scholarly journals Stress Triggers a Process That Limits Activation of the Bacillus subtilis Stress Transcription Factor ςB

2000 ◽  
Vol 182 (5) ◽  
pp. 1452-1456 ◽  
Author(s):  
Janelle M. Scott ◽  
Theresa Mitchell ◽  
W. G. Haldenwang
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Regulatory Protein ◽  
Ethanol Stress ◽  
Gene Products ◽  
Ethanol Treatment ◽  
Induced Expression ◽  
Ethanol Effect ◽  
Stress Pathway ◽  
Stress Activation

ABSTRACT Stress-induced activation of the Bacillus subtilistranscription factor ςB is transitory. To determine whether the process that limits ςB activation is itself triggered by stress, B. subtilis strains in which the stress pathway was artificially activated by the induced expression of a positive regulatory protein (RsbT) were exposed to ethanol stress and were monitored for the persistence of ςB activity. Without ethanol treatment, the induced cultures displayed continuously high ςB activity. Ethanol treatment restricted ongoing ςB activity, but only in strains with intactrsbX and -S genes. The loss of other gene products (RsbR and Obg) known to participate in the stress activation pathway had little influence in blocking the ethanol effect. The data argue that stress upregulates the activity of the RsbX-S regulatory pair to restrict ςB induction following stress.

scholarly journals Stressosomes Formed in Bacillus subtilis from the RsbR Protein of Listeria monocytogenes Allow σB Activation following Exposure to either Physical or Nutritional Stress

2010 ◽  
Vol 192 (23) ◽  
pp. 6279-6286 ◽  
Author(s):  
Luis Martinez ◽  
Adam Reeves ◽  
William Haldenwang
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Listeria Monocytogenes ◽  
Nutritional Stress ◽  
Sole Source ◽  
Stress Signaling ◽  
Homologous Proteins ◽  
Stress Induction ◽  
Phosphorylation Reaction ◽  
Stress Activation

ABSTRACT The general stress regulon of Bacillus subtilis is controlled by σB, a transcription factor that is activated by physical or nutritional stress. In B. subtilis, each of these two stresses is communicated to the primary σB regulators by distinct pathways. Physical stress activation of σB involves a large-molecular-mass (>106-Da) structure (stressosome) formed by one or more homologous proteins (RsbRA, -B, -C, and -D) onto which the pathway's principal regulators are bound. The RsbR proteins are thought to be potential receptors for stress signaling. Listeria monocytogenes encodes orthologs of σB and its principal regulators; however, unlike B. subtilis, L. monocytogenes appears to use the stressosome pathway for both physical and nutritional stress activation of σB. In the current work, a B. subtilis strain that expressed L. monocytogenes rsbR (rsbRLm ) in lieu of B. subtilis rsbR (rsbRBs ) was created and was found to display the Listeria phenotype of σB activation following exposure to either physical or nutritional stress. B. subtilis expressing either the RsbR paralog rsbRC or rsbRD, but not rsbRA or rsbRB, as the sole source of RsbR also allowed σB induction following nutritional stress. It is unclear whether the nutritional stress induction seen in these strains is the result of a direct effect of nutritional stress on stressosome activity or a consequence of the background levels of σB activation in these strains and the effects of diminished ATP on the downstream phosphorylation reaction needed to reinactivate σB.

comK encodes the competence transcription factor, the key regulatory protein for competence development in Bacillus subtilis

1995 ◽  
Vol 15 (3) ◽  
pp. 455-462 ◽  
Author(s):  
Douwe Sinderen ◽  
Amy Luttinger ◽  
Liyun Kong ◽  
David Dubnau ◽  
Gerard Venema ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Regulatory Protein ◽  
Competence Development

scholarly journals RelA Is a Component of the Nutritional Stress Activation Pathway of the Bacillus subtilis Transcription Factor σB

2003 ◽  
Vol 185 (19) ◽  
pp. 5714-5721 ◽  
Author(s):  
Shuyu Zhang ◽  
W. G. Haldenwang
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Stringent Response ◽  
Nutritional Stress ◽  
High Energy ◽  
Culture Conditions ◽  
Insertion Mutation ◽  
Glucose Limitation ◽  
Unique Type ◽  
Stress Activation

