scholarly journals Mutational Analysis of the Bacillus subtilis RNA Polymerase α C-Terminal Domain Supports the Interference Model of Spx-Dependent Repression

2006 ◽  
Vol 188 (12) ◽  
pp. 4300-4311 ◽  
Author(s):  
Ying Zhang ◽  
Shunji Nakano ◽  
Soon-Yong Choi ◽  
Peter Zuber
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Transcriptional Activation ◽  
Transcriptional Control ◽  
Mutational Analysis ◽  
Solid Phase ◽  
Response Regulator ◽  
Negative Control ◽  
Alanine Scanning Mutagenesis ◽  
Terminal Domain

ABSTRACT The Spx protein of Bacillus subtilis exerts both positive and negative transcriptional control in response to oxidative stress by interacting with the C-terminal domain of the RNA polymerase (RNAP) alpha subunit (αCTD). Thus, transcription of the srf operon at the onset of competence development, which requires the ComA response regulator of the ComPA signal transduction system, is repressed by Spx-αCTD interaction. Previous genetic and structural analyses have determined that an Spx-binding surface resides in and around the α1 region of αCTD. Alanine-scanning mutagenesis of B. subtilis αCTD uncovered residue positions required for Spx function and ComA-dependent srf transcriptional activation. Analysis of srf-lacZ fusion expression, DNase I footprinting, and solid-phase promoter retention experiments indicate that Spx interferes with ComA-αCTD interaction and that residues Y263, C265, and K267 of the α1 region lie within overlapping ComA- and Spx-binding sites for αCTD interaction. Evidence is also presented that oxidized Spx, while enhancing interference of activator-RNAP interaction, is not essential for negative control.

scholarly journals Mutational Analysis of the Signal-Sensing Domain of ResE Histidine Kinase from Bacillus subtilis

2004 ◽  
Vol 186 (6) ◽  
pp. 1694-1704 ◽  
Author(s):  
Avanti Baruah ◽  
Brett Lindsey ◽  
Yi Zhu ◽  
Michiko M. Nakano
Keyword(s):  
Bacillus Subtilis ◽  
Transcriptional Activation ◽  
Catalytic Domain ◽  
Mutational Analysis ◽  
Response Regulator ◽  
Regulatory Region ◽  
Regulatory System ◽  
Oxygen Limitation ◽  
Nitrate Respiration ◽  
Terminal Domain

ABSTRACT The Bacillus subtilis ResD-ResE two-component regulatory system activates genes involved in nitrate respiration in response to oxygen limitation or nitric oxide (NO). The sensor kinase ResE activates the response regulator ResD through phosphorylation, which then binds to the regulatory region of genes involved in anaerobiosis to activate their transcription. ResE is composed of an N-terminal signal input domain and a C-terminal catalytic domain. The N-terminal domain contains two transmembrane subdomains and a large extracytoplasmic loop. It also has a cytoplasmic PAS subdomain between the HAMP linker and C-terminal kinase domain. In an attempt to identify the signal-sensing subdomain of ResE, a series of deletions and amino acid substitutions were generated in the N-terminal domain. The results indicated that cytoplasmic ResE lacking the transmembrane segments and the extracytoplasmic loop retains the ability to sense oxygen limitation and NO, which leads to transcriptional activation of ResDE-dependent genes. This activity was eliminated by the deletion of the PAS subdomain, demonstrating that the PAS subdomain participates in signal reception. The study also raised the possibility that the extracytoplasmic region may serve as a second signal-sensing subdomain. This suggests that the extracytoplasmic region could contribute to amplification of ResE activity leading to the robust activation of genes required for anaerobic metabolism in B. subtilis.

scholarly journals Transcriptional Activation of the Bacillus subtilis spoIIG Promoter by the Response Regulator Spo0A Is Independent of the C-Terminal Domain of the RNA Polymerase Alpha Subunit

1998 ◽  
Vol 180 (17) ◽  
pp. 4760-4763 ◽  
Author(s):  
Dean A. Rowe-Magnus ◽  
Mario Mencía ◽  
Fernando Rojo ◽  
Margarita Salas ◽  
George B. Spiegelman
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Transcriptional Activation ◽  
Response Regulator ◽  
In Vitro Transcription ◽  
Alpha Subunit ◽  
Deletion Mutants ◽  
Wild Type ◽  
Initiation Mechanism

ABSTRACT In vitro transcription from the spoIIG promoter byBacillus subtilis RNA polymerase reconstituted with wild-type alpha subunits and with C-terminal deletion mutants of the alpha subunit was equally stimulated by the response regulator Spo0A. Some differences in the structure of open complexes formed by RNA polymerase containing alpha subunit mutants were noted, although the wild-type and mutant polymerases appeared to use the same initiation mechanism.

