1
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Mäntynen S, Salomaa MM, Poranen MM. Diversity and Current Classification of dsRNA Bacteriophages. Viruses 2023; 15:2154. [PMID: 38005832 PMCID: PMC10674327 DOI: 10.3390/v15112154] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/11/2023] [Accepted: 10/22/2023] [Indexed: 11/26/2023] Open
Abstract
Half a century has passed since the discovery of Pseudomonas phage phi6, the first enveloped dsRNA bacteriophage to be isolated. It remained the sole known dsRNA phage for a quarter of a century and the only recognised member of the Cystoviridae family until the year 2018. After the initial discovery of phi6, additional dsRNA phages have been isolated from globally distant locations and identified in metatranscriptomic datasets, suggesting that this virus type is more ubiquitous in nature than previously acknowledged. Most identified dsRNA phages infect Pseudomonas strains and utilise either pilus or lipopolysaccharide components of the host as the primary receptor. In addition to the receptor-mediated strictly lytic lifestyle, an alternative persistent infection strategy has been described for some dsRNA phages. To date, complete genome sequences of fourteen dsRNA phage isolates are available. Despite the high sequence diversity, similar sets of genes can typically be found in the genomes of dsRNA phages, suggesting shared evolutionary trajectories. This review provides a brief overview of the recognised members of the Cystoviridae virus family and related dsRNA phage isolates, outlines the current classification of dsRNA phages, and discusses their relationships with eukaryotic RNA viruses.
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Affiliation(s)
- Sari Mäntynen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland; (M.M.S.); (M.M.P.)
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2
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Luo Y, Yu L, Feng Z, Chen Q, Lu L, Zhang Q, Xu D. Integrated analysis of viral miRNAs, mRNA and protein in the caudal fin cells of C. auratus gibelio with cyprinid herpesvirus 2 infection. JOURNAL OF FISH DISEASES 2021; 44:441-460. [PMID: 33577719 DOI: 10.1111/jfd.13289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/26/2020] [Accepted: 09/29/2020] [Indexed: 06/12/2023]
Abstract
Cyprinid herpesvirus 2 (CyHV-2), a member of the genus Cyprinivirus in the family Alloherpesviridae, has attracted worldwide attention because it causes severe disease and high mortality in crucian carp and goldfish. In this study, we focus on mRNA, protein and viral miRNA expression profiles in C. auratus gibelio caudal fin (GiCF) cells infected with CyHV-2, using high-throughput sequence techniques and TMT-labelled analyses. The results revealed that 156 virus genes were differentially expressed during the infection. Among these differentially expressed genes, 7 viral genes were significantly up-regulated and 28 were significantly down-regulated at 96 hpi (hours post-infection) vs 48 hpi. Besides, a total of 78 viral proteins, including a large number of membrane proteins and capsid proteins associated with the viral assembly, were successfully detected by using proteome analysis. Furthermore, a total of 225,143,474 raw reads were generated from cDNA library of CyHV-2-infected GiCF cells using high-throughput sequencing technology. Following annotation and secondary structure prediction, 10 viral miRNAs were found as significantly modulated in CyHV-2-infected GiCF cells (2 down-regulated and 8 up-regulated). Finally, the CyHV-2 genes (orf19, orf23, orf118, orf121, orf127) targeted by the viral miRNA CyHV-2-KT-635 identified in this study, were predicted and validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR), and the regulation of CyHV-2-KT-635 on orf121 protein expression was verified by western blotting assay. Taken together, this study provides a valuable basis for further research on the expression of virus genes during CyHV-2 replication and the molecular mechanisms by which miRNA may regulate CyHV-2 virus.
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Affiliation(s)
- Yang Luo
- National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China
- Key Laboratory of Aquaculture Ministry for Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Shanghai, China
| | - Lu Yu
- National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China
- Key Laboratory of Aquaculture Ministry for Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Shanghai, China
| | - Zizhao Feng
- National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China
- Key Laboratory of Aquaculture Ministry for Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Shanghai, China
| | - Qikang Chen
- National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China
- Key Laboratory of Aquaculture Ministry for Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Shanghai, China
| | - Liqun Lu
- National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China
- Key Laboratory of Aquaculture Ministry for Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Shanghai, China
- National Experimental Teaching Demonstration Center for Fishery Sciences, Shanghai Ocean University, Shanghai, China
| | - Qiya Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Wuhan, China
| | - Dan Xu
- National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, China
- Key Laboratory of Aquaculture Ministry for Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Shanghai, China
- National Experimental Teaching Demonstration Center for Fishery Sciences, Shanghai Ocean University, Shanghai, China
- Guangxi Key Laboratory of Marine Natural Products and Combinatorial Biosynthesis Chemistry, Guangxi Academy of Sciences, Nanning, China
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3
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Structure Unveils Relationships between RNA Virus Polymerases. Viruses 2021; 13:v13020313. [PMID: 33671332 PMCID: PMC7922027 DOI: 10.3390/v13020313] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 12/30/2022] Open
Abstract
RNA viruses are the fastest evolving known biological entities. Consequently, the sequence similarity between homologous viral proteins disappears quickly, limiting the usability of traditional sequence-based phylogenetic methods in the reconstruction of relationships and evolutionary history among RNA viruses. Protein structures, however, typically evolve more slowly than sequences, and structural similarity can still be evident, when no sequence similarity can be detected. Here, we used an automated structural comparison method, homologous structure finder, for comprehensive comparisons of viral RNA-dependent RNA polymerases (RdRps). We identified a common structural core of 231 residues for all the structurally characterized viral RdRps, covering segmented and non-segmented negative-sense, positive-sense, and double-stranded RNA viruses infecting both prokaryotic and eukaryotic hosts. The grouping and branching of the viral RdRps in the structure-based phylogenetic tree follow their functional differentiation. The RdRps using protein primer, RNA primer, or self-priming mechanisms have evolved independently of each other, and the RdRps cluster into two large branches based on the used transcription mechanism. The structure-based distance tree presented here follows the recently established RdRp-based RNA virus classification at genus, subfamily, family, order, class and subphylum ranks. However, the topology of our phylogenetic tree suggests an alternative phylum level organization.
