scholarly journals Asymmetric localization of the cell division machinery during Bacillus subtilis sporulation

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Kanika Khanna ◽  
Javier Lopez Garrido ◽  
Joseph Sugie ◽  
Kit Pogliano ◽  
Elizabeth Villa
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Mother Cell ◽  
Electron Tomography ◽  
Leading Edge ◽  
Specific Protein ◽  
Bacterial Cell Division ◽  
Daughter Cells ◽  
Septal Thickness ◽  
Cryo Electron Tomography

The Gram-positive bacterium Bacillus subtilis can divide via two modes. During vegetative growth, the division septum is formed at the midcell 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. Using cryo-electron tomography, genetics and fluorescence microscopy, we found that the organization of the division machinery is different in the two septa. While FtsAZ filaments, the major orchestrators of bacterial cell division, are present uniformly around the leading edge of the invaginating vegetative septa, they are only present on the mother cell side of the invaginating sporulation septa. We provide evidence suggesting that the different distribution and number of FtsAZ filaments impact septal thickness, causing vegetative septa to be thicker than sporulation septa already during constriction. Finally, we show that a sporulation-specific protein, SpoIIE, regulates asymmetric divisome localization and septal thickness during sporulation.

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 The molecular architecture of engulfment during Bacillus subtilis sporulation

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Kanika Khanna ◽  
Javier Lopez-Garrido ◽  
Ziyi Zhao ◽  
Reika Watanabe ◽  
Yuan Yuan ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Mother Cell ◽  
Cell Biology ◽  
Focused Ion Beam ◽  
High Spatial Resolution ◽  
Electron Tomography ◽  
Ion Beam ◽  
Molecular Architecture ◽  
Native State ◽  
Cryo Electron Tomography

The study of bacterial cell biology is limited by difficulties in visualizing cellular structures at high spatial resolution within their native milieu. Here, we visualize Bacillus subtilis sporulation using cryo-electron tomography coupled with cryo-focused ion beam milling, allowing the reconstruction of native-state cellular sections at molecular resolution. During sporulation, an asymmetrically-positioned septum generates a larger mother cell and a smaller forespore. Subsequently, the mother cell engulfs the forespore. We show that the septal peptidoglycan is not completely degraded at the onset of engulfment. Instead, the septum is uniformly and only slightly thinned as it curves towards the mother cell. Then, the mother cell membrane migrates around the forespore in tiny finger-like projections, whose formation requires the mother cell SpoIIDMP protein complex. We propose that a limited number of SpoIIDMP complexes tether to and degrade the peptidoglycan ahead of the engulfing membrane, generating an irregular membrane front.

scholarly journals The molecular architecture of engulfment during Bacillussubtilis sporulation

2018 ◽  
Author(s):  
Kanika Khanna ◽  
Javier Lopez-Garrido ◽  
Ziyi Zhao ◽  
Reika Watanabe ◽  
Yuan Yuan ◽  
...  
Keyword(s):  
Mother Cell ◽  
Cell Biology ◽  
Focused Ion Beam ◽  
Electron Tomography ◽  
Molecular Model ◽  
Ion Beam ◽  
Leading Edge ◽  
Cellular Structures ◽  
Molecular Architecture ◽  
Cryo Electron Tomography

AbstractThe study of cell biology is limited by the difficulty in visualizing cellular structures at high spatial resolution within their native milieu. Here, we have visualized sporulation inBacillus subtilisusing cryo-electron tomography coupled with cryo-focused ion beam milling, a technique that allows the 3D reconstruction of cellular structures in near-native state at molecular resolution. During sporulation, an asymmetrically-positioned septum divides the cell into a larger mother cell and a smaller forespore. Subsequently, the mother cell phagocytoses the forespore in a process called engulfment, which entails a dramatic rearrangement of the peptidoglycan (PG) cell wall around the forespore. By imaging wild-type sporangia, engulfment mutants, and sporangia treated with PG synthesis inhibitors, we show that the initiation of engulfment does not entail the complete dissolution of the septal PG by the mother cell SpoIIDMP complex, as was previously thought. Instead, DMP is required to maintain a flexible septum that is uniformly and only slightly thinned at the onset of engulfment. Then, the mother cell membrane migrates around the forespore by forming tiny finger-like projections, the formation of which requires both SpoIIDMP and new PG synthesized ahead of the leading edge of the engulfing membrane. We propose a molecular model for engulfment membrane migration in which a limited number of SpoIIDMP complexes tether the membrane to and degrade the new PG ahead of the leading edge, thereby generating an irregular engulfing membrane front. Our data also reveal other structures that will provide a valuable resource for future mechanistic studies of endospore formation.

