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Yang L, Lawhorn S, Bongrand C, Kosmopoulos JC, Kuwabara J, VanNieuwenhze M, Mandel MJ, McFall-Ngai M, Ruby E. Bacterial growth dynamics in a rhythmic symbiosis. Mol Biol Cell 2024; 35:ar79. [PMID: 38598294 PMCID: PMC11238090 DOI: 10.1091/mbc.e24-01-0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/01/2024] [Accepted: 04/04/2024] [Indexed: 04/12/2024] Open
Abstract
The symbiotic relationship between the bioluminescent bacterium Vibrio fischeri and the bobtail squid Euprymna scolopes serves as a valuable system to investigate bacterial growth and peptidoglycan (PG) synthesis within animal tissues. To better understand the growth dynamics of V. fischeri in the crypts of the light-emitting organ of its juvenile host, we showed that, after the daily dawn-triggered expulsion of most of the population, the remaining symbionts rapidly proliferate for ∼6 h. At that point the population enters a period of extremely slow growth that continues throughout the night until the next dawn. Further, we found that PG synthesis by the symbionts decreases as they enter the slow-growing stage. Surprisingly, in contrast to the most mature crypts (i.e., Crypt 1) of juvenile animals, most of the symbiont cells in the least mature crypts (i.e., Crypt 3) were not expelled and, instead, remained in the slow-growing state throughout the day, with almost no cell division. Consistent with this observation, the expression of the gene encoding the PG-remodeling enzyme, L,D-transpeptidase (LdtA), was greatest during the slowly growing stage of Crypt 1 but, in contrast, remained continuously high in Crypt 3. Finally, deletion of the ldtA gene resulted in a symbiont that grew and survived normally in culture, but was increasingly defective in competing against its parent strain in the crypts. This result suggests that remodeling of the PG to generate additional 3-3 linkages contributes to the bacterium's fitness in the symbiosis, possibly in response to stresses encountered during the very slow-growing stage.
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Affiliation(s)
- Liu Yang
- Carnegie Institution for Science, Pasadena, CA 91101
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI 96848
| | - Susannah Lawhorn
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI 96848
| | - Clotilde Bongrand
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI 96848
| | - James C. Kosmopoulos
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Jill Kuwabara
- Carnegie Institution for Science, Pasadena, CA 91101
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI 96848
| | | | - Mark J. Mandel
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI 53706
| | - Margaret McFall-Ngai
- Carnegie Institution for Science, Pasadena, CA 91101
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI 96848
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Edward Ruby
- Carnegie Institution for Science, Pasadena, CA 91101
- Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI 96848
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125
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2
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Niault T, Czarnecki J, Lambérioux M, Mazel D, Val ME. Cell cycle-coordinated maintenance of the Vibrio bipartite genome. EcoSal Plus 2023; 11:eesp00082022. [PMID: 38277776 PMCID: PMC10729929 DOI: 10.1128/ecosalplus.esp-0008-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
To preserve the integrity of their genome, bacteria rely on several genome maintenance mechanisms that are co-ordinated with the cell cycle. All members of the Vibrio family have a bipartite genome consisting of a primary chromosome (Chr1) homologous to the single chromosome of other bacteria such as Escherichia coli and a secondary chromosome (Chr2) acquired by a common ancestor as a plasmid. In this review, we present our current understanding of genome maintenance in Vibrio cholerae, which is the best-studied model for bacteria with multi-partite genomes. After a brief overview on the diversity of Vibrio genomic architecture, we describe the specific, common, and co-ordinated mechanisms that control the replication and segregation of the two chromosomes of V. cholerae. Particular attention is given to the unique checkpoint mechanism that synchronizes Chr1 and Chr2 replication.
