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Douillard FP, Portinha IM, Derman Y, Woudstra C, Mäklin T, Dorner MB, Korkeala H, Henriques AO, Lindström M. A Novel Prophage-like Insertion Element within yabG Triggers Early Entry into Sporulation in Clostridium botulinum. Viruses 2023; 15:2431. [PMID: 38140671 PMCID: PMC10747680 DOI: 10.3390/v15122431] [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] [Received: 05/25/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Sporulation is a finely regulated morphogenetic program important in the ecology and epidemiology of Clostridium botulinum. Exogenous elements disrupting sporulation-associated genes contribute to sporulation regulation and introduce diversity in the generally conserved sporulation programs of endospore formers. We identified a novel prophage-like DNA segment, termed the yin element, inserted within yabG, encoding a sporulation-specific cysteine protease, in an environmental isolate of C. botulinum. Bioinformatic analysis revealed that the genetic structure of the yin element resembles previously reported mobile intervening elements associated with sporulation genes. Within a pure C. botulinum culture, we observed two subpopulations of cells with the yin element either integrated into the yabG locus or excised as a circular DNA molecule. The dynamics between the two observed conformations of the yin element was growth-phase dependent and likely mediated by recombination events. The yin element was not required for sporulation by C. botulinum but triggered an earlier entry into sporulation than in a related isolate lacking this element. So far, the yin element has not been found in any other C. botulinum strains or other endospore-forming species. It remains to be demonstrated what kind of competitive edge it provides for C. botulinum survival and persistence.
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Affiliation(s)
- François P. Douillard
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Inês Martins Portinha
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Yağmur Derman
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Cédric Woudstra
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Tommi Mäklin
- Department of Mathematics and Statistics, Faculty of Science, University of Helsinki, 00560 Helsinki, Finland;
| | - Martin B. Dorner
- Centre for Biological Threats and Special Pathogens, ZBS3—Biological Toxins, Robert Koch Institute, 13353 Berlin, Germany;
| | - Hannu Korkeala
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Adriano O. Henriques
- Institute of Chemical and Biological Technology, NOVA University Lisbon, 2780-157 Oeiras, Portugal;
| | - Miia Lindström
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
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2
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Abe K, Kato H, Hasegawa Y, Yamamoto T, Nomura N, Obana N. Visualization and characterization of spore morphogenesis in Paenibacillus polymyxa ATCC39564. J GEN APPL MICROBIOL 2022; 68:79-86. [PMID: 35418538 DOI: 10.2323/jgam.2021.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Paenibacillus polymyxa is a spore-forming Gram-positive bacterial species. Both its sporulation process and the spore properties are poorly understood. Here, we investigated sporulation in P. polymyxa ATCC39564. When cultured at 37℃ for 24 h in sporulation medium, more than 80% of the total cells in the culture were spores. Time-lapse imaging revealed that cellular morphological changes during sporulation of P. polymyxa were highly similar to those of B. subtilis. We demonstrated that genetic deletion of spo0A, sigE, sigF, sigG, or sigK, which are highly conserved transcriptional regulators in spore forming bacteria, abolished spore formation. In P. polymyxa, spo0A was required for cell growth in sporulation medium, as well as for the initiation of sporulation. The sigE and sigF mutants formed abnormal multiple asymmetric septa during the early stage of sporulation. The sigG and sigK mutants formed forespores in the sporangium, but they did not become mature. Moreover, fluorescence reporter analysis confirmed compartment-specific gene expression of spoIID and spoVFA in the mother cell and spoIIQ and sspF in the forespore. Transmission electron microscopy imaging revealed that P. polymyxa produces multilayered endospores but lacking a balloon-shaped exosporium. Our results indicate that spore morphogenesis is conserved between P. polymyxa and B. subtilis. However, P. polymyxa genomes lack many homologues encoding spore-coat proteins that are found in B. subtills, suggesting that there are differences in the spore coat composition and surface structure between P. polymyxa and B. subtilis.