scholarly journals Artificial Septal Targeting of Bacillus subtilis Cell Division Proteins in Escherichia coli: an Interspecies Approach to the Study of Protein-Protein Interactions in Multiprotein Complexes

2008 ◽  
Vol 190 (18) ◽  
pp. 6048-6059 ◽  
Author(s):  
Carine Robichon ◽  
Glenn F. King ◽  
Nathan W. Goehring ◽  
Jon Beckwith
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Protein Interactions ◽  
Fluorescent Protein ◽  
Bacterial Cell Division ◽  
Protein Protein Interactions ◽  
Positive Interaction ◽  
E Coli ◽  
Multiprotein Complexes

ABSTRACT Bacterial cell division is mediated by a set of proteins that assemble to form a large multiprotein complex called the divisome. Recent studies in Bacillus subtilis and Escherichia coli indicate that cell division proteins are involved in multiple cooperative binding interactions, thus presenting a technical challenge to the analysis of these interactions. We report here the use of an E. coli artificial septal targeting system for examining the interactions between the B. subtilis cell division proteins DivIB, FtsL, DivIC, and PBP 2B. This technique involves the fusion of one of the proteins (the “bait”) to ZapA, an E. coli protein targeted to mid-cell, and the fusion of a second potentially interacting partner (the “prey”) to green fluorescent protein (GFP). A positive interaction between two test proteins in E. coli leads to septal localization of the GFP fusion construct, which can be detected by fluorescence microscopy. Using this system, we present evidence for two sets of strong protein-protein interactions between B. subtilis divisomal proteins in E. coli, namely, DivIC with FtsL and DivIB with PBP 2B, that are independent of other B. subtilis cell division proteins and that do not disturb the cytokinesis process in the host cell. Our studies based on the coexpression of three or four of these B. subtilis cell division proteins suggest that interactions among these four proteins are not strong enough to allow the formation of a stable four-protein complex in E. coli in contrast to previous suggestions. Finally, our results demonstrate that E. coli artificial septal targeting is an efficient and alternative approach for detecting and characterizing stable protein-protein interactions within multiprotein complexes from other microorganisms. A salient feature of our approach is that it probably only detects the strongest interactions, thus giving an indication of whether some interactions suggested by other techniques may either be considerably weaker or due to false positives.

scholarly journals Generation of asymmetry during development. Segregation of type-specific proteins in Caulobacter.

1979 ◽  
Vol 81 (1) ◽  
pp. 123-136 ◽  
Author(s):  
N Agabian ◽  
M Evinger ◽  
G Parker
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Messenger Rna ◽  
Cell Types ◽  
Specific Protein ◽  
Soluble Proteins ◽  
Specific Cell ◽  
Daughter Cells ◽  
Specific Proteins ◽  
Entire Cell

An essential event in developmental processes is the introduction of asymmetry into an otherwise undifferentiated cell population. Cell division in Caulobacter is asymmetric; the progeny cells are structurally different and follow different sequences of development, thus providing a useful model system for the study of differentiation. Because the progeny cells are different from one another, there must be a segregation of morphogenetic and informational components at some time in the cell cycle. We have examined the pattern of specific protein segregation between Caulobacter stalked and swarmer daughter cells, with the rationale that such a progeny analysis would identify both structurally and developmentally important proteins. To complement the study, we have also examined the pattern of protein synthesis during synchronous growth and in various cellular fractions. We show here, for the first time, that the association of proteins with a specific cell type may result not only from their periodicity of synthesis, but also from their pattern of distribution at the time of cell division. Several membrane-associated and soluble proteins are segregated asymmetrically between progeny stalked and swarmer cells. The data further show that a subclass of soluble proteins becomes associated with the membrane of the progeny stalked cells. Therefore, although the principal differentiated cell types possess different synthetic capabilities and characteristic proteins, the asymmetry between progeny stalked and swarmer cells is generated primarily by the preferential association of specific soluble proteins with the membrane of only one daughter cell. The majority of the proteins which exhibit this segregation behavior are synthesized during the entire cell cycle and exhibit relatively long, functional messenger RNA half-lives.

