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Waschestjuk D, Murata K, Takemura M. Complete genome sequence of Tornadovirus japonicus, a relative of Pacmanvirus, isolated from the Tamagawa River in Japan. Microbiol Resour Announc 2024:e0026524. [PMID: 38860801 DOI: 10.1128/mra.00265-24] [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: 03/15/2024] [Accepted: 05/23/2024] [Indexed: 06/12/2024] Open
Abstract
Here, we report the isolation and genome sequencing of a new Pacmanvirus-related isolate, Tornadovirus japonicus, from the Tamagawa River in Japan. This icosahedral virus has a genome of approximately 380 kb and 465 open reading frames, including two tRNA genes. The name "tornado" is based on its morphological features revealed by transmission electron microscopy analysis.
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Affiliation(s)
- Daniel Waschestjuk
- Graduate School of Science, Tokyo University of Science, Shinjuku, Tokyo, Japan
- Rijksuniversiteit Groningen, Faculty of Science and Engineering, Groningen, the Netherlands
| | - Kazuyoshi Murata
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institute of Natural Sciences, Okazaki, Aichi, Japan
- National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Department of Physiological Sciences, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, Japan
| | - Masaharu Takemura
- Graduate School of Science, Tokyo University of Science, Shinjuku, Tokyo, Japan
- Laboratory of Biology, Institute of Arts and Sciences, Tokyo University of Science, Shinjuku, Tokyo, Japan
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2
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Alempic JM, Bisio H, Villalta A, Santini S, Lartigue A, Schmitt A, Bugnot C, Notaro A, Belmudes L, Adrait A, Poirot O, Ptchelkine D, De Castro C, Couté Y, Abergel C. Functional redundancy revealed by the deletion of the mimivirus GMC-oxidoreductase genes. MICROLIFE 2024; 5:uqae006. [PMID: 38659623 PMCID: PMC11042495 DOI: 10.1093/femsml/uqae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 04/04/2024] [Indexed: 04/26/2024]
Abstract
The mimivirus 1.2 Mb genome was shown to be organized into a nucleocapsid-like genomic fiber encased in the nucleoid compartment inside the icosahedral capsid. The genomic fiber protein shell is composed of a mixture of two GMC-oxidoreductase paralogs, one of them being the main component of the glycosylated layer of fibrils at the surface of the virion. In this study, we determined the effect of the deletion of each of the corresponding genes on the genomic fiber and the layer of surface fibrils. First, we deleted the GMC-oxidoreductase, the most abundant in the genomic fiber, and determined its structure and composition in the mutant. As expected, it was composed of the second GMC-oxidoreductase and contained 5- and 6-start helices similar to the wild-type fiber. This result led us to propose a model explaining their coexistence. Then we deleted the GMC-oxidoreductase, the most abundant in the layer of fibrils, to analyze its protein composition in the mutant. Second, we showed that the fitness of single mutants and the double mutant were not decreased compared with the wild-type viruses under laboratory conditions. Third, we determined that deleting the GMC-oxidoreductase genes did not impact the glycosylation or the glycan composition of the layer of surface fibrils, despite modifying their protein composition. Because the glycosylation machinery and glycan composition of members of different clades are different, we expanded the analysis of the protein composition of the layer of fibrils to members of the B and C clades and showed that it was different among the three clades and even among isolates within the same clade. Taken together, the results obtained on two distinct central processes (genome packaging and virion coating) illustrate an unexpected functional redundancy in members of the family Mimiviridae, suggesting this may be the major evolutionary force behind their giant genomes.
