1
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Craske MW, Wilson JS, Fogg PCM. Gene transfer agents: structural and functional properties of domesticated viruses. Trends Microbiol 2024:S0966-842X(24)00133-1. [PMID: 38806321 DOI: 10.1016/j.tim.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/02/2024] [Accepted: 05/07/2024] [Indexed: 05/30/2024]
Abstract
Horizontal exchange of DNA between bacteria and archaea is prevalent and has major potential implications for genome evolution, plasticity, and population fitness. Several transfer mechanisms have been identified, including gene transfer agents (GTAs). GTAs are intricately regulated domesticated viruses that package host DNA into virus-like capsids and transfer this DNA throughout the bacterial community. Several important advances have recently been made in our understanding of these unusual particles. In this review, we highlight some of these findings, primarily for the model GTA produced by Rhodobacter capsulatus but also for newly identified GTA producers. We provide key insights into these important genetic elements, including the differences between GTAs from their ancestral bacteriophages, their regulation and control, and their elusive evolutionary function.
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Affiliation(s)
| | - Jason S Wilson
- Biology Department, University of York, York YO10 5DD, UK; York Structural Biology Laboratory (YSBL), University of York, York YO10 5DD, UK
| | - Paul C M Fogg
- Biology Department, University of York, York YO10 5DD, UK; York Biomedical Research Institute (YBRI), University of York, York YO10 5NG, UK.
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2
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Banks EJ, Le TBK. Co-opting bacterial viruses for DNA exchange: structure and regulation of gene transfer agents. Curr Opin Microbiol 2024; 78:102431. [PMID: 38309246 DOI: 10.1016/j.mib.2024.102431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/03/2024] [Accepted: 01/09/2024] [Indexed: 02/05/2024]
Abstract
Horizontal gene transfer occurs via a range of mechanisms, including transformation, conjugation and bacteriophage transduction. Gene transfer agents (GTAs) are an alternative, less-studied route for interbacterial DNA exchange. Encoded within bacterial or archaeal genomes, GTAs assemble into phage-like particles that selflessly package and transmit host DNA to recipient bacteria. Several unique features distinguish GTAs from canonical phages such as an inability to self-replicate, thus producing non-infectious particles. GTAs are also deeply integrated into the physiology of the host cell and are maintained under tight host-regulatory control. Recent advances in understanding the structure and regulation of GTAs have provided further insights into a DNA transfer mechanism that is proving increasingly widespread across the bacterial tree of life.
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Affiliation(s)
- Emma J Banks
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, UK.
| | - Tung B K Le
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, UK.
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3
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Fogg PCM. Gene transfer agents: The ambiguous role of selfless viruses in genetic exchange and bacterial evolution. Mol Microbiol 2024. [PMID: 38511257 DOI: 10.1111/mmi.15251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 03/22/2024]
Abstract
Gene transfer agents (GTAs) are genetic elements derived from ancestral bacteriophages that have become domesticated by the host. GTAs are present in diverse prokaryotic organisms, where they can facilitate horizontal gene transfer under certain conditions. Unlike typical bacteriophages, GTAs do not exhibit any preference for the replication or transfer of the genes encoding them; instead, they exhibit a remarkable capacity to package chromosomal, and sometimes extrachromosomal, DNA into virus-like capsids and disseminate it to neighboring cells. Because GTAs resemble defective prophages, identification of novel GTAs is not trivial. The detection of candidates relies on the genetic similarity to known GTAs, which has been fruitful in α-proteobacterial lineages but challenging in more distant bacteria. Here we consider several fundamental questions: What is the true prevalence of GTAs in prokaryote genomes? Given there are high costs for GTA production, what advantage do GTAs provide to the bacterial host to justify their maintenance? How is the bacterial chromosome recognized and processed for inclusion in GTA particles? This article highlights the challenges in comprehensively understanding GTAs' prevalence, function and DNA packaging method. Going forward, broad study of atypical GTAs and use of ecologically relevant conditions are required to uncover their true impact on bacterial chromosome evolution.
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4
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Kuhn JH, Koonin EV. Viriforms-A New Category of Classifiable Virus-Derived Genetic Elements. Biomolecules 2023; 13:289. [PMID: 36830658 PMCID: PMC9953437 DOI: 10.3390/biom13020289] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The International Committee on Taxonomy of Viruses (ICTV) recently accepted viriforms as a new polyphyletic category of classifiable virus-derived genetic elements, juxtaposed to the polyphyletic virus, viroid, and satellite nucleic acid categories. Viriforms are endogenized former viruses that have been exapted by their cellular hosts to fulfill functions important for the host's life cycle. While morphologically resembling virions, particles made by viriforms do not package the viriform genomes but instead transport host genetic material. Known viriforms are highly diverse: members of family Polydnaviriformidae (former Polydnaviridae) have thus far been found exclusively in the genomes of braconid and ichneumonid parasitoid wasps, whereas the completely unrelated gene transfer agents (GTAs) are widely distributed among prokaryotes. In addition, recent discoveries likely extend viriforms to mammalian genomes. Here, we briefly outline the properties of these viriform groups and the first accepted and proposed ICTV frameworks for viriform classification.
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Affiliation(s)
- Jens H. Kuhn
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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5
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Gozzi K, Tran NT, Modell JW, Le TBK, Laub MT. Prophage-like gene transfer agents promote Caulobacter crescentus survival and DNA repair during stationary phase. PLoS Biol 2022; 20:e3001790. [PMID: 36327213 PMCID: PMC9632790 DOI: 10.1371/journal.pbio.3001790] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 08/09/2022] [Indexed: 11/05/2022] Open
Abstract
Gene transfer agents (GTAs) are prophage-like entities found in many bacterial genomes that cannot propagate themselves and instead package approximately 5 to 15 kbp fragments of the host genome that can then be transferred to related recipient cells. Although suggested to facilitate horizontal gene transfer (HGT) in the wild, no clear physiological role for GTAs has been elucidated. Here, we demonstrate that the α-proteobacterium Caulobacter crescentus produces bona fide GTAs. The production of Caulobacter GTAs is tightly regulated by a newly identified transcription factor, RogA, that represses gafYZ, the direct activators of GTA synthesis. Cells lacking rogA or expressing gafYZ produce GTAs harboring approximately 8.3 kbp fragment of the genome that can, after cell lysis, be transferred into recipient cells. Notably, we find that GTAs promote the survival of Caulobacter in stationary phase and following DNA damage by providing recipient cells a template for homologous recombination-based repair. This function may be broadly conserved in other GTA-producing organisms and explain the prevalence of this unusual HGT mechanism.
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Affiliation(s)
- Kevin Gozzi
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Ngat T. Tran
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Joshua W. Modell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Tung B. K. Le
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Michael T. Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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6
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Kogay R, Koppenhöfer S, Beatty JT, Kuhn JH, Lang AS, Zhaxybayeva O. Formal recognition and classification of gene transfer agents as viriforms. Virus Evol 2022; 8:veac100. [PMID: 36381234 PMCID: PMC9662315 DOI: 10.1093/ve/veac100] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/10/2022] [Accepted: 10/14/2022] [Indexed: 06/19/2024] Open
Abstract
Morphological and genetic features strongly suggest that gene transfer agents (GTAs) are caudoviricete-derived entities that have evolved in concert with cellular genomes to such a degree that they should not be considered viruses. Indeed, GTA particles resemble caudoviricete virions, but, in contrast to caudoviricetes (or any viruses), GTAs can encapsidate at best only part of their own genomes, are induced solely in small subpopulations of prokaryotic host cells, and are transmitted vertically as part of cellular genomes during replication and division. Therefore, the lifecycles of GTAs are analogous to virus-derived entities found in the parasitoid wasps, which have recently been recognized as non-virus entities and therefore reclassified as viriforms. We evaluated three distinct, independently exapted GTA groups, for which the genetic basis for GTA particle production has been established. Based on the evidence, we outline a classification scheme for these viriforms.
