1
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Maio N, Heffner AL, Rouault TA. Iron‑sulfur clusters in viral proteins: Exploring their elusive nature, roles and new avenues for targeting infections. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119723. [PMID: 38599324 PMCID: PMC11139609 DOI: 10.1016/j.bbamcr.2024.119723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/13/2024] [Accepted: 04/01/2024] [Indexed: 04/12/2024]
Abstract
Viruses have evolved complex mechanisms to exploit host factors for replication and assembly. In response, host cells have developed strategies to block viruses, engaging in a continuous co-evolutionary battle. This dynamic interaction often revolves around the competition for essential resources necessary for both host cell and virus replication. Notably, iron, required for the biosynthesis of several cofactors, including iron‑sulfur (FeS) clusters, represents a critical element in the ongoing competition for resources between infectious agents and host. Although several recent studies have identified FeS cofactors at the core of virus replication machineries, our understanding of their specific roles and the cellular processes responsible for their incorporation into viral proteins remains limited. This review aims to consolidate our current knowledge of viral components that have been characterized as FeS proteins and elucidate how viruses harness these versatile cofactors to their benefit. Its objective is also to propose that viruses may depend on incorporation of FeS cofactors more extensively than is currently known. This has the potential to revolutionize our understanding of viral replication, thereby carrying significant implications for the development of strategies to target infections.
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Affiliation(s)
- Nunziata Maio
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA.
| | - Audrey L Heffner
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA; Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Tracey A Rouault
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
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2
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Talbert PB, Henikoff S, Armache KJ. Giant variations in giant virus genome packaging. Trends Biochem Sci 2023; 48:1071-1082. [PMID: 37777391 DOI: 10.1016/j.tibs.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 10/02/2023]
Abstract
Giant viruses (Nucleocytoviricota) have a largely conserved lifecycle, yet how they cram their large genomes into viral capsids is mostly unknown. The major capsid protein and the packaging ATPase (pATPase) comprise a highly conserved morphogenesis module in giant viruses, yet some giant viruses dispense with an icosahedral capsid, and others encode multiple versions of pATPases, including conjoined ATPase doublets, or encode none. Some giant viruses have acquired DNA-condensing proteins to compact their genomes, including sheath-like structures encasing folded DNA or densely packed viral nucleosomes that show a resemblance to eukaryotic nucleosomes at the telomeres. Here, we review what is known and unknown about these ATPases and condensing proteins, and place these variations in the context of viral lifecycles.
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Affiliation(s)
- Paul B Talbert
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Karim-Jean Armache
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
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3
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Kashnikov AY, Epifanova NV, Novikova NA. On the nature of picobirnaviruses. Vavilovskii Zhurnal Genet Selektsii 2023; 27:264-275. [PMID: 37293447 PMCID: PMC10244588 DOI: 10.18699/vjgb-23-32] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 06/10/2023] Open
Abstract
The picobirnaviruses (Picobirnaviridae, Picobirnavirus, PBVs) are currently thought to be animal viruses, as they are usually found in animal stool samples. However, no animal model or cell culture for their propagation has yet been found. In 2018, a hypothetical assumption about PBVs belonging to prokaryotic viruses was put forward and experimentally substantiated. This hypothesis is based on the presence of Shine-Dalgarno sequences in the genome of all PBVs before three reading frames (ORF) at the ribosomal binding site, with which the prokaryotic genome is saturated, while in the eukaryotic genome such regions occur with low frequency. The genome saturation with the Shine-Dalgarno sequences, as well as the preservation of this saturation in the progeny, according to scientists, allows us to attribute PBVs to prokaryotic viruses. On the other hand, there is a possibility that PBVs belong to viruses of eukaryotic hosts - fungi or invertebrates, since PBV-like sequences similar to the genome of fungal viruses from the families of mitoviruses and partitiviruses have been identified. In this regard, the idea arose that, in terms of reproduction mode, PBVs resemble fungal viruses. The divergence of views on the true PBV host(s) has sparked discussions among scientists and required further research to elucidate their nature. The review highlights the results of the search for a PBV host. The reasons for the occurrence of atypical sequences among the PBV genome sequences that use an alternative mitochondrial code of lower eukaryotes (fungi and invertebrates) for the translation of viral RNA-dependent RNA polymerase (RdRp) instead of the standard genetic code are analyzed. The purpose of the review was to collect arguments in support of the hypothesis about the phage nature of PBVs and to find the most realistic explanation of the reasons for identifying non-standard genomic sequences for PBVs. Based on the hypothesis about the genealogical relationship of PBVs with RNA viruses from other families with similar segmented genomes, such as Reoviridae, Cystoviridae, Totiviridae and Partitiviridae, virologists support the assumption of a decisive role in the origin of atypical PBV-like reassortment strains between PBVs and viruses of the listed families. The collected arguments given in this review indicate a high probability of a phage nature of PBVs. The data presented in the review show that the belonging of PBV-like progeny to prokaryotic or eukaryotic viruses is determined not only by its genome saturation level with a prokaryotic motif, standard or mitochondrial genetic code. The primary structure of the gene encoding the viral capsid protein responsible for the presence or absence of specific proteolytic properties of the virus that determine its ability for independent horizontal transmission into new cells may also be a decisive factor.
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Affiliation(s)
- A Yu Kashnikov
- I.N. Blokhina Nizhny Novgorod Research Institute of Epidemiology and Microbiology, Nizhny Novgorod, Russia
| | - N V Epifanova
- I.N. Blokhina Nizhny Novgorod Research Institute of Epidemiology and Microbiology, Nizhny Novgorod, Russia
| | - N A Novikova
- I.N. Blokhina Nizhny Novgorod Research Institute of Epidemiology and Microbiology, Nizhny Novgorod, Russia
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4
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Roux S, Fischer MG, Hackl T, Katz LA, Schulz F, Yutin N. Updated Virophage Taxonomy and Distinction from Polinton-like Viruses. Biomolecules 2023; 13:204. [PMID: 36830574 PMCID: PMC9952930 DOI: 10.3390/biom13020204] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/02/2023] [Accepted: 01/04/2023] [Indexed: 01/20/2023] Open
Abstract
Virophages are small dsDNA viruses that hijack the machinery of giant viruses during the co-infection of a protist (i.e., microeukaryotic) host and represent an exceptional case of "hyperparasitism" in the viral world. While only a handful of virophages have been isolated, a vast diversity of virophage-like sequences have been uncovered from diverse metagenomes. Their wide ecological distribution, idiosyncratic infection and replication strategy, ability to integrate into protist and giant virus genomes and potential role in antiviral defense have made virophages a topic of broad interest. However, one limitation for further studies is the lack of clarity regarding the nomenclature and taxonomy of this group of viruses. Specifically, virophages have been linked in the literature to other "virophage-like" mobile genetic elements and viruses, including polinton-like viruses (PLVs), but there are no formal demarcation criteria and proper nomenclature for either group, i.e., virophage or PLVs. Here, as part of the ICTV Virophage Study Group, we leverage a large set of genomes gathered from published datasets as well as newly generated protist genomes to propose delineation criteria and classification methods at multiple taxonomic ranks for virophages 'sensu stricto', i.e., genomes related to the prototype isolates Sputnik and mavirus. Based on a combination of comparative genomics and phylogenetic analyses, we show that this group of virophages forms a cohesive taxon that we propose to establish at the class level and suggest a subdivision into four orders and seven families with distinctive ecogenomic features. Finally, to illustrate how the proposed delineation criteria and classification method would be used, we apply these to two recently published datasets, which we show include both virophages and other virophage-related elements. Overall, we see this proposed classification as a necessary first step to provide a robust taxonomic framework in this area of the virosphere, which will need to be expanded in the future to cover other virophage-related viruses such as PLVs.