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Zheng Y, Tai W. Insight into the siRNA transmembrane delivery—From cholesterol conjugating to tagging. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2019; 12:e1606. [DOI: 10.1002/wnan.1606] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 01/25/2023]
Affiliation(s)
- Yan Zheng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University Wuhan China
| | - Wanyi Tai
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Education, School of Pharmaceutical Sciences, Wuhan University Wuhan China
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5
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Mäntynen S, Sundberg LR, Oksanen HM, Poranen MM. Half a Century of Research on Membrane-Containing Bacteriophages: Bringing New Concepts to Modern Virology. Viruses 2019; 11:E76. [PMID: 30669250 PMCID: PMC6356626 DOI: 10.3390/v11010076] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 12/14/2022] Open
Abstract
Half a century of research on membrane-containing phages has had a major impact on virology, providing new insights into virus diversity, evolution and ecological importance. The recent revolutionary technical advances in imaging, sequencing and lipid analysis have significantly boosted the depth and volume of knowledge on these viruses. This has resulted in new concepts of virus assembly, understanding of virion stability and dynamics, and the description of novel processes for viral genome packaging and membrane-driven genome delivery to the host. The detailed analyses of such processes have given novel insights into DNA transport across the protein-rich lipid bilayer and the transformation of spherical membrane structures into tubular nanotubes, resulting in the description of unexpectedly dynamic functions of the membrane structures. Membrane-containing phages have provided a framework for understanding virus evolution. The original observation on membrane-containing bacteriophage PRD1 and human pathogenic adenovirus has been fundamental in delineating the concept of "viral lineages", postulating that the fold of the major capsid protein can be used as an evolutionary fingerprint to trace long-distance evolutionary relationships that are unrecognizable from the primary sequences. This has brought the early evolutionary paths of certain eukaryotic, bacterial, and archaeal viruses together, and potentially enables the reorganization of the nearly immeasurable virus population (~1 × 1031) on Earth into a reasonably low number of groups representing different architectural principles. In addition, the research on membrane-containing phages can support the development of novel tools and strategies for human therapy and crop protection.
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Affiliation(s)
- Sari Mäntynen
- Center of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland.
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA.
| | - Lotta-Riina Sundberg
- Center of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland.
| | - Hanna M Oksanen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
| | - Minna M Poranen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
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6
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Controlled Disassembly and Purification of Functional Viral Subassemblies Using Asymmetrical Flow Field-Flow Fractionation (AF4). Viruses 2018; 10:v10110579. [PMID: 30360510 PMCID: PMC6265779 DOI: 10.3390/v10110579] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/17/2018] [Accepted: 10/19/2018] [Indexed: 02/07/2023] Open
Abstract
Viruses protect their genomes by enclosing them into protein capsids that sometimes contain lipid bilayers that either reside above or below the protein layer. Controlled dissociation of virions provides important information on virion composition, interactions, and stoichiometry of virion components, as well as their possible role in virus life cycles. Dissociation of viruses can be achieved by using various chemicals, enzymatic treatments, and incubation conditions. Asymmetrical flow field-flow fractionation (AF4) is a gentle method where the separation is based on size. Here, we applied AF4 for controlled dissociation of enveloped bacteriophage φ6. Our results indicate that AF4 can be used to assay the efficiency of the dissociation process and to purify functional subviral particles.
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7
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Callanan J, Stockdale SR, Shkoporov A, Draper LA, Ross RP, Hill C. RNA Phage Biology in a Metagenomic Era. Viruses 2018; 10:E386. [PMID: 30037084 PMCID: PMC6071253 DOI: 10.3390/v10070386] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/22/2022] Open
Abstract
The number of novel bacteriophage sequences has expanded significantly as a result of many metagenomic studies of phage populations in diverse environments. Most of these novel sequences bear little or no homology to existing databases (referred to as the "viral dark matter"). Also, these sequences are primarily derived from DNA-encoded bacteriophages (phages) with few RNA phages included. Despite the rapid advancements in high-throughput sequencing, few studies enrich for RNA viruses, i.e., target viral rather than cellular fraction and/or RNA rather than DNA via a reverse transcriptase step, in an attempt to capture the RNA viruses present in a microbial communities. It is timely to compile existing and relevant information about RNA phages to provide an insight into many of their important biological features, which should aid in sequence-based discovery and in their subsequent annotation. Without comprehensive studies, the biological significance of RNA phages has been largely ignored. Future bacteriophage studies should be adapted to ensure they are properly represented in phageomic studies.