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Affiliation(s)
- Roman Kogay
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH, USA
| | | | - J Thomas Beatty
- Department of Microbiology and Immunology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, B-8200 Research Plaza, Fort Detrick, Frederick, MD 21702, USA
| | - Andrew S Lang
- Department of Biology, Memorial University of Newfoundland, 45 Arctic Ave., St. John’s, NL A1C 5S7, Canada
| | - Olga Zhaxybayeva
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH, USA
- Department of Biology, Memorial University of Newfoundland, 45 Arctic Ave., St. John’s, NL A1C 5S7, Canada
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7
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Gophna U, Altman-Price N. Horizontal Gene Transfer in Archaea-From Mechanisms to Genome Evolution. Annu Rev Microbiol 2022; 76:481-502. [PMID: 35667126 DOI: 10.1146/annurev-micro-040820-124627] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Archaea remains the least-studied and least-characterized domain of life despite its significance not just to the ecology of our planet but also to the evolution of eukaryotes. It is therefore unsurprising that research into horizontal gene transfer (HGT) in archaea has lagged behind that of bacteria. Indeed, several archaeal lineages may owe their very existence to large-scale HGT events, and thus understanding both the molecular mechanisms and the evolutionary impact of HGT in archaea is highly important. Furthermore, some mechanisms of gene exchange, such as plasmids that transmit themselves via membrane vesicles and the formation of cytoplasmic bridges that allows transfer of both chromosomal and plasmid DNA, may be archaea specific. This review summarizes what we know about HGT in archaea, and the barriers that restrict it, highlighting exciting recent discoveries and pointing out opportunities for future research. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Uri Gophna
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; ,
| | - Neta Altman-Price
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; , .,Department of Natural and Life Sciences, The Open University of Israel, Raanana, Israel
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8
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Borodovich T, Shkoporov AN, Ross RP, Hill C. OUP accepted manuscript. Gastroenterol Rep (Oxf) 2022; 10:goac012. [PMID: 35425613 PMCID: PMC9006064 DOI: 10.1093/gastro/goac012] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 02/08/2022] [Accepted: 03/04/2022] [Indexed: 11/26/2022] Open
Abstract
Horizontal gene transfer (HGT) in the microbiome has profound consequences for human health and disease. The spread of antibiotic resistance genes, virulence, and pathogenicity determinants predominantly occurs by way of HGT. Evidence exists of extensive horizontal transfer in the human gut microbiome. Phage transduction is a type of HGT event in which a bacteriophage transfers non-viral DNA from one bacterial host cell to another. The abundance of tailed bacteriophages in the human gut suggests that transduction could act as a significant mode of HGT in the gut microbiome. Here we review in detail the known mechanisms of phage-mediated HGT, namely specialized and generalized transduction, lateral transduction, gene-transfer agents, and molecular piracy, as well as methods used to detect phage-mediated HGT, and discuss its potential implications for the human gut microbiome.
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Affiliation(s)
- Tatiana Borodovich
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- Corresponding author. APC Microbiome Ireland, Biosciences Institute, University College Cork, Room 3.63, College Road, Cork, T12 YT20, Ireland.
| | - Andrey N Shkoporov
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
| | - R Paul Ross
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
| | - Colin Hill
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
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9
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Sivabalasarma S, Wetzel H, Nußbaum P, van der Does C, Beeby M, Albers SV. Analysis of Cell-Cell Bridges in Haloferax volcanii Using Electron Cryo-Tomography Reveal a Continuous Cytoplasm and S-Layer. Front Microbiol 2021; 11:612239. [PMID: 33519769 PMCID: PMC7838353 DOI: 10.3389/fmicb.2020.612239] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/11/2020] [Indexed: 01/28/2023] Open
Abstract
Halophilic archaea have been proposed to exchange DNA and proteins using a fusion-based mating mechanism. Scanning electron microscopy previously suggested that mating involves an intermediate state, where cells are connected by an intercellular bridge. To better understand this process, we used electron cryo-tomography (cryoET) and fluorescence microscopy to visualize cells forming these intercellular bridges. CryoET showed that the observed bridges were enveloped by an surface layer (S-layer) and connected mating cells via a continuous cytoplasm. Macromolecular complexes like ribosomes and unknown thin filamentous helical structures were visualized in the cytoplasm inside the bridges, demonstrating that these bridges can facilitate exchange of cellular components. We followed formation of a cell–cell bridge by fluorescence time-lapse microscopy between cells at a distance of 1.5 μm. These results shed light on the process of haloarchaeal mating and highlight further mechanistic questions.
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Affiliation(s)
- Shamphavi Sivabalasarma
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Hanna Wetzel
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Phillip Nußbaum
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Chris van der Does
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
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10
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Colombet J, Fuster M, Billard H, Sime-Ngando T. Femtoplankton: What's New? Viruses 2020; 12:E881. [PMID: 32806713 PMCID: PMC7472349 DOI: 10.3390/v12080881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/10/2020] [Accepted: 08/10/2020] [Indexed: 01/01/2023] Open
Abstract
Since the discovery of high abundances of virus-like particles in aquatic environment, emergence of new analytical methods in microscopy and molecular biology has allowed significant advances in the characterization of the femtoplankton, i.e., floating entities filterable on a 0.2 µm pore size filter. The successive evidences in the last decade (2010-2020) of high abundances of biomimetic mineral-organic particles, extracellular vesicles, CPR/DPANN (Candidate phyla radiation/Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota and Nanohaloarchaeota), and very recently of aster-like nanoparticles (ALNs), show that aquatic ecosystems form a huge reservoir of unidentified and overlooked femtoplankton entities. The purpose of this review is to highlight this unsuspected diversity. Herein, we focus on the origin, composition and the ecological potentials of organic femtoplankton entities. Particular emphasis is given to the most recently discovered ALNs. All the entities described are displayed in an evolutionary context along a continuum of complexity, from minerals to cell-like living entities.
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Affiliation(s)
- Jonathan Colombet
- Laboratoire Microorganismes: Génome et Environnement (LMGE), UMR CNRS 6023, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France; (M.F.); (H.B.); (T.S.-N.)
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11
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Abstract
Prokaryotes commonly undergo genome reduction, particularly in the case of symbiotic bacteria. Genome reductions tend toward the energetically favorable removal of unnecessary, redundant, or nonfunctional genes. However, without mechanisms to compensate for these losses, deleterious mutation and genetic drift might otherwise overwhelm a population. Among the mechanisms employed to counter gene loss and share evolutionary success within a population, gene transfer agents (GTAs) are increasingly becoming recognized as important contributors. Although viral in origin, GTA particles package fragments of their "host" genome for distribution within a population of cells, often in a synchronized manner, rather than selfishly packaging genes necessary for their spread. Microbes as diverse as archaea and alpha-proteobacteria have been known to produce GTA particles, which are capable of transferring selective advantages such as virulence factors and antibiotic resistance. In this review, we discuss the various types of GTAs identified thus far, focusing on a defined set of symbiotic alpha-proteobacteria known to carry them. Drawing attention to the predicted presence of these genes, we discuss their potential within the selective marine and terrestrial environments occupied by mutualistic, parasitic, and endosymbiotic microbes.
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Affiliation(s)
- Steen Christensen
- Department of Biological Sciences, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Laura R Serbus
- Department of Biological Sciences, Florida International University, Miami, FL, USA. .,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA.
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12
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Identification of the First Gene Transfer Agent (GTA) Small Terminase in Rhodobacter capsulatus and Its Role in GTA Production and Packaging of DNA. J Virol 2019; 93:JVI.01328-19. [PMID: 31534034 PMCID: PMC6854486 DOI: 10.1128/jvi.01328-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 09/10/2019] [Indexed: 12/17/2022] Open
Abstract
Genetic exchange mediated by viruses of bacteria (bacteriophages) is the primary driver of rapid bacterial evolution. The priority of viruses is usually to propagate themselves. Most bacteriophages use the small terminase protein to identify their own genome and direct its inclusion into phage capsids. Gene transfer agents (GTAs) are descended from bacteriophages, but they instead package fragments of the entire bacterial genome without preference for their own genes. GTAs do not selectively target specific DNA, and no GTA small terminases are known. Here, we identified the small terminase from the model Rhodobacter capsulatus GTA, which then allowed prediction of analogues in other species. We examined the role of the small terminase in GTA production and propose a structural basis for random DNA packaging.IMPORTANCE Random transfer of any and all genes between bacteria could be influential in the spread of virulence or antimicrobial resistance genes. Discovery of the true prevalence of GTAs in sequenced genomes is hampered by their apparent similarity to bacteriophages. Our data allowed the prediction of small terminases in diverse GTA producer species, and defining the characteristics of a "GTA-type" terminase could be an important step toward novel GTA identification. Importantly, the GTA small terminase shares many features with its phage counterpart. We propose that the GTA terminase complex could become a streamlined model system to answer fundamental questions about double-stranded DNA (dsDNA) packaging by viruses that have not been forthcoming to date.