scholarly journals Competence Modulation by the NADH Oxidase ofStreptococcus pneumoniae Involves Signal Transduction

2001 ◽  
Vol 183 (2) ◽  
pp. 768-772 ◽  
Author(s):  
José R. Echenique ◽  
Marie C. Trombe
Keyword(s):  
Signal Transduction ◽  
Transcriptional Activation ◽  
Transcriptional Control ◽  
Nadh Oxidase ◽  
Response Regulator ◽  
Transcriptional Analysis ◽  
Genetic Dissection ◽  
Oxygen Signaling ◽  
Two Component Signal Transduction ◽  
Signal Transduction Systems

ABSTRACT Oxygen controls competence development in Streptococcus pneumoniae. Oxygen signaling involves the two-component signal transduction systems CiaRH and ComDE and the competence-stimulating peptide encoded by comC and processed by ComAB. We found that NADH oxidase (Nox) was required for optimal competence. Transcriptional analysis and genetic dissection showed that Nox was involved in post-transcriptional activation of the response regulator ComE and in the transcriptional control of ciaRH andcomCDE. Thus, in S. pneumoniae, Nox, with O2 as its secondary substrate, is part of the O2-signaling pathway.

scholarly journals Mutational Analysis of Conserved Residues in the Putative DNA-Binding Domain of the Response Regulator Spo0A ofBacillus subtilis

2000 ◽  
Vol 182 (24) ◽  
pp. 6975-6982 ◽  
Author(s):  
Janet K. Hatt ◽  
Philip Youngman
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Mutational Analysis ◽  
Response Regulator ◽  
Gene Activation ◽  
Binding Domain ◽  
Site Directed Mutagenesis ◽  
Specific Gene ◽  
Dna Binding Domain ◽  
Conserved Residues

ABSTRACT The Spo0A protein of Bacillus subtilis is a DNA-binding protein that is required for the expression of genes involved in the initiation of sporulation. Spo0A binds directly to and both activates and represses transcription from the promoters of several genes required during the onset of endospore formation. The C-terminal 113 residues are known to contain the DNA-binding activity of Spo0A. Previous studies identified a region of the C-terminal half of Spo0A that is highly conserved among species of endospore-formingBacillus and Clostridium and which encodes a putative helix-turn-helix DNA-binding domain. To test the functional significance of this region and determine if this motif is involved in DNA binding, we changed three conserved residues, S210, E213, and R214, to Gly and/or Ala by site-directed mutagenesis. We then isolated and analyzed the five substitution-containing Spo0A proteins for DNA binding and sporulation-specific gene activation. The S210A Spo0A mutant exhibited no change from wild-type binding, although it was defective in spoIIA and spoIIE promoter activation. In contrast, both the E213G and E213A Spo0A variants showed decreased binding and completely abolished transcriptional activation of spoIIA and spoIIE, while the R214G and R214A variants completely abolished both DNA binding and transcriptional activation. These data suggest that these conserved residues are important for transcriptional activation and that the E213 residue is involved in DNA binding.

scholarly journals Exploring the Amino Acid Residue Requirements of the RNA Polymerase (RNAP) α Subunit C-Terminal Domain for Productive Interaction between Spx and RNAP of Bacillus subtilis

2017 ◽  
Vol 199 (14) ◽  
Author(s):  
Cierra A. Birch ◽  
Madison J. Davis ◽  
Lea Mbengi ◽  
Peter Zuber
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Amino Acid ◽  
Dna Binding ◽  
Rna Polymerase ◽  
Α Subunit ◽  
Stress Induction ◽  
Content Type ◽  
Terminal Domain ◽  
Codon Substitution