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Affiliation(s)
- Simon Roux
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Matthias G. Fischer
- Max Planck Institute for Medical Research, Department of Biomolecular Mechanisms, 69120 Heidelberg, Germany
| | - Thomas Hackl
- Groningen Institute of Evolutionary Life Sciences, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Laura A. Katz
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA
| | - Frederik Schulz
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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5
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Silva JM, Pratas D, Caetano T, Matos S. The complexity landscape of viral genomes. Gigascience 2022; 11:6661051. [PMID: 35950839 PMCID: PMC9366995 DOI: 10.1093/gigascience/giac079] [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: 03/03/2022] [Revised: 05/25/2022] [Accepted: 07/26/2022] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Viruses are among the shortest yet highly abundant species that harbor minimal instructions to infect cells, adapt, multiply, and exist. However, with the current substantial availability of viral genome sequences, the scientific repertory lacks a complexity landscape that automatically enlights viral genomes' organization, relation, and fundamental characteristics. RESULTS This work provides a comprehensive landscape of the viral genome's complexity (or quantity of information), identifying the most redundant and complex groups regarding their genome sequence while providing their distribution and characteristics at a large and local scale. Moreover, we identify and quantify inverted repeats abundance in viral genomes. For this purpose, we measure the sequence complexity of each available viral genome using data compression, demonstrating that adequate data compressors can efficiently quantify the complexity of viral genome sequences, including subsequences better represented by algorithmic sources (e.g., inverted repeats). Using a state-of-the-art genomic compressor on an extensive viral genomes database, we show that double-stranded DNA viruses are, on average, the most redundant viruses while single-stranded DNA viruses are the least. Contrarily, double-stranded RNA viruses show a lower redundancy relative to single-stranded RNA. Furthermore, we extend the ability of data compressors to quantify local complexity (or information content) in viral genomes using complexity profiles, unprecedently providing a direct complexity analysis of human herpesviruses. We also conceive a features-based classification methodology that can accurately distinguish viral genomes at different taxonomic levels without direct comparisons between sequences. This methodology combines data compression with simple measures such as GC-content percentage and sequence length, followed by machine learning classifiers. CONCLUSIONS This article presents methodologies and findings that are highly relevant for understanding the patterns of similarity and singularity between viral groups, opening new frontiers for studying viral genomes' organization while depicting the complexity trends and classification components of these genomes at different taxonomic levels. The whole study is supported by an extensive website (https://asilab.github.io/canvas/) for comprehending the viral genome characterization using dynamic and interactive approaches.
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Affiliation(s)
- Jorge Miguel Silva
- Institute of Electronics and Informatics Engineering of Aveiro, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Diogo Pratas
- Institute of Electronics and Informatics Engineering of Aveiro, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.,Department of Electronics Telecommunications and Informatics, University of Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro, Portugal.,Department of Virology, University of Helsinki, Haartmaninkatu 3, 00014 Helsinki, Finland
| | - Tânia Caetano
- Department of Biology, University of Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro, Portugal
| | - Sérgio Matos
- Institute of Electronics and Informatics Engineering of Aveiro, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.,Department of Electronics Telecommunications and Informatics, University of Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro, Portugal
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6
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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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7
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Current Opinion in LAIV: A Matter of Parent Virus Choice. Int J Mol Sci 2022; 23:ijms23126815. [PMID: 35743258 PMCID: PMC9224562 DOI: 10.3390/ijms23126815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 01/26/2023] Open
Abstract
Influenza is still a frequent seasonal infection of the upper respiratory tract, which may have deadly consequences, especially for the elderly. This is in spite of the availability of vaccines suggested for persons above 65 years of age. Two types of conventional influenza vaccines are currently licensed for use-live attenuated and inactivated vaccines. Depending on local regulatory requirements, live attenuated vaccines are produced by the reverse genetics technique or by classical reassortment in embryonated chicken eggs. Sometimes, the efficiency of classical reassortment is complicated by certain properties of the wild-type parent virus. Cases of low efficacy of vaccines have been noted, which, among other reasons, may be associated with suboptimal properties of the wild-type parent virus that are not considered when recommendations for influenza vaccine composition are made. Unfortunately, knowledge surrounding the roles of properties of the circulating influenza virus and its impact on the efficacy of the reassortment process, vaccination efficiency, the infectivity of the vaccine candidates, etc., is now scattered in different publications. This review summarizes the main features of the influenza virus that may dramatically affect different aspects of the preparation of egg-derived live attenuated vaccine candidates and their effectiveness. The author expresses her personal view, which may not coincide with the opinion of other experts in the field of influenza vaccines.
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8
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Isolation and Identification of a Large Green Alga Virus ( Chlorella Virus XW01) of Mimiviridae and Its Virophage ( Chlorella Virus Virophage SW01) by Using Unicellular Green Algal Cultures. J Virol 2022; 96:e0211421. [PMID: 35262372 DOI: 10.1128/jvi.02114-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Virophages are a group of small double-stranded DNA viruses that infect protist hosts and parasitize the viral factory of host giant/large viruses to propagate. Here, we discover a novel cell-virus-virophage (CVv) tripartite interaction system by using unicellular micro-green algae (Chlorella sp.) as eukaryotic hosts for the first time. Viral particles, resembling known virophages and large alga viruses, are detected in culture supernatants and inside algal cells. Complete genomic sequences of the virophage (Chlorella virus virophage SW01 [CVv-SW01]; 24,744 bp) and large virus (Chlorella virus XW01 [CV-XW01]; 407,612 bp) are obtained from the cocultures. Both genomic and phylogenetic analyses show that CVv-SW01 is closely related to virophages previously found in Dishui Lake. CV-XW01 shares the greatest number of homologous genes (n = 82) with Cafeteria roenbergensis virus (CroV) and phylogenetically represents the closest relative to CroV. This is the first report of a large green alga virus being affiliated with a heterotrophic zooplankton-infecting Cafeteriavirus of the family Mimiviridae. Moreover, the codon usage preferences of CV-XW01 and CVv-SW01 are highly similar to those of CroV and its virophage Mavirus, respectively. The discovery of such a novel CVv system with the green alga Chlorella sp. as the single cellular eukaryotic host paves a way to further investigate the potential interaction mechanism of CVv and its significance in the ecology of green algae and the evolution of large/giant viruses and their parasitic viruses. IMPORTANCE Parasitic virophages are small unicellular eukaryotic dsDNA viruses that rely on the viral factories of coinfecting giant/large dsDNA viruses for propagation. Presently, the identified eukaryotic hosts of isolated virophages were restricted to a free-living amoeba, Acanthamoeba polyphaga, and a widespread marine heterotrophic flagellate, Cafeteria roenbergensis. In this study, we successfully discovered and identified a novel tripartite interaction system comprised of a micro-green alga (Chlorella sp.), Mimiviridae large green alga virus, and virophage at the coculture level, with Chlorella sp. as the eukaryotic host, based on combination analysis of infection, morphotype, genome, and phylogeny. The large green alga virus CV-XW01 represents the closest relative to the Mimiviridae giant virus Cafeteria roenbergensis virus, host virus of the virophage Mavirus, as well as a novel large virus of Mimiviridae that infects a non-protozoan protist host. The virophage CVv-SW01 highly resembles Mavirus in its codon usage frequency and preference, although they are phylogenetically distantly related. These findings give novel insights into the diversity of large/giant viruses and their virophages.