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13
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Grüll MP, Mulligan ME, Lang AS. Small extracellular particles with big potential for horizontal gene transfer: membrane vesicles and gene transfer agents. FEMS Microbiol Lett 2019; 365:5067299. [PMID: 30085064 DOI: 10.1093/femsle/fny192] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 08/04/2018] [Indexed: 12/18/2022] Open
Abstract
Bacteria are known to release different types of particles that serve various purposes such as the processing of metabolites, communication, and the transfer of genetic material. One of the most interesting aspects of the production of such particles is the biogenesis and trafficking of complex particles that can carry DNA, RNA, proteins or toxins into the surrounding environment to aid in bacterial survival or lead to gene transfer. Two important bacterial extracellular complexes are membrane vesicles and gene transfer agents. In this review, we will discuss the production, contents and functions of these two types of particles as related to their abilities to facilitate horizontal gene transfer.
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Affiliation(s)
| | - M E Mulligan
- Biochemistry, Memorial University of Newfoundland, St John's, NL, Canada
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14
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Québatte M, Dehio C. Bartonella gene transfer agent: Evolution, function, and proposed role in host adaptation. Cell Microbiol 2019; 21:e13068. [PMID: 31231937 PMCID: PMC6899734 DOI: 10.1111/cmi.13068] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/09/2019] [Accepted: 06/13/2019] [Indexed: 01/05/2023]
Abstract
The processes underlying host adaptation by bacterial pathogens remain a fundamental question with relevant clinical, ecological, and evolutionary implications. Zoonotic pathogens of the genus Bartonella constitute an exceptional model to study these aspects. Bartonellae have undergone a spectacular diversification into multiple species resulting from adaptive radiation. Specific adaptations of a complex facultative intracellular lifestyle have enabled the colonisation of distinct mammalian reservoir hosts. This remarkable host adaptability has a multifactorial basis and is thought to be driven by horizontal gene transfer (HGT) and recombination among a limited genus‐specific pan genome. Recent functional and evolutionary studies revealed that the conserved Bartonella gene transfer agent (BaGTA) mediates highly efficient HGT and could thus drive this evolution. Here, we review the recent progress made towards understanding BaGTA evolution, function, and its role in the evolution and pathogenesis of Bartonella spp. We notably discuss how BaGTA could have contributed to genome diversification through recombination of beneficial traits that underlie host adaptability. We further address how BaGTA may counter the accumulation of deleterious mutations in clonal populations (Muller's ratchet), which are expected to occur through the recurrent transmission bottlenecks during the complex infection cycle of these pathogens in their mammalian reservoir hosts and arthropod vectors.
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15
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Contrasting in vitro and in vivo methanol oxidation activities of lanthanide-dependent alcohol dehydrogenases XoxF1 and ExaF from Methylobacterium extorquens AM1. Sci Rep 2019; 9:4248. [PMID: 30862918 PMCID: PMC6414531 DOI: 10.1038/s41598-019-41043-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 02/28/2019] [Indexed: 11/19/2022] Open
Abstract
Lanthanide (Ln) elements are utilized as cofactors for catalysis by XoxF-type methanol dehydrogenases (MDHs). A primary assumption is that XoxF enzymes produce formate from methanol oxidation, which could impact organisms that require formaldehyde for assimilation. We report genetic and phenotypic evidence showing that XoxF1 (MexAM1_1740) from Methylobacterium extorquens AM1 produces formaldehyde, and not formate, during growth with methanol. Enzyme purified with lanthanum or neodymium oxidizes formaldehyde. However, formaldehyde oxidation via 2,6-dichlorophenol-indophenol (DCPIP) reduction is not detected in cell-free extracts from wild-type strain methanol- and lanthanum-grown cultures. Formaldehyde activating enzyme (Fae) is required for Ln methylotrophic growth, demonstrating that XoxF1-mediated production of formaldehyde is essential. Addition of exogenous lanthanum increases growth rate with methanol by 9–12% but does not correlate with changes to methanol consumption or formaldehyde accumulation. Transcriptomics analysis of lanthanum methanol growth shows upregulation of xox1 and downregulation of mxa genes, consistent with the Ln-switch, no differential expression of formaldehyde conversion genes, downregulation of pyrroloquinoline quinone (PQQ) biosynthesis genes, and upregulation of fdh4 formate dehydrogenase (FDH) genes. Additionally, the Ln-dependent ethanol dehydrogenase ExaF reduces methanol sensitivity in the fae mutant strain when lanthanides are present, providing evidence for the capacity of an auxiliary role for ExaF during Ln-dependent methylotrophy.
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16
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Tomasch J, Wang H, Hall ATK, Patzelt D, Preusse M, Petersen J, Brinkmann H, Bunk B, Bhuju S, Jarek M, Geffers R, Lang AS, Wagner-Döbler I. Packaging of Dinoroseobacter shibae DNA into Gene Transfer Agent Particles Is Not Random. Genome Biol Evol 2018; 10:359-369. [PMID: 29325123 PMCID: PMC5786225 DOI: 10.1093/gbe/evy005] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2018] [Indexed: 02/07/2023] Open
Abstract
Gene transfer agents (GTAs) are phage-like particles which contain a fragment of genomic DNA of the bacterial or archaeal producer and deliver this to a recipient cell. GTA gene clusters are present in the genomes of almost all marine Rhodobacteraceae (Roseobacters) and might be important contributors to horizontal gene transfer in the world’s oceans. For all organisms studied so far, no obvious evidence of sequence specificity or other nonrandom process responsible for packaging genomic DNA into GTAs has been found. Here, we show that knock-out of an autoinducer synthase gene of Dinoroseobacter shibae resulted in overproduction and release of functional GTA particles (DsGTA). Next-generation sequencing of the 4.2-kb DNA fragments isolated from DsGTAs revealed that packaging was not random. DNA from low-GC conjugative plasmids but not from high-GC chromids was excluded from packaging. Seven chromosomal regions were strongly overrepresented in DNA isolated from DsGTA. These packaging peaks lacked identifiable conserved sequence motifs that might represent recognition sites for the GTA terminase complex. Low-GC regions of the chromosome, including the origin and terminus of replication, were underrepresented in DNA isolated from DsGTAs. DNA methylation reduced packaging frequency while the level of gene expression had no influence. Chromosomal regions found to be over- and underrepresented in DsGTA-DNA were regularly spaced. We propose that a “headful” type of packaging is initiated at the sites of coverage peaks and, after linearization of the chromosomal DNA, proceeds in both directions from the initiation site. GC-content, DNA-modifications, and chromatin structure might influence at which sides GTA packaging can be initiated.