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Affiliation(s)
- Julie Callanan
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- School of Microbiology, University College Cork, Cork, T12 YN60, Ireland.
| | - Stephen R Stockdale
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, P61 C996, Ireland.
| | - Andrey Shkoporov
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
| | - Lorraine A Draper
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- School of Microbiology, University College Cork, Cork, T12 YN60, Ireland.
| | - R Paul Ross
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- School of Microbiology, University College Cork, Cork, T12 YN60, Ireland.
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, P61 C996, Ireland.
| | - Colin Hill
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- School of Microbiology, University College Cork, Cork, T12 YN60, Ireland.
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8
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Mäntynen S, Sundberg LR, Poranen MM. Recognition of six additional cystoviruses: Pseudomonas virus phi6 is no longer the sole species of the family Cystoviridae. Arch Virol 2017; 163:1117-1124. [PMID: 29260329 DOI: 10.1007/s00705-017-3679-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/10/2017] [Indexed: 12/27/2022]
Abstract
Cystoviridae is a family of bacterial viruses (bacteriophages) with a tri-segmented dsRNA genome. It includes a single genus Cystovirus, which has presently only one recognised virus species, Pseudomonas virus phi6. However, a large number of additional dsRNA phages have been isolated from various environmental samples, indicating that such viruses are more widespread and abundant than previously recognised. Six of the additional dsRNA phage isolates (Pseudomonas phages phi8, phi12, phi13, phi2954, phiNN and phiYY) have been fully sequenced. They all infect Pseudomonas species, primarily plant pathogenic Pseudomonas syringae strains. Due to the notable genetic and structural similarities with Pseudomonas phage phi6, we propose that these viruses should be included into the Cystovirus genus (and consequently into the Cystoviridae family). Here, we present an updated taxonomy of the family Cystoviridae and give a short overview of the properties of the type member phi6 as well as the putative new members of the family.
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Affiliation(s)
- Sari Mäntynen
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
| | - Lotta-Riina Sundberg
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Minna M Poranen
- Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
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9
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Abstract
The family Cystoviridae includes enveloped viruses with a tri-segmented dsRNA genome and a double-layered protein capsid. The innermost protein shell is a polymerase complex responsible for genome packaging, replication and transcription. Cystoviruses infect Gram-negative bacteria, primarily plant-pathogenic Pseudomonas syringae strains. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Cystoviridae, which is available at http://www.ictv.global/report/cystoviridae.
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Affiliation(s)
- Minna M Poranen
- Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
| | - Sari Mäntynen
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, 40014 Jyväskylä, Finland
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10
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Alphonse S, Ghose R. Cystoviral RNA-directed RNA polymerases: Regulation of RNA synthesis on multiple time and length scales. Virus Res 2017; 234:135-152. [PMID: 28104452 PMCID: PMC5476504 DOI: 10.1016/j.virusres.2017.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 01/04/2017] [Accepted: 01/09/2017] [Indexed: 12/18/2022]
Abstract
Role of the RNA polymerase in the cystoviral life-cycle. Spatio-temporal regulation of RNA synthesis in cystoviruses. Emerging role of conformational dynamics in polymerase function.
P2, an RNA-directed RNA polymerase (RdRP), is encoded on the largest of the three segments of the double-stranded RNA genome of cystoviruses. P2 performs the dual tasks of replication and transcription de novo on single-stranded RNA templates, and plays a critical role in the viral life-cycle. Work over the last few decades has yielded a wealth of biochemical and structural information on the functional regulation of P2, on its role in the spatiotemporal regulation of RNA synthesis and its variability across the Cystoviridae family. These range from atomic resolution snapshots of P2 trapped in functionally significant states, in complex with catalytic/structural metal ions, polynucleotide templates and substrate nucleoside triphosphates, to P2 in the context of viral capsids providing structural insight into the assembly of supramolecular complexes and regulatory interactions therein. They include in vitro biochemical studies using P2 purified to homogeneity and in vivo studies utilizing infectious core particles. Recent advances in experimental techniques have also allowed access to the temporal dimension and enabled the characterization of dynamics of P2 on the sub-nanosecond to millisecond timescale through measurements of nuclear spin relaxation in solution and single molecule studies of transcription from seconds to minutes. Below we summarize the most significant results that provide critical insight into the role of P2 in regulating RNA synthesis in cystoviruses.
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Affiliation(s)
- Sébastien Alphonse
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, United States.
| | - Ranajeet Ghose
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, United States; Graduate Programs in Biochemistry, The Graduate Center of CUNY, New York, NY 10016, United States; Graduate Programs in Chemistry, The Graduate Center of CUNY, New York, NY 10016, United States; Graduate Programs in Physics, The Graduate Center of CUNY, New York, NY 10016, United States.