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Affiliation(s)
- Kimihiro Abe
- Faculty of Life and Environmental Sciences, University of Tsukuba
| | - Hiroko Kato
- Gradudate School of Life and Environmental Sciences, University of Tsukuba
| | - Yuta Hasegawa
- Gradudate School of Life and Environmental Sciences, University of Tsukuba
| | - Tatsuya Yamamoto
- Faculty of Life and Environmental Sciences, University of Tsukuba
| | - Nobuhiko Nomura
- Faculty of Life and Environmental Sciences, University of Tsukuba.,Microbiology Research Center for Sustainability, University of Tsukuba
| | - Nozomu Obana
- Microbiology Research Center for Sustainability, University of Tsukuba.,Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba
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3
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Kohm K, Floccari VA, Lutz VT, Nordmann B, Mittelstädt C, Poehlein A, Dragoš A, Commichau FM, Hertel R. The Bacillus phage SPβ and its relatives: a temperate phage model system reveals new strains, species, prophage integration loci, conserved proteins and lysogeny management components. Environ Microbiol 2022; 24:2098-2118. [PMID: 35293111 DOI: 10.1111/1462-2920.15964] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 03/02/2022] [Indexed: 11/28/2022]
Abstract
The Bacillus phage SPβ has been known for about 50 years, but only a few strains are available. We isolated four new wild-type strains of the SPbeta species. Phage vB_BsuS-Goe14 introduces its prophage into the spoVK locus, previously not observed to be used by SPβ-like phages. Sequence data revealed the genome replication strategy and the genome packaging mode of SPβ-like phages. We extracted 55 SPβ-like prophages from public Bacillus genomes, thereby discovering three more integration loci and one additional type of integrase. The identified prophages resemble four new species clusters and three species orphans in the genus Spbetavirus. The determined core proteome of all SPβ-like prophages consists of 38 proteins. The integration cassette proved to be not conserved, even though, present in all strains. It consists of distinct integrases. Analysis of SPβ transcriptomes revealed three conserved genes, yopQ, yopR, and yokI, to be transcribed from a dormant prophage. While yopQ and yokI could be deleted from the prophage without activating the prophage, damaging of yopR led to a clear-plaque phenotype. Under the applied laboratory conditions, the yokI mutant showed an elevated virion release implying the YokI protein being a component of the arbitrium system.
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Affiliation(s)
- Katharina Kohm
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, 01968, Germany
| | | | - Veronika T Lutz
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, 1870, Denmark
| | - Birthe Nordmann
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August University, Göttingen, 37077, Germany
| | - Carolin Mittelstädt
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, 01968, Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August University, Göttingen, 37077, Germany
| | - Anna Dragoš
- Biotechnical Faculty, University of Ljubljana, Ljubljana, 1000, Slovenia
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, 01968, Germany
| | - Robert Hertel
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, 01968, Germany
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4
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Łubkowska B, Jeżewska-Frąckowiak J, Sobolewski I, Skowron PM. Bacteriophages of Thermophilic ' Bacillus Group' Bacteria-A Review. Microorganisms 2021; 9:1522. [PMID: 34361957 PMCID: PMC8303945 DOI: 10.3390/microorganisms9071522] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/03/2021] [Accepted: 07/12/2021] [Indexed: 11/17/2022] Open
Abstract
Bacteriophages of thermophiles are of increasing interest owing to their important roles in many biogeochemical, ecological processes and in biotechnology applications, including emerging bionanotechnology. However, due to lack of in-depth investigation, they are underrepresented in the known prokaryotic virosphere. Therefore, there is a considerable potential for the discovery of novel bacteriophage-host systems in various environments: marine and terrestrial hot springs, compost piles, soil, industrial hot waters, among others. This review aims at providing a reference compendium of thermophages characterized thus far, which infect the species of thermophilic 'Bacillus group' bacteria, mostly from Geobacillus sp. We have listed 56 thermophages, out of which the majority belong to the Siphoviridae family, others belong to the Myoviridae and Podoviridae families and, apparently, a few belong to the Sphaerolipoviridae, Tectiviridae or Corticoviridae families. All of their genomes are composed of dsDNA, either linear, circular or circularly permuted. Fourteen genomes have been sequenced; their sizes vary greatly from 35,055 bp to an exceptionally large genome of 160,590 bp. We have also included our unpublished data on TP-84, which infects Geobacillus stearothermophilus (G. stearothermophilus). Since the TP-84 genome sequence shows essentially no similarity to any previously characterized bacteriophage, we have defined TP-84 as a new species in the newly proposed genus Tp84virus within the Siphoviridae family. The information summary presented here may be helpful in comparative deciphering of the molecular basis of the thermophages' biology, biotechnology and in analyzing the environmental aspects of the thermophages' effect on the thermophile community.
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Affiliation(s)
- Beata Łubkowska
- Department of Molecular Biotechnology, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland; (J.J.-F.); (I.S.); (P.M.S.)