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Zhang R, Endo H, Takemura M, Ogata H. RNA Sequencing of Medusavirus Suggests Remodeling of the Host Nuclear Environment at an Early Infection Stage. Microbiol Spectr 2021; 9:e0006421. [PMID: 34585975 PMCID: PMC8557863 DOI: 10.1128/spectrum.00064-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 08/16/2021] [Indexed: 12/22/2022] Open
Abstract
Viruses of the phylum Nucleocytoviricota, or nucleo-cytoplasmic large DNA viruses (NCLDVs), undergo a cytoplasmic or nucleo-cytoplasmic cycle, the latter of which involves both nuclear and cytoplasmic compartments to proceed viral replication. Medusavirus, a recently isolated NCLDV, has a nucleo-cytoplasmic replication cycle in amoebas during which the host nuclear membrane apparently remains intact, a unique feature among amoeba-infecting NCLDVs. The medusavirus genome lacks most transcription genes but encodes a full set of histone genes. To investigate its infection strategy, we performed a time course RNA sequencing (RNA-seq) experiment. All viral genes were transcribed and classified into five temporal expression clusters. The immediate early genes (cluster 1, 42 genes) were mostly (83%) of unknown functions, frequently (95%) associated with a palindromic promoter-like motif, and often (45%) encoded putative nucleus-localized proteins. These results suggest massive reshaping of the host nuclear environment by viral proteins at an early stage of infection. Genes in other expression clusters (clusters 2 to 5) were assigned to various functional categories. The virally encoded core histone genes were in cluster 3, whereas the viral linker histone H1 gene was in cluster 1, suggesting they have distinct roles during the course of the virus infection. The transcriptional profile of the host Acanthamoeba castellanii genes was greatly altered postinfection. Several encystment-related host genes showed increased representation levels at 48 h postinfection, which is consistent with the previously reported amoeba encystment upon medusavirus infection. IMPORTANCE Medusavirus is an amoeba-infecting giant virus that was isolated from a hot spring in Japan. It belongs to the proposed family "Medusaviridae" in the phylum Nucleocytoviricota. Unlike other amoeba-infecting giant viruses, medusavirus initiates its DNA replication in the host nucleus without disrupting the nuclear membrane. Our RNA sequencing (RNA-seq) analysis of its infection course uncovered ordered viral gene expression profiles. We identified temporal expression clusters of viral genes and associated putative promoter motifs. The subcellular localization prediction showed a clear spatiotemporal correlation between gene expression timing and localization of the encoded proteins. Notably, the immediate early expression cluster was enriched in genes targeting the nucleus, suggesting the priority of remodeling the host intranuclear environment during infection. The transcriptional profile of amoeba genes was greatly altered postinfection.
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Affiliation(s)
- Ruixuan Zhang
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho, Japan
| | - Hisashi Endo
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho, Japan
| | - Masaharu Takemura
- Laboratory of Biology, Institute of Arts and Sciences, Tokyo University of Science, Shinjuku, Tokyo, Japan
| | - Hiroyuki Ogata
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho, Japan
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10
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Mohanta TK, Mishra AK, Mohanta YK, Al-Harrasi A. Virtual 2D mapping of the viral proteome reveals host-specific modality distribution of molecular weight and isoelectric point. Sci Rep 2021; 11:21291. [PMID: 34711905 PMCID: PMC8553790 DOI: 10.1038/s41598-021-00797-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/18/2021] [Indexed: 02/07/2023] Open
Abstract
A proteome-wide study of the virus kingdom based on 1.713 million protein sequences from 19,128 virus proteomes was conducted to construct an overall proteome map of the virus kingdom. Viral proteomes encode an average of 386.214 amino acids per protein with the variation in the number of protein-coding sequences being host-specific. The proteomes of viruses of fungi hosts (882.464) encoded the greatest number of amino acids, while the viral proteome of bacterial host (210.912) encoded the smallest number of amino acids. Viral proteomes were found to have a host-specific amino acid composition. Leu (8.556%) was the most abundant and Trp (1.274%) the least abundant amino acid in the collective proteome of viruses. Viruses were found to exhibit a host-dependent molecular weight and isoelectric point of encoded proteins. The isoelectric point (pI) of viral proteins was found in the acidic range, having an average pI of 6.89. However, the pI of viral proteins of algal (pI 7.08) and vertebrate (pI 7.09) hosts was in the basic range. The virtual 2D map of the viral proteome from different hosts exhibited host-dependent modalities. The virus proteome from algal hosts and archaea exhibited a bimodal distribution of molecular weight and pI, while the virus proteome of bacterial host exhibited a trimodal distribution, and the virus proteome of fungal, human, land plants, invertebrate, protozoa, and vertebrate hosts exhibited a unimodal distribution.
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Affiliation(s)
- Tapan Kumar Mohanta
- Department of Biotech and Omics, Natural and Medical Sciences Research Center, University of Nizwa, Nizwa, 616, Oman.
| | | | - Yugal Kishore Mohanta
- Department of Applied Biology, School of Biological Sciences, University of Science and Technology Meghalaya, Techno City, Baridua, Ri-Bhoi, Meghalaya, 793101, India
| | - Ahmed Al-Harrasi
- Department of Biotech and Omics, Natural and Medical Sciences Research Center, University of Nizwa, Nizwa, 616, Oman.