ABSTRACT Bacillus subtilis Spx is a global transcriptional regulator that is conserved among Gram-positive bacteria, in which Spx is required for preventing oxidatively induced proteotoxicity. Upon stress induction, Spx engages RNA polymerase (RNAP) through interaction with the C-terminal domain of the rpoA-encoded RNAP α subunit (αCTD). Previous mutational analysis of rpoA revealed that substitutions of Y263 in αCTD severely impaired Spx-activated transcription. Attempts to substitute alanine for αCTD R261, R268, R289, E255, E298, and K294 were unsuccessful, suggesting that these residues are essential. To determine whether these RpoA residues were required for productive Spx-RNAP interaction, we ectopically expressed the putatively lethal rpoA mutant alleles in the rpoAY263C mutant, where “Y263C” indicates the amino acid change that results from mutation of the allele. By complementation analysis, we show that Spx-bound αCTD amino acid residues are not essential for Spx-activated transcription in vivo but that R261A, E298A, and E255A mutants confer a partial defect in NaCl-stress induction of Spx-controlled genes. In addition, strains expressing rpoAE255A are defective in disulfide stress resistance and produce RNAP having a reduced affinity for Spx. The E255 residue corresponds to Escherichia coli αD259, which has been implicated in αCTD-σ70 interaction (σ70 R603, corresponding to R362 of B. subtilis σA). However, the combined rpoAE255A and sigAR362A mutations have an additive negative effect on Spx-dependent expression, suggesting the residues' differing roles in Spx-activated transcription. Our findings suggest that, while αCTD is essential for Spx-activated transcription, Spx is the primary DNA-binding determinant of the Spx-αCTD complex. IMPORTANCE Though extensively studied in Escherichia coli, the role of αCTD in activator-stimulated transcription is largely uncharacterized in Bacillus subtilis. Here, we conduct phenotypic analyses of putatively lethal αCTD alanine codon substitution mutants to determine whether these residues function in specific DNA binding at the Spx-αCTD-DNA interface. Our findings suggest that multisubunit RNAP contact to Spx is optimal for activation while Spx fulfills the most stringent requirement of upstream promoter binding. Furthermore, several αCTD residues targeted for mutagenesis in this study are conserved among many bacterial species and thus insights on their function in other regulatory systems may be suggested herein.

scholarly journals Crystal structure of the in vivo-assembled Bacillus subtilis Spx/RNA polymerase α subunit C-terminal domain complex

2009 ◽  
Vol 168 (2) ◽  
pp. 352-356 ◽  
Author(s):  
Valerie Lamour ◽  
Lars F. Westblade ◽  
Elizabeth A. Campbell ◽  
Seth A. Darst
Keyword(s):  
Crystal Structure ◽  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Α Subunit ◽  
Subunit C ◽  
Terminal Domain

scholarly journals Mechanism of ToxT-Dependent Transcriptional Activation at the Vibrio cholerae tcpA Promoter

2002 ◽  
Vol 184 (20) ◽  
pp. 5533-5544 ◽  
Author(s):  
Robin R. Hulbert ◽  
Ronald K. Taylor
Keyword(s):  
Rna Polymerase ◽  
Vibrio Cholerae ◽  
Transcriptional Activation ◽  
Point Mutations ◽  
Virulence Gene ◽  
Binding Studies ◽  
Virulence Gene Expression ◽  
Terminal Domain ◽  
Truncation Mutation ◽  
Genes Encoding

ABSTRACT The AraC homolog ToxT coordinately regulates virulence gene expression in Vibrio cholerae. ToxT is required for transcriptional activation of the genes encoding cholera toxin and the toxin coregulated pilus, among others. In this work we focused on the interaction of ToxT with the tcpA promoter and investigated the mechanism of ToxT-dependent transcriptional activation at tcpA. Deletion analysis showed that a region from −95 to +2 was sufficient for ToxT binding and activation, both of which were simultaneously lost when the deletion was extended to −63. A collection of point mutations generated by error-prone PCR revealed two small regions required for ToxT-dependent transactivation. Binding studies performed with representative mutations showed that the two regions define sites at which ToxT binds to the tcpA promoter region, most likely as a dimer. Results obtained by using a rpoA truncation mutation showed that ToxT-dependent activation at tcpA involves the C-terminal domain of the RNA polymerase alpha subunit. A model of ToxT-dependent transcriptional activation at tcpA is proposed, in which ToxT interacts with two A-rich regions of tcpA centered at −72 and −51 and requires the alpha C-terminal domain of RNA polymerase.

scholarly journals Uncovering New Metabolic Capabilities of Bacillus subtilis Using Phenotype Profiling of Rifampin-Resistant rpoB Mutants

2007 ◽  
Vol 190 (3) ◽  
pp. 807-814 ◽  
Author(s):  
Amy E. Perkins ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Metabolic Profiling ◽  
Transcriptional Control ◽  
Β Subunit ◽  
Subunit Gene ◽  
Wild Type ◽  
Mutant Strains ◽  
Utilization Patterns ◽  
Flow Of Information

