scholarly journals SOS Induction in a Subpopulation of Structural Maintenance of Chromosome (Smc) Mutant Cells in Bacillus subtilis

2007 ◽  
Vol 189 (12) ◽  
pp. 4359-4366 ◽  
Author(s):  
Robert A. Britton ◽  
Elke Küster-Schöck ◽  
Thomas A. Auchtung ◽  
Alan D. Grossman
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Topoisomerase I ◽  
Dna Microarrays ◽  
Single Cells ◽  
Sos Response ◽  
Dna Supercoiling ◽  
Phage Gene ◽  
Chromosome Partitioning ◽  
Structural Maintenance Of Chromosome

ABSTRACT The structural maintenance of chromosome (Smc) protein is highly conserved and involved in chromosome compaction, cohesion, and other DNA-related processes. In Bacillus subtilis, smc null mutations cause defects in DNA supercoiling, chromosome compaction, and chromosome partitioning. We investigated the effects of smc mutations on global gene expression in B. subtilis using DNA microarrays. We found that an smc null mutation caused partial induction of the SOS response, including induction of the defective prophage PBSX. Analysis of SOS and phage gene expression in single cells indicated that approximately 1% of smc mutants have fully induced SOS and PBSX gene expression while the other 99% of cells appear to have little or no expression. We found that induction of PBSX was not responsible for the chromosome partitioning or compaction defects of smc mutants. Similar inductions of the SOS response and PBSX were observed in cells depleted of topoisomerase I, an enzyme that relaxes negatively supercoiled DNA.

scholarly journals Control of Sporulation Gene Expression in Bacillus subtilis by the Chromosome Partitioning Proteins Soj (ParA) and Spo0J (ParB)

2000 ◽  
Vol 182 (12) ◽  
pp. 3446-3451 ◽  
Author(s):  
John D. Quisel ◽  
Alan D. Grossman
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Promoter Region ◽  
Null Mutant ◽  
Promoter Regions ◽  
Heterologous Promoter ◽  
Phosphorylated Form ◽  
Chromosome Partitioning ◽  
Inhibit Gene Expression

ABSTRACT Two chromosome partitioning proteins, Soj (ParA) and Spo0J (ParB), regulate the initiation of sporulation in Bacillus subtilis. In a spo0J null mutant, sporulation is inhibited by the action of Soj. Soj negatively regulates expression of several sporulation genes by binding to the promoter regions and inhibiting transcription. All of the genes known to be inhibited by Soj are also activated by the phosphorylated form of the transcription factor Spo0A (Spo0A∼P). We found that, in a spo0J null mutant, Soj affected sporulation, in part, by decreasing the level of Spo0A protein. Soj negatively regulated transcription ofspo0A and associated with the spo0A promoter region in vivo. Expression of spo0A from a heterologous promoter in a spo0J null mutant restored Spo0A levels and partly bypassed the sporulation and gene expression defects. Soj did not appear to significantly affect phosphorylation of Spo0A. Thus, in the absence of Spo0J, Soj inhibits sporulation and sporulation gene expression by inhibiting accumulation of the activator protein Spo0A and by acting downstream of Spo0A to inhibit gene expression directly.

scholarly journals Changes in DnaA-Dependent Gene Expression Contribute to the Transcriptional and Developmental Response of Bacillus subtilis to Manganese Limitation in Luria-Bertani Medium

2010 ◽  
Vol 192 (15) ◽  
pp. 3915-3924 ◽  
Author(s):  
Sharon E. Hoover ◽  
Weihong Xu ◽  
Wenzhong Xiao ◽  
William F. Burkholder
Keyword(s):  
Gene Expression ◽  
Dna Damage ◽  
Bacillus Subtilis ◽  
Dna Replication ◽  
Alkylating Agents ◽  
Transcriptional Response ◽  
Sos Response ◽  
Replication Initiation ◽  
Specific Gene ◽  
Transcriptional Responses