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11
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Characterization of the first double-stranded RNA bacteriophage infecting Pseudomonas aeruginosa. Sci Rep 2016; 6:38795. [PMID: 27934909 PMCID: PMC5146939 DOI: 10.1038/srep38795] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/14/2016] [Indexed: 11/29/2022] Open
Abstract
Bacteriophages (phages) are widely distributed in the biosphere and play a key role in modulating microbial ecology in the soil, ocean, and humans. Although the role of DNA bacteriophages is well described, the biology of RNA bacteriophages is poorly understood. More than 1900 phage genomes are currently deposited in NCBI, but only 6 dsRNA bacteriophages and 12 ssRNA bacteriophages genome sequences are reported. The 6 dsRNA bacteriophages were isolated from legume samples or lakes with Pseudomonas syringae as the host. Here, we report the first Pseudomonas aeruginosa phage phiYY with a three-segmented dsRNA genome. phiYY was isolated from hospital sewage in China with the clinical P. aeruginosa strain, PAO38, as a host. Moreover, the dsRNA phage phiYY has a broad host range, which infects 99 out of 233 clinical P. aeruginosa strains isolated from four provinces in China. This work presented a detailed characterization of the dsRNA bacteriophage infecting P. aeruginosa.
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12
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Svirskaitė J, Oksanen HM, Daugelavičius R, Bamford DH. Monitoring Physiological Changes in Haloarchaeal Cell during Virus Release. Viruses 2016; 8:59. [PMID: 26927156 PMCID: PMC4810249 DOI: 10.3390/v8030059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/11/2016] [Accepted: 02/15/2016] [Indexed: 01/14/2023] Open
Abstract
The slow rate of adsorption and non-synchronous release of some archaeal viruses have hindered more thorough analyses of the mechanisms of archaeal virus release. To address this deficit, we utilized four viruses that infect Haloarcula hispanica that represent the four virion morphotypes currently known for halophilic euryarchaeal viruses: (1) icosahedral internal membrane-containing SH1; (2) icosahedral tailed HHTV-1; (3) spindle-shaped His1; and (4) pleomorphic His2. To discern the events occurring as the progeny viruses exit, we monitored culture turbidity, as well as viable cell and progeny virus counts of infected and uninfected cultures. In addition to these traditional metrics, we measured three parameters associated with membrane integrity: the binding of the lipophilic anion phenyldicarbaundecaborane, oxygen consumption, and both intra- and extra-cellular ATP levels.
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Affiliation(s)
- Julija Svirskaitė
- Department of Biosciences, Institute of Biotechnology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland.
| | - Hanna M Oksanen
- Department of Biosciences, Institute of Biotechnology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland.
| | - Rimantas Daugelavičius
- Department of Biochemistry, Vytautas Magnus University, Vileikos g. 8, 44404 Kaunas, Lithuania.
| | - Dennis H Bamford
- Department of Biosciences, Institute of Biotechnology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland.
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13
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Atanasova NS, Senčilo A, Pietilä MK, Roine E, Oksanen HM, Bamford DH. Comparison of lipid-containing bacterial and archaeal viruses. Adv Virus Res 2015; 92:1-61. [PMID: 25701885 DOI: 10.1016/bs.aivir.2014.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Lipid-containing bacteriophages were discovered late and considered to be rare. After further phage isolations and the establishment of the domain Archaea, several new prokaryotic viruses with lipids were observed. Consequently, the presence of lipids in prokaryotic viruses is reasonably common. The wealth of information about how prokaryotic viruses use their lipids comes from a few well-studied model viruses (PM2, PRD1, and ϕ6). These bacteriophages derive their lipid membranes selectively from the host during the virion assembly process which, in the case of PM2 and PRD1, culminates in the formation of protein capsid with an inner membrane, and for ϕ6 an outer envelope. Several inner membrane-containing viruses have been described for archaea, and their lipid acquisition models are reminiscent to those of PM2 and PRD1. Unselective acquisition of lipids has been observed for bacterial mycoplasmaviruses and archaeal pleolipoviruses, which resemble each other by size, morphology, and life style. In addition to these shared morphotypes of bacterial and archaeal viruses, archaea are infected by viruses with unique morphotypes, such as lemon-shaped, helical, and globular ones. It appears that structurally related viruses may or may not have a lipid component in the virion, suggesting that the significance of viral lipids might be to provide viruses extended means to interact with the host cell.
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Affiliation(s)
- Nina S Atanasova
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Ana Senčilo
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Maija K Pietilä
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Elina Roine
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hanna M Oksanen
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Dennis H Bamford
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
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14
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Assembly of Large Icosahedral Double-Stranded RNA Viruses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 726:379-402. [DOI: 10.1007/978-1-4614-0980-9_17] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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15
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Cvirkaitė-Krupovič V, Poranen MM, Bamford DH. Phospholipids act as secondary receptor during the entry of the enveloped, double-stranded RNA bacteriophage φ6. J Gen Virol 2010; 91:2116-2120. [DOI: 10.1099/vir.0.020305-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteriophage φ6 is the type member of the family Cystoviridae and infects Gram-negative Pseudomonas syringae cells. The virion consists of a protein-rich lipid envelope enclosing a nucleocapsid. The nucleocapsid covers the icosahedral polymerase complex that encloses the double-stranded RNA genome. Here, we demonstrate that nucleocapsid surface protein P8 is the single nucleocapsid component interacting with the cytoplasmic membrane. This interaction takes place between P8 and phospholipid. Based on this and previous studies, we propose a model where the periplasmic nucleocapsid interacts with the phospholipid head groups and, when the membrane voltage exceeds the threshold of 110 mV, this interaction drives the nucleocapsid through the cytoplasmic membrane, resulting in an intracellular vesicle containing the nucleocapsid.