scholarly journals Acyldepsipeptide antibiotics – current state of knowledge

2015 ◽  
Vol 64 (2) ◽  
pp. 85-92
Author(s):  
MICHAŁ T. PSTRĄGOWSKI ◽  
MAGDALENA BUJALSKA-ZADROŻNY
Keyword(s):  
Staphylococcus Aureus ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Animal Studies ◽  
Potential Mechanism ◽  
Bacterial Cell Division ◽  
Resistance Development ◽  
Bacillus Subtilis 168 ◽  
Current State

The objective of this paper is to review and summarize the antimicrobial efficacy of the acyldepsipeptides and to indicate the prospects of the therapeutic values of these compounds. This work is enriched by the description of the mutations within the clpP1clpP2 and c1pP3clpP4 operons of Streptomyces lividans, which are considered to be the potential mechanism of the acyldepsipeptide (ADEP)-resistance development. The researchers' conclusions demonstrated a significant impact on microorganisms including the destabilization of bacterial cell division in Bacillus subtilis 168, Staphylococcus aureus HG001 and Streptococcus pneumoniae G9A strains. The results of animal studies show higher bactericidal effectiveness of the acyldepsipeptides ADEP-2 and ADEP-4 compared to linezolid. ADEPs may be considered as a very important mechanism of defense against the increasing resistance of microorganisms . They also might prevent or reduce the risk of many epidemiological events.

Relative daughter cell volume and position of the division furrow in Tetrahymena

1983 ◽  
Vol 61 (1) ◽  
pp. 273-287
Author(s):  
K.K. Hjelm
Keyword(s):  
Cell Division ◽  
Cell Surface ◽  
Cell Volume ◽  
Mother Cell ◽  
Daughter Cell ◽  
Tetrahymena Pyriformis ◽  
Posterior Pole ◽  
Live Cells ◽  
Final Position ◽  
Daughter Cells

The relative daughter cell volume (RDCV) values for Tetrahymena pyriformis were determined at division on live cells. It was found that the anterior cell is generally larger than the posterior cell, and that the RDCV values are distributed in groups 5–6% apart. The RDCV value was found to be independent of predivision cell volume, indicating that the mother cell is divided into proportional volumes. The cells seem, however, not to assess volume directly but rather a parameter related to the cell volume. Furthermore, the RDCV value was found to increase during cell division, so that the final value is not reached until actual separation of daughter cells. It is suggested that the division furrow is positioned so that the area of the cell surface lying between the old oral apparatus and the posterior pole of the cell is divided into equal parts. It is further suggested that several alternative values of the RDCV are possible, only one of which is expressed in each cell. The early division furrow is placed anteriorly to its final position, and its location is adjusted during cytokinesis.

Cell Volume and the Control of the Chlamydomonas Cell Cycle

1982 ◽  
Vol 54 (1) ◽  
pp. 173-191 ◽  
Author(s):  
R. A. CRAIGIE ◽  
T. CAVALIER-SMITH
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Division ◽  
Simple Model ◽  
Cell Volume ◽  
Mother Cell ◽  
Dark Period ◽  
Size Fractions ◽  
Daughter Cells ◽  
Mother Cell Wall

Chlamydomonas reinhardii divides by multiple fission to produce 2n daughter cells per division burst, where n is an integer. By separating predivision cells from synchronous cultures into fractions of differing mean cell volumes, and electronically measuring the numbers and volume distributions of the daughter cells produced by the subsequent division burst, we have shown that n is determined by the volume of the parent cell. Control of n can occur simply, if after every cell division the daughter cells monitor their volume and divide again if, and only if, their volume is greater than a fixed minimum value. In cultures synchronized by 12-h light/12-h dark cycles, the larger parent cells divide earlier in the dark period than do smaller cells. This has been shown by two independent methods: (1) by separating cells into different size fractions by Percoll density-gradient centrifugation and using the light microscope to see when they divide; and (2) by studying changes in the cell volume distribution of unfractioned cultures. Since daughter cells remain within the mother-cell wall for some hours after cell division, and cell division causes an overall swelling of the mother-cell wall, the timing of division can be determined electronically by measuring this increase in cell volume that occurs in the dark period in the absence of growth; we find that cells at the large end of the size distribution range undergo this swelling first, and are then followed by successively smaller size fractions. A simple model embodying a sizer followed by a timer gives a good quantitative fit to these data for 12-h light/12-h dark cycles if cell division occurs 12-h after attaining a critical volume of approximately 140 μm3. However, this simple model is called into question by our finding that alterations in the length of the light period alter the rate of progress towards division even of cells that have attained their critical volume. We discuss the relative roles of light and cell volume in the control of division timing in the Chlamydomonas cell cycle.

