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 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.

Dynamic localization of penicillin-binding proteins during spore development in Bacillus subtilis

Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 999-1012 ◽  
Author(s):  
Dirk-Jan Scheffers
Keyword(s):  
Bacillus Subtilis ◽  
Green Fluorescent Protein ◽  
Binding Proteins ◽  
Cytoplasmic Membrane ◽  
Fluorescent Protein ◽  
Spore Formation ◽  
The Other ◽  
Spore Development ◽  
Penicillin Binding Proteins ◽  
Green Fluorescent

During Bacillus subtilis spore formation, many membrane proteins that function in spore development localize to the prespore septum and, subsequently, to the outer prespore membrane. Recently, it was shown that the cell-division-specific penicillin-binding proteins (PBPs) 1 and 2b localize to the asymmetric prespore septum. Here, the author studied the localization of other PBPs, fused to green fluorescent protein (GFP), during spore formation. Fusions to PBPs 4, 2c, 2d, 2a, 3, H, 4b, 5, 4a, 4* and X were expressed during vegetative growth, and their localization was monitored during sporulation. Of these PBPs, 2c, 2d, 4b and 4* have been implicated as having a function in sporulation. It was found that PBP2c, 2d and X changed their localization, while the other PBPs tested were not affected. The putative endopeptidase PbpX appears to spiral out in a pattern that resembles FtsZ redistribution during sporulation, but a pbpX knockout strain had no distinguishable phenotype. PBP2c and 2d localize to the prespore septum and follow the membrane during engulfment, and so are redistributed to the prespore membrane. A similar pattern was observed when GFP–PBP2c was expressed in the mother cell from a sporulation-specific promoter. This work shows that various PBPs known to function during sporulation are redistributed from the cytoplasmic membrane to the prespore.

scholarly journals Contrasting Effects of σE on Compartmentalization of σF Activity during Sporulation of Bacillus subtilis

2004 ◽  
Vol 186 (7) ◽  
pp. 1983-1990 ◽  
Author(s):  
David W. Hilbert ◽  
Vasant K. Chary ◽  
Patrick J. Piggot
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Mother Cell ◽  
Cell Fates ◽  
Gene Encoding ◽  
Primitive Form ◽  
Small Proteins ◽  
Dna Translocase

ABSTRACT Spore formation by Bacillus subtilis is a primitive form of development. In response to nutrient starvation and high cell density, B. subtilis divides asymmetrically, resulting in two cells with different sizes and cell fates. Immediately after division, the transcription factor σF becomes active in the smaller prespore, which is followed by the activation of σE in the larger mother cell. In this report, we examine the role of the mother cell-specific transcription factor σE in maintaining the compartmentalization of gene expression during development. We have studied a strain with a deletion of the spoIIIE gene, encoding a DNA translocase, that exhibits uncompartmentalized σF activity. We have determined that the deletion of spoIIIE alone does not substantially impact compartmentalization, but in the spoIIIE mutant, the expression of putative peptidoglycan hydrolases under the control of σE in the mother cell destroys the integrity of the septum. As a consequence, small proteins can cross the septum, thereby abolishing compartmentalization. In addition, we have found that in a mutant with partially impaired control of σF, the activation of σE in the mother cell is important to prevent the activation of σF in this compartment. Therefore, the activity of σE can either maintain or abolish the compartmentalization of σF, depending upon the genetic makeup of the strain. We conclude that σE activity must be carefully regulated in order to maintain compartmentalization of gene expression during development.

scholarly journals A ring-shaped conduit connects the mother cell and forespore during sporulation in Bacillus subtilis

2016 ◽  
Vol 113 (41) ◽  
pp. 11585-11590 ◽  
Author(s):  
Christopher D. A. Rodrigues ◽  
Xavier Henry ◽  
Emmanuelle Neumann ◽  
Vilius Kurauskas ◽  
Laure Bellard ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Type Iii Secretion ◽  
Mother Cell ◽  
Strong Support ◽  
Spore Formation ◽  
Intermembrane Space ◽  
Secretion Systems ◽  
Remote Homology ◽  
Type Iii ◽  
Type Iii Secretion Systems

During spore formation in Bacillus subtilis a transenvelope complex is assembled across the double membrane that separates the mother cell and forespore. This complex (called the “A–Q complex”) is required to maintain forespore development and is composed of proteins with remote homology to components of type II, III, and IV secretion systems found in Gram-negative bacteria. Here, we show that one of these proteins, SpoIIIAG, which has remote homology to ring-forming proteins found in type III secretion systems, assembles into an oligomeric ring in the periplasmic-like space between the two membranes. Three-dimensional reconstruction of images generated by cryo-electron microscopy indicates that the SpoIIIAG ring has a cup-and-saucer architecture with a 6-nm central pore. Structural modeling of SpoIIIAG generated a 24-member ring with dimensions similar to those of the EM-derived saucer. Point mutations in the predicted oligomeric interface disrupted ring formation in vitro and impaired forespore gene expression and efficient spore formation in vivo. Taken together, our data provide strong support for the model in which the A–Q transenvelope complex contains a conduit that connects the mother cell and forespore. We propose that a set of stacked rings spans the intermembrane space, as has been found for type III secretion systems.