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Affiliation(s)
- Théophile Niault
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
- Collège Doctoral, Sorbonne Université, Paris, France
| | - Jakub Czarnecki
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
| | - Morgan Lambérioux
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
- Collège Doctoral, Sorbonne Université, Paris, France
| | - Didier Mazel
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
| | - Marie-Eve Val
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
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3
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Goudin A, Ferat JL, Possoz C, Barre FX, Galli E. Recovery of Vibrio cholerae polarized cellular organization after exit from a non-proliferating spheroplast state. PLoS One 2023; 18:e0293276. [PMID: 37883451 PMCID: PMC10602287 DOI: 10.1371/journal.pone.0293276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023] Open
Abstract
Vibrio cholerae, the causative agent of cholera epidemics, is a rod-shaped bacterium with a highly polarized cellular organization. It can survive harmful growth conditions by entering a non-proliferating spheroplast state, which involves loss of the cell envelope and polarity. How polarized rod organization cells are formed when the spheroplasts exit the non-proliferating state remains largely uncharacterized. To address this question, we investigated how L-arabinose-induced V. cholerae spheroplasts return to growth. We found that de novo morphogenesis started with the elimination of an excess of periplasm, which was immediately followed by cell elongation and the formation of cell branches with a diameter similar to that of normal V. cholerae cells. Periplasm elimination was driven by bifunctional peptidoglycan synthases involved in cell-wall maintenance, the aPBPs. Elongation and branching relied on the MreB-associated monofunctional peptidoglycan synthase PBP2. The cell division monofunctional peptidoglycan synthase FtsI was not involved in any of these processes. However, the FtsK cell division protein specifically targeted the sites of vesicle extrusion. Genetic material was amplified by synchronous waves of DNA replication as periplasmic elimination began. The HubP polarity factor targeted the tip of the branches as they began to form. However, HubP-mediated polarization was not involved in the efficiency of the recovery process. Finally, our results suggest that the positioning of HubP and the activities of the replication terminus organizer of the two V. cholerae chromosomes, MatP, are independent of cell division. Taken together, these results confirm the interest of L-arabinose-induced V. cholerae spheroplasts to study how cell shape is generated and shed light on the de novo establishment of the intracellular organization and cell polarization in V. cholerae.
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Affiliation(s)
- Anthony Goudin
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Jean-Luc Ferat
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Christophe Possoz
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - François-Xavier Barre
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Elisa Galli
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
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4
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Abstract
Most bacteria are protected from environmental offenses by a cell wall consisting of strong yet elastic peptidoglycan. The cell wall is essential for preserving bacterial morphology and viability, and thus the enzymes involved in the production and turnover of peptidoglycan have become preferred targets for many of our most successful antibiotics. In the past decades, Vibrio cholerae, the gram-negative pathogen causing the diarrheal disease cholera, has become a major model for understanding cell wall genetics, biochemistry, and physiology. More than 100 articles have shed light on novel cell wall genetic determinants, regulatory links, and adaptive mechanisms. Here we provide the first comprehensive review of V. cholerae's cell wall biology and genetics. Special emphasis is placed on the similarities and differences with Escherichia coli, the paradigm for understanding cell wall metabolism and chemical structure in gram-negative bacteria.
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Affiliation(s)
- Laura Alvarez
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå SE-90187, Sweden;
| | - Sara B Hernandez
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå SE-90187, Sweden;
| | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå SE-90187, Sweden;
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5
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Ortega DR, Kjær A, Briegel A. The chemosensory systems of Vibrio cholerae. Mol Microbiol 2020; 114:367-376. [PMID: 32347610 PMCID: PMC7534058 DOI: 10.1111/mmi.14520] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/16/2020] [Accepted: 04/16/2020] [Indexed: 12/11/2022]
Abstract
Vibrio cholerae, the causative agent of the acute diarrheal disease cholera, is able to thrive in diverse habitats such as natural water bodies and inside human hosts. To ensure their survival, these bacteria rely on chemosensory pathways to sense and respond to changing environmental conditions. These pathways constitute a highly sophisticated cellular control system in Bacteria and Archaea. Reflecting the complex life cycle of V. cholerae, this organism has three different chemosensory pathways that together contain over 50 proteins expressed under different environmental conditions. Only one of them is known to control motility, while the function of the other two remains to be discovered. Here, we provide an overview of the chemosensory systems in V. cholerae and the advances toward understanding their structure and function.