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Affiliation(s)
- Jean-Marie Alempic
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
| | - Hugo Bisio
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
| | - Alejandro Villalta
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
| | - Sébastien Santini
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
| | - Audrey Lartigue
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
| | - Alain Schmitt
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
| | - Claire Bugnot
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
| | - Anna Notaro
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici, Italy
| | - Lucid Belmudes
- Univ. Grenoble Alpes, CEA, INSERM, UA13 BGE, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Annie Adrait
- Univ. Grenoble Alpes, CEA, INSERM, UA13 BGE, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Olivier Poirot
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
| | - Denis Ptchelkine
- Aix–Marseille University, Centre National de la Recherche Scientifique, Architecture et Fonction des Macromolécules Biologiques, Unité Mixte de Recherche 7257 (IM2B), 13288 Marseille Cedex 9, France
| | - Cristina De Castro
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici, Italy
| | - Yohann Couté
- Univ. Grenoble Alpes, CEA, INSERM, UA13 BGE, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Chantal Abergel
- Aix–Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479, IM2B, IOM), 13288 Marseille Cedex 9, France
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Nagata K, Tezuka K, Kuramitsu M, Fuchi N, Hasegawa Y, Hamaguchi I, Miura K. Establishment of a novel human T-cell leukemia virus type 1 infection model using cell-free virus. J Virol 2024; 98:e0186223. [PMID: 38294250 PMCID: PMC10878273 DOI: 10.1128/jvi.01862-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024] Open
Abstract
The primary mode of infection by human T-cell leukemia virus type 1 (HTLV-1) is cell-to-cell transmission during contact between infected cells and target cells. Cell-free HTLV-1 infections are known to be less efficient than infections with other retroviruses, and transmission of free HTLV-1 is considered not to occur in vivo. However, it has been demonstrated that cell-free HTLV-1 virions can infect primary lymphocytes and dendritic cells in vitro, and that virions embedded in biofilms on cell membranes can contribute to transmission. The establishment of an efficient cell-free HTLV-1 infection model would be a useful tool for analyzing the replication process of HTLV-1 and the clonal expansion of infected cells. We first succeeded in obtaining supernatants with high-titer cell-free HTLV-1 using a highly efficient virus-producing cell line. The HTLV-1 virions retained the structural characteristics of retroviruses. Using this cell-free infection model, we confirmed that a variety of cell lines and primary cultured cells can be infected with HTLV-1 and demonstrated that the provirus was randomly integrated into all chromosomes in the target cells. The provirus-integrated cell lines were HTLV-1-productive. Furthermore, we demonstrated for the first time that cell-free HTLV-1 is infectious in vivo using a humanized mouse model. These results indicate that this cell-free infection model recapitulates the HTLV-1 life cycle, including entry, reverse transcription, integration into the host genome, viral replication, and secondary infection. The new cell-free HTLV-1 infection model is promising as a practical resource for studying HTLV-1 infection.IMPORTANCECo-culture of infected and target cells is frequently used for studying HTLV-1 infection. Although this method efficiently infects HTLV-1, the cell mixture is complex, and it is extremely difficult to distinguish donor infected cells from target cells. In contrast, cell-free HTLV-1 infection models allow for more strict experimental conditions. In this study, we established a novel and efficient cell-free HTLV-1 infection model. Using this model, we successfully evaluated the infectivity titers of cell-free HTLV-1 as proviral loads (copies per 100 cells) in various cell lines, primary cultured cells, and a humanized mouse model. Interestingly, the HTLV-1-associated viral biofilms played an important role in enhancing the infectivity of the cell-free infection model. This cell-free HTLV-1 infection model reproduces the replication cycle of HTLV-1 and provides a simple, powerful, and alternative tool for researching HTLV-1 infection.