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Affiliation(s)
- Jürgen Tomasch
- Group Microbial Communication, Helmholtz-Centre for Infection Research, Braunschweig, Germany.,Department of Molecular Bacteriology, Helmholtz-Centre for Infection Research, Braunschweig, Germany
| | - Hui Wang
- Group Microbial Communication, Helmholtz-Centre for Infection Research, Braunschweig, Germany
| | - April T K Hall
- Department of Biology, Memorial University of Newfoundland, St John's, Newfoundland and Labrador, Canada
| | - Diana Patzelt
- Group Microbial Communication, Helmholtz-Centre for Infection Research, Braunschweig, Germany
| | - Matthias Preusse
- Department of Molecular Bacteriology, Helmholtz-Centre for Infection Research, Braunschweig, Germany
| | - Jörn Petersen
- Department of Microbial Ecology and Diversity Research, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Henner Brinkmann
- Department of Microbial Ecology and Diversity Research, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Boyke Bunk
- Department of Microbial Ecology and Diversity Research, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Sabin Bhuju
- Group Genome Analytics, Helmholtz-Center for Infection Research, Braunschweig, Germany
| | - Michael Jarek
- Group Genome Analytics, Helmholtz-Center for Infection Research, Braunschweig, Germany
| | - Robert Geffers
- Group Genome Analytics, Helmholtz-Center for Infection Research, Braunschweig, Germany
| | - Andrew S Lang
- Department of Biology, Memorial University of Newfoundland, St John's, Newfoundland and Labrador, Canada
| | - Irene Wagner-Döbler
- Group Microbial Communication, Helmholtz-Centre for Infection Research, Braunschweig, Germany
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17
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Shakya M, Soucy SM, Zhaxybayeva O. Insights into origin and evolution of α-proteobacterial gene transfer agents. Virus Evol 2017; 3:vex036. [PMID: 29250433 PMCID: PMC5721377 DOI: 10.1093/ve/vex036] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Several bacterial and archaeal lineages produce nanostructures that morphologically resemble small tailed viruses, but, unlike most viruses, contain apparently random pieces of the host genome. Since these elements can deliver the packaged DNA to other cells, they were dubbed gene transfer agents (GTAs). Because many genes involved in GTA production have viral homologs, it has been hypothesized that the GTA ancestor was a virus. Whether GTAs represent an atypical virus, a defective virus, or a virus co-opted by the prokaryotes for some function, remains to be elucidated. To evaluate these possibilities, we examined the distribution and evolutionary histories of genes that encode a GTA in the α-proteobacterium Rhodobacter capsulatus (RcGTA). We report that although homologs of many individual RcGTA genes are abundant across bacteria and their viruses, RcGTA-like genomes are mainly found in one subclade of α-proteobacteria. When compared with the viral homologs, genes of the RcGTA-like genomes evolve significantly slower, and do not have higher %A+T nucleotides than their host chromosomes. Moreover, they appear to reside in stable regions of the bacterial chromosomes that are generally conserved across taxonomic orders. These findings argue against RcGTA being an atypical or a defective virus. Our phylogenetic analyses suggest that RcGTA ancestor likely originated in the lineage that gave rise to contemporary α-proteobacterial orders Rhizobiales, Rhodobacterales, Caulobacterales, Parvularculales, and Sphingomonadales, and since that time the RcGTA-like element has co-evolved with its host chromosomes. Such evolutionary history is compatible with maintenance of these elements by bacteria due to some selective advantage. As for many other prokaryotic traits, horizontal gene transfer played a substantial role in the evolution of RcGTA-like elements, not only in shaping its genome components within the orders, but also in occasional dissemination of RcGTA-like regions across the orders and even to different bacterial phyla.
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Affiliation(s)
- Migun Shakya
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
| | - Shannon M Soucy
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
| | - Olga Zhaxybayeva
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA.,Department of Computer Science, Dartmouth College, 6211 Sudikoff Lab, Hanover, NH 03755, USA
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18
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Lang AS, Westbye AB, Beatty JT. The Distribution, Evolution, and Roles of Gene Transfer Agents in Prokaryotic Genetic Exchange. Annu Rev Virol 2017; 4:87-104. [DOI: 10.1146/annurev-virology-101416-041624] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Andrew S. Lang
- Department of Biology, Memorial University of Newfoundland, St. John's, A1B 3X9, Canada
| | - Alexander B. Westbye
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - J. Thomas Beatty
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, V6T 1Z3, Canada
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19
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Beyond the canonical strategies of horizontal gene transfer in prokaryotes. Curr Opin Microbiol 2017; 38:95-105. [PMID: 28600959 DOI: 10.1016/j.mib.2017.04.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 01/16/2023]
Abstract
Efforts to identify and characterize strategies for horizontal gene transfer (HGT) in prokaryotes could have overlooked some mechanisms that do not entirely fit in with the canonical ones most often described (conjugation of plasmids, phage transduction and transformation). The difficulty in distinguishing the different HGT strategies could have contributed to underestimate their real extent. Here we review non classical HGT strategies: some that require mobile genetic elements (MGEs) and others independent of MGE. Among those strategies that require MGEs, there is a range of newly reported, hybrid and intermediate MGEs mobilizing only their own DNA, others that mobilize preferentially bacterial DNA, or both. Considering HGT strategies independent of MGE, a few are even not restricted to DNA transfer, but can also mobilize other molecules. This review considers those HGT strategies that are less commonly dealt with in the literature. The real impact of these elements could, in some conditions, be more relevant than previously thought.
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20
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Wagner A, Whitaker RJ, Krause DJ, Heilers JH, van Wolferen M, van der Does C, Albers SV. Mechanisms of gene flow in archaea. Nat Rev Microbiol 2017; 15:492-501. [DOI: 10.1038/nrmicro.2017.41] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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21
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Hynes AP, Shakya M, Mercer RG, Grüll MP, Bown L, Davidson F, Steffen E, Matchem H, Peach ME, Berger T, Grebe K, Zhaxybayeva O, Lang AS. Functional and Evolutionary Characterization of a Gene Transfer Agent's Multilocus "Genome". Mol Biol Evol 2016; 33:2530-43. [PMID: 27343288 PMCID: PMC5026251 DOI: 10.1093/molbev/msw125] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Gene transfer agents (GTAs) are phage-like particles that can package and transfer a random piece of the producing cell’s genome, but are unable to transfer all the genes required for their own production. As such, GTAs represent an evolutionary conundrum: are they selfish genetic elements propagating through an unknown mechanism, defective viruses, or viral structures “repurposed” by cells for gene exchange, as their name implies? In Rhodobacter capsulatus, production of the R. capsulatus GTA (RcGTA) particles is associated with a cluster of genes resembling a small prophage. Utilizing transcriptomic, genetic and biochemical approaches, we report that the RcGTA “genome” consists of at least 24 genes distributed across five distinct loci. We demonstrate that, of these additional loci, two are involved in cell recognition and binding and one in the production and maturation of RcGTA particles. The five RcGTA “genome” loci are widespread within Rhodobacterales, but not all loci have the same evolutionary histories. Specifically, two of the loci have been subject to frequent, probably virus-mediated, gene transfer events. We argue that it is unlikely that RcGTA is a selfish genetic element. Instead, our findings are compatible with the scenario that RcGTA is a virus-derived element maintained by the producing organism due to a selective advantage of within-population gene exchange. The modularity of the RcGTA “genome” is presumably a result of selection on the host organism to retain GTA functionality.
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Affiliation(s)
- Alexander P Hynes
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Migun Shakya
- Department of Biological Sciences, Dartmouth College
| | - Ryan G Mercer
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Marc P Grüll
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Luke Bown
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Fraser Davidson
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Ekaterina Steffen
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Heidi Matchem
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Mandy E Peach
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Tim Berger
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Katherine Grebe
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
| | - Olga Zhaxybayeva
- Department of Biological Sciences, Dartmouth College Department of Computer Science, Dartmouth College
| | - Andrew S Lang
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
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22
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Novick RP, Ram G. The Floating (Pathogenicity) Island: A Genomic Dessert. Trends Genet 2016; 32:114-126. [PMID: 26744223 PMCID: PMC4733582 DOI: 10.1016/j.tig.2015.11.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 11/17/2015] [Accepted: 11/30/2015] [Indexed: 12/30/2022]
Abstract
Among the prokaryotic genomic islands (GIs) involved in horizontal gene transfer (HGT) are the classical pathogenicity islands, including the integrative and conjugative elements (ICEs), the gene-transfer agents (GTAs), and the staphylococcal pathogenicity islands (SaPIs), the primary focus of this review. While the ICEs and GTAs mediate HGT autonomously, the SaPIs are dependent on specific phages. The ICEs transfer primarily their own DNA, the GTAs exclusively transfer unlinked host DNA, and the SaPIs combine the capabilities of both. Thus the SaPIs derive their importance from the genes they carry (their genetic cargo) and the genes they move. They act not only as versatile high-frequency mobilizers but also as mediators of phage interference and consequently are major benefactors of their host bacteria.
