scholarly journals Control of the Expression and Compartmentalization of σG Activity during Sporulation of Bacillus subtilis by Regulators of σF and σE

2005 ◽  
Vol 187 (19) ◽  
pp. 6832-6840 ◽  
Author(s):  
Vasant K. Chary ◽  
Mauro Meloni ◽  
David W. Hilbert ◽  
Patrick J. Piggot
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Structural Gene ◽  
Sigma Factor ◽  
Mother Cell ◽  
Cell Formation ◽  
Spore Formation ◽  
Deletion Mutants ◽  
Septum Formation

ABSTRACT During formation of spores by Bacillus subtilis the RNA polymerase factor σG ordinarily becomes active during spore formation exclusively in the prespore upon completion of engulfment of the prespore by the mother cell. Formation and activation of σG ordinarily requires prior activity of σF in the prespore and σE in the mother cell. Here we report that in spoIIA mutants lacking both σF and the anti-sigma factor SpoIIAB and in which σE is not active, σG nevertheless becomes active. Further, its activity is largely confined to the mother cell. Thus, there is a switch in the location of σG activity from prespore to mother cell. Factors contributing to the mother cell location are inferred to be read-through of spoIIIG, the structural gene for σG, from the upstream spoIIG locus and the absence of SpoIIAB, which can act in the mother cell as an anti-sigma factor to σG. When the spoIIIG locus was moved away from spoIIG to the distal amyE locus, σG became active earlier in sporulation in spoIIA deletion mutants, and the sporulation septum was not formed, suggesting that premature σG activation can block septum formation. We report a previously unrecognized control in which SpoIIGA can prevent the appearance of σG activity, and pro-σE (but not σE) can counteract this effect of SpoIIGA. We find that in strains lacking σF and SpoIIAB and engineered to produce active σE in the mother cell without the need for SpoIIGA, σG also becomes active in the mother cell.

scholarly journals Expression of spoIIIJ in the Prespore Is Sufficient for Activation of σG and for Sporulation in Bacillus subtilis

2003 ◽  
Vol 185 (13) ◽  
pp. 3905-3917 ◽  
Author(s):  
Mónica Serrano ◽  
Luísa Côrte ◽  
Jason Opdyke ◽  
Charles P. Moran, ◽  
Adriano O. Henriques
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Sigma Factor ◽  
Vegetative Growth ◽  
Mother Cell ◽  
Asymmetric Division ◽  
Developmental Program ◽  
Inactive Form

ABSTRACT During sporulation in Bacillus subtilis, the prespore-specific developmental program is initiated soon after asymmetric division of the sporangium by the compartment-specific activation of RNA polymerase sigma factor σF. σF directs transcription of spoIIIG, encoding the late forespore-specific regulator σG. Following synthesis, σG is initially kept in an inactive form, presumably because it is bound to the SpoIIAB anti-sigma factor. Activation of σG occurs only after the complete engulfment of the prespore by the mother cell. Mutations in spoIIIJ arrest sporulation soon after conclusion of the engulfment process and prevent activation of σG. Here we show that σG accumulates but is mostly inactive in a spoIIIJ mutant. We also show that expression of the spoIIIGE155K allele, encoding a form of σG that is not efficiently bound by SpoIIAB in vitro, restores σG-directed gene expression to a spoIIIJ mutant. Expression of spoIIIJ occurs during vegetative growth. However, we show that expression of spoIIIJ in the prespore is sufficient for σG activation and for sporulation. Mutations in the mother cell-specific spoIIIA locus are known to arrest sporulation just after completion of the engulfment process. Previous work has also shown that σG accumulates in an inactive form in spoIIIA mutants and that the need for spoIIIA expression for σG activation can be circumvented by the spoIIIGE155K allele. However, in contrast to the case for spoIIIJ, we show that expression of spoIIIA in the prespore does not support efficient sporulation. The results suggest that the activation of σG at the end of the engulfment process involves the action of spoIIIA from the mother cell and of spoIIIJ from the prespore.

scholarly journals Separation of Chromosome Termini during Sporulation of Bacillus subtilis Depends on SpoIIIE

2007 ◽  
Vol 189 (9) ◽  
pp. 3564-3572 ◽  
Author(s):  
Marina Bogush ◽  
Panagiotis Xenopoulos ◽  
Patrick J. Piggot
Keyword(s):  
Bacillus Subtilis ◽  
Vegetative Growth ◽  
Mother Cell ◽  
Spore Formation ◽  
The Other ◽  
Septum Formation ◽  
Chromosome Separation ◽  
Dna Translocase