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Affiliation(s)
- Davi R. Ortega
- Institute of BiologyLeiden UniversityLeidenThe Netherlands
- Present address:
Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Andreas Kjær
- Department of BiochemistryUniversity of OxfordOxfordUK
| | - Ariane Briegel
- Institute of BiologyLeiden UniversityLeidenThe Netherlands
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6
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Weaver AI, Jiménez-Ruiz V, Tallavajhala SR, Ransegnola BP, Wong KQ, Dörr T. Lytic transglycosylases RlpA and MltC assist in Vibrio cholerae daughter cell separation. Mol Microbiol 2019; 112:1100-1115. [PMID: 31286580 DOI: 10.1111/mmi.14349] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2019] [Indexed: 12/21/2022]
Abstract
The cell wall is a crucial structural feature in the vast majority of bacteria and comprises a covalently closed network of peptidoglycan (PG) strands. While PG synthesis is important for survival under many conditions, the cell wall is also a dynamic structure, undergoing degradation and remodeling by 'autolysins', enzymes that break down PG. Cell division, for example, requires extensive PG remodeling, especially during separation of daughter cells, which depends heavily upon the activity of amidases. However, in Vibrio cholerae, we demonstrate that amidase activity alone is insufficient for daughter cell separation and that lytic transglycosylases RlpA and MltC both contribute to this process. MltC and RlpA both localize to the septum and are functionally redundant under normal laboratory conditions; however, only RlpA can support normal cell separation in low-salt media. The division-specific activity of lytic transglycosylases has implications for the local structure of septal PG, suggesting that there may be glycan bridges between daughter cells that cannot be resolved by amidases. We propose that lytic transglycosylases at the septum cleave PG strands that are crosslinked beyond the reach of the highly regulated activity of the amidase and clear PG debris that may block the completion of outer membrane invagination.
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Affiliation(s)
- Anna I Weaver
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA.,Department of Microbiology, Cornell University, Ithaca, NY, 14853, USA
| | - Valeria Jiménez-Ruiz
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Srikar R Tallavajhala
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Brett P Ransegnola
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Kimberly Q Wong
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, 14853, USA.,Department of Microbiology, Cornell University, Ithaca, NY, 14853, USA.,Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, 14853, USA
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7
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Park S, Yoon J, Lee CR, Lee JY, Kim YR, Jang KS, Lee KH, Seok YJ. Polar landmark protein HubP recruits flagella assembly protein FapA under glucose limitation in Vibrio vulnificus. Mol Microbiol 2019; 112:266-279. [PMID: 31058375 DOI: 10.1111/mmi.14268] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2019] [Indexed: 12/26/2022]
Abstract
How motile bacteria recognize their environment and decide whether to stay or navigate toward more favorable location is a fundamental issue in survival. The flagellum is an elaborate molecular device responsible for bacterial locomotion, and the flagellum-driven motility allows bacteria to move themselves to the appropriate location at the right time. Here, we identify the polar landmark protein HubP as a modulator of polar flagellation that recruits the flagellar assembly protein FapA to the old cell pole, thereby controlling its activity for the early events of flagellar assembly in Vibrio vulnificus. We show that dephosphorylated EIIAGlc of the PEP-dependent sugar transporting phosphotransferase system sequesters FapA from HubP in response to glucose and hence inhibits FapA-mediated flagellation. Thus, flagellar assembly and motility is governed by spatiotemporal control of FapA, which is orchestrated by the competition between dephosphorylated EIIAGlc and HubP, in the human pathogen V. vulnificus.
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Affiliation(s)
- Soyoung Park
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jihee Yoon
- Department of Biophysics and Chemical Biology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Chang-Ro Lee
- Department of Biological Sciences, Myongji University, Yongin, 17058, Republic of Korea
| | - Ju Yeon Lee
- Biomedical Omics Group, Korea Basic Science Institute, Cheongju, 28119, Republic of Korea
| | - Yeon-Ran Kim
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Kyoung-Soon Jang
- Biomedical Omics Group, Korea Basic Science Institute, Cheongju, 28119, Republic of Korea
| | - Kyu-Ho Lee
- Department of Biological Sciences, Sogang University, Seoul, 04107, Republic of Korea
| | - Yeong-Jae Seok
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 08826, Republic of Korea.,Department of Biophysics and Chemical Biology, Seoul National University, Seoul, 08826, Republic of Korea
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8
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Altinoglu I, Merrifield CJ, Yamaichi Y. Single molecule super-resolution imaging of bacterial cell pole proteins with high-throughput quantitative analysis pipeline. Sci Rep 2019; 9:6680. [PMID: 31040310 PMCID: PMC6491441 DOI: 10.1038/s41598-019-43051-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 04/05/2019] [Indexed: 12/17/2022] Open
Abstract
Bacteria show sophisticated control of their cellular organization, and many bacteria deploy different polar landmark proteins to organize the cell pole. Super-resolution microscopy, such as Photo-Activated Localization Microscopy (PALM), provides the nanoscale localization of molecules and is crucial for better understanding of organization and dynamics in single-molecule. However, analytical tools are not fully available yet, in particular for bacterial cell biology. For example, quantitative and statistical analyses of subcellular localization with multiple cells from multiple fields of view are lacking. Furthermore, brightfield images are not sufficient to get accurate contours of small and low contrast bacterial cells, compared to subpixel presentation of target molecules. Here we describe a novel analytic tool for PALM which integrates precisely drawn cell outlines, of either inner membrane or periplasm, labelled by PALM-compatible fluorescent protein fusions, with molecule data for >10,000 molecules from >100 cells by fitting each cell into an oval arc. In the vibrioid bacterium Vibrio cholerae, the polar anchor HubP constitutes a big polar complex which includes multiple proteins involved in chemotaxis and the flagellum. With this pipeline, HubP is shown to be slightly skewed towards the inner curvature side of the cell, while its interaction partners showed rather loose polar localization.