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Affiliation(s)
- Richard P Novick
- Department of Medicine, Skirball Institute, New York University Medical School, New York, NY 10016, USA; Department of Microbiology, Skirball Institute, New York University Medical School, New York, NY 10016, USA.
| | - Geeta Ram
- Department of Medicine, Skirball Institute, New York University Medical School, New York, NY 10016, USA; Department of Microbiology, Skirball Institute, New York University Medical School, New York, NY 10016, USA
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23
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Luk AWS, Williams TJ, Erdmann S, Papke RT, Cavicchioli R. Viruses of haloarchaea. Life (Basel) 2014; 4:681-715. [PMID: 25402735 PMCID: PMC4284463 DOI: 10.3390/life4040681] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/23/2014] [Accepted: 10/24/2014] [Indexed: 12/26/2022] Open
Abstract
In hypersaline environments, haloarchaea (halophilic members of the Archaea) are the dominant organisms, and the viruses that infect them, haloarchaeoviruses are at least ten times more abundant. Since their discovery in 1974, described haloarchaeoviruses include head-tailed, pleomorphic, spherical and spindle-shaped morphologies, representing Myoviridae, Siphoviridae, Podoviridae, Pleolipoviridae, Sphaerolipoviridae and Fuselloviridae families. This review overviews current knowledge of haloarchaeoviruses, providing information about classification, morphotypes, macromolecules, life cycles, genetic manipulation and gene regulation, and host-virus responses. In so doing, the review incorporates knowledge from laboratory studies of isolated viruses, field-based studies of environmental samples, and both genomic and metagenomic analyses of haloarchaeoviruses. What emerges is that some haloarchaeoviruses possess unique morphological and life cycle properties, while others share features with other viruses (e.g., bacteriophages). Their interactions with hosts influence community structure and evolution of populations that exist in hypersaline environments as diverse as seawater evaporation ponds, to hot desert or Antarctic lakes. The discoveries of their wide-ranging and important roles in the ecology and evolution of hypersaline communities serves as a strong motivator for future investigations of both laboratory-model and environmental systems.
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Affiliation(s)
- Alison W S Luk
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - Susanne Erdmann
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269-3125, USA.
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
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24
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Naor A, Gophna U. Cell fusion and hybrids in Archaea: prospects for genome shuffling and accelerated strain development for biotechnology. Bioengineered 2012; 4:126-9. [PMID: 23111319 DOI: 10.4161/bioe.22649] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The ability to exchange DNA between cells is a molecular process that exists in different species in the domain Archaea. Such horizontal gene transfer events were shown to take place between distant species of archaea and to result in the transfer of large genomic regions. Here we describe recent progress in this field, discuss the potential use of natural gene exchange processes to perform genome shuffling and argue its possible biotechnological applications.
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Affiliation(s)
- Adit Naor
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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25
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McDaniel LD, Young EC, Ritchie KB, Paul JH. Environmental factors influencing gene transfer agent (GTA) mediated transduction in the subtropical ocean. PLoS One 2012; 7:e43506. [PMID: 22905268 PMCID: PMC3419701 DOI: 10.1371/journal.pone.0043506] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 07/24/2012] [Indexed: 11/18/2022] Open
Abstract
Microbial genomic sequence analyses have indicated widespread horizontal gene transfer (HGT). However, an adequate mechanism accounting for the ubiquity of HGT has been lacking. Recently, high frequencies of interspecific gene transfer have been documented, catalyzed by Gene Transfer Agents (GTAs) of marine α-Proteobacteria. It has been proposed that the presence of bacterial genes in highly purified viral metagenomes may be due to GTAs. However, factors influencing GTA-mediated gene transfer in the environment have not yet been determined. Several genomically sequenced strains containing complete GTA sequences similar to Rhodobacter capsulatus (RcGTA, type strain) were screened to ascertain if they produced putative GTAs, and at what abundance. Five of nine marine strains screened to date spontaneously produced virus-like particles (VLP's) in stationary phase. Three of these strains have demonstrated gene transfer activity, two of which were documented by this lab. These two strains Roseovarius nubinhibens ISM and Nitratireductor 44B9s, were utilized to produce GTAs designated RnGTA and NrGTA and gene transfer activity was verified in culture. Cell-free preparations of purified RnGTA and NrGTA particles from marked donor strains were incubated with natural microbial assemblages to determine the level of GTA-mediated gene transfer. In conjunction, several ambient environmental parameters were measured including lysogeny indicated by prophage induction. GTA production in culture systems indicated that approximately half of the strains produced GTA-like particles and maximal GTA counts ranged from 10-30% of host abundance. Modeling of GTA-mediated gene transfer frequencies in natural samples, along with other measured environmental variables, indicated a strong relationship between GTA mediated gene transfer and the combined factors of salinity, multiplicity of infection (MOI) and ambient bacterial abundance. These results indicate that GTA-mediated HGT in the marine environment with the strains examined is favored during times of elevated bacterial and GTA abundance as well as in areas of higher salinity.
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Affiliation(s)
- Lauren D McDaniel
- College of Marine Science, University of South Florida, St. Petersburg, Florida, United States of America.
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26
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Lang AS, Zhaxybayeva O, Beatty JT. Gene transfer agents: phage-like elements of genetic exchange. Nat Rev Microbiol 2012; 10:472-82. [PMID: 22683880 DOI: 10.1038/nrmicro2802] [Citation(s) in RCA: 255] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Horizontal gene transfer is important in the evolution of bacterial and archaeal genomes. An interesting genetic exchange process is carried out by diverse phage-like gene transfer agents (GTAs) that are found in a wide range of prokaryotes. Although GTAs resemble phages, they lack the hallmark capabilities that define typical phages, and they package random pieces of the producing cell's genome. In this Review, we discuss the defining characteristics of the GTAs that have been identified to date, along with potential functions for these agents and the possible evolutionary forces that act on the genes involved in their production.
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Affiliation(s)
- Andrew S Lang
- Department of Biology, Memorial University, St. John's, Newfoundland and Labrador A1B 3X9, Canada.
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27
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A thaumarchaeal provirus testifies for an ancient association of tailed viruses with archaea. Biochem Soc Trans 2011; 39:82-8. [PMID: 21265751 DOI: 10.1042/bst0390082] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Archaeal viruses, or archaeoviruses, display a wide range of virion morphotypes. Whereas the majority of those morphotypes are unique to archaeal viruses, some are more widely distributed across different cellular domains. Tailed double-stranded DNA archaeoviruses are remarkably similar to viruses of the same morphology (order Caudovirales) that infect many bacterial hosts. They have, so far, only been found in one phylum of the archaea, the Euryarchaeota, which has led to controversial hypotheses about their origin. In the present paper, we describe the identification and analysis of a putative provirus present in the genome of a mesophilic thaumarchaeon. We show that the provirus is related to tailed bacterial and euryarchaeal viruses and encodes a full complement of proteins that are required to build a tailed virion. The recently discovered wide distribution of tailed viruses in Euryarchaeota and the identification of a related provirus in Thaumarchaeota, an archaeal phylum which might have branched off before the separation of Crenarchaeota and Euryarchaeota, suggest that an association of these viruses with Archaea might be more ancient than previously anticipated.
