcription, allowing SinR to repress spo0A, spoIIA, spoIIG, and spoIIE expression (18,31,32,33,50) and to upregulate genes involved in motility and competence (15,46). The finding that a sinR deletion can suppress the sporulation phenotypes caused by mutations in spo0K and the cell cycle control gene ftsA (31) is consistent with this interpretation.…”

Section: Discussionmentioning

confidence: 64%

“…The SinR tetramer represses transcription of the spoIIG promoter by inducing DNA conformational changes, preventing activation of transcription by Spo0AϳP (7). SinR is an activator of competence, motility, and autolysin production (15,46). The sin operon is expressed from three differentially regulated promoters (17); promoters P1 and P2 precede sinI and produce RNAs which span the operon and terminate at two rho-independent terminators; the P3 promoter abuts the sinR gene and produces a transcript which starts 15 nucleotides (nt) upstream of the first sinR codon and terminates at the rho-independent termination sites.…”

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confidence: 99%

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Postexponential Regulation of sin Operon Expression in Bacillus subtilis

et al. 2002

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The expression of many gene products required during the early stages of Bacillus subtilis sporulation is regulated by sinIR operon proteins. Transcription of sinIR from the P1 promoter is induced at the end of exponential growth. In vivo transcription studies suggest that P1 induction is repressed by the transition-state regulatory protein Hpr and is induced by the phosphorylated form of Spo0A. In vitro DNase I footprinting studies confirmed that Hpr, AbrB, and Spo0A are trans-acting transcriptional factors that bind to the P1 promoter region of sinIR. We have also determined that the P1 promoter is transcribed in vitro by the major vegetative sigma factor, A , form of RNA polymerase.Natural environments are oligotrophic (35). Organisms such as the common soil bacterium Bacillus subtilis frequently exist in slow-or nongrowing physiological states. The rich diversity of B. subtilis transition-state regulatory systems (50,55,56) confirms the biological importance of managing the transition from rapid-to slow-to nongrowing cell states. Depending on the environmental cues present, B. subtilis transition-state regulation can channel a cell toward motility, nutrient scavenging through the production of extracellular enzymes, competence, or sporulation cell fates (for a review, see references 12 and 53). The best-characterized B. subtilis transition-state regulators are the AbrB, Hpr, Spo0A, and SinR DNA-binding proteins.Recent structural studies have shown that the AbrB protein is a tetramer of 10,500-Da subunits that interacts with a variety of specific nucleotide sequences, presumably by recognizing a particular three-dimensional DNA architecture (54,59,62). AbrB can function as a repressor of genes such as spo0E, spo0H, spoVG, and aprE (14,34,43,64) and as an activator of genes such as hpr and the rbs operon (52, 53). Transcription of abrB is controlled by negative autoregulation and repression by Spo0A (53, 55). The hpr gene product is a 23,718-Da protein, which was originally identified as a locus (hpr, scoC, and catA) for mutations causing protease overproduction and cataboliteresistant sporulation (10,21,39). Hpr binds to a consensus DNA sequence RATAnTATY (25,53). Hpr represses the expression of the protease genes aprE and nprE and oligopeptide permease operons (20,26) and when present on a multicopy plasmid can inhibit sporulation in an as-yet-undetermined manner (39). The Spo0A 29,691-Da protein is the master controller of early developmental events (55, 56). Metabolic and environmental signals cause the autophosphorylation of sensor kinases such as KinA, KinB, and KinC (1, 24, 27, 41), which transfer phosphate groups through a phosphorelay (Spo0F and Spo0B) to generate Spo0AϳP (24, 55, 57). Spo0AϳP recognizes a 0A box DNA sequence, TGNCGAA (51). Spo0AϳP is a repressor of abrB transcription and an activator of spoIIA, spoIIG, and spoIIE operon expression (4,45,51,57,63). spo0A expression is controlled by A and H promoters (9, 44, 49). Vegetative spo0A expression originates from the A promoter, and cataboli...

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Section: Discussionmentioning

confidence: 64%

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confidence: 99%

Postexponential Regulation of sin Operon Expression in Bacillus subtilis

et al. 2002

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“…The sigD gene encodes a flagellum-associated sigma factor, D , which directs transcription of the class three flagellar genes encoding the flagellin, motor, and chemotaxis proteins (1). Although a direct role for SinR in flagellar regulation has not been revealed, sinR mutation does reduce the expression of D -regulated genes (16). Thus, although swarming motility is not strictly required for pellicle formation, flagella appear to play some role in pellicle formation.…”

Section: Resultsmentioning

confidence: 95%

Bacillus subtilisPellicle Formation Proceeds through Genetically Defined Morphological Changes

2007

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Biofilms are structured multicellular communities of bacteria that form through a developmental process. In standing culture, undomesticated strains of Bacillus subtilis produce a floating biofilm, called a pellicle, with a distinct macroscopic architecture. Here we report on a comprehensive analysis of B. subtilis pellicle formation, with a focus on transcriptional regulators and morphological changes. To date, 288 known or putative transcriptional regulators encoded by the B. subtilis genome have been identified or assigned based on similarity to other known proteins. The genes encoding these regulators were systematically disrupted, and the effects of the mutations on pellicle formation were examined, resulting in the identification of 19 regulators involved in pellicle formation. In addition, morphological analysis revealed that pellicle formation begins with the formation of cell chains, which is followed by clustering and degradation of cell chains. Genetic and morphological evidence showed that each stage of morphological change can be defined genetically, based on mutants of transcriptional regulators, each of which blocks pellicle formation at a specific morphological stage.

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“…As this protein is produced at very low levels it has so far proved impracticable to purify enough protein for analysis. T o circumvent this problem we have constructed a strain bearing an inducible sigD gene in a fEgM (anti-sigma factor) (Fredrick & Helmann, 1996) background. Overexpression of the 49 kDa enzyme in this strain will allow further analysis.…”

Section: Discussionmentioning

confidence: 99%

The role of autolysins during vegetative growth of Bacillus subtilis 168

1998

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A set of isogenic mutants of Bacillus subtilis 168, insertionally inactivated in the genes encoding a number of lytic enzymes and a sigma factor (aD, which controls the expression of a number of autolysins) was constructed. Phenotypic analysis of the mutants determined the individual and combined roles of the autolysins in vegetative growth. The major vegetative autolysins of B. subtilis, LytC (50 kDa amidase) and LytD (90 kDa glucosaminidase), were shown to have roles in cell separation, cell wall turnover, antibiotic-induced lysis and motility. LytC was also shown to have a role in general cell lysis induced by sodium aside. Renaturing SDS-PAGE of cell-wall-binding protein extracts of the mutant strains revealed the presence of a novel autolysin that was previously masked by LytC. This 49 kDa enzyme was shown to be aDcontrolled and was identified as a candidate cell separation and cell wall turnover enzyme. A multiple mutant strain, lacking LytC, LytD and the 49 kDa enzyme, retained a t least ten bands of autolytic activity. These may correspond to individual or proteolytically processed novel autolysins, the functions of which are unknown. The multiple mutant strains facilitate the study of these, and other lytic enzymes, to determine their cellular functions. 1

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FlgM is a primary regulator of sigmaD activity, and its absence restores motility to a sinR mutant

Cited by 48 publications

References 30 publications

Postexponential Regulation of sin Operon Expression in Bacillus subtilis

Postexponential Regulation of sin Operon Expression in Bacillus subtilis

Bacillus subtilisPellicle Formation Proceeds through Genetically Defined Morphological Changes

The role of autolysins during vegetative growth of Bacillus subtilis 168

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