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Affiliation(s)
- Virginija Cvirkaitė-Krupovič
- Department of Biosciences and Institute of Biotechnology, Biocenter 2, PO Box 56 (Viikinkaari 5), FIN-00014 University of Helsinki, Finland
| | - Minna M. Poranen
- Department of Biosciences and Institute of Biotechnology, Biocenter 2, PO Box 56 (Viikinkaari 5), FIN-00014 University of Helsinki, Finland
| | - Dennis H. Bamford
- Department of Biosciences and Institute of Biotechnology, Biocenter 2, PO Box 56 (Viikinkaari 5), FIN-00014 University of Helsinki, Finland
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16
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Agarkova I, Dunigan D, Gurnon J, Greiner T, Barres J, Thiel G, Van Etten JL. Chlorovirus-mediated membrane depolarization of Chlorella alters secondary active transport of solutes. J Virol 2008; 82:12181-90. [PMID: 18842725 PMCID: PMC2593333 DOI: 10.1128/jvi.01687-08] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 09/30/2008] [Indexed: 11/20/2022] Open
Abstract
Paramecium bursaria chlorella virus 1 (PBCV-1) is the prototype of a family of large, double-stranded DNA, plaque-forming viruses that infect certain eukaryotic chlorella-like green algae from the genus Chlorovirus. PBCV-1 infection results in rapid host membrane depolarization and potassium ion release. One interesting feature of certain chloroviruses is that they code for functional potassium ion-selective channel proteins (Kcv) that are considered responsible for the host membrane depolarization and, as a consequence, the efflux of potassium ions. This report examines the relationship between cellular depolarization and solute uptake. Annotation of the virus host Chlorella strain NC64A genome revealed 482 putative transporter-encoding genes; 224 are secondary active transporters. Solute uptake experiments using seven radioactive compounds revealed that virus infection alters the transport of all the solutes. However, the degree of inhibition varied depending on the solute. Experiments with nystatin, a drug known to depolarize cell membranes, produced changes in solute uptake that are similar but not identical to those that occurred during virus infection. Therefore, these studies indicate that chlorovirus infection causes a rapid and sustained depolarization of the host plasma membrane and that this depolarization leads to the inhibition of secondary active transporters that changes solute uptake.
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Affiliation(s)
- Irina Agarkova
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68583-0900, USA
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17
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Roles of the minor capsid protein P7 in the assembly and replication of double-stranded RNA bacteriophage phi6. J Mol Biol 2008; 383:529-38. [PMID: 18793644 DOI: 10.1016/j.jmb.2008.08.082] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/20/2008] [Accepted: 08/25/2008] [Indexed: 11/23/2022]
Abstract
The polymerase complexes of double-stranded RNA (dsRNA) viruses are multifunctional RNA processing machineries that carry out viral genome packaging, replication, and transcription. The polymerase complex forms the innermost virion shell and is structurally related in dsRNA viruses infecting a diversity of host organisms. In this study, we analyzed the properties and functions of the minor polymerase complex protein P7 of dsRNA bacteriophage phi6 using terminally truncated P7 polypeptides and an in vitro self-assembly system established for the phi6 polymerase complex. The N-terminally truncated P7 failed to dimerize, whereas C-terminally truncated P7 polypeptides formed functional dimers that were incorporated into the polymerase complex. Nevertheless, the polymerase complex assembly kinetics and stability were altered by the incorporation of the C-terminally truncated P7. Using the in vitro assembly system for phi6 nucleocapsids and subsequent infectivity assays, we confirmed that full-length P7 is necessary for the formation of infectious viral particles. Contrary to previous results, we found that P7 must be incorporated into polymerase complexes during shell assembly.
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18
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Daugelavicius R, Gaidelyte A, Cvirkaite-Krupovic V, Bamford DH. On-line monitoring of changes in host cell physiology during the one-step growth cycle of Bacillus phage Bam35. J Microbiol Methods 2007; 69:174-9. [PMID: 17289190 DOI: 10.1016/j.mimet.2006.12.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 12/22/2006] [Accepted: 12/22/2006] [Indexed: 11/30/2022]
Abstract
In this study an on-line electrochemical method was developed to examine the one-step growth cycle (OSGC) of the bacteriophage Bam35. The on-line conditions for monitoring the OSGC and the effect of aeration on the duration of the OSGC were defined. The data indicate that binding of phenyldicarbaundecaborane anions to Bacillus thuringiensis cells infected with Bam35 can be used as a sensitive indicator of cell lysis.
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Affiliation(s)
- Rimantas Daugelavicius
- Department of Biological and Environmental Sciences and Institute of Biotechnology, University of Helsinki, Finland
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19
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Gaidelyte A, Cvirkaite-Krupovic V, Daugelavicius R, Bamford JKH, Bamford DH. The entry mechanism of membrane-containing phage Bam35 infecting Bacillus thuringiensis. J Bacteriol 2006; 188:5925-34. [PMID: 16885461 PMCID: PMC1540063 DOI: 10.1128/jb.00107-06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The temperate double-stranded DNA bacteriophage Bam35 infects gram-positive Bacillus thuringiensis cells. Bam35 has an icosahedral protein coat surrounding the viral membrane that encloses the linear 15-kbp DNA genome. The protein coat of Bam35 uses the same assembly principle as that of PRD1, a lytic bacteriophage infecting gram-negative hosts. In this study, we dissected the process of Bam35 entry into discrete steps: receptor binding, peptidoglycan penetration, and interaction with the plasma membrane (PM). Bam35 very rapidly adsorbs to the cell surface, and N-acetyl-muramic acid is essential for Bam35 binding. Zymogram analysis demonstrated that peptidoglycan-hydrolyzing activity is associated with the Bam35 virion. We showed that the penetration of Bam35 through the PM is a divalent-cation-dependent process, whereas adsorption and peptidoglycan digestion are not.