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28
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Chiura HX, Kogure K, Hagemann S, Ellinger A, Velimirov B. Evidence for particle-induced horizontal gene transfer and serial transduction between bacteria. FEMS Microbiol Ecol 2011; 76:576-91. [PMID: 21361998 DOI: 10.1111/j.1574-6941.2011.01077.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Incubation of the amino acid-deficient strain Escherichia coli AB1157 with particles harvested from an oligotrophic environment revealed evidence of horizontal gene transfer (HGT) with restoration of all deficiencies in revertant cells with frequencies up to 1.94 × 10(-5). None of the markers were preferentially transferred, indicating that the DNA transfer is performed by generalized transduction. The highest gene transfer frequencies were obtained for single markers, with values up to 1.04 × 10(-2). All revertants were able to produce particles of comparable size, appearing at the beginning of the stationary phase. Examination of the revertants using electron microscopy showed bud-like structures with electron-dense bodies. The particles that display the structural features of membrane vesicles were again infectious to E. coli AB1157, producing new infectious particles able to transduce genetic information, a phenomenon termed serial transduction. Thus, the <0.2-μm particle fraction from seawater contains a particle size fraction with high potential for gene transfer. Biased sinusoidal field gel electrophoresis indicated a DNA content for the particles of 370 kbp, which was higher than that of known membrane vesicles. These findings provide evidence of a new method of HGT, in which mobilizable DNA is trafficked from donor to recipient cells via particles.
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Affiliation(s)
- Hiroshi Xavier Chiura
- Marine Microbiology Laboratory, Department of Marine Ecosystems Dynamics, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Chiba, Japan
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29
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Hartman AL, Norais C, Badger JH, Delmas S, Haldenby S, Madupu R, Robinson J, Khouri H, Ren Q, Lowe TM, Maupin-Furlow J, Pohlschroder M, Daniels C, Pfeiffer F, Allers T, Eisen JA. The complete genome sequence of Haloferax volcanii DS2, a model archaeon. PLoS One 2010; 5:e9605. [PMID: 20333302 PMCID: PMC2841640 DOI: 10.1371/journal.pone.0009605] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 02/11/2010] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Haloferax volcanii is an easily culturable moderate halophile that grows on simple defined media, is readily transformable, and has a relatively stable genome. This, in combination with its biochemical and genetic tractability, has made Hfx. volcanii a key model organism, not only for the study of halophilicity, but also for archaeal biology in general. METHODOLOGY/PRINCIPAL FINDINGS We report here the sequencing and analysis of the genome of Hfx. volcanii DS2, the type strain of this species. The genome contains a main 2.848 Mb chromosome, three smaller chromosomes pHV1, 3, 4 (85, 438, 636 kb, respectively) and the pHV2 plasmid (6.4 kb). CONCLUSIONS/SIGNIFICANCE The completed genome sequence, presented here, provides an invaluable tool for further in vivo and in vitro studies of Hfx. volcanii.
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Affiliation(s)
- Amber L. Hartman
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
- UC Davis Genome Center, University of California Davis, Davis, California, United States of America
| | - Cédric Norais
- Institut de Génétique et Microbiologie, Université Paris-Sud, Paris, France
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jonathan H. Badger
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Stéphane Delmas
- Institute of Genetics, University of Nottingham, Nottingham, United Kingdom
| | - Sam Haldenby
- Institute of Genetics, University of Nottingham, Nottingham, United Kingdom
| | - Ramana Madupu
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Jeffrey Robinson
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Hoda Khouri
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Qinghu Ren
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Todd M. Lowe
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Julie Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Mecky Pohlschroder
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Charles Daniels
- Department of Microbiology, Ohio State University, Columbus, Ohio, United States of America
| | - Friedhelm Pfeiffer
- Department of Membrane Biochemistry, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Thorsten Allers
- Institute of Genetics, University of Nottingham, Nottingham, United Kingdom
| | - Jonathan A. Eisen
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
- UC Davis Genome Center, University of California Davis, Davis, California, United States of America
- Department of Medical Microbiology and Immunology, University of California Davis, Davis, California, United States of America
- Department of Evolution and Ecology, University of California Davis, Davis, California, United States of America
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30
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Krupovič M, Forterre P, Bamford DH. Comparative Analysis of the Mosaic Genomes of Tailed Archaeal Viruses and Proviruses Suggests Common Themes for Virion Architecture and Assembly with Tailed Viruses of Bacteria. J Mol Biol 2010; 397:144-60. [DOI: 10.1016/j.jmb.2010.01.037] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/12/2010] [Accepted: 01/19/2010] [Indexed: 10/19/2022]
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31
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Berglund EC, Frank AC, Calteau A, Vinnere Pettersson O, Granberg F, Eriksson AS, Näslund K, Holmberg M, Lindroos H, Andersson SGE. Run-off replication of host-adaptability genes is associated with gene transfer agents in the genome of mouse-infecting Bartonella grahamii. PLoS Genet 2009; 5:e1000546. [PMID: 19578403 PMCID: PMC2697382 DOI: 10.1371/journal.pgen.1000546] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 06/01/2009] [Indexed: 11/20/2022] Open
Abstract
The genus Bartonella comprises facultative intracellular bacteria adapted to mammals, including previously recognized and emerging human pathogens. We report the 2,341,328 bp genome sequence of Bartonella grahamii, one of the most prevalent Bartonella species in wild rodents. Comparative genomics revealed that rodent-associated Bartonella species have higher copy numbers of genes for putative host-adaptability factors than the related human-specific pathogens. Many of these gene clusters are located in a highly dynamic region of 461 kb. Using hybridization to a microarray designed for the B. grahamii genome, we observed a massive, putatively phage-derived run-off replication of this region. We also identified a novel gene transfer agent, which packages the bacterial genome, with an over-representation of the amplified DNA, in 14 kb pieces. This is the first observation associating the products of run-off replication with a gene transfer agent. Because of the high concentration of gene clusters for host-adaptation proteins in the amplified region, and since the genes encoding the gene transfer agent and the phage origin are well conserved in Bartonella, we hypothesize that these systems are driven by selection. We propose that the coupling of run-off replication with gene transfer agents promotes diversification and rapid spread of host-adaptability factors, facilitating host shifts in Bartonella. Emerging infectious diseases represent an increasing human health problem with many examples of disease outbreaks caused by transmissions from animals to humans, such as, most recently, the bird flu virus. Genes involved in virulence and antibiotic resistance are often carried by mobile elements like plasmids and viruses, which mediate transfer between cells at an amazing speed. Rodents represent a major carrier of infectious agents, and it is therefore particularly important to study the gene transfer processes in bacteria that use rodents as their natural host reservoir. We have studied the genome of a bacterium that is naturally adapted to mice and identified many more putative host-interaction genes than were observed in previously recognized human pathogens. Furthermore, most of these genes are located in a segment of about 25% of the genome, which was massively amplified and packaged into viral particles. This is the first demonstration of targeted packaging of a portion of the bacterial chromosome into viral particles, and we propose that this is a novel strategy for increased exchange of genes involved in the infectious process.
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Affiliation(s)
- Eva C. Berglund
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - A. Carolin Frank
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Alexandra Calteau
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Olga Vinnere Pettersson
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Fredrik Granberg
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Ann-Sofie Eriksson
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Kristina Näslund
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Martin Holmberg
- Department of Medical Sciences, Section for Infectious Diseases, Uppsala University Hospital, Uppsala, Sweden
| | - Hillevi Lindroos
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Siv G. E. Andersson
- Department of Molecular Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- * E-mail:
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32
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Identification of a divided genome for VSH-1, the prophage-like gene transfer agent of Brachyspira hyodysenteriae. J Bacteriol 2008; 191:1719-21. [PMID: 19103931 DOI: 10.1128/jb.01359-08] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Brachyspira hyodysenteriae B204 genome sequence revealed three VSH-1 tail genes, hvp31, hvp60, and hvp37, in a 3.6-kb cluster. The location and transcription direction of these genes relative to those of the previously described VSH-1 16.3-kb gene operon indicate that the gene transfer agent VSH-1 has a noncontiguous, divided genome.