ABSTRACT The general stress regulon of Bacillus subtilis is induced by the activation of the σB transcription factor. Activation of σB occurs when one of two phosphatases (RsbU and RsbP), each responding to a unique type of stress, actuates a positive regulator of σB by dephosphorylation. Nutritional stress triggers the RsbP phosphatase. The mechanism by which RsbP becomes active is unknown; however, its activation coincides with culture conditions that are likely to reduce the cell's levels of high-energy nucleotides. We now present evidence that RelA, a (p)ppGpp synthetase and the key enzyme of the stringent response, plays a role in nutritional stress activation of σB. An insertion mutation that disrupts relA blocks the activation of σB in response to PO4 or glucose limitation and inhibits the drop in ATP/GTP levels that normally accompanies σB induction under these conditions. In contrast, the activation of σB by physical stress (e.g., ethanol treatment) is not affected by the loss of RelA. RelA's role in σB activation appears to be distinct from its participation in the stringent response. Amino acid analogs which induce the stringent response and RelA-dependent (p)ppGpp synthesis do not trigger σB activity. In addition, neither a missense mutation in relA (relA240GE) nor a null mutation in rplK (rplK54), either of which is sufficient to inhibit the stringent response and RelA-dependent (p)ppGpp synthesis, fails to block σB activation by PO4 or glucose limitation.

scholarly journals SpoIVB and CtpB Are Both Forespore Signals in the Activation of the Sporulation Transcription Factor σK in Bacillus subtilis

2007 ◽  
Vol 189 (16) ◽  
pp. 6021-6027 ◽  
Author(s):  
Nathalie Campo ◽  
David Z. Rudner
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Mother Cell ◽  
Serine Proteases ◽  
Regulatory Protein ◽  
Signal Transduction Pathway ◽  
Proteolytic Activation ◽  
Proper Timing

ABSTRACT The proteolytic activation of the mother cell transcription factor pro-σK is controlled by a signal transduction pathway during sporulation in the bacterium Bacillus subtilis. The pro-σK processing enzyme SpoIVFB, a membrane-embedded metalloprotease, is held inactive by two other integral membrane proteins, SpoIVFA and BofA, in the mother cell membrane that surrounds the forespore. Two signaling serine proteases, SpoIVB and CtpB, trigger pro-σK processing by cleaving the regulatory protein SpoIVFA. The SpoIVB signal is absolutely required to activate pro-σK processing and is derived from the forespore compartment. CtpB is necessary for the proper timing of σK activation and was thought to be a mother cell signal. Here, we show that the ctpB gene is expressed in both the mother cell and forespore compartments but that synthesis in the forespore under the control of σG is both necessary and sufficient for the proper timing of pro-σK processing. We further show that SpoIVB cleaves CtpB in vitro and in vivo but that this cleavage does not appear to be necessary for CtpB activation. Thus, both signaling proteins are made in the forespore and independently target the same regulatory protein.

scholarly journals Coexpression Patterns of σB Regulators in Bacillus subtilis Affect σB Inducibility

2005 ◽  
Vol 187 (24) ◽  
pp. 8520-8525 ◽  
Author(s):  
Shuyu Zhang ◽  
Adam Reeves ◽  
Robyn L. Woodbury ◽  
W. G. Haldenwang
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Physical Stress ◽  
Negative Regulator ◽  
Current Work ◽  
Wild Type ◽  
Essential Component ◽  
Alternative Site ◽  
A Site ◽  
Stress Pathway

ABSTRACT RsbT is an essential component of the pathway that activates the Bacillus subtilis σB transcription factor in response to physical stress. rsbT is located within an operon that includes the genes for its principal negative regulator (RsbS) and the stress pathway component that it activates (RsbU), as immediate upstream and downstream neighbors. In the current work we demonstrate that RsbT's ability to function is strongly influenced by coexpression with these adjoining genes. When rsbT is expressed at a site displaced from rsbS and rsbU, RsbT accumulates but it is unable to activate σB following stress. RsbT activity is restored if rsbT is cotranscribed at the alternative site with the genes that normally abut it. Additionally, an rsbS allele whose product allows constitutively high RsbT-dependent σB activity displays this activity in rsbS merodiploid strains only when cotranscribed with rsbT and is recessive to a wild-type rsbS allele only if the wild-type rsbS gene is not cotranscribed with an rsbT gene of its own. The data suggest that RsbS and RsbT are synthesized in equivalent amounts and interact coincidently with their synthesis to form stable regulatory complexes that maintain RsbT in a state from which it can be stress activated.