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11
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Hackl T, Duponchel S, Barenhoff K, Weinmann A, Fischer MG. Virophages and retrotransposons colonize the genomes of a heterotrophic flagellate. eLife 2021; 10:72674. [PMID: 34698016 PMCID: PMC8547959 DOI: 10.7554/elife.72674] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 09/28/2021] [Indexed: 11/24/2022] Open
Abstract
Virophages can parasitize giant DNA viruses and may provide adaptive anti-giant virus defense in unicellular eukaryotes. Under laboratory conditions, the virophage mavirus integrates into the nuclear genome of the marine flagellate Cafeteria burkhardae and reactivates upon superinfection with the giant virus CroV. In natural systems, however, the prevalence and diversity of host-virophage associations has not been systematically explored. Here, we report dozens of integrated virophages in four globally sampled C. burkhardae strains that constitute up to 2% of their host genomes. These endogenous mavirus-like elements (EMALEs) separated into eight types based on GC-content, nucleotide similarity, and coding potential and carried diverse promoter motifs implicating interactions with different giant viruses. Between host strains, some EMALE insertion loci were conserved indicating ancient integration events, whereas the majority of insertion sites were unique to a given host strain suggesting that EMALEs are active and mobile. Furthermore, we uncovered a unique association between EMALEs and a group of tyrosine recombinase retrotransposons, revealing yet another layer of parasitism in this nested microbial system. Our findings show that virophages are widespread and dynamic in wild Cafeteria populations, supporting their potential role in antiviral defense in protists. Viruses exist in all ecosystems in vast numbers and infect many organisms. Some of them are harmful but others can protect the organisms they infect. For example, a group of viruses called virophages protect microscopic sea creatures called plankton from deadly infections by so-called giant viruses. In fact, virophages need plankton infected with giant viruses to survive because they use enzymes from the giant viruses to turn on their own genes. A virophage called mavirus integrates its genes into the DNA of a type of plankton called Cafeteria. It lays dormant in the DNA until a giant virus called CroV infects the plankton. This suggests that the mavirus may be a built-in defense against CroV infections and laboratory studies seem to confirm this. But whether wild Cafeteria also use these defenses is unknown. Hackl et al. show that virophages are common in the DNA of wild Cafeteria and that the two appear to have a mutually beneficial relationship. In the experiments, the researchers sequenced the genomes of four Cafeteria populations from the Atlantic and Pacific Oceans and looked for virophages in their DNA. Each of the four Cafeteria genomes contained dozens of virophages, which suggests that virophages are important to these plankton. This included several relatives of the mavirus and seven new virophages. Virophage genes were often interrupted by so called jumping genes, which may take advantage of the virophages the way the virophages use giant viruses to meet their own needs. The experiments show that virophages often co-exist with marine plankton from around the world and these relationships are likely beneficial. In fact, the experiments suggest that the virophages may have played an important role in the evolution of these plankton. Further studies may help scientists learn more about virus ecology and how viruses have shaped the evolution of other creatures.
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Affiliation(s)
- Thomas Hackl
- Max Planck Institute for Medical Research, Department of Biomolecular Mechanisms, Heidelberg, Germany
| | - Sarah Duponchel
- Max Planck Institute for Medical Research, Department of Biomolecular Mechanisms, Heidelberg, Germany
| | - Karina Barenhoff
- Max Planck Institute for Medical Research, Department of Biomolecular Mechanisms, Heidelberg, Germany
| | - Alexa Weinmann
- Max Planck Institute for Medical Research, Department of Biomolecular Mechanisms, Heidelberg, Germany
| | - Matthias G Fischer
- Max Planck Institute for Medical Research, Department of Biomolecular Mechanisms, Heidelberg, Germany
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12
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Moelling K, Broecker F. Viroids and the Origin of Life. Int J Mol Sci 2021; 22:ijms22073476. [PMID: 33800543 PMCID: PMC8036462 DOI: 10.3390/ijms22073476] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 11/16/2022] Open
Abstract
Viroids are non-coding circular RNA molecules with rod-like or branched structures. They are often ribozymes, characterized by catalytic RNA. They can perform many basic functions of life and may have played a role in evolution since the beginning of life on Earth. They can cleave, join, replicate, and undergo Darwinian evolution. Furthermore, ribozymes are the essential elements for protein synthesis of cellular organisms as parts of ribosomes. Thus, they must have preceded DNA and proteins during evolution. Here, we discuss the current evidence for viroids or viroid-like RNAs as a likely origin of life on Earth. As such, they may also be considered as models for life on other planets or moons in the solar system as well as on exoplanets.
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Affiliation(s)
- Karin Moelling
- Institute of Medical Microbiology, University of Zurich, Gloriastr 30, 8006 Zurich, Switzerland
- Max Planck Institute for molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany
- Correspondence: ; Tel.: +49-(172)-3274306
| | - Felix Broecker
- Vaxxilon Deutschland GmbH, Magnusstr. 11, 12489 Berlin, Germany;
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13
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Nasir A, Romero-Severson E, Claverie JM. Investigating the Concept and Origin of Viruses. Trends Microbiol 2020; 28:959-967. [PMID: 33158732 PMCID: PMC7609044 DOI: 10.1016/j.tim.2020.08.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 12/21/2022]
Abstract
The ongoing COVID-19 pandemic has piqued public interest in the properties, evolution, and emergence of viruses. Here, we discuss how these basic questions have surprisingly remained disputed despite being increasingly within the reach of scientific analysis. We review recent data-driven efforts that shed light into the origin and evolution of viruses and explain factors that resist the widespread acceptance of new views and insights. We propose a new definition of viruses that is not restricted to the presence or absence of any genetic or physical feature, detail a scenario for how viruses likely originated from ancient cells, and explain technical and conceptual biases that limit our understanding of virus evolution. We note that the philosophical aspects of virus evolution also impact the way we might prepare for future outbreaks.
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Affiliation(s)
- Arshan Nasir
- Theoretical Biology and Biophysics (T-6), Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - Ethan Romero-Severson
- Theoretical Biology and Biophysics (T-6), Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Jean-Michel Claverie
- Aix Marseille University, CNRS, IGS, Structural and Genomic Information Laboratory (UMR7256), Mediterranean Institute of Microbiology (FR3479), Marseille, France
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14
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Xian Y, Avila R, Pant A, Yang Z, Xiao C. The Role of Tape Measure Protein in Nucleocytoplasmic Large DNA Virus Capsid Assembly. Viral Immunol 2020; 34:41-48. [PMID: 33074779 DOI: 10.1089/vim.2020.0038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Nucleocytoplasmic large DNA viruses (NCLDVs) are a group of large viruses that infect a wide range of hosts, from animals to protists. These viruses are grouped together in NCLDV based on genomic sequence analyses. They share a set of essential genes for virion morphogenesis and replication. Most NCLDVs generally have large physical sizes while their morphologies vary in different families, such as icosahedral, brick, or oval shape, raising the question of the possible regulatory factor on their morphogenesis. The capsids of icosahedral NCLDVs are assembled from small building blocks, named capsomers, which are the trimeric form of the major capsid proteins. Note that the capsids of immature poxvirus are spherical even though they are assembled from capsomers that share high structural conservation with those icosahedral NCLDVs. The recently published high resolution structure of NCLDVs, Paramecium bursaria Chlorella virus 1 and African swine fever virus, described the intensive network of minor capsid proteins that are located underneath the capsomers. Among these minor proteins is the elongated tape measure protein (TmP) that spans from one icosahedral fivefold vertex to another. In this study, we focused on the critical roles that TmP plays in the assembly of icosahedral NCLDV capsids, answering a question raised in a previously proposed spiral mechanism. Interestingly, basic local alignment search on the TmPs showed no significant hits in poxviruses, which might be the factor that differentiates poxviruses and icosahedral NCLDVs in their morphogenesis.