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Affiliation(s)
- Koh Nagata
- Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kenta Tezuka
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Tokyo, Japan
| | - Madoka Kuramitsu
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Tokyo, Japan
| | - Naoki Fuchi
- Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yuri Hasegawa
- Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Isao Hamaguchi
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kiyonori Miura
- Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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de Aquino ILM, Barcelos MG, Machado TB, Serafim MSM, Abrahão JS. Surface fibrils on the particles of nucleocytoviruses: A review. Exp Biol Med (Maywood) 2023; 248:2045-2052. [PMID: 37955170 PMCID: PMC10800130 DOI: 10.1177/15353702231208410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023] Open
Abstract
The capsid has a central role in viruses' life cycle. Although one of its major functions is to protect the viral genome, the capsid may be composed of elements that, at some point, promote interaction with host cells and trigger infection. Considering the scenario of multiple origins of viruses along the viral evolution, a substantial number of capsid shapes, sizes, and symmetries have been described. In this context, capsids of giant viruses (GV) that infect protists have drawn the attention of the scientific community, especially in the last 20 years, specifically for having bacterial-like dimensions with hundreds of different proteins and exclusive features. For instance, the surface fibrils present on the mimivirus capsid are one of the most intriguing features of the known virosphere. They are 150-nm-long structures attached to a 450-nm capsid, resulting in a particle with a hairy appearance. Surface fibrils have also been described in the capsids of other nucleocytoviruses, although they may differ substantially among them. In this mini review for non-experts, we compile the most important available information on surface fibrils of nucleocytoviruses, discussing their putative functions, composition, length, organization, and origins.
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Affiliation(s)
- Isabella Luiza Martins de Aquino
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Matheus Gomes Barcelos
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Talita Bastos Machado
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Mateus Sá Magalhães Serafim
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Jônatas Santos Abrahão
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
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Fukaya S, Masuda L, Takemura M. Analysis of Morphological Changes in the Nucleus and Vacuoles of Acanthamoeba castellanii following Giant Virus Infection. Microbiol Spectr 2023; 11:e0418222. [PMID: 36943052 PMCID: PMC10100661 DOI: 10.1128/spectrum.04182-22] [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: 10/13/2022] [Accepted: 02/28/2023] [Indexed: 03/23/2023] Open
Abstract
Acanthamoeba castellanii medusavirus is a member of the phylum Nucleocytoviricota, also known as giant viruses, and has a unique strategy of infecting Acanthamoeba castellanii and replicating viral genes in the host nucleus. Here, we show time series changes in the intracellular morphology, including the nucleus, of host cells infected with four types of giant viruses, including medusavirus, using time-lapse phase-contrast microscopy and image analysis. We updated our phase-contrast-based kinetic analysis algorithm for amoebae (PKA3) to use multiple microscopic images with different focus positions to allow a more detailed analysis of their intracellular structures. Image analysis using PKA3 revealed that as medusavirus infection progressed, the host nucleus increased in size and the number of vacuoles decreased. In addition, infected host cells are known to become smaller and rounder at later stages of infection, but here they were found to be larger than uninfected cells at earlier stages. These results suggested that the propagation mechanism of medusavirus includes the formation of empty virus particles in the host cytoplasm, packaging of the viral genome replicated in the host nucleus, and then the release of viral particles. IMPORTANCE In this study, we quantitatively revealed how long the increase in host cell size or the increase in host nucleus size occurs after infection with giant viruses, especially medusavirus. To understand the underlying mechanism, we performed image analysis and determined that the host cell size increased at approximately 6 h postinfection (hpi) and the host nucleus enlarged at approximately 22 hpi, pointing to the importance of biochemical experiments. In addition, we showed that the intracellular structures could be quantitatively analyzed using multiple phase-contrast microscopy images with different focus positions at the same time point. Hence, morphological analyses of intracellular structures using phase-contrast microscopy, which have wide applications in live-cell observations, may be useful in studying various organisms that infect or are symbiotic with A. castellanii.