- The High School of Health in Gdansk, Pelplinska 7, 80-335 Gdansk, Poland
| | - Joanna Jeżewska-Frąckowiak
- Department of Molecular Biotechnology, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland; (J.J.-F.); (I.S.); (P.M.S.)
| | - Ireneusz Sobolewski
- Department of Molecular Biotechnology, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland; (J.J.-F.); (I.S.); (P.M.S.)
| | - Piotr M. Skowron
- Department of Molecular Biotechnology, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland; (J.J.-F.); (I.S.); (P.M.S.)
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5
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Abe K, Takahashi T, Sato T. Extreme C-terminal element of SprA serine integrase is a potential component of the "molecular toggle switch" which controls the recombination and its directionality. Mol Microbiol 2020; 115:1110-1121. [PMID: 33244797 DOI: 10.1111/mmi.14654] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 10/26/2020] [Accepted: 11/21/2020] [Indexed: 12/11/2022]
Abstract
In Bacillus subtilis, a sporulation-related gene, spsM, is disrupted by SPβ prophage, but reconstituted during sporulation through SPβ excision. The spsM reconstitution is catalyzed by a site-specific DNA recombinase, SprA, and its cognate recombination directionality factor, SprB. SprB interacts with SprA, directing the SprA-mediated recombination reaction from integration to excision; however, the details of the directionality control remains unclear. Here, we demonstrate the importance of the extreme C-terminal region (ECT) of SprA in the DNA recombination and directionality control. We created a series of SprA C-terminal deletants and examined their DNA-binding and recombination activities. Deletions in the ECT caused a loss of integration and excision activity, the magnitudes of which positively correlated with the deletion size. Gel shift study revealed that the loss of the integration activity was attributable to the failure of synaptic complex formation. The excision deficiency was caused by defective interaction with SprB. Moreover, alanine scanning analysis revealed that Phe532 is essential to interact with SprB. SprAF532A , therefore, showed almost no excision activity, while retaining the integration activity. Collectively, these results suggest that the ECT plays the crucial roles in the interaction of SprA with SprB and possibly in the directional control of the recombination.
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Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Japan
| | - Takumi Takahashi
- Department of Frontier Bioscience, Hosei University, Koganei, Japan
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Japan.,Department of Frontier Bioscience, Hosei University, Koganei, Japan
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6
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Abe K, Nomura N, Suzuki S. Biofilms: hot spots of horizontal gene transfer (HGT) in aquatic environments, with a focus on a new HGT mechanism. FEMS Microbiol Ecol 2020; 96:5766226. [PMID: 32109282 PMCID: PMC7189800 DOI: 10.1093/femsec/fiaa031] [Citation(s) in RCA: 159] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/27/2020] [Indexed: 12/21/2022] Open
Abstract
Biofilms in water environments are thought to be hot spots for horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs). ARGs can be spread via HGT, though mechanisms are known and have been shown to depend on the environment, bacterial communities and mobile genetic elements. Classically, HGT mechanisms include conjugation, transformation and transduction; more recently, membrane vesicles (MVs) have been reported as DNA reservoirs implicated in interspecies HGT. Here, we review the current knowledge on the HGT mechanisms with a focus on the role of MVs and the methodological innovations in the HGT research.