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Affiliation(s)
- Yuejiao Xian
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas, USA
| | - Ricardo Avila
- Bioinformatics Program, University of Texas at El Paso, El Paso, Texas, USA
| | - Anil Pant
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Zhilong Yang
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Chuan Xiao
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas, USA
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15
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Claverie JM. Fundamental Difficulties Prevent the Reconstruction of the Deep Phylogeny of Viruses. Viruses 2020; 12:E1130. [PMID: 33036160 PMCID: PMC7600955 DOI: 10.3390/v12101130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/01/2020] [Accepted: 10/03/2020] [Indexed: 12/11/2022] Open
Abstract
The extension of virology beyond its traditional medical, veterinary, or agricultural applications, now called environmental virology, has shown that viruses are both the most numerous and diverse biological entities on Earth. In particular, virus isolations from unicellular eukaryotic hosts (heterotrophic and photosynthetic protozoans) revealed numerous viral types previously unexpected in terms of virion structure, gene content, or mode of replication. Complemented by large-scale metagenomic analyses, these discoveries have rekindled interest in the enigma of the origin of viruses, for which a description encompassing all their diversity remains not available. Several laboratories have repeatedly tackled the deep reconstruction of the evolutionary history of viruses, using various methods of molecular phylogeny applied to the few shared "core" genes detected in certain virus groups (e.g., the Nucleocytoviricota). Beyond the practical difficulties of establishing reliable homology relationships from extremely divergent sequences, I present here conceptual arguments highlighting several fundamental limitations plaguing the reconstruction of the deep evolutionary history of viruses, and even more the identification of their unique or multiple origin(s). These arguments also underline the risk of establishing premature high level viral taxonomic classifications. Those limitations are direct consequences of the random mechanisms governing the reductive/retrogressive evolution of all obligate intracellular parasites.
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Affiliation(s)
- Jean-Michel Claverie
- Structural & Genomic Information Laboratory (IGS, UMR 7256), Mediterranean Institute of Microbiology (FR3479), Aix-Marseille University and CNRS, 13288 Marseille, France
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16
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Xian Y, Xiao C. Current capsid assembly models of icosahedral nucleocytoviricota viruses. Adv Virus Res 2020; 108:275-313. [PMID: 33837719 PMCID: PMC8328511 DOI: 10.1016/bs.aivir.2020.09.006] [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: 10/23/2022]
Abstract
Nucleocytoviricota viruses (NCVs) belong to a newly established phylum originally grouped as Nucleocytoplasmic large DNA viruses. NCVs are unique because of their large and complicated genomes that contain cellular genes with homologs from all kingdoms of life, raising intensive debates on their evolutional origins. Many NCVs pack their genomes inside massive icosahedral capsids assembled from thousands of proteins. Studying the assembly mechanism of such capsids has been challenging until breakthroughs from structural studies. Subsequently, several models of the capsid assembly were proposed, which provided some interesting insights on this elaborate process. In this review, we discuss three of the most recent assembly models as well as supporting experimental observations. Furthermore, we propose a new model that combines research developments from multiple sources. Investigation of the assembly process of these vast NCV capsids will facilitate future deciphering of the molecular mechanisms driving the formation of similar supramolecular complexes.
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Affiliation(s)
- Yuejiao Xian
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, El Paso, Texas, United States
| | - Chuan Xiao
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, El Paso, Texas, United States.
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17
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Colombet J, Fuster M, Billard H, Sime-Ngando T. Femtoplankton: What's New? Viruses 2020; 12:E881. [PMID: 32806713 PMCID: PMC7472349 DOI: 10.3390/v12080881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/10/2020] [Accepted: 08/10/2020] [Indexed: 01/01/2023] Open
Abstract
Since the discovery of high abundances of virus-like particles in aquatic environment, emergence of new analytical methods in microscopy and molecular biology has allowed significant advances in the characterization of the femtoplankton, i.e., floating entities filterable on a 0.2 µm pore size filter. The successive evidences in the last decade (2010-2020) of high abundances of biomimetic mineral-organic particles, extracellular vesicles, CPR/DPANN (Candidate phyla radiation/Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota and Nanohaloarchaeota), and very recently of aster-like nanoparticles (ALNs), show that aquatic ecosystems form a huge reservoir of unidentified and overlooked femtoplankton entities. The purpose of this review is to highlight this unsuspected diversity. Herein, we focus on the origin, composition and the ecological potentials of organic femtoplankton entities. Particular emphasis is given to the most recently discovered ALNs. All the entities described are displayed in an evolutionary context along a continuum of complexity, from minerals to cell-like living entities.
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Affiliation(s)
- Jonathan Colombet
- Laboratoire Microorganismes: Génome et Environnement (LMGE), UMR CNRS 6023, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France; (M.F.); (H.B.); (T.S.-N.)
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18
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Trinh JT, Shao Q, Guan J, Zeng L. Emerging heterogeneous compartments by viruses in single bacterial cells. Nat Commun 2020; 11:3813. [PMID: 32732913 PMCID: PMC7393140 DOI: 10.1038/s41467-020-17515-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/06/2020] [Indexed: 11/17/2022] Open
Abstract
Spatial organization of biological processes allows for variability in molecular outcomes and coordinated development. Here, we investigate how organization underpins phage lambda development and decision-making by characterizing viral components and processes in subcellular space. We use live-cell and in situ fluorescence imaging at the single-molecule level to examine lambda DNA replication, transcription, virion assembly, and resource recruitment in single-cell infections, uniting key processes of the infection cycle into a coherent model of phage development encompassing space and time. We find that different viral DNAs establish separate subcellular compartments within cells, which sustains heterogeneous viral development in single cells. These individual phage compartments are physically separated by the E. coli nucleoid. Our results provide mechanistic details describing how separate viruses develop heterogeneously to resemble single-cell phenotypes. Here, the authors apply live-cell and in situ fluorescence imaging at the single-molecule level to examine lambda DNA replication in single cells, finding that individual phage DNAs sequester host factors to their own vicinity and confine their replicated DNAs into separate compartments, suggesting that phage decision-making transcripts are spatially organized in separate compartments to allow distinct subcellular decisions to develop.