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Affiliation(s)
- Ausra Gaidelyte
- Department of Biological and Environmental Sciences and Institute of Biotechnology, Biocenter 2, P.O. Box 56 (Viikinkaari 5), 00014 University of Helsinki, Finland
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20
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Huiskonen JT, de Haas F, Bubeck D, Bamford DH, Fuller SD, Butcher SJ. Structure of the bacteriophage phi6 nucleocapsid suggests a mechanism for sequential RNA packaging. Structure 2006; 14:1039-48. [PMID: 16765897 DOI: 10.1016/j.str.2006.03.018] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 03/29/2006] [Accepted: 03/29/2006] [Indexed: 12/01/2022]
Abstract
Bacteriophage phi6 is an enveloped dsRNA virus with a segmented genome. Phi6 specifically packages one copy of each of its three genome segments into a preassembled polymerase complex. This leads to expansion of the polymerase complex, minus and plus strand RNA synthesis, and assembly of the nucleocapsid. The phi6 in vitro assembly and packaging system is a valuable model for dsRNA virus replication. The structure of the nucleocapsid at 7.5 A resolution presented here reveals the secondary structure of the two major capsid proteins. Asymmetric P1 dimers organize as an inner T = 1 shell, and P8 trimers organize as an outer T = 13 laevo shell. The organization of the P1 molecules in the unexpanded and expanded polymerase complex suggests that the expansion is accomplished by rigid body movements of the P1 monomers. This leads to exposure of new potential RNA binding surfaces to control the sequential packaging of the genome segments.
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Affiliation(s)
- Juha T Huiskonen
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FIN-00014 Helsinki, Finland
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21
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Affiliation(s)
- Minna M Poranen
- Department of Biological and Environmental Sciences and Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
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22
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Daugelavicius R, Cvirkaite V, Gaidelyte A, Bakiene E, Gabrenaite-Verkhovskaya R, Bamford DH. Penetration of enveloped double-stranded RNA bacteriophages phi13 and phi6 into Pseudomonas syringae cells. J Virol 2005; 79:5017-26. [PMID: 15795287 PMCID: PMC1069564 DOI: 10.1128/jvi.79.8.5017-5026.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Bacteriophages phi6 and phi13 are related enveloped double-stranded RNA viruses that infect gram-negative Pseudomonas syringae cells. phi6 uses a pilus as a receptor, and phi13 attaches to the host lipopolysaccharide. We compared the entry-related events of these two viruses, including receptor binding, envelope fusion, peptidoglycan penetration, and passage through the plasma membrane. The infection-related events are dependent on the multiplicity of infection in the case of phi13 but not with phi6. A temporal increase of host outer membrane permeability to lipophilic ions was observed from 1.5 to 4 min postinfection in both virus infections. This enhanced permeability period coincided with the fast dilution of octadecyl rhodamine B-labeled virus-associated lipid molecules. This result is in agreement with membrane fusion, and the presence of temporal virus-derived membrane patches on the outer membrane. Similar to phi6, phi13 contains a thermosensitive lytic enzyme involved in peptidoglycan penetration. The phage entry also caused a limited depolarization of the plasma membrane. Inhibition of host respiration considerably decreased the efficiency of irreversible virus binding and membrane fusion. An active role of cell energy metabolism in restoring the infection-induced defects in the cell envelope was also observed.
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Affiliation(s)
- Rimantas Daugelavicius
- Department of Biological and Environmental Sciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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23
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Kivelä HM, Daugelavicius R, Hankkio RH, Bamford JKH, Bamford DH. Penetration of membrane-containing double-stranded-DNA bacteriophage PM2 into Pseudoalteromonas hosts. J Bacteriol 2004; 186:5342-54. [PMID: 15292135 PMCID: PMC490941 DOI: 10.1128/jb.186.16.5342-5354.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The icosahedral bacteriophage PM2 has a circular double-stranded DNA (dsDNA) genome and an internal lipid membrane. It is the only representative of the Corticoviridae family. How the circular supercoiled genome residing inside the viral membrane is translocated into the gram-negative marine Pseudoalteromonas host has been an intriguing question. Here we demonstrate that after binding of the virus to an abundant cell surface receptor, the protein coat is most probably dissociated. During the infection process, the host cell outer membrane becomes transiently permeable to lipophilic gramicidin D molecules proposing fusion with the viral membrane. One of the components of the internal viral lipid core particle is the integral membrane protein P7, with muralytic activity that apparently aids the process of peptidoglycan penetration. Entry of the virion also causes a limited depolarization of the cytoplasmic membrane. These phenomena differ considerably from those observed in the entry process of bacteriophage PRD1, a dsDNA virus, which uses its internal membrane to make a cell envelope-penetrating tubular structure.