ABSTRACT The SOS response to DNA damage in bacteria is a well-known component of the complex transcriptional responses to genotoxic environmental stresses such as exposure to reactive oxygen species, alkylating agents, and many of the antibiotics targeting DNA replication. However, bacteria such as Bacillus subtilis also respond to conditions that perturb DNA replication via a transcriptional response mediated by the replication initiation protein DnaA. In addition to regulating the initiation of DNA replication, DnaA directly regulates the transcription of specific genes. Conditions that perturb DNA replication can trigger the accumulation of active DnaA, activating or repressing the transcription of genes in the DnaA regulon. We report here that simply growing B. subtilis in LB medium altered DnaA-dependent gene expression in a manner consistent with the accumulation of active DnaA and that this was part of a general transcriptional response to manganese limitation. The SOS response to DNA damage was not induced under these conditions. One of the genes positively regulated by DnaA in Bacillus subtilis encodes a protein that inhibits the initiation of sporulation, Sda. Sda expression was induced as cells entered stationary phase in LB medium but not in LB medium supplemented with manganese, and the induction of Sda inhibited sporulation-specific gene expression and the onset of spore morphogenesis. In the absence of Sda, manganese-limited cells initiated spore development but failed to form mature spores. These data highlight that DnaA-dependent gene expression may influence the response of bacteria to a range of environmental conditions, including conditions that are not obviously associated with genotoxic stress.

scholarly journals Identification of Catabolite Repression as a Physiological Regulator of Biofilm Formation by Bacillus subtilis by Use of DNA Microarrays

2003 ◽  
Vol 185 (6) ◽  
pp. 1951-1957 ◽  
Author(s):  
Nicola R. Stanley ◽  
Robert A. Britton ◽  
Alan D. Grossman ◽  
Beth A. Lazazzera
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Transcription Factors ◽  
Biofilm Formation ◽  
Dna Microarrays ◽  
Transcriptional Profiling ◽  
Open Reading Frames ◽  
Differentially Expressed ◽  
Confocal Scanning Laser Microscopy ◽  
Glucose Depletion

ABSTRACT Biofilms are structured communities of cells that are encased in a self-produced polymeric matrix and are adherent to a surface. Many biofilms have a significant impact in medical and industrial settings. The model gram-positive bacterium Bacillus subtilis has recently been shown to form biofilms. To gain insight into the genes involved in biofilm formation by this bacterium, we used DNA microarrays representing >99% of the annotated B. subtilis open reading frames to follow the temporal changes in gene expression that occurred as cells transitioned from a planktonic to a biofilm state. We identified 519 genes that were differentially expressed at one or more time points as cells transitioned to a biofilm. Approximately 6% of the genes of B. subtilis were differentially expressed at a time when 98% of the cells in the population were in a biofilm. These genes were involved in motility, phage-related functions, and metabolism. By comparing the genes differentially expressed during biofilm formation with those identified in other genomewide transcriptional-profiling studies, we were able to identify several transcription factors whose activities appeared to be altered during the transition from a planktonic state to a biofilm. Two of these transcription factors were Spo0A and sigma-H, which had previously been shown to affect biofilm formation by B. subtilis. A third signal that appeared to be affecting gene expression during biofilm formation was glucose depletion. Through quantitative biofilm assays and confocal scanning laser microscopy, we observed that glucose inhibited biofilm formation through the catabolite control protein CcpA.

scholarly journals Modulation of the ComA-Dependent Quorum Response in Bacillus subtilis by Multiple Rap Proteins and Phr Peptides

2006 ◽  
Vol 188 (14) ◽  
pp. 5273-5285 ◽  
Author(s):  
Jennifer M. Auchtung ◽  
Catherine A. Lee ◽  
Alan D. Grossman
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Dna Microarrays ◽  
Response Regulator ◽  
Biological Processes ◽  
Expression Of Genes ◽  
Signaling Peptides ◽  
Number Of Genes ◽  
Signaling Modules ◽  
Different Levels

ABSTRACT In Bacillus subtilis, extracellular peptide signaling regulates several biological processes. Secreted Phr signaling peptides are imported into the cell and act intracellularly to antagonize the activity of regulators known as Rap proteins. B. subtilis encodes several Rap proteins and Phr peptides, and the processes regulated by many of these Rap proteins and Phr peptides are unknown. We used DNA microarrays to characterize the roles that several rap-phr signaling modules play in regulating gene expression. We found that rapK-phrK regulates the expression of a number of genes activated by the response regulator ComA. ComA activates expression of genes involved in competence development and the production of several secreted products. Two Phr peptides, PhrC and PhrF, were previously known to stimulate the activity of ComA. We assayed the roles that PhrC, PhrF, and PhrK play in regulating gene expression and found that these three peptides stimulate ComA-dependent gene expression to different levels and are all required for full expression of genes activated by ComA. The involvement of multiple Rap proteins and Phr peptides allows multiple physiological cues to be integrated into a regulatory network that modulates the timing and magnitude of the ComA response.

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