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Affiliation(s)
- Sho Fukaya
- Department of Applied Information Engineering, Faculty of Engineering, Suwa University of Science, Chino, Nagano, Japan
- Laboratory of Biology, Institute of Arts and Sciences, Tokyo University of Science, Shinjuku, Tokyo, Japan
| | - Lisa Masuda
- Laboratory of Biology, Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku, Tokyo, Japan
| | - Masaharu Takemura
- Laboratory of Biology, Institute of Arts and Sciences, Tokyo University of Science, Shinjuku, Tokyo, Japan
- Laboratory of Biology, Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku, Tokyo, Japan
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6
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Widespread Distribution and Evolution of Poxviral Entry-Fusion Complex Proteins in Giant Viruses. Microbiol Spectr 2023:e0494422. [PMID: 36912656 PMCID: PMC10100723 DOI: 10.1128/spectrum.04944-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023] Open
Abstract
Poxviruses are known to encode a set of proteins that form an entry-fusion complex (EFC) to mediate virus entry. However, the diversity, evolution, and origin of these EFC proteins remain poorly understood. Here, we identify the EFC protein homologs in poxviruses and other giant viruses of the phylum Nucleocytoviricota. The 11 EFC genes are present in almost all poxviruses, with the two smallest, G3 and O3, being absent in Entomopoxvirinae and basal lineages of Chordopoxvirinae. Five of the EFC genes are further grouped into two families, A16/G9/J5 and F9/L1, which are widely distributed across other major lineages of Nucleocytoviricota, including metagenome-assembled genomes, but are generally absent in viruses infecting algae or nonamoebozoan heterotrophic protists. The A16/G9/J5 and F9/L1 families cooccur, mostly as single copies, in 93% of the non-Poxviridae giant viruses that have at least one of them. Distribution and phylogenetic patterns suggest that both families originated in the ancestor of Nucleocytoviricota. In addition to the Poxviridae genes, homologs from each of the other Nucleocytoviricota families are largely clustered together, suggesting their ancient presence and vertical inheritance. Despite deep sequence divergences, we observed noticeable conservation of cysteine residues and predicted structures between EFC proteins of Poxviridae and other families. Overall, our study reveals widespread distribution of these EFC protein homologs beyond poxviruses, implies the existence of a conserved membrane fusion mechanism, and sheds light on host range and ancient evolution of Nucleocytoviricota. IMPORTANCE Fusion between virus and host membranes is critical for viruses to release genetic materials and to initiate infection. Whereas most viruses use a single protein for membrane fusion, poxviruses employ a multiprotein entry-fusion complex (EFC). We report that two major families of the EFC proteins are widely distributed within the virus phylum Nucleocytoviricota, which includes poxviruses and other double-stranded (dsDNA) giant viruses that infect animals, amoebozoans, algae, and various microbial eukaryotes. Each of these two protein families is structurally conserved, traces its origin to the root of Nucleocytoviricota, was passed down to the major subclades of Nucleocytoviricota, and is retained in most giant viruses known to infect animals and amoebozoans. The EFC proteins therefore represent a potential mechanism for virus entry in diverse giant viruses. We hypothesize that they may have facilitated the infection of an animal/amoebozoan-like host by the last Nucleocytoviricota common ancestor.
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Schulz F, Abergel C, Woyke T. Giant virus biology and diversity in the era of genome-resolved metagenomics. Nat Rev Microbiol 2022; 20:721-736. [PMID: 35902763 DOI: 10.1038/s41579-022-00754-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2022] [Indexed: 11/09/2022]
Abstract
The discovery of giant viruses, with capsids as large as some bacteria, megabase-range genomes and a variety of traits typically found only in cellular organisms, was one of the most remarkable breakthroughs in biology. Until recently, most of our knowledge of giant viruses came from ~100 species-level isolates for which genome sequences were available. However, these isolates were primarily derived from laboratory-based co-cultivation with few cultured protists and algae and, thus, did not reflect the true diversity of giant viruses. Although virus co-cultures enabled valuable insights into giant virus biology, many questions regarding their origin, evolution and ecological importance remain unanswered. With advances in sequencing technologies and bioinformatics, our understanding of giant viruses has drastically expanded. In this Review, we summarize our understanding of giant virus diversity and biology based on viral isolates as laboratory cultivation has enabled extensive insights into viral morphology and infection strategies. We then explore how cultivation-independent approaches have heightened our understanding of the coding potential and diversity of the Nucleocytoviricota. We discuss how metagenomics has revolutionized our perspective of giant viruses by revealing their distribution across our planet's biomes, where they impact the biology and ecology of a wide range of eukaryotic hosts and ultimately affect global nutrient cycles.