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Affiliation(s)
- Kimihiro Abe
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8577 Japan
| | - Nobuhiko Nomura
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8577 Japan.,Microbiology Research Center for Sustainability, University of Tsukuba, Tsukuba, 305-8577 Japan
| | - Satoru Suzuki
- Center for Marine Environmental Studies, Ehime University, Matsuyama, 790-8577 Japan
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7
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Compatibility of Site-Specific Recombination Units between Mobile Genetic Elements. iScience 2019; 23:100805. [PMID: 31926432 PMCID: PMC6957869 DOI: 10.1016/j.isci.2019.100805] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/06/2019] [Accepted: 12/19/2019] [Indexed: 12/17/2022] Open
Abstract
Site-specific recombination (SSR) systems are employed for transfer of mobile genetic elements (MGEs), such as lysogenic phages and integrative conjugative elements (ICEs). SSR between attP/I and attB sites is mediated by an integrase (Int) and a recombination directionality factor (RDF). The genome of Bacillus subtilis 168 contains SPβ, an active prophage, skin, a defective prophage, and ICEBs1, an integrative conjugative element. Each of these MGEs harbors the classic SSR unit attL-int-rdf-attR. Here, we demonstrate that these SSR units are all compatible and can substitute for one another. Specifically, when SPβ is turned into a defective prophage by deletion of its SSR unit, introduction of the SSR unit of skin or ICE converts it back to an active prophage. We also identified closely related prophages with distinct SSR units that control developmentally regulated gene rearrangements of kamA (L-lysine 2,3-aminomutase). These results suggest that SSR units are interchangeable components of MGEs. Lysogenic phage-derived SSR unit is sufficient to drive SSR of ICE and vice versa Defective prophage-derived SSR unit can drive the excision of the active lysogenic phage Closely related prophages with distinct SSR units control each gene rearrangements Correspondence between MGEs and their cognate SSR units is not absolute
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8
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Abe K, Takamatsu T, Sato T. Mechanism of bacterial gene rearrangement: SprA-catalyzed precise DNA recombination and its directionality control by SprB ensure the gene rearrangement and stable expression of spsM during sporulation in Bacillus subtilis. Nucleic Acids Res 2017; 45:6669-6683. [PMID: 28535266 PMCID: PMC5499854 DOI: 10.1093/nar/gkx466] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/12/2017] [Indexed: 12/17/2022] Open
Abstract
A sporulation-specific gene, spsM, is disrupted by an active prophage, SPβ, in the genome of Bacillus subtilis. SPβ excision is required for two critical steps: the onset of the phage lytic cycle and the reconstitution of the spsM-coding frame during sporulation. Our in vitro study demonstrated that SprA, a serine-type integrase, catalyzed integration and excision reactions between attP of SPβ and attB within spsM, while SprB, a recombination directionality factor, was necessary only for the excision between attL and attR in the SPβ lysogenic chromosome. DNA recombination occurred at the center of the short inverted repeat motif in the unique conserved 16 bp sequence among the att sites (5΄-ACAGATAA/AGCTGTAT-3΄; slash, breakpoint; underlines, inverted repeat), where SprA produced the 3΄-overhanging AA and TT dinucleotides for rejoining the DNA ends through base-pairing. Electrophoretic mobility shift assay showed that SprB promoted synapsis of SprA subunits bound to the two target sites during excision but impaired it during integration. In vivo data demonstrated that sprB expression that lasts until the late stage of sporulation is crucial for stable expression of reconstituted spsM without reintegration of the SPβ prophage. These results present a deeper understanding of the mechanism of the prophage-mediated bacterial gene regulatory system.
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Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan
| | - Takuo Takamatsu
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan.,Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan
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9
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Abe K, Shimizu SY, Tsuda S, Sato T. A novel non prophage(-like) gene-intervening element within gerE that is reconstituted during sporulation in Bacillus cereus ATCC10987. Sci Rep 2017; 7:11426. [PMID: 28900282 PMCID: PMC5595907 DOI: 10.1038/s41598-017-11796-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/30/2017] [Indexed: 11/10/2022] Open
Abstract
Gene rearrangement is a widely-shared phenomenon in spore forming bacteria, in which prophage(-like) elements interrupting sporulation-specific genes are excised from the host genome to reconstitute the intact gene. Here, we report a novel class of gene-intervening elements, named gin, inserted in the 225 bp gerE-coding region of the B. cereus ATCC10987 genome, which generates a sporulation-specific rearrangement. gin has no phage-related genes and possesses three site-specific recombinase genes; girA, girB, and girC. We demonstrated that the gerE rearrangement occurs at the middle stage of sporulation, in which site-specific DNA recombination took place within the 9 bp consensus sequence flanking the disrupted gerE segments. Deletion analysis of gin uncovered that GirC and an additional factor, GirX, are responsible for gerE reconstitution. Involvement of GirC and GirX in DNA recombination was confirmed by an in vitro recombination assay. These results broaden the definition of the sporulation-specific gene rearrangement phenomenon: gene-intervening elements are not limited to phage DNA but may include non-viral genetic elements that carry a developmentally-regulated site-specific recombination system.
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Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan
| | - Shin-Ya Shimizu
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Shuhei Tsuda
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan. .,Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan.