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Affiliation(s)
- Jimmy T Trinh
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.,Center for Phage Technology, Texas A&M University, College Station, TX, 77843, USA
| | - Qiuyan Shao
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.,Center for Phage Technology, Texas A&M University, College Station, TX, 77843, USA
| | - Jingwen Guan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.,Center for Phage Technology, Texas A&M University, College Station, TX, 77843, USA.,Molecular and Environmental Plant Science, Texas A&M University, College Station, TX, 77843, USA
| | - Lanying Zeng
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA. .,Center for Phage Technology, Texas A&M University, College Station, TX, 77843, USA. .,Molecular and Environmental Plant Science, Texas A&M University, College Station, TX, 77843, USA.
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19
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Abstract
Wastewater is a rich source of microbial life and contains bacteria, viruses, and other microbes found in human waste as well as environmental runoff sources. As part of an effort to characterize the New York City wastewater metagenome, we profiled the viral community of sewage samples across all five boroughs of NYC and found that local sampling sites have unique sets of viruses. We focused on bacteriophages, or viruses of bacteria, to understand how they may influence the microbial ecology of this system. We identified several new clusters of phages and successfully associated them with bacterial hosts, providing insight into virus-host interactions in urban wastewater. This study provides a first look into the viral communities present across the wastewater system in NYC and points to their functional importance in this environment. Bacteriophages are abundant members of all microbiomes studied to date, influencing microbial communities through interactions with their bacterial hosts. Despite their functional importance and ubiquity, phages have been underexplored in urban environments compared to their bacterial counterparts. We profiled the viral communities in New York City (NYC) wastewater using metagenomic data collected in November 2014 from 14 wastewater treatment plants. We show that phages accounted for the largest viral component of the sewage samples and that specific virus communities were associated with local environmental conditions within boroughs. The vast majority of the virus sequences had no homology matches in public databases, forming an average of 1,700 unique virus clusters (putative genera). These new clusters contribute to elucidating the overwhelming proportion of data that frequently goes unidentified in viral metagenomic studies. We assigned potential hosts to these phages, which appear to infect a wide range of bacterial genera, often outside their presumed host. We determined that infection networks form a modular-nested pattern, indicating that phages include a range of host specificities, from generalists to specialists, with most interactions organized into distinct groups. We identified genes in viral contigs involved in carbon and sulfur cycling, suggesting functional importance of viruses in circulating pathways and gene functions in the wastewater environment. In addition, we identified virophage genes as well as a nearly complete novel virophage genome. These findings provide an understanding of phage abundance and diversity in NYC wastewater, previously uncharacterized, and further examine geographic patterns of phage-host association in urban environments. IMPORTANCE Wastewater is a rich source of microbial life and contains bacteria, viruses, and other microbes found in human waste as well as environmental runoff sources. As part of an effort to characterize the New York City wastewater metagenome, we profiled the viral community of sewage samples across all five boroughs of NYC and found that local sampling sites have unique sets of viruses. We focused on bacteriophages, or viruses of bacteria, to understand how they may influence the microbial ecology of this system. We identified several new clusters of phages and successfully associated them with bacterial hosts, providing insight into virus-host interactions in urban wastewater. This study provides a first look into the viral communities present across the wastewater system in NYC and points to their functional importance in this environment.
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20
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Lood C, Danis‐Wlodarczyk K, Blasdel BG, Jang HB, Vandenheuvel D, Briers Y, Noben J, van Noort V, Drulis‐Kawa Z, Lavigne R. Integrative omics analysis of Pseudomonas aeruginosa virus PA5oct highlights the molecular complexity of jumbo phages. Environ Microbiol 2020; 22:2165-2181. [PMID: 32154616 PMCID: PMC7318152 DOI: 10.1111/1462-2920.14979] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 03/06/2020] [Indexed: 11/28/2022]
Abstract
Pseudomonas virus vB_PaeM_PA5oct is proposed as a model jumbo bacteriophage to investigate phage-bacteria interactions and is a candidate for phage therapy applications. Combining hybrid sequencing, RNA-Seq and mass spectrometry allowed us to accurately annotate its 286,783 bp genome with 461 coding regions including four non-coding RNAs (ncRNAs) and 93 virion-associated proteins. PA5oct relies on the host RNA polymerase for the infection cycle and RNA-Seq revealed a gradual take-over of the total cell transcriptome from 21% in early infection to 93% in late infection. PA5oct is not organized into strictly contiguous regions of temporal transcription, but some genomic regions transcribed in early, middle and late phases of infection can be discriminated. Interestingly, we observe regions showing limited transcription activity throughout the infection cycle. We show that PA5oct upregulates specific bacterial operons during infection including operons pncA-pncB1-nadE involved in NAD biosynthesis, psl for exopolysaccharide biosynthesis and nap for periplasmic nitrate reductase production. We also observe a downregulation of T4P gene products suggesting mechanisms of superinfection exclusion. We used the proteome of PA5oct to position our isolate amongst other phages using a gene-sharing network. This integrative omics study illustrates the molecular diversity of jumbo viruses and raises new questions towards cellular regulation and phage-encoded hijacking mechanisms.
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Affiliation(s)
- Cédric Lood
- Department of Biosystems, Laboratory of Gene Technology, KU LeuvenLeuvenBelgium
- Department of Microbial and Molecular Systems, Laboratory of Computational Systems Biology, KU LeuvenLeuvenBelgium
| | - Katarzyna Danis‐Wlodarczyk
- Department of Biosystems, Laboratory of Gene Technology, KU LeuvenLeuvenBelgium
- Department of Pathogen Biology and ImmunologyInstitute of Genetics and Microbiology, University of WroclawWroclawPoland
| | - Bob G. Blasdel
- Department of Biosystems, Laboratory of Gene Technology, KU LeuvenLeuvenBelgium
| | - Ho Bin Jang
- Department of Biosystems, Laboratory of Gene Technology, KU LeuvenLeuvenBelgium
| | - Dieter Vandenheuvel
- Department of Biosystems, Laboratory of Gene Technology, KU LeuvenLeuvenBelgium
| | - Yves Briers
- Department of Biosystems, Laboratory of Gene Technology, KU LeuvenLeuvenBelgium
| | - Jean‐Paul Noben
- Biomedical Research Institute and Transnational University LimburgHasselt UniversityDiepenbeekBelgium
| | - Vera van Noort
- Department of Microbial and Molecular Systems, Laboratory of Computational Systems Biology, KU LeuvenLeuvenBelgium
- Institute of Biology, Leiden UniversityLeidenThe Netherlands
| | - Zuzanna Drulis‐Kawa
- Department of Pathogen Biology and ImmunologyInstitute of Genetics and Microbiology, University of WroclawWroclawPoland
| | - Rob Lavigne
- Department of Biosystems, Laboratory of Gene Technology, KU LeuvenLeuvenBelgium
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21
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Mougari S, Chelkha N, Sahmi-Bounsiar D, Di Pinto F, Colson P, Abrahao J, La Scola B. A virophage cross-species infection through mutant selection represses giant virus propagation, promoting host cell survival. Commun Biol 2020; 3:248. [PMID: 32439847 PMCID: PMC7242381 DOI: 10.1038/s42003-020-0970-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 04/15/2020] [Indexed: 01/03/2023] Open
Abstract
Virus adaptation to new hosts is a major cause of infectious disease emergence. This mechanism has been intensively studied in the context of zoonotic virus spillover, due to its impact on global health. However, it remains unclear for virophages, parasites of giant viruses and potential regulators of microbial communities. Here, we present, for the first time to our knowledge, evidence of cross-species infection of a virophage. We demonstrated that challenging the native population of Guarani virophage with two previously unidentified giant viruses, previously nonpermissive to this virophage, allows the selection of a mutant genotype able to infect these giant viruses. We were able to characterize the potential genetic determinant (deletion) carried by the virophage with the expanded-host range. Our study also highlights the relevant biological impact of this host adaptation by demonstrating that coinfection with the mixture containing the mutant virophage abolishes giant virus production and rescues the host cell population from lysis.