ABSTRACT RNA polymerase is a central macromolecular machine controlling the flow of information from genotype to phenotype, and insights into global transcriptional regulation can be gained by studying mutational perturbations in the enzyme. Mutations in the RNA polymerase β subunit gene rpoB causing resistance to rifampin (Rifr) in Bacillus subtilis were previously shown to lead to alterations in the expression of a number of global phenotypes known to be under transcriptional control, such as growth, competence for transformation, sporulation, and germination (H. Maughan, B. Galeano, and W. L. Nicholson, J. Bacteriol. 186:2481-2486, 2004). To better understand the global effects of rpoB mutations on metabolism, wild-type and 11 distinct congenic Rifr mutant strains of B. subtilis were tested for utilization of 95 substrates by use of Biolog GP2 MicroPlates. A number of alterations of substrate utilization patterns were observed in the Rifr mutants, including the utilization of novel substrates previously unknown in B. subtilis, such as gentiobiose, β-methyl-d-glucoside, and d-psicose. The results indicate that combining global metabolic profiling with mutations in RNA polymerase provides a system-wide approach for uncovering previously unknown metabolic capabilities and further understanding global transcriptional control circuitry in B. subtilis.

scholarly journals Sulfate-Dependent Repression of Genes That Function in Organosulfur Metabolism in Bacillus subtilis Requires Spx

2005 ◽  
Vol 187 (12) ◽  
pp. 4042-4049 ◽  
Author(s):  
Kyle N. Erwin ◽  
Shunji Nakano ◽  
Peter Zuber
Keyword(s):  
Oxidative Stress ◽  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Transcriptional Control ◽  
Sulfur Metabolism ◽  
Growth Conditions ◽  
Sulfur Source ◽  
Dependent Manner ◽  
Α Subunit ◽  
A Genome

ABSTRACT Oxidative stress in Bacillus subtilis results in the accumulation of Spx protein, which exerts both positive and negative transcriptional control over a genome-wide scale through its interaction with the RNA polymerase α subunit. Previous microarray transcriptome studies uncovered a unique class of genes that are controlled by Spx-RNA polymerase interaction under normal growth conditions that do not promote Spx overproduction. These genes were repressed by Spx when sulfate was present as a sole sulfur source. The genes include those of the ytmI, yxeI, and ssu operons, which encode products resembling proteins that function in the uptake and desulfurization of organic sulfur compounds. Primer extension and analysis of operon-lacZ fusion expression revealed that the operons are repressed by sulfate and cysteine; however, Spx functioned only in sulfate-dependent repression. Both the ytmI operon and the divergently transcribed ytlI, encoding a LysR-type regulator that positively controls ytmI operon transcription, are repressed by Spx in sulfate-containing media. The CXXC motif of Spx, which is necessary for redox sensitive control of Spx activity in response to oxidative stress, is not required for sulfate-dependent repression. The yxeL-lacZ and ssu-lacZ fusions were also repressed in an Spx-dependent manner in media containing sulfate as the sole sulfur source. This work uncovers a new role for Spx in the control of sulfur metabolism in a gram-positive bacterium under nonstressful growth conditions.

scholarly journals Mutational Analysis of RsbT, an Activator of the Bacillus subtilis Stress Response Transcription Factor, σB

2004 ◽  
Vol 186 (9) ◽  
pp. 2789-2797 ◽  
Author(s):  
Robyn L. Woodbury ◽  
Tingqiu Luo ◽  
Lindsay Grant ◽  
W. G. Haldenwang
Keyword(s):  
Amino Acids ◽  
Bacillus Subtilis ◽  
Tertiary Structure ◽  
Mutational Analysis ◽  
Physical Stress ◽  
Negative Regulator ◽  
Alanine Scanning Mutagenesis ◽  
Charged Amino Acids ◽  
Carboxy Terminal ◽  
Stress Pathway

ABSTRACT σB, the stress-activated σ factor of Bacillus subtilis, requires the RsbT protein as an essential positive regulator of its physical stress pathway. Stress triggers RsbT to both inactivate the principal negative regulator of the physical stress pathway (RsbS) by phosphorylation and activate a phosphatase (RsbU) required for σB induction. Neither the regions of RsbT that are involved in responding to stress signaling nor those required for downstream events have been established. We used alanine scanning mutagenesis to examine the contributions of RsbT's charged amino acids to the protein's stability and activities. Eleven of eighteen rsbT mutations blocked σB induction by stress. The carboxy terminus of RsbT proved to be particularly important for accumulation in Bacillus subtilis. Four of the five most carboxy-terminal mutations yielded rsbT alleles whose products were undetectable in B. subtilis extracts. Charged amino acids in the central region of RsbT were less critical, with four of the five substitutions in this region having no measurable effect on RsbT accumulation or activity. Only when the substitutions extended into a region of kinase homology was σB induction affected. Six other RsbT variants, although present at levels adequate for activity, failed to activate σB and displayed significant changes in their ability to interact with RsbT's normal binding partners in a yeast dihybrid assay. These changes either dramatically altered the proteins' tertiary structure without affecting their stability or defined regions of RsbT that are involved in multiple interactions.

Sign in / Sign up

Export Citation Format

Share Document