scholarly journals The Bacillus subtilis GTP Binding Protein Obg and Regulators of the ςB Stress Response Transcription Factor Cofractionate with Ribosomes

2000 ◽  
Vol 182 (10) ◽  
pp. 2771-2777 ◽  
Author(s):  
Janelle M. Scott ◽  
Jingliang Ju ◽  
Theresa Mitchell ◽  
W. G. Haldenwang
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Fluorescent Protein ◽  
Binding Protein ◽  
Fluorescent Microscopy ◽  
Gel Filtration ◽  
Gtp Binding Protein ◽  
Ribosomal Subunits ◽  
Gtp Binding ◽  
Stress Activation

ABSTRACT Obg, an essential GTP binding protein of Bacillus subtilis, is necessary for stress activation of the ςB transcription factor. We investigated Obg's cellular associations by differential centrifugation of crude B. subtilis extracts, using an anti-Obg antibody as a probe to monitor Obg during the fractionation, and by fluorescent microscopy of a B. subtilis strain in which Obg was fused to green fluorescent protein. The results indicated that Obg is part of a large cytoplasmic complex. In subsequent analyses, Obg coeluted with ribosomal subunits during gel filtration of B. subtilislysates on Sephacryl S-400 and specifically bound to ribosomal protein L13 in an affinity blot assay. Probing the gel filtration fractions with antibodies specific for ςB and its coexpressed regulators (Rsb proteins) revealed coincident elution of the upstream components of the ςB stress activation pathway (RsbR, -S, and -T) with Obg and the ribosomal subunits. The data implicate ribosome function as a possible mediator of the activity of Obg and the stress induction of ςB.

scholarly journals Postexponential Regulation of sin Operon Expression in Bacillus subtilis

2002 ◽  
Vol 184 (2) ◽  
pp. 564-571 ◽  
Author(s):  
Sasha H. Shafikhani ◽  
Ines Mandic-Mulec ◽  
Mark A. Strauch ◽  
Issar Smith ◽  
Terrance Leighton
Keyword(s):  
Bacillus Subtilis ◽  
Sigma Factor ◽  
Promoter Region ◽  
Regulatory Protein ◽  
Gene Products ◽  
Phosphorylated Form ◽  
Dnase I Footprinting ◽  
Operon Expression

ABSTRACT 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, ςA, form of RNA polymerase.

scholarly journals The REG1 Gene Product Is Required for Repression of INO1 and Other Inositol-Sensitive Upstream Activating Sequence-Containing Genes of Yeast

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Qian Ouyang ◽  
Monica Ruiz-Noriega ◽  
Susan A Henry
Keyword(s):  
Regulatory Protein ◽  
Deletion Mutation ◽  
Negative Regulator ◽  
Regulatory Subunit ◽  
Bhlh Protein ◽  
Gene Products ◽  
Glucose Response ◽  
Upstream Activating Sequence ◽  
Missense Mutant ◽  
Single Base Pair

Abstract A search was conducted for suppressors of the inositol auxotrophic phenotype of the ino4-8 mutant of yeast. The ino4-8 mutation is a single base pair change that results in substitution of lysine for glutamic acid at position 79 in the bHLH domain of the yeast regulatory protein, Ino4p. Ino4p dimerizes with a second bHLH protein, Ino2p, to form a complex that binds to the promoter of the INO1 gene, activating transcription. Of 31 recessive suppressors of ino4-8 isolated, 29 proved to be alleles of a single locus, identified as REG1, which encodes a regulatory subunit of a protein phosphatase involved in the glucose response pathway. The suppressor mutation, sia1-1, identified as an allele of REG1, caused constitutive INO1 expression and was capable of suppressing the inositol auxotrophy of a second ino4 missense mutant, ino4-26, as well as ino2-419, a missense mutation of INO2. The suppressors analyzed were unable to suppress ino2 and ino4 null mutations, but the reg1 deletion mutation could suppress ino4-8. A deletion mutation in the OPI1 negative regulator was incapable of suppressing ino4-8. The relative roles of the OPI1 and REG1 gene products in control of INO1 expression are discussed.

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