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Affiliation(s)
- Said Mougari
- Unité MEPHI, Aix-Marseille Univ., Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), 19-21 boulevard Jean Moulin, 13005, Marseille, France.
- IHU Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005, Marseille, France.
| | - Nisrine Chelkha
- Unité MEPHI, Aix-Marseille Univ., Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), 19-21 boulevard Jean Moulin, 13005, Marseille, France
- IHU Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005, Marseille, France
| | - Dehia Sahmi-Bounsiar
- Unité MEPHI, Aix-Marseille Univ., Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), 19-21 boulevard Jean Moulin, 13005, Marseille, France
- IHU Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005, Marseille, France
| | - Fabrizio Di Pinto
- Unité MEPHI, Aix-Marseille Univ., Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), 19-21 boulevard Jean Moulin, 13005, Marseille, France
- IHU Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005, Marseille, France
| | - Philippe Colson
- Unité MEPHI, Aix-Marseille Univ., Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), 19-21 boulevard Jean Moulin, 13005, Marseille, France
- IHU Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005, Marseille, France
| | - Jonatas Abrahao
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil, postal code 31270-901.
| | - Bernard La Scola
- Unité MEPHI, Aix-Marseille Univ., Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), 19-21 boulevard Jean Moulin, 13005, Marseille, France.
- IHU Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005, Marseille, France.
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22
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Horie M. Interactions among eukaryotes, retrotransposons and riboviruses: endogenous riboviral elements in eukaryotic genomes. Genes Genet Syst 2020; 94:253-267. [PMID: 31257309 DOI: 10.1266/ggs.18-00049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Riboviruses are viruses that have RNA genomes and replicate only via RNA intermediates. Although they do not require a DNA phase for replication and do not encode reverse transcriptase, the presence of DNA forms of riboviral sequences in ribovirus-infected cells has been reported since the 1970s. Additionally, heritable ribovirus-derived sequences, called riboviral endogenous viral elements (EVEs), have been found in the genomes of many eukaryotes. These are now thought to be formed by the reverse transcription machineries of retrotransposons within eukaryotic genomes sometimes referred to as selfish elements. Surprisingly, some reverse-transcribed riboviral DNAs (including EVEs) provide physiological functions for their hosts, suggesting the occurrence of novel interactions among eukaryotic genomes, retrotransposons and riboviruses, and opening the door to new avenues of investigation. Here I review current knowledge on these triangular interactions, and discuss future directions in this field.
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Affiliation(s)
- Masayuki Horie
- Hakubi Center for Advanced Research, and Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University
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23
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Exploration of the propagation of transpovirons within Mimiviridae reveals a unique example of commensalism in the viral world. ISME JOURNAL 2019; 14:727-739. [PMID: 31822788 PMCID: PMC7031253 DOI: 10.1038/s41396-019-0565-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 01/27/2023]
Abstract
Acanthamoeba-infecting Mimiviridae are giant viruses with dsDNA genome up to 1.5 Mb. They build viral factories in the host cytoplasm in which the nuclear-like virus-encoded functions take place. They are themselves the target of infections by 20-kb-dsDNA virophages, replicating in the giant virus factories and can also be found associated with 7-kb-DNA episomes, dubbed transpovirons. Here we isolated a virophage (Zamilon vitis) and two transpovirons respectively associated to B- and C-clade mimiviruses. We found that the virophage could transfer each transpoviron provided the host viruses were devoid of a resident transpoviron (permissive effect). If not, only the resident transpoviron originally isolated from the corresponding virus was replicated and propagated within the virophage progeny (dominance effect). Although B- and C-clade viruses devoid of transpoviron could replicate each transpoviron, they did it with a lower efficiency across clades, suggesting an ongoing process of adaptive co-evolution. We analysed the proteomes of host viruses and virophage particles in search of proteins involved in this adaptation process. This study also highlights a unique example of intricate commensalism in the viral world, where the transpoviron uses the virophage to propagate and where the Zamilon virophage and the transpoviron depend on the giant virus to replicate, without affecting its infectious cycle.
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Seligmann H. Syntenies Between Cohosted Mitochondrial, Chloroplast, and Phycodnavirus Genomes: Functional Mimicry and/or Common Ancestry? DNA Cell Biol 2019; 38:1257-1268. [DOI: 10.1089/dna.2019.4858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Hervé Seligmann
- The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel
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Metagenomic Analysis of Virus Diversity and Relative Abundance in a Eutrophic Freshwater Harbour. Viruses 2019; 11:v11090792. [PMID: 31466255 PMCID: PMC6784016 DOI: 10.3390/v11090792] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/13/2019] [Accepted: 08/25/2019] [Indexed: 11/17/2022] Open
Abstract
Aquatic viruses have been extensively studied over the past decade, yet fundamental aspects of freshwater virus communities remain poorly described. Our goal was to characterize virus communities captured in the >0.22 µm size-fraction seasonally and spatially in a freshwater harbour. Community DNA was extracted from water samples and sequenced on an Illumina HiSeq platform. Assembled contigs were annotated as belonging to the virus groups (i.e., order or family) Caudovirales, Mimiviridae, Phycodnaviridae, and virophages (Lavidaviridae), or to other groups of undefined viruses. Virophages were often the most abundant group, and discrete virophage taxa were remarkably stable across sites and dates despite fluctuations in Mimiviridae community composition. Diverse Mimiviridae contigs were detected in the samples and the two sites contained distinct Mimiviridae communities, suggesting that Mimiviridae are important algal viruses in this system. Caudovirales and Phycodnaviridae were present at low abundances in most samples. Of the 18 environmental parameters tested, only chlorophyll a explained the variation in the data at the order or family level of classification. Overall, our findings provide insight into freshwater virus community assemblages by expanding the documented diversity of freshwater virus communities, highlighting the potential ecological importance of virophages, and revealing distinct communities over small spatial scales.