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Affiliation(s)
- Hanna M Kivelä
- Faculty of Biosciences and Institute of Biotechnology, University of Helsinki, Finland
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24
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Häse CC. Ion motive force dependence of protease secretion and phage tranduction inVibrio choleraeandPseudomonas aeruginosa. FEMS Microbiol Lett 2003; 227:65-71. [PMID: 14568149 DOI: 10.1016/s0378-1097(03)00649-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Vibrio cholerae is known to secrete a large number of proteins into the extracellular milieu, including the important virulence factor cholera toxin (CT). However, one of the most abundant proteins found in V. cholerae supernatants is the zinc-metalloprotease HA/protease (HAP). Whereas efficient protein secretion in Escherichia coli requires ATP hydrolysis and the proton motive force (pmf), little is known about the energy requirements for protein secretion in V. cholerae. To analyze some of the energy requirements for protein secretion in V. cholerae, HAP accumulation in culture supernatants following growth in the presence of various ionophores was assayed. Extracellular production of HAP was strongly reduced in the presence of monensin, an artificial Na(+)/H(+) antiporter that collapses the DeltapNa(+) across the membrane without affecting Deltapsi, whereas the protonophore CCCP had no significant effect on the extracellular accumulation of HAP. In contrast, extracellular protease production in Pseudomonas aeruginosa was affected by CCCP, but not monensin. Furthermore, extracellular protease production of V. cholerae, but not P. aeruginosa, was increased in increasing amounts of NaCl in the culture medium. Together these results indicate that the V. cholerae HAP requires an intact sodium motive force (smf) for its efficient translocation across the membranes, whereas extracellular protease production by P. aeruginosa requires only pmf. As the entry of some bacteriophage genomes has been reported to require pmf, the effects of ionophores on the efficiency of tranduction of V. cholerae by the CTXPhi phage were analyzed. CTXPhi transduction was strongly affected by CCCP, but not monensin, suggesting that phage entry requires pmf but not smf. Understanding the energy requirements for these potentially important virulence aspects of pathogens might lead to novel intervention strategies.
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Affiliation(s)
- Claudia C Häse
- Department of Microbiology, Oregon State University, 220 Nash Hall, Corvallis, OR 97331, USA.
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25
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Bamford DH. Self-organization: making complex infectious viral particles from purified precursors. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2003; 361:1187-1203. [PMID: 12816606 DOI: 10.1098/rsta.2003.1193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Viruses have served as excellent model systems in which to study biological self-organization. Purified virion structural constituents have been shown to self-assemble into particles that can initiate a productive infection in the host cell resulting in the release of progeny virions. Accumulating information on virus structures and assembly principles has revealed unexpected similarities between viruses that infect hosts as diverse as bacteria and humans, suggesting that these viruses had an early common ancestor. I will describe, in more detail, the assembly pathway of a complex double-stranded RNA bacterial virus. In this system, infectious viral particles are produced starting from purified protein and nucleic acid constituents through an elaborate self-assembly, RNA-packaging and synthesis pathway.
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Affiliation(s)
- Dennis H Bamford
- Institute of Biotechnology and Department of Biosciences, PO Box 56 (Viikinkaari 5), 00014 University of Helsinki, Finland.
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26
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Abstract
Viruses occur throughout the biosphere. Cells of Eukarya, Bacteria, and Archaea are infected by a variety of viruses that considerably outnumber the host cells. Although viruses have adapted to different host systems during evolution and many different viral strategies have developed, certain similarities can be found. Viruses encounter common problems during their entry process into the host cells, and similar strategies seem to ensure, for example, that the movement toward the site of replication and the translocation through the host membrane occur. The penetration of the host cell's external envelope involves, across the viral world, either fusion between two membranes, channel formation through the host envelope, disruption of the membrane vesicle, or a combination of these events. Endocytic-type events may occur during the entry of a bacterial virus as well as during the entry of an animal virus; the same applies for membrane fusion.
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Affiliation(s)
- Minna M Poranen
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Finland.
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27
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Grahn AM, Daugelavicius R, Bamford DH. Sequential model of phage PRD1 DNA delivery: active involvement of the viral membrane. Mol Microbiol 2002; 46:1199-209. [PMID: 12453208 DOI: 10.1046/j.1365-2958.2002.03250.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
DNA translocation across the barriers of recipient cells is not well understood. Viral DNA delivery mechanisms offer an opportunity to obtain useful information in systems in which the process can be arrested to a number of stages. PRD1 is an icosahedral double-stranded (ds)DNA bacterial virus with an internal membrane. It is an atypical dsDNA phage, as any of the vertex spikes can be used for receptor recognition. In this report, we dissect the PRD1 DNA entry into a number of steps: (i) outer membrane (OM) penetration; (ii) peptidoglycan digestion; (iii) cytoplasmic membrane (CM) penetration; and (iv) DNA translocation. We present a model for PRD1 DNA entry proposing that the initial stage of entry is powered by the pressure build-up during DNA packaging. The viral protein P11 is shown to function as the first DNA delivery protein needed to penetrate the OM. We also report a DNA translocation machinery composed of at least three viral integral membrane proteins, P14, P18 and P32.