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33
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Zaneveld JR, Nemergut DR, Knight R. Are all horizontal gene transfers created equal? Prospects for mechanism-based studies of HGT patterns. MICROBIOLOGY-SGM 2008; 154:1-15. [PMID: 18174121 DOI: 10.1099/mic.0.2007/011833-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Detecting patterns of horizontal gene transfer (HGT) in genomic sequences is an important problem, with implications for evolution, ecology, biotechnology and medicine. Extensive genetic, biochemical and genomic studies have provided a good understanding of sequence features that are associated with many (though not all) known mobile elements and mechanisms of gene transfer. This information, however, is not currently incorporated into automated methods for gene transfer detection in genomic data. In this review, we argue that automated annotation of sequence features associated with gene transfer mechanisms could be used both to build more sensitive, mechanism-specific compositional models for the detection of some types of HGT in genomic data, and to ask new questions about the classes of genes most frequently transferred by each mechanism. We then summarize the genes and sequence features associated with different mechanisms of horizontal transfer, emphasizing those that are most useful for distinguishing types of transfer when examining genomic data, and noting those classes of transfers that cannot be distinguished in genomic data using existing techniques. Finally, we describe software, databases and algorithms for identifying particular classes of mobile elements, and outline prospects for better detection of HGT based on specific mechanisms of transfer.
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Affiliation(s)
- Jesse R Zaneveld
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Diana R Nemergut
- Institute of Arctic and Alpine Research (INSTAAR) and Environmental Studies Program, University of Colorado, Boulder, CO 80309, USA
| | - Rob Knight
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
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34
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Matson EG, Zuerner RL, Stanton TB. Induction and transcription of VSH-1, a prophage-like gene transfer agent of Brachyspira hyodysenteriae. Anaerobe 2007; 13:89-97. [PMID: 17540587 DOI: 10.1016/j.anaerobe.2007.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2006] [Revised: 04/06/2007] [Accepted: 04/18/2007] [Indexed: 11/16/2022]
Abstract
The anaerobic spirochete Brachyspira hyodysenteriae is host to a bacteriophage-like agent known as VSH-1. VSH-1 is a novel gene transfer mechanism which does not self-propagate and transfers random 7.5kb fragments of host DNA between B. hyodysenteriae cells. In these investigations early events during VSH-1 induction by mitomycin C were examined. Quantitative PCR analysis revealed that VSH-1 hvp38 and hvp53 genes did not detectably increase in copy numbers during induction. Based on Northern blot hybridization assays, transcription of VSH-1 genes hvp38, hvp53, hvp45, hvp101, and lys increased fivefold to tenfold between 2 and 4h after induction whereas mRNA levels for B. hyodysenteriae flaA1 declined over the same time period. Chloramphenicol prevented the mitomycin C-induced increases in VSH-1 gene transcription. Hydrogen peroxide (300muM) substituted for mitomycin C as an inducer of VSH-1 gene transcription and is a possible 'natural' inducer of VSH-1 production in vivo. Northern blot hybridization, RT PCR, and primer extension analyses showed that VSH-1 genes are co-transcribed at an initiation site upstream of the VSH-1 gene operon. Two direct heptanucleotide repeats (ACTTATA) were identified between the putative -35 and -10 positions of the VSH-1 gene operon and are likely to represent a binding site for transcription proteins. These findings indicate VSH-1 virion production does not require genome replication, consistent with the inability of VSH-1 to self-propagate. Early events in VSH-1 induction include de novo synthesis of protein(s) essential for transcription of VSH-1 genes as polycistronic mRNA initiating upstream of the hvp45 gene.
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Affiliation(s)
- Eric G Matson
- Department of Microbiology, Iowa State University, Ames, IA 50010, USA
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35
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Stanton TB. Prophage-like gene transfer agents-novel mechanisms of gene exchange for Methanococcus, Desulfovibrio, Brachyspira, and Rhodobacter species. Anaerobe 2007; 13:43-9. [PMID: 17513139 DOI: 10.1016/j.anaerobe.2007.03.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 03/04/2007] [Indexed: 11/29/2022]
Abstract
Gene transfer agents (GTAs) are novel mechanisms for bacterial gene transfer. They resemble small, tailed bacteriophages in ultrastructure and act like generalized transducing prophages. In contrast to functional prophages, GTAs package random fragments of bacterial genomes and incomplete copies of their own genomes. The packaged DNA content is characteristic of the GTA and ranges in size from 4.4 to 13.6kb. GTAs have been reported in species of Brachyspira, Methanococcus, Desulfovibrio, and Rhodobacter. The best studied GTAs are VSH-1 of the anaerobic, pathogenic spirochete Brachyspira hyodysenteriae and RcGTA of the nonsulfur, purple, photosynthetic bacterium Rhodobacter capsulatus. VSH-1 and RcGTA have likely contributed to the ecology and evolution of these bacteria. The existence of GTAs in phylogenetically diverse bacteria suggests GTAs may be more common in nature than is now appreciated.
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Affiliation(s)
- Thad B Stanton
- Enteric Diseases and Food Safety Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, 2300 Dayton Road, Ames, IA 50010, USA.
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36
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Lang AS, Beatty JT. Importance of widespread gene transfer agent genes in α-proteobacteria. Trends Microbiol 2007; 15:54-62. [PMID: 17184993 DOI: 10.1016/j.tim.2006.12.001] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 11/13/2006] [Accepted: 12/06/2006] [Indexed: 10/23/2022]
Abstract
The gene transfer agent produced by Rhodobacter capsulatus (RcGTA) is a model for several virus-like elements that seem to function solely for mediating gene exchange. Several genes that encode RcGTA are clearly related to bacteriophage genes but the cellular regulatory mechanisms that control RcGTA production indicate that RcGTA is more than just a defective prophage. Genome sequencing projects show that seemingly functional RcGTA-like structural gene clusters are present in many other species of alpha-proteobacteria, which might also produce RcGTA-like particles. Here, we use the genomic sequence data that are currently available to identify candidate GTA-producing species and propose an evolutionary scheme for RcGTA-like elements in the alpha-proteobacteria.
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Affiliation(s)
- Andrew S Lang
- Department of Biology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada.
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37
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Matson EG, Thompson MG, Humphrey SB, Zuerner RL, Stanton TB. Identification of genes of VSH-1, a prophage-like gene transfer agent of Brachyspira hyodysenteriae. J Bacteriol 2005; 187:5885-92. [PMID: 16109929 PMCID: PMC1196157 DOI: 10.1128/jb.187.17.5885-5892.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
VSH-1 is a mitomycin C-inducible prophage of the anaerobic spirochete Brachyspira hyodysenteriae. Purified VSH-1 virions are noninfectious, contain random 7.5-kb fragments of the bacterial genome, and mediate generalized transduction of B. hyodysenteriae cells. In order to identify and sequence genes of this novel gene transfer agent (GTA), proteins associated either with VSH-1 capsids or with tails were purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal amino acid sequences of 11 proteins were determined. Degenerate PCR primers were designed from the amino acid sequences and used to amplify several VSH-1 genes from B. hyodysenteriae strain B204 DNA. A lambda clone library of B. hyodysenteriae B204 DNA was subsequently screened by Southern hybridization methods and used to identify and sequence overlapping DNA inserts containing additional VSH-1 genes. VSH-1 genes spanned 16.3 kb of the B. hyodysenteriae chromosome and were flanked by bacterial genes. VSH-1 identified genes and unidentified, intervening open reading frames were consecutively organized in head (seven genes), tail (seven genes), and lysis (four genes) clusters in the same transcriptional direction. Putative lysis genes encoding endolysin (Lys) and holin proteins were identified from sequence and structural similarities of their translated protein products with GenBank bacteriophage proteins. Recombinant Lys protein hydrolyzed peptidoglycan purified from B. hyodysenteriae cells. The identified VSH-1 genes exceed the DNA capacity of VSH-1 virions and do not encode traditional bacteriophage early functions involved in DNA replication. These genome properties explain the noninfectious nature of VSH-1 virions and further confirm its resemblance to known prophage-like, GTAs of other bacterial species, such as the GTA from Rhodobacter capsulatus. The identification of VSH-1 genes will enable analysis of the regulation of this GTA and should facilitate investigations of VSH-1-like prophages from other Brachyspira species.