scholarly journals FtsA Mutants of Bacillus subtilis Impaired in Sporulation

2002 ◽  
Vol 184 (14) ◽  
pp. 3856-3863 ◽  
Author(s):  
Jennifer T. Kemp ◽  
Adam Driks ◽  
Richard Losick
Keyword(s):  
Electron Microscopy ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Amino Acid ◽  
Fluorescence Microscopy ◽  
Protein Interaction ◽  
Regulatory Protein ◽  
Specific Protein ◽  
Morphological Process ◽  
Polar Division

ABSTRACT Spore formation in Bacillus subtilis involves a switch in the site of cell division from the midcell to a polar position. Both medial division and polar division are mediated in part by the actin-like, cytokinetic protein FtsA. We report the isolation of an FtsA mutant (FtsAD265G) that is defective in sporulation but is apparently unimpaired in vegetative growth. Sporulating cells of the mutant reach the stage of asymmetric division but are partially blocked in the subsequent morphological process of engulfment. As judged by fluorescence microscopy and electron microscopy, the FtsAD265G mutant produces normal-looking medial septa but immature (abnormally thin) polar septa. The mutant was unimpaired in transcription under the control of Spo0A, the master regulator for entry into sporulation, but was defective in transcription under the control of σF, a regulatory protein whose activation is known to depend on polar division. An amino acid substitution at a residue (Y264) adjacent to D265 also caused a defect in sporulation. D265 and Y264 are conserved among endospore-forming bacteria, raising the possibility that these residues are involved in a sporulation-specific protein interaction that facilitates maturation of the sporulation septum and the activation of σF.

scholarly journals LocZ Is a New Cell Division Protein Involved in Proper Septum Placement in Streptococcus pneumoniae

mBio ◽  
2014 ◽  
Vol 6 (1) ◽  
Author(s):  
Nela Holečková ◽  
Linda Doubravová ◽  
Orietta Massidda ◽  
Virginie Molle ◽  
Karolína Buriánková ◽  
...  
Keyword(s):  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Protein Kinase ◽  
Bacterial Cell Division ◽  
Content Type ◽  
Daughter Cells ◽  
Division Site ◽  
Z Ring ◽  
Specific Shape ◽  
Cell Division Protein

ABSTRACTHow bacteria control proper septum placement at midcell, to guarantee the generation of identical daughter cells, is still largely unknown. Although different systems involved in the selection of the division site have been described in selected species, these do not appear to be widely conserved. Here, we report that LocZ (Spr0334), a newly identified cell division protein, is involved in proper septum placement inStreptococcus pneumoniae. We show thatlocZis not essential but that its deletion results in cell division defects and shape deformation, causing cells to divide asymmetrically and generate unequally sized, occasionally anucleated, daughter cells. LocZ has a unique localization profile. It arrives early at midcell, before FtsZ and FtsA, and leaves the septum early, apparently moving along with the equatorial rings that mark the future division sites. Consistently, cells lacking LocZ also show misplacement of the Z-ring, suggesting that it could act as a positive regulator to determine septum placement. LocZ was identified as a substrate of the Ser/Thr protein kinase StkP, which regulates cell division in S. pneumoniae. Interestingly, homologues of LocZ are found only in streptococci, lactococci, and enterococci, indicating that this close phylogenetically related group of bacteria evolved a specific solution to spatially regulate cell division.IMPORTANCEBacterial cell division is a highly ordered process regulated in time and space. Recently, we reported that the Ser/Thr protein kinase StkP regulates cell division in Streptococcus pneumoniae, through phosphorylation of several key proteins. Here, we characterized one of the StkP substrates, Spr0334, which we named LocZ. We show that LocZ is a new cell division protein important for proper septum placement and likely functions as a marker of the cell division site. Consistently, LocZ supports proper Z-ring positioning at midcell. LocZ is conserved only among streptococci, lactococci, and enterococci, which lack homologues of the Min and nucleoid occlusion effectors, indicating that these bacteria adapted a unique mechanism to find their middle, reflecting their specific shape and symmetry.

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