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Affiliation(s)
- A Marika Grahn
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Finland
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28
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Benevides JM, Juuti JT, Tuma R, Bamford DH, Thomas GJ. Characterization of subunit-specific interactions in a double-stranded RNA virus: Raman difference spectroscopy of the phi6 procapsid. Biochemistry 2002; 41:11946-53. [PMID: 12356294 DOI: 10.1021/bi0201623] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The icosahedral core of a double-stranded (ds) RNA virus hosts RNA-dependent polymerase activity and provides the molecular machinery for RNA packaging. The stringent requirements of dsRNA metabolism may explain the similarities observed in core architecture among a broad spectrum of dsRNA viruses, from the mammalian rotaviruses to the Pseudomonas bacteriophage phi6. Although the structure of the assembled core has been described in atomic detail for Reoviridae (blue tongue virus and reovirus), the molecular mechanism of assembly has not been characterized in terms of conformational changes and key interactions of protein constituents. In the present study, we address such questions through the application of Raman spectroscopy to an in vitro core assembly system--the procapsid of phi6. The phi6 procapsid, which comprises multiple copies of viral proteins P1 (copy number 120), P2 (12), P4 (72), and P7 (60), represents a precursor of the core that is devoid of RNA. Raman signatures of the procapsid, its purified recombinant core protein components, and purified sub-assemblies lacking either one or two of the protein components have been obtained and interpreted. The major procapsid protein (P1), which forms the skeletal frame of the core, is an elongated and monomeric molecule of high alpha-helical content. The fold of the core RNA polymerase (P2) is also mostly alpha-helical. On the other hand, the folds of both the procapsid accessory protein (P7) and RNA-packaging ATPase (P4) are of the alpha/beta type. Raman difference spectra show that conformational changes occur upon interaction of P1 with either P4 or P7 in the procapsid. These changes involve substantial ordering of the polypeptide backbone. Conversely, conformations of procapsid subunits are not significantly affected by interactions with P2. An assembly model is proposed in which P1 induces alpha-helix in P4 during formation of the nucleation complex. Subsequently, the partially disordered P7 subunit is folded within the context of the procapsid shell.
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Affiliation(s)
- James M Benevides
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
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29
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Daugelavicius R, Bakiene E, Berzinskiene J, Bamford DH. Use of lipophilic anions for estimation of biomass and cell viability. Biotechnol Bioeng 2001; 71:208-16. [PMID: 11291030 DOI: 10.1002/1097-0290(2000)71:3<208::aid-bit1010>3.0.co;2-0] [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: 11/11/2022]
Abstract
A method is described to estimate the microbial biomass of a sample, to enumerate the cells, and to distinguish the portion of metabolically active cells in the population by measuring the binding of phenyldicarbaundecaborane (PCB(-)) to the cells. This method can also be used for the analysis of a complex population of microorganisms if the cells composing the sample are sensitive to different biocidal agents. In addition, the analysis of PCB(-) binding is useful for the enumeration of the phage-infected cells and phage particles.
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Affiliation(s)
- R Daugelavicius
- Department of Biochemistry and Biophysics, Vilnius University, Ciurlionio 21, LT-2009 Vilnius, Lithuania.
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30
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Poranen MM, Paatero AO, Tuma R, Bamford DH. Self-assembly of a viral molecular machine from purified protein and RNA constituents. Mol Cell 2001; 7:845-54. [PMID: 11336707 DOI: 10.1016/s1097-2765(01)00228-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present the assembly of the polymerase complex (procapsid) of a dsRNA virus from purified recombinant proteins. This molecular machine packages and replicates viral ssRNA genomic precursors in vitro. After addition of an external protein shell, these in vitro self-assembled viral core particles can penetrate the host plasma membrane and initiate a productive infection. Thus, a viral procapsid has been assembled and rendered infectious using purified components. Using this system, we have studied the mechanism of assembly of the common dsRNA virus shell and the incorporation of a symmetry mismatch within an icosahedral capsid. Our work demonstrates that this molecular machine, self-assembled under defined conditions in vitro, can function in its natural environment, the cell cytoplasm.
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Affiliation(s)
- M M Poranen
- Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
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31
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Grahn AM, Caldentey J, Bamford JK, Bamford DH. Stable packaging of phage PRD1 DNA requires adsorption protein P2, which binds to the IncP plasmid-encoded conjugative transfer complex. J Bacteriol 1999; 181:6689-96. [PMID: 10542170 PMCID: PMC94133 DOI: 10.1128/jb.181.21.6689-6696.1999] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/1999] [Accepted: 05/18/1999] [Indexed: 11/20/2022] Open
Abstract
The double-stranded DNA bacteriophage PRD1 uses an IncP plasmid-encoded conjugal transfer complex as a receptor. Plasmid functions in the PRD1 life cycle are restricted to phage adsorption and DNA entry. A single phage structural protein, P2, located at the fivefold capsid vertices, is responsible for PRD1 attachment to its host. The purified recombinant adsorption protein was judged to be monomeric by gel filtration, rate zonal centrifugation, analytical ultracentrifugation, and chemical cross-linking. It binds to its receptor with an apparent K(d) of 0.20 nM, and this binding prevents phage adsorption. P2-deficient particles are unstable and spontaneously release the DNA with concomitant formation of the tail-like structure originating from the phage membrane. We envisage the DNA to be packaged through one vertex, but the presence of P2 on the other vertices suggests a mechanism whereby the injection vertex is determined by P2 binding to the receptor.
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Affiliation(s)
- A M Grahn
- Department of Biosciences and Institute of Biotechnology, Viikki Biocenter, FIN-00014 University of Helsinki, Finland
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