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Affiliation(s)
- Eric G Matson
- Enteric Diseases and Food Safety Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, 2300 Dayton Road, Ames, IA 50010, USA
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Abstract
For decades, archaea were misclassified as bacteria because of their prokaryotic morphology. Molecular phylogeny eventually revealed that archaea, like bacteria and eukaryotes, are a fundamentally distinct domain of life. Genome analyses have confirmed that archaea share many features with eukaryotes, particularly in information processing, and therefore can serve as streamlined models for understanding eukaryotic biology. Biochemists and structural biologists have embraced the study of archaea but geneticists have been more wary, despite the fact that genetic techniques for archaea are quite sophisticated. It is time for geneticists to start asking fundamental questions about our distant relatives.
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Affiliation(s)
- Thorsten Allers
- Institute of Genetics, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
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39
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Chiura HX, Umitsu M. Isolation and Characterisation of Broad-Host Range Gene Transporter Particles from Geo-Thermal Vent of the Toyoha Mine. Microbes Environ 2004. [DOI: 10.1264/jsme2.19.20] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Hiroshi Xavier Chiura
- Department of Biology, Division of Natural Sciences, International Christian University
| | - Masataka Umitsu
- Department of Biology, Division of Natural Sciences, International Christian University
- KOKORO Biology Group, Laboratories for Integrated Biology, Graduate School of Frontier Biosciences, Osaka University
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40
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Affiliation(s)
- Hiroshi Xavier Chiura
- Department of Biology, Division of Natural Sciences, International Christian University
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41
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Shingaki R, Kasahara Y, Inoue T, Kokeguchi S, Fukui K. Chromosome DNA fragmentation and excretion caused by defective prophage gene expression in the early-exponential-phase culture of Bacillus subtilis. Can J Microbiol 2003; 49:313-25. [PMID: 12897825 DOI: 10.1139/w03-041] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bacillus subtilis 168 and its major autolysin mutant, AN8, were shown to excrete two size classes of DNA when cultured in Luria-Bertani medium. Pulsed-field gel electrophoresis of DNA harvested from the cell surface demonstrated the presence of 13-kb-long and circa 50-kb-long strands. Restriction digestion of both sizes of DNA resulted in a smearing pattern, as observed by agarose gel electrophoresis. Shotgun sequencing of DNase I partial digests of 50-kb DNA fragments revealed that the strands originate from various sites on the chromosome. SDS-PAGE analysis of cell surface fractions and culture supernatants demonstrated the presence of several proteins that were thought to be associated with the DNA. Of these, three major proteins were identified, i.e., XkdG, XkdK, and XkdM, by tandem mass spectrometry, all of which were proteins of a defective prophage PBSX residing in the Bacillus subtilis chromosome. Disruption of these PBSX genes resulted in a reduction of 13-kb fragment generation and excretion and also a great reduction of 50-kb fragment excretion. Electron microscopy showed that a few mature phages and numerous membrane vesicle-like particles existed in the cell surface fractions of strain 168. The present findings suggest that the spontaneous generation and excretion of chromosome DNA fragments in Bacillus subtilis are both closely related to the expression of defective prophage genes.
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Affiliation(s)
- Ryuji Shingaki
- Department of Oral Microbiology, Okayama University Graduate School of Medicine and Dentistry, Shikata-cho, Okayama 700-8525, Japan.
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42
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Bibb LA, Hatfull GF. Integration and excision of the Mycobacterium tuberculosis prophage-like element, phiRv1. Mol Microbiol 2002; 45:1515-26. [PMID: 12354222 DOI: 10.1046/j.1365-2958.2002.03130.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The genomes of Mycobacterium tuberculosis H37Rv and CDC1551 each contain two prophage-like elements, phiRv1 and phiRv2. The phiRv1 element is not only absent from Mycobacterium bovis BCG but is in different locations within the two sequenced M. tuberculosis genomes; in both cases phiRv1 is inserted into a REP13E12 repeated sequence, which presumably contains the bacterial attachment site, attB, for phiRv1. Although phiRv1 is probably too small to encode infectious phage particles, it may nevertheless have an active integration/excision system and be capable of moving from one chromosomal position to another. We show here that the M. tuberculosis H37Rv phiRv1 element does indeed encode an active site-specific recombination system in which an integrase of the serine recombinase family (Rv1586c) catalyses integration and excision and a small, basic phiRv1-encoded protein (Rv1584c) controls the directionality of re-combination. Integration-proficient plasmid vectors derived from phiRv1 efficiently transform BCG, can utilize four of the seven REP13E12 sites present in BCG as attachment sites, and can occupy more than one site simultaneously.
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Affiliation(s)
- Lori A Bibb
- Department of Biological Sciences, University of Pittsburgh, PA 15260, USA
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43
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Chiura HX. Broad Host Range Xenotrophic Gene Transfer by Virus-Like Particles from a Hot Spring. Microbes Environ 2002. [DOI: 10.1264/jsme2.2002.53] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Hiroshi Xavier Chiura
- Department of Biology, Division of Natural Sciences, International Christian University
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44
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Abstract
Members of the Archaea domain are extremely diverse in their adaptation to extreme environments, yet also widespread in "normal" habitats. Altogether, among the best characterized archaeal representatives all mechanisms of gene transfer such as transduction, conjugation, and transformation have been discovered, as briefly reviewed here. For some halophiles and mesophilic methanogens, usable genetic tools were developed for in vivo studies. However, on an individual basis no single organism has evolved into the "E. coli of Archaea" as far as genetics is concerned. Currently, and unfortunately, most of the genome sequences available are those of microorganisms which are either not amenable to gene transfer or not among the most promising candidates for genetic studies.
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Affiliation(s)
- Y Luo
- Institute of Microbiology, Swiss Federal Institute of Technology Zürich
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45
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Lang AS, Beatty JT. Genetic analysis of a bacterial genetic exchange element: the gene transfer agent of Rhodobacter capsulatus. Proc Natl Acad Sci U S A 2000; 97:859-64. [PMID: 10639170 PMCID: PMC15421 DOI: 10.1073/pnas.97.2.859] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An unusual system of genetic exchange exists in the purple nonsulfur bacterium Rhodobacter capsulatus. DNA transmission is mediated by a small bacteriophage-like particle called the gene transfer agent (GTA) that transfers random 4.5-kb segments of the producing cell's genome to recipient cells, where allelic replacement occurs. This paper presents the results of gene cloning, analysis, and mutagenesis experiments that show that GTA resembles a defective prophage related to bacteriophages from diverse genera of bacteria, which has been adopted by R. capsulatus for genetic exchange. A pair of cellular proteins, CckA and CtrA, appear to constitute part of a sensor kinase/response regulator signaling pathway that is required for expression of GTA structural genes. This signaling pathway controls growth-phase-dependent regulation of GTA gene messages, yielding maximal gene expression in the stationary phase. We suggest that GTA is an ancient prophage remnant that has evolved in concert with the bacterial genome, resulting in a genetic exchange process controlled by the bacterial cell.
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Affiliation(s)
- A S Lang
- Department of Microbiology and Immunology, University of British Columbia, 6174 University Boulevard, Vancouver, British Columbia, Canada, V6T 1Z3
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46
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Eiserling F, Pushkin A, Gingery M, Bertani G. Bacteriophage-like particles associated with the gene transfer agent of methanococcus voltae PS. J Gen Virol 1999; 80 ( Pt 12):3305-3308. [PMID: 10567664 DOI: 10.1099/0022-1317-80-12-3305] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The methanogenic archaeobacterium Methanococcus voltae (strain PS) is known to produce a filterable, DNase-resistant agent (called VTA, for voltae transfer agent), which carries very small fragments (4400 bp) of bacterial DNA and is able to transduce bacterial genes between derivatives of the strain. Examination by electron microscopy of two preparations of VTA that were concentrated and partially purified by different methods showed virus-like particles with isometric heads, about 40 nm in diameter, and with 61 nm long tails. These particles co-sedimented with the minute bacteriophage φX174 in a sucrose density gradient.
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Affiliation(s)
- F Eiserling
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA1
| | - A Pushkin
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA1
| | - M Gingery
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA1
| | - G Bertani
- Jet Propulsion Laboratory 125-224, California Institute of Technology, Pasadena, CA 91109, USA2
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