ABSTRACT Bacillus subtilis undergoes a highly distinctive division during spore formation. It yields two unequal cells, the mother cell and the prespore, and septum formation is completed before the origin-distal 70% of the chromosome has entered the smaller prespore. The mother cell subsequently engulfs the prespore. Two different probes were used to study the behavior of the terminus (ter) region of the chromosome during spore formation. Only one ter region was observed at the time of sporulation division. A second ter region, indicative of chromosome separation, was not distinguishable until engulfment was nearing completion, when one was in the mother cell and the other in the prespore. Separation of the two ter regions depended on the DNA translocase SpoIIIE. It is concluded that SpoIIIE is required during spore formation for chromosome separation as well as for translocation; SpoIIIE is not required for separation during vegetative growth.

scholarly journals ςK Can Negatively RegulatesigE Expression by Two Different Mechanisms during Sporulation of Bacillus subtilis

1999 ◽  
Vol 181 (13) ◽  
pp. 4081-4088 ◽  
Author(s):  
Bin Zhang ◽  
Paolo Struffi ◽  
Lee Kroos
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Sigma Factor ◽  
Mother Cell ◽  
Transcriptional Activity ◽  
The Other ◽  
Mutant Form ◽  
Gene Encoding ◽  
Negative Effect ◽  
Cell Gene Expression

ABSTRACT Temporal and spatial gene regulation during Bacillus subtilis sporulation involves the activation and inactivation of multiple sigma subunits of RNA polymerase in a cascade. In the mother cell compartment of sporulating cells, expression of thesigE gene, encoding the earlier-acting sigma factor, ςE, is negatively regulated by the later-acting sigma factor, ςK. Here, it is shown that the negative feedback loop does not require SinR, an inhibitor of sigEtranscription. Production of ςK about 1 h earlier than normal does affect Spo0A, which when phosphorylated is an activator of sigE transcription. A mutation in thespo0A gene, which bypasses the phosphorelay leading to the phosphorylation of Spo0A, diminished the negative effect of early ςK production on sigE expression early in sporulation. Also, early production of ςK reduced expression of other Spo0A-dependent genes but not expression of the Spo0A-independent ald gene. In contrast, bothsigE and ald were overexpressed late in development of cells that fail to make ςK. Theald promoter, like the sigE promoter, is believed to be recognized by ςA RNA polymerase, suggesting that ςK may inhibit ςA activity late in sporulation. To exert this negative effect, ςKmust be transcriptionally active. A mutant form of ςKthat associates with core RNA polymerase, but does not direct transcription of a ςK-dependent gene, failed to negatively regulate expression of sigE or aldlate in development. On the other hand, the negative effect of early ςK production on sigE expression early in sporulation did not require transcriptional activity of ςK RNA polymerase. These results demonstrate that ςK can negatively regulate sigE expression by two different mechanisms, one observed when ςK is produced earlier than normal, which does not require ςKto be transcriptionally active and affects Spo0A, and the other observed when ςK is produced at the normal time, which requires ςK RNA polymerase transcriptional activity. The latter mechanism facilitates the switch from ςE to ςK in the cascade controlling mother cell gene expression.

scholarly journals Sigma Factor Displacement from RNA Polymerase during Bacillus subtilis Sporulation

1999 ◽  
Vol 181 (16) ◽  
pp. 4969-4977 ◽  
Author(s):  
Jingliang Ju ◽  
Theresa Mitchell ◽  
Howard Peters ◽  
W. G. Haldenwang
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Western Blot ◽  
Relative Abundance ◽  
Sigma Factor ◽  
Mother Cell ◽  
Vegetative Cell ◽  
Wild Type