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Affiliation(s)
- Frederik Schulz
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Chantal Abergel
- Aix Marseille University, CNRS, IGS UMR7256, IMM FR3479, IM2B, IO, Marseille, France
| | - Tanja Woyke
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,University of California Merced, Merced, CA, USA.
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Speciale I, Notaro A, Abergel C, Lanzetta R, Lowary TL, Molinaro A, Tonetti M, Van Etten JL, De Castro C. The Astounding World of Glycans from Giant Viruses. Chem Rev 2022; 122:15717-15766. [PMID: 35820164 PMCID: PMC9614988 DOI: 10.1021/acs.chemrev.2c00118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Viruses are a heterogeneous ensemble of entities, all
sharing the
need for a suitable host to replicate. They are extremely diverse,
varying in morphology, size, nature, and complexity of their genomic
content. Typically, viruses use host-encoded glycosyltransferases
and glycosidases to add and remove sugar residues from their glycoproteins.
Thus, the structure of the glycans on the viral proteins have, to
date, typically been considered to mimick those of the host. However,
the more recently discovered large and giant viruses differ from this
paradigm. At least some of these viruses code for an (almost) autonomous
glycosylation pathway. These viral genes include those that encode
the production of activated sugars, glycosyltransferases, and other
enzymes able to manipulate sugars at various levels. This review focuses
on large and giant viruses that produce carbohydrate-processing enzymes.
A brief description of those harboring these features at the genomic
level will be discussed, followed by the achievements reached with
regard to the elucidation of the glycan structures, the activity of
the proteins able to manipulate sugars, and the organic synthesis
of some of these virus-encoded glycans. During this progression, we
will also comment on many of the challenging questions on this subject
that remain to be addressed.
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Affiliation(s)
- Immacolata Speciale
- Department of Agricultural Sciences, University of Napoli, Via Università 100, 80055 Portici, Italy
| | - Anna Notaro
- Department of Agricultural Sciences, University of Napoli, Via Università 100, 80055 Portici, Italy.,Centre National de la Recherche Scientifique, Information Génomique & Structurale, Aix-Marseille University, Unité Mixte de Recherche 7256, IMM, IM2B, 13288 Marseille, Cedex 9, France
| | - Chantal Abergel
- Centre National de la Recherche Scientifique, Information Génomique & Structurale, Aix-Marseille University, Unité Mixte de Recherche 7256, IMM, IM2B, 13288 Marseille, Cedex 9, France
| | - Rosa Lanzetta
- Department of Chemical Sciences, University of Napoli, Via Cintia 4, 80126 Napoli, Italy
| | - Todd L Lowary
- Institute of Biological Chemistry, Academia Sinica, Academia Road, Section 2, Nangang 11529, Taipei, Taiwan
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Napoli, Via Cintia 4, 80126 Napoli, Italy
| | - Michela Tonetti
- Department of Experimental Medicine and Center of Excellence for Biomedical Research, University of Genova, 16132 Genova, Italy
| | - James L Van Etten
- Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska 68583-0900, United States.,Department of Plant Pathology, University of Nebraska, Lincoln, Nebraska 68583-0722, United States
| | - Cristina De Castro
- Department of Agricultural Sciences, University of Napoli, Via Università 100, 80055 Portici, Italy
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Xia Y, Cheng H, Zhong J. Hybrid Sequencing Resolved Inverted Terminal Repeats in the Genome of Megavirus Baoshan. Front Microbiol 2022; 13:831659. [PMID: 35620092 PMCID: PMC9127612 DOI: 10.3389/fmicb.2022.831659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/21/2022] [Indexed: 12/12/2022] Open
Abstract
Mimivirus is a group of amoeba-infecting DNA viruses with linear double-strand genome. It is found to be ubiquitous in nature worldwide. Here, we reported the complete genome of a new member of Mimivirus lineage C isolated from a fresh water pond in Shanghai, China. Its 1,224,839-bp genome encoded 1,062 predicted ORFs. Combining the results of Nanopore, Illumina, and Sanger sequencing technologies, two identical 23,919 bp inverted terminal repeats (ITRs) were identified at both extremities of the viral linear genome, one of which was missing in the draft assembly based on Illumina data only. The discovery of ITRs of Mimivirus provided a new insight into Mimivirus genome structure.