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Affiliation(s)
- Ipek Altinoglu
- Department of Genome Biology, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Univ. Paris Sud, Gif sur Yvette, France.,Graduate School of Structure and Dynamics of Living Systems, Univ. Paris-Sud, Orsay, France
| | - Christien J Merrifield
- Department of Cell Biology, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Univ. Paris Sud, Gif sur Yvette, France
| | - Yoshiharu Yamaichi
- Department of Genome Biology, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Univ. Paris Sud, Gif sur Yvette, France.
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9
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Ringgaard S, Yang W, Alvarado A, Schirner K, Briegel A. Chemotaxis arrays in Vibrio species and their intracellular positioning by the ParC/ParP system. J Bacteriol 2018; 200:e00793-17. [PMID: 29531180 PMCID: PMC6040185 DOI: 10.1128/jb.00793-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Most motile bacteria are able to bias their movement towards more favorable environments or to escape from obnoxious substances by a process called chemotaxis. Chemotaxis depends on a chemosensory system that is able to sense specific environmental signals and generate a behavioral response. Typically, the signal is transmitted to the bacterial flagellum, ultimately regulating the swimming behavior of individual cells. Chemotaxis is mediated by proteins that assemble into large, highly ordered arrays. It is imperative for successful chemotactic behavior and cellular competitiveness that chemosensory arrays form and localize properly within the cell. Here we review how chemotaxis arrays form and localize in Vibrio cholerae and Vibrio parahaemolyticus We focus on how the ParC/ParP-system mediates cell cycle-dependent polar localization of chemotaxis arrays and thus ensures proper cell pole development and array inheritance upon cell division.
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Affiliation(s)
- Simon Ringgaard
- Departmet of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
| | - Wen Yang
- Institute of Biology, Leiden University, Leiden, Netherlands
| | - Alejandra Alvarado
- Departmet of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Ariane Briegel
- Institute of Biology, Leiden University, Leiden, Netherlands
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10
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He Z, Guo K. Exploration of cell division times during bacterial cytokinesis. Phys Chem Chem Phys 2018; 19:32038-32046. [PMID: 29181464 DOI: 10.1039/c7cp05050j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Filamenting temperature-sensitive mutant Z (FtsZ), an essential cell division protein in bacteria, has recently emerged as an important and exploitable antibacterial target. The perturbation of FtsZ assembly is found to have an effect on cell cytokinesis and cell survival. Cell division time is an important physical parameter in cell cytokinesis. Here, the theoretical framework that has been developed by combining a phase field model for rod-shaped cells with a kinetic description for FtsZ ring maintenance is extended to explore cell division times during bacterial cytokinesis. The cell division times of around 72 s in the numerical studies have the same magnitude as the division time of several minutes observed physiologically. The dependence of the cell division time on parameters such as the initial state of rod-shaped cells and various kinetic rates of FtsZ assembly dynamics is thoroughly investigated. The theoretical analysis of the relations between the cell division time and these parameters is found to coincide well with the numerical calculated results.
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Affiliation(s)
- Zi He
- College of Materials Science and Engineering, Hunan University, Changsha, 410082, China.
