Asymmetric localization of the cell division machinery during Bacillus subtilis sporulation
- University of California, San Diego, United States
Abstract
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.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Additionally, we have deposited representative tomograms for each growth condition in the Electron Microscopy Data Bank (EMDB) accession codes EMD-23963, EMD-23964, EMD-23965, EMD-23966, EMD-23967 and EMD-23968, and tilt series in the Electron Microscopy Public Image Archive (EMPIAR) database accession code EMPIAR-10710.
-
Tomogram of a dividing vegetative cell of Bacillus subtilisElectron Microscopy Data Bank ID EMD-20335.
-
Tomogram of a dividing vegetative cell of Bacillus subtilisElectron Microscopy Data Bank ID EMD-20335.
-
Tomogram of a dividing vegetative cell of Bacillus subtilis FtsZ-linker(Q-rich) strainElectron Microscopy Data Bank ID EMD-20335.
-
Tomogram of a dividing sporulating cell of Bacillus subtilisElectron Microscopy Data Bank ID EMD-20335.
-
Tomogram of a dividing sporulating cell of Bacillus subtilisElectron Microscopy Data Bank ID EMD-20335.
-
Tomogram of a dividing sporulating cell of Bacillus subtilis SpoIIE null mutantElectron Microscopy Data Bank ID EMD-20335.
-
Tilt series of dividing vegetative and sporulating cells of Bacillus subtilisElectron Microscopy Public Image Archive ID EMPIAR-10710.
Article and author information
Author details
Funding
National Institutes of Health (R01-GM057045)
- Kit Pogliano
- Elizabeth Villa
National Science Foundation (DBI 1920374)
- Elizabeth Villa
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. We acknowledge the use of San Diego Nanotechnology Infrastructure (SDNI) of UC San Diego, a member of the National Nanotechnology Coordinated Infrastructure, supported by the NSF grant ECCS-1542148. Please note it was not possible to add this to the above above Funders tab as it was not awarded to an author.
Copyright
© 2021, Khanna et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 3,835
- views
-
- 521
- downloads
-
- 36
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Asymmetric localization of the cell division machinery during Bacillus subtilis sporulation
eLife 10:e62204.
https://doi.org/10.7554/eLife.62204
Further reading
-
- Biochemistry and Chemical Biology
- Microbiology and Infectious Disease
Teichoic acids (TA) are linear phospho-saccharidic polymers and important constituents of the cell envelope of Gram-positive bacteria, either bound to the peptidoglycan as wall teichoic acids (WTA) or to the membrane as lipoteichoic acids (LTA). The composition of TA varies greatly but the presence of both WTA and LTA is highly conserved, hinting at an underlying fundamental function that is distinct from their specific roles in diverse organisms. We report the observation of a periplasmic space in Streptococcus pneumoniae by cryo-electron microscopy of vitreous sections. The thickness and appearance of this region change upon deletion of genes involved in the attachment of TA, supporting their role in the maintenance of a periplasmic space in Gram-positive bacteria as a possible universal function. Consequences of these mutations were further examined by super-resolved microscopy, following metabolic labeling and fluorophore coupling by click chemistry. This novel labeling method also enabled in-gel analysis of cell fractions. With this approach, we were able to titrate the actual amount of TA per cell and to determine the ratio of WTA to LTA. In addition, we followed the change of TA length during growth phases, and discovered that a mutant devoid of LTA accumulates the membrane-bound polymerized TA precursor.
-
- Microbiology and Infectious Disease
The persistence of latent viral reservoirs remains the major obstacle to eradicating human immunodeficiency virus (HIV). We herein found that ICP34.5 can act as an antagonistic factor for the reactivation of HIV latency by herpes simplex virus type I (HSV-1), and thus recombinant HSV-1 with ICP34.5 deletion could more effectively reactivate HIV latency than its wild-type counterpart. Mechanistically, HSV-ΔICP34.5 promoted the phosphorylation of HSF1 by decreasing the recruitment of protein phosphatase 1 (PP1α), thus effectively binding to the HIV LTR to reactivate the latent reservoirs. In addition, HSV-ΔICP34.5 enhanced the phosphorylation of IKKα/β through the degradation of IκBα, leading to p65 accumulation in the nucleus to elicit NF-κB pathway-dependent reactivation of HIV latency. Then, we constructed the recombinant HSV-ΔICP34.5 expressing simian immunodeficiency virus (SIV) env, gag, or the fusion antigen sPD1-SIVgag as a therapeutic vaccine, aiming to achieve a functional cure by simultaneously reactivating viral latency and eliciting antigen-specific immune responses. Results showed that these constructs effectively elicited SIV-specific immune responses, reactivated SIV latency, and delayed viral rebound after the interruption of antiretroviral therapy (ART) in chronically SIV-infected rhesus macaques. Collectively, these findings provide insights into the rational design of HSV-vectored therapeutic strategies for pursuing an HIV functional cure.