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Affiliation(s)
- Yucheng Xia
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Department of Microbiology and Immunology, School of Life Sciences, Fudan University, Shanghai, China
| | - Huanyu Cheng
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Department of Microbiology and Immunology, School of Life Sciences, Fudan University, Shanghai, China
| | - Jiang Zhong
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Department of Microbiology and Immunology, School of Life Sciences, Fudan University, Shanghai, China
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Fukaya S, Takemura M. Kinetic Analysis of Acanthamoeba castellanii Infected with Giant Viruses Quantitatively Revealed Process of Morphological and Behavioral Changes in Host Cells. Microbiol Spectr 2021; 9:e0036821. [PMID: 34431709 PMCID: PMC8552732 DOI: 10.1128/spectrum.00368-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/27/2021] [Indexed: 01/22/2023] Open
Abstract
Most virus-infected cells show morphological and behavioral changes, which are called cytopathic effects. Acanthamoeba castellanii, an abundant, free-living protozoan, serves as a laboratory host for some viruses of the phylum Nucleocytoviricota-the giant viruses. Many of these viruses cause cell rounding in the later stages of infection in the host cells. Here, we show the changes that lead to cell rounding in the host cells through time-lapse microscopy and image analysis. Time-lapse movies of A. castellanii cells infected with Mimivirus shirakomae, kyotovirus, medusavirus, or Pandoravirus japonicus were generated using a phase-contrast microscope. We updated our phase-contrast-based kinetic analysis algorithm for amoebae (PKA3) and used it to analyze these time-lapse movies. Image analysis revealed that the process leading to cell rounding varies among the giant viruses; for example, M. shirakomae infection did not cause changes for some time after the infection, kyotovirus infection caused an early decrease in the number of cells with typical morphologies, and medusavirus and P. japonicus infection frequently led to the formation of intercellular bridges and rotational behavior of host cells. These results suggest that in the case of giant viruses, the putative reactions of host cells against infection and the putative strategies of virus spread are diverse. IMPORTANCE Quantitative analysis of the infection process is important for a better understanding of viral infection strategies and virus-host interactions. Here, an image analysis of the phase-contrast time-lapse movies displayed quantitative differences in the process of cytopathic effects due to the four giant viruses in Acanthamoeba castellanii, which were previously unclear. It was revealed that medusavirus and Pandoravirus japonicus infection led to the formation of a significant number of elongated particles related to intercellular bridges, emphasizing the importance of research on the interaction of viruses with host cell nuclear function. Mimivirus shirakomae infection did not cause any changes in the host cells initially, so it is thought that the infected cells can actively move and spread over a wider area, emphasizing the importance of observation in a wider area and analysis of infection efficiency. These results suggest that a kinetic analysis using the phase-contrast-based kinetic analysis algorithm for amoebae (PKA3) reveals the infection strategies of each giant virus.
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Affiliation(s)
- Sho Fukaya
- Department of Applied Information Engineering, Faculty of Engineering, Suwa University of Science, Chino, Nagano, Japan
- Laboratory of Biology, Institute of Arts and Sciences, Tokyo University of Science, Shinjuku, Tokyo, Japan
| | - Masaharu Takemura
- Laboratory of Biology, Institute of Arts and Sciences, Tokyo University of Science, Shinjuku, Tokyo, Japan
- Laboratory of Biology, Graduate School of Mathematics and Science Education, Tokyo University of Science, Shinjuku, Tokyo, Japan
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