ABSTRACT As Bacillus subtilis proceeds through sporulation, the principal vegetative cell ς subunit (ςA) persists in the cell but is replaced in the extractable RNA polymerase (RNAP) by sporulation-specific ς factors. To explore how this holoenzyme changeover might occur, velocity centrifugation techniques were used in conjunction with Western blot analyses to monitor the associations of RNAP with ςA and two mother cell ς factors, ςE and ςK, which successively replace ςA on RNAP. Although the relative abundance of ςA with respect to RNAP remained virtually unchanged during sporulation, the percentage of the detectable ςAwhich cosedimented with RNAP fell from approximately 50% at the onset of sporulation (T 0) to 2 to 8% by 3 h into the process (T 3). In a strain that failed to synthesize ςE, the first of the mother cell-specific ς factors, approximately 40% of the ςA remained associated with RNAP at T 3. The level of ςA-RNAP cosedimentation dropped to less than 10% in a strain which synthesized a ςE variant (ςECR119) that could bind to RNAP but was unable to direct ςE-dependent transcription. The E-ςE-to-E-ςK changeover was characterized by both the displacement of ςE from RNAP and the disappearance of ςE from the cell. Analyses of extracts from wild-type and mutant B. subtilis showed that the ςK protein is required for the displacement of ςE from RNAP and also confirmed that ςK is needed for the loss of the ςE protein. The results indicate that the successive appearance of mother cell ς factors, but not necessarily their activities, is an important element in the displacement of preexisting ς factors from RNAP. It suggests that competition for RNAP by consecutive sporulation ς factors may be an important feature of the holoenzyme changeovers that occur during sporulation.

scholarly journals Loss of Compartmentalization of σE Activity Need Not Prevent Formation of Spores by Bacillus subtilis

2010 ◽  
Vol 192 (21) ◽  
pp. 5616-5624 ◽  
Author(s):  
Vasant K. Chary ◽  
Panagiotis Xenopoulos ◽  
Avigdor Eldar ◽  
Patrick J. Piggot
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Mother Cell ◽  
Active Form ◽  
Sigma Factors ◽  
Spore Formation ◽  
Signaling Protein ◽  
Sporulation Efficiency ◽  
Activation Signaling ◽  
Constitutively Active

ABSTRACT Compartmentalization of the activities of RNA polymerase sigma factors is a hallmark of formation of spores by Bacillus subtilis. It is initiated soon after the asymmetrically located sporulation division takes place with the activation of σF in the smaller cell, the prespore. σF then directs a signal via the membrane protease SpoIIGA to activate σE in the larger mother cell by processing of pro-σE. Here, we show that σE can be activated in the prespore with little effect on sporulation efficiency, implying that complete compartmentalization of σE activity is not essential for spore formation. σE activity in the prespore can be obtained by inducing transcription in the prespore of spoIIGA or of sigE*, which encodes a constitutively active form of σE, but not of spoIIGB, which encodes pro-σE. We infer that σE compartmentalization is partially attributed to a competition between the compartments for the activation signaling protein SpoIIR. Normally, SpoIIGA is predominantly located in the mother cell and as a consequence confines σE activation to it. In addition, we find that CsfB, previously shown to inhibit σG, is independently inhibiting σE activity in the prespore. CsfB thus appears to serve a gatekeeper function in blocking the action of two sigma factors in the prespore: it prevents σG from becoming active before completion of engulfment and helps prevent σE from becoming active at all.

scholarly journals Genome-Wide Analysis of the Stationary-Phase Sigma Factor (Sigma-H) Regulon of Bacillus subtilis

2002 ◽  
Vol 184 (17) ◽  
pp. 4881-4890 ◽  
Author(s):  
Robert A. Britton ◽  
Patrick Eichenberger ◽  
Jose Eduardo Gonzalez-Pastor ◽  
Paul Fawcett ◽  
Rita Monson ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Rna Polymerase ◽  
Stationary Phase ◽  
Sigma Factor ◽  
Transcriptional Profiling ◽  
Open Reading Frames ◽  
Nutrient Sources ◽  
Genome Wide ◽  
A Genome ◽  
Sigma H

ABSTRACT Sigma-H is an alternative RNA polymerase sigma factor that directs the transcription of many genes that function at the transition from exponential growth to stationary phase in Bacillus subtilis. Twenty-three promoters, which drive transcription of 33 genes, are known to be recognized by sigma-H-containing RNA polymerase. To identify additional genes under the control of sigma-H on a genome-wide basis, we carried out transcriptional profiling experiments using a DNA microarray containing >99% of the annotated B. subtilis open reading frames. In addition, we used a bioinformatics-based approach aimed at the identification of promoters recognized by RNA polymerase containing sigma-H. This combination of approaches was successful in confirming most of the previously described sigma-H-controlled genes. In addition, we identified 26 putative promoters that drive expression of 54 genes not previously known to be under the direct control of sigma-H. Based on the known or inferred function of most of these genes, we conclude that, in addition to its previously known roles in sporulation and competence, sigma-H controls genes involved in many physiological processes associated with the transition to stationary phase, including cytochrome biogenesis, generation of potential nutrient sources, transport, and cell wall metabolism.

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