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10
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Serrano M, Kint N, Pereira FC, Saujet L, Boudry P, Dupuy B, Henriques AO, Martin-Verstraete I. A Recombination Directionality Factor Controls the Cell Type-Specific Activation of σK and the Fidelity of Spore Development in Clostridium difficile. PLoS Genet 2016; 12:e1006312. [PMID: 27631621 PMCID: PMC5025042 DOI: 10.1371/journal.pgen.1006312] [Citation(s) in RCA: 26] [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: 05/24/2016] [Accepted: 08/21/2016] [Indexed: 01/05/2023] Open
Abstract
The strict anaerobe Clostridium difficile is the most common cause of nosocomial diarrhea, and the oxygen-resistant spores that it forms have a central role in the infectious cycle. The late stages of sporulation require the mother cell regulatory protein σK. In Bacillus subtilis, the onset of σK activity requires both excision of a prophage-like element (skinBs) inserted in the sigK gene and proteolytical removal of an inhibitory pro-sequence. Importantly, the rearrangement is restricted to the mother cell because the skinBs recombinase is produced specifically in this cell. In C. difficile, σK lacks a pro-sequence but a skinCd element is present. The product of the skinCd gene CD1231 shares similarity with large serine recombinases. We show that CD1231 is necessary for sporulation and skinCd excision. However, contrary to B. subtilis, expression of CD1231 is observed in vegetative cells and in both sporangial compartments. Nevertheless, we show that skinCd excision is under the control of mother cell regulatory proteins σE and SpoIIID. We then demonstrate that σE and SpoIIID control the expression of the skinCd gene CD1234, and that this gene is required for sporulation and skinCd excision. CD1231 and CD1234 appear to interact and both proteins are required for skinCd excision while only CD1231 is necessary for skinCd integration. Thus, CD1234 is a recombination directionality factor that delays and restricts skinCd excision to the terminal mother cell. Finally, while the skinCd element is not essential for sporulation, deletion of skinCd results in premature activity of σK and in spores with altered surface layers. Thus, skinCd excision is a key element controlling the onset of σK activity and the fidelity of spore development.
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Affiliation(s)
- Mónica Serrano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Nicolas Kint
- Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France
- University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Fátima C. Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Laure Saujet
- Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France
- University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Pierre Boudry
- Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France
- University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Bruno Dupuy
- Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France
- University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Adriano O. Henriques
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- * E-mail: (AOH); (IMV)
| | - Isabelle Martin-Verstraete
- Laboratoire Pathogénese des Bactéries Anaérobies, Institut Pasteur, Paris, France
- University Paris Diderot, Sorbonne Paris Cité, Paris, France
- * E-mail: (AOH); (IMV)
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11
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Feiner R, Argov T, Rabinovich L, Sigal N, Borovok I, Herskovits AA. A new perspective on lysogeny: prophages as active regulatory switches of bacteria. Nat Rev Microbiol 2016; 13:641-50. [PMID: 26373372 DOI: 10.1038/nrmicro3527] [Citation(s) in RCA: 269] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Unlike lytic phages, temperate phages that enter lysogeny maintain a long-term association with their bacterial host. In this context, mutually beneficial interactions can evolve that support efficient reproduction of both phages and bacteria. Temperate phages are integrated into the bacterial chromosome as large DNA insertions that can disrupt gene expression, and they may pose a fitness burden on the cell. However, they have also been shown to benefit their bacterial hosts by providing new functions in a bacterium-phage symbiotic interaction termed lysogenic conversion. In this Opinion article, we discuss another type of bacterium-phage interaction, active lysogeny, in which phages or phage-like elements are integrated into the bacterial chromosome within critical genes or operons and serve as switches that regulate bacterial genes via genome excision.