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11
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Dalia TN, Yoon SH, Galli E, Barre FX, Waters CM, Dalia AB. Enhancing multiplex genome editing by natural transformation (MuGENT) via inactivation of ssDNA exonucleases. Nucleic Acids Res 2017; 45:7527-7537. [PMID: 28575400 PMCID: PMC5499599 DOI: 10.1093/nar/gkx496] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Accepted: 05/24/2017] [Indexed: 01/17/2023] Open
Abstract
Recently, we described a method for multiplex genome editing by natural transformation (MuGENT). Mutant constructs for MuGENT require large arms of homology (>2000 bp) surrounding each genome edit, which necessitates laborious in vitro DNA splicing. In Vibrio cholerae, we uncover that this requirement is due to cytoplasmic ssDNA exonucleases, which inhibit natural transformation. In ssDNA exonuclease mutants, one arm of homology can be reduced to as little as 40 bp while still promoting integration of genome edits at rates of ∼50% without selection in cis. Consequently, editing constructs are generated in a single polymerase chain reaction where one homology arm is oligonucleotide encoded. To further enhance editing efficiencies, we also developed a strain for transient inactivation of the mismatch repair system. As a proof-of-concept, we used these advances to rapidly mutate 10 high-affinity binding sites for the nucleoid occlusion protein SlmA and generated a duodecuple mutant of 12 diguanylate cyclases in V. cholerae. Whole genome sequencing revealed little to no off-target mutations in these strains. Finally, we show that ssDNA exonucleases inhibit natural transformation in Acinetobacter baylyi. Thus, rational removal of ssDNA exonucleases may be broadly applicable for enhancing the efficacy and ease of MuGENT in diverse naturally transformable species.
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Affiliation(s)
- Triana N. Dalia
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
| | - Soo Hun Yoon
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Elisa Galli
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, 91198 Gif sur Yvette, France
| | - Francois-Xavier Barre
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, 91198 Gif sur Yvette, France
| | - Christopher M. Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Ankur B. Dalia
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
- To whom correspondence should be addressed. Tel: +1 812 856 1895; Fax: +1 812 855 6705;
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12
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Galli E, Midonet C, Paly E, Barre FX. Fast growth conditions uncouple the final stages of chromosome segregation and cell division in Escherichia coli. PLoS Genet 2017; 13:e1006702. [PMID: 28358835 PMCID: PMC5391129 DOI: 10.1371/journal.pgen.1006702] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 04/13/2017] [Accepted: 03/16/2017] [Indexed: 11/21/2022] Open
Abstract
Homologous recombination between the circular chromosomes of bacteria can generate chromosome dimers. They are resolved by a recombination event at a specific site in the replication terminus of chromosomes, dif, by dedicated tyrosine recombinases. The reaction is under the control of a cell division protein, FtsK, which assembles into active DNA pumps at mid-cell during septum formation. Previous studies suggested that activation of Xer recombination at dif was restricted to chromosome dimers in Escherichia coli but not in Vibrio cholerae, suggesting that FtsK mainly acted on chromosome dimers in E. coli but frequently processed monomeric chromosomes in V. cholerae. However, recent microscopic studies suggested that E. coli FtsK served to release the MatP-mediated cohesion and/or cell division apparatus-interaction of sister copies of the dif region independently of chromosome dimer formation. Here, we show that these apparently paradoxical observations are not linked to any difference in the dimer resolution machineries of E. coli and V. cholerae but to differences in the timing of segregation of their chromosomes. V. cholerae harbours two circular chromosomes, chr1 and chr2. We found that whatever the growth conditions, sister copies of the V. cholerae chr1 dif region remain together at mid-cell until the onset of constriction, which permits their processing by FtsK and the activation of dif-recombination. Likewise, sister copies of the dif region of the E. coli chromosome only separate after the onset of constriction in slow growth conditions. However, under fast growth conditions the dif sites separate before constriction, which restricts XerCD-dif activity to resolving chromosome dimers.
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Affiliation(s)
- Elisa Galli
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, Gif sur Yvette, France
| | - Caroline Midonet
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, Gif sur Yvette, France
| | - Evelyne Paly
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, Gif sur Yvette, France
| | - François-Xavier Barre
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, Gif sur Yvette, France
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