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 Asymmetric localization of the cell division machinery during Bacillus subtilis sporulation

2020 ◽  
Author(s):  
Kanika Khanna ◽  
Javier López-Garrido ◽  
Joseph Sugie ◽  
Kit Pogliano ◽  
Elizabeth Villa
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Vegetative Growth ◽  
Bacterial Cell ◽  
Mother Cell ◽  
Electron Tomography ◽  
Leading Edge ◽  
Specific Protein ◽  
Bacterial Cell Division ◽  
Division Plane

The mechanistic details of bacterial cell division are poorly understood. The Gram-positive bacterium Bacillus subtilis can divide via two modes. During vegetative growth, the division septum is formed at the mid cell to produce two equal daughter cells. However, during sporulation, the division septum is formed closer to one pole to yield a smaller forespore and a larger mother cell. We use cryo-electron tomography to visualize the architectural differences in the organization of FtsAZ filaments, the major orchestrators of bacterial cell division during these conditions. We demonstrate that during vegetative growth, FtsAZ filaments are present uniformly around the leading edge of the invaginating septum but during sporulation, they are only present on the mother cell side. Our data show that the sporulation septum is thinner than the vegetative septum during constriction, and that this correlates with half as many FtsZ filaments tracking the division plane during sporulation as compared to vegetative growth. We further find that a sporulation-specific protein, SpoIIE, regulates divisome localization and septal thickness during sporulation. Our data provide first evidence of asymmetric localization of the cell division machinery, and not just septum formation, to produce different cell types with diverse fates in bacteria.

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 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 Polar Localization and Compartmentalization of ClpP Proteases during Growth and Sporulation in Bacillus subtilis

2008 ◽  
Vol 190 (20) ◽  
pp. 6749-6757 ◽  
Author(s):  
James Kain ◽  
Gina G. He ◽  
Richard Losick
Keyword(s):  
Bacillus Subtilis ◽  
Mother Cell ◽  
Regulatory Networks ◽  
Fluorescent Protein ◽  
The Other ◽  
Spatial Control ◽  
Polar Localization ◽  
Cell Compartments ◽  
Green Fluorescent ◽  
Necessary And Sufficient

ABSTRACT Spatial control of proteolysis is emerging as a common feature of regulatory networks in bacteria. In the spore-forming bacterium Bacillus subtilis, the peptidase ClpP can associate with any of three ATPases: ClpC, ClpE, and ClpX. Here, we report that ClpCP, ClpEP, and ClpXP localize in foci often near the poles of growing cells and that ClpP and the ATPase are each capable of polar localization independently of the other component. A region of ClpC containing an AAA domain was necessary and sufficient for polar localization. We also report that ClpCP and ClpXP proteases differentially localize to the forespore and mother cell compartments of the sporangium during spore formation. Moreover, model substrates for each protease created by appending recognition sequences for ClpCP or ClpXP to the green fluorescent protein were preferentially eliminated from the forespore or the mother cell, respectively. Biased accumulation of ClpCP in the forespore may contribute to the cell-specific activation of the transcription factor σF by preferential ClpCP-dependent degradation of the anti-σF factor SpoIIAB.

scholarly journals Postdivisional Synthesis of the Sporosarcina ureae DNA Translocase SpoIIIE either in the Mother Cell or in the Prespore Enables Bacillus subtilis To Translocate DNA from the Mother Cell to the Prespore

2003 ◽  
Vol 185 (3) ◽  
pp. 879-886 ◽  
Author(s):  
Vasant K. Chary ◽  
Patrick J. Piggot
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Mother Cell ◽  
Asymmetric Cell Division ◽  
Dna Translocation ◽  
Sporosarcina Ureae ◽  
Correct Orientation ◽  
Chromosome Partitioning ◽  
Specific Synthesis ◽  
Dna Translocase

ABSTRACT The differentiation of vegetative cells of Bacillus subtilis into spores involves asymmetric cell division, which precedes complete chromosome partitioning. The DNA translocase SpoIIIE is required to translocate the origin distal 70% of the chromosome from the larger mother cell into the smaller prespore, the two cells that result from the division. We have tested the effect of altering the time and location of SpoIIIE synthesis on spore formation. We have expressed the spoIIIE homologue from Sporosarcina ureae in B. subtilis under the control of different promoters. Expression from either a weak mother cell-specific (σE) promoter or a weak prespore-specific (σF) promoter partly complemented the sporulation defect of a spoIIIE36 mutant; however, expression from a strong prespore-specific (σF) promoter did not. DNA translocation from the mother cell to the prespore was assayed using spoIIQ-lacZ inserted at thrC; transcription of spoIIQ occurs only in the prespore. Translocation of thrC::spoIIQ-lacZ into the prespore occurred efficiently when spoIIIE Su was expressed from the weak σE- or σF-controlled promoters but not when it was expressed from the strong σF-controlled promoter. It is speculated that the mechanism directing SpoIIIE insertion into the septum in the correct orientation may accommodate slow postseptational, prespore-specific SpoIIIE synthesis but may be swamped by strong prespore-specific synthesis.

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