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Affiliation(s)
- Ron Feiner
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tal Argov
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Lev Rabinovich
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nadejda Sigal
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Anat A Herskovits
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
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Abe K, Kawano Y, Iwamoto K, Arai K, Maruyama Y, Eichenberger P, Sato T. Developmentally-regulated excision of the SPβ prophage reconstitutes a gene required for spore envelope maturation in Bacillus subtilis. PLoS Genet 2014; 10:e1004636. [PMID: 25299644 PMCID: PMC4191935 DOI: 10.1371/journal.pgen.1004636] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 07/29/2014] [Indexed: 01/25/2023] Open
Abstract
Temperate phages infect bacteria by injecting their DNA into bacterial cells, where it becomes incorporated into the host genome as a prophage. In the genome of Bacillus subtilis 168, an active prophage, SPβ, is inserted into a polysaccharide synthesis gene, spsM. Here, we show that a rearrangement occurs during sporulation to reconstitute a functional composite spsM gene by precise excision of SPβ from the chromosome. SPβ excision requires a putative site-specific recombinase, SprA, and an accessory protein, SprB. A minimized SPβ, where all the SPβ genes were deleted, except sprA and sprB, retained the SPβ excision activity during sporulation, demonstrating that sprA and sprB are necessary and sufficient for the excision. While expression of sprA was observed during vegetative growth, sprB was induced during sporulation and upon mitomycin C treatment, which triggers the phage lytic cycle. We also demonstrated that overexpression of sprB (but not of sprA) resulted in SPβ prophage excision without triggering the lytic cycle. These results suggest that sprB is the factor that controls the timing of phage excision. Furthermore, we provide evidence that spsM is essential for the addition of polysaccharides to the spore envelope. The presence of polysaccharides on the spore surface renders the spore hydrophilic in water. This property may be beneficial in allowing spores to disperse in natural environments via water flow. A similar rearrangement occurs in Bacillus amyloliquefaciens FZB42, where a SPβ-like element is excised during sporulation to reconstitute a polysaccharide synthesis gene, suggesting that this type of gene rearrangement is common in spore-forming bacteria because it can be spread by phage infection. Integration of prophages into protein-coding sequences of the host chromosome generally results in loss of function of the interrupted gene. In the endospore-forming organism Bacillus subtilis strain 168, the SPβ prophage is inserted into a previously-uncharacterized spore polysaccharide synthesis gene, spsM. In vegetative cells, the lytic cycle is induced in response to DNA damage. In the process, SPβ is excised from the genome to form phage particles. Here, we demonstrate that SPβ excision is also a developmentally-regulated event that occurs systematically during sporulation to reconstitute a functional spsM gene. Following asymmetric division of the sporulating cell, two cellular compartments are generated, the forespore, which will mature into a spore, and the mother cell, which is essential to the process of spore maturation. Because phage excision is limited to the mother cell genome, and does not occur in the forespore genome, SPβ is an integral part of the spore genome. Thus, after the spores germinate, the vegetative cells resume growth and the SPβ prophage is propagated vertically to the progeny along with the rest of the host genome. Our results suggest that the two pathways of SPβ excision support both the phage life cycle and normal sporulation of the host cells.
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Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan
| | - Yuta Kawano
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Keito Iwamoto
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Kenji Arai
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Yuki Maruyama
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Patrick Eichenberger
- Center for Genomics and Systems Biology, New York University, New York, New York, United States of America
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
- * E-mail:
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Abstract
Large-scale rearrangements may be important in evolution because they can alter chromosome organization and gene expression in ways not possible through point mutations. In a long-term evolution experiment, twelve Escherichia coli populations have been propagated in a glucose-limited environment for over 25 years. We used whole-genome mapping (optical mapping) combined with genome sequencing and PCR analysis to identify the large-scale chromosomal rearrangements in clones from each population after 40,000 generations. A total of 110 rearrangement events were detected, including 82 deletions, 19 inversions, and 9 duplications, with lineages having between 5 and 20 events. In three populations, successive rearrangements impacted particular regions. In five populations, rearrangements affected over a third of the chromosome. Most rearrangements involved recombination between insertion sequence (IS) elements, illustrating their importance in mediating genome plasticity. Two lines of evidence suggest that at least some of these rearrangements conferred higher fitness. First, parallel changes were observed across the independent populations, with ~65% of the rearrangements affecting the same loci in at least two populations. For example, the ribose-utilization operon and the manB-cpsG region were deleted in 12 and 10 populations, respectively, suggesting positive selection, and this inference was previously confirmed for the former case. Second, optical maps from clones sampled over time from one population showed that most rearrangements occurred early in the experiment, when fitness was increasing most rapidly. However, some rearrangements likely occur at high frequency and may have simply hitchhiked to fixation. In any case, large-scale rearrangements clearly influenced genomic evolution in these populations. Bacterial chromosomes are dynamic structures shaped by long histories of evolution. Among genomic changes, large-scale DNA rearrangements can have important effects on the presence, order, and expression of genes. Whole-genome sequencing that relies on short DNA reads cannot identify all large-scale rearrangements. Therefore, deciphering changes in the overall organization of genomes requires alternative methods, such as optical mapping. We analyzed the longest-running microbial evolution experiment (more than 25 years of evolution in the laboratory) by optical mapping, genome sequencing, and PCR analyses. We found multiple large genome rearrangements in all 12 independently evolving populations. In most cases, it is unclear whether these changes were beneficial themselves or, alternatively, hitchhiked to fixation with other beneficial mutations. In any case, many genome rearrangements accumulated over decades of evolution, providing these populations with genetic plasticity reminiscent of that observed in some pathogenic bacteria.
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