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Mougari S, Sahmi-Bounsiar D, Levasseur A, Colson P, La Scola B. Virophages of Giant Viruses: An Update at Eleven. Viruses 2019; 11:v11080733. [PMID: 31398856 PMCID: PMC6723459 DOI: 10.3390/v11080733] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 07/31/2019] [Accepted: 08/02/2019] [Indexed: 12/19/2022] Open
Abstract
The last decade has been marked by two eminent discoveries that have changed our perception of the virology field: The discovery of giant viruses and a distinct new class of viral agents that parasitize their viral factories, the virophages. Coculture and metagenomics have actively contributed to the expansion of the virophage family by isolating dozens of new members. This increase in the body of data on virophage not only revealed the diversity of the virophage group, but also the relevant ecological impact of these small viruses and their potential role in the dynamics of the microbial network. In addition, the isolation of virophages has led us to discover previously unknown features displayed by their host viruses and cells. In this review, we present an update of all the knowledge on the isolation, biology, genomics, and morphological features of the virophages, a decade after the discovery of their first member, the Sputnik virophage. We discuss their parasitic lifestyle as bona fide viruses of the giant virus factories, genetic parasites of their genomes, and then their role as a key component or target for some host defense mechanisms during the tripartite virophage–giant virus–host cell interaction. We also present the latest advances regarding their origin, classification, and definition that have been widely discussed.
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Affiliation(s)
- Said Mougari
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Microbes Evolution Phylogeny and Infections (MEPHI), 27 boulevard Jean Moulin, 13005 Marseille, France
- Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005 Marseille, France
| | - Dehia Sahmi-Bounsiar
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Microbes Evolution Phylogeny and Infections (MEPHI), 27 boulevard Jean Moulin, 13005 Marseille, France
- Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005 Marseille, France
| | - Anthony Levasseur
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Microbes Evolution Phylogeny and Infections (MEPHI), 27 boulevard Jean Moulin, 13005 Marseille, France
- Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005 Marseille, France
| | - Philippe Colson
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Microbes Evolution Phylogeny and Infections (MEPHI), 27 boulevard Jean Moulin, 13005 Marseille, France.
- Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005 Marseille, France.
| | - Bernard La Scola
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Microbes Evolution Phylogeny and Infections (MEPHI), 27 boulevard Jean Moulin, 13005 Marseille, France.
- Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, 19-21 boulevard Jean Moulin, 13005 Marseille, France.
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Complex Membrane Remodeling during Virion Assembly of the 30,000-Year-Old Mollivirus Sibericum. J Virol 2019; 93:JVI.00388-19. [PMID: 30996095 DOI: 10.1128/jvi.00388-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/11/2019] [Indexed: 01/14/2023] Open
Abstract
Cellular membranes ensure functional compartmentalization by dynamic fusion-fission remodeling and are often targeted by viruses during entry, replication, assembly, and egress. Nucleocytoplasmic large DNA viruses (NCLDVs) can recruit host-derived open membrane precursors to form their inner viral membrane. Using complementary three-dimensional (3D)-electron microscopy techniques, including focused-ion beam scanning electron microscopy and electron tomography, we show that the giant Mollivirus sibericum utilizes the same strategy but also displays unique features. Indeed, assembly is specifically triggered by an open cisterna with a flat pole in its center and open curling ends that grow by recruitment of vesicles never reported for NCLDVs. These vesicles, abundant in the viral factory (VF), are initially closed but open once in close proximity to the open curling ends of the growing viral membrane. The flat pole appears to play a central role during the entire virus assembly process. While additional capsid layers are assembled from it, it also shapes the growing cisterna into immature crescent-like virions and is located opposite to the membrane elongation and closure sites, thereby providing virions with a polarity. In the VF, DNA-associated filaments are abundant, and DNA is packed within virions prior to particle closure. Altogether, our results highlight the complexity of the interaction between giant viruses and their host. Mollivirus assembly relies on the general strategy of vesicle recruitment, opening, and shaping by capsid layers similar to all NCLDVs studied until now. However, the specific features of its assembly suggest that the molecular mechanisms for cellular membrane remodeling and persistence are unique.IMPORTANCE Since the first giant virus Mimivirus was identified, other giant representatives are isolated regularly around the world and appear to be unique in several aspects. They belong to at least four viral families, and the ways they interact with their hosts remain poorly understood. We focused on Mollivirus sibericum, the sole representative of "Molliviridae," which was isolated from a 30,000-year-old permafrost sample and exhibits spherical virions of complex composition. In particular, we show that (i) assembly is initiated by a unique structure containing a flat pole positioned at the center of an open cisterna, (ii) core packing involves another cisterna-like element seemingly pushing core proteins into particles being assembled, and (iii) specific filamentous structures contain the viral genome before packaging. Altogether, our findings increase our understanding of how complex giant viruses interact with their host and provide the foundation for future studies to elucidate the molecular mechanisms of Mollivirus assembly.
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Abstract
Genes encoding cytochrome P450 (CYP; P450) enzymes occur widely in the Archaea, Bacteria, and Eukarya, where they play important roles in metabolism of endogenous regulatory molecules and exogenous chemicals. We now report that genes for multiple and unique P450s occur commonly in giant viruses in the Mimiviridae, Pandoraviridae, and other families in the proposed order Megavirales. P450 genes were also identified in a herpesvirus (Ranid herpesvirus 3) and a phage (Mycobacterium phage Adler). The Adler phage P450 was classified as CYP102L1, and the crystal structure of the open form was solved at 2.5 Å. Genes encoding known redox partners for P450s (cytochrome P450 reductase, ferredoxin and ferredoxin reductase, and flavodoxin and flavodoxin reductase) were not found in any viral genome so far described, implying that host redox partners may drive viral P450 activities. Giant virus P450 proteins share no more than 25% identity with the P450 gene products we identified in Acanthamoeba castellanii, an amoeba host for many giant viruses. Thus, the origin of the unique P450 genes in giant viruses remains unknown. If giant virus P450 genes were acquired from a host, we suggest it could have been from an as yet unknown and possibly ancient host. These studies expand the horizon in the evolution and diversity of the enormously important P450 superfamily. Determining the origin and function of P450s in giant viruses may help to discern the origin of the giant viruses themselves.
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Mougari S, Bekliz M, Abrahao J, Di Pinto F, Levasseur A, La Scola B. Guarani Virophage, a New Sputnik-Like Isolate From a Brazilian Lake. Front Microbiol 2019; 10:1003. [PMID: 31130943 PMCID: PMC6510173 DOI: 10.3389/fmicb.2019.01003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/18/2019] [Indexed: 01/23/2023] Open
Abstract
Virophages are critical regulators of viral population dynamics and potential actors in the stability of the microbial networks. These small biological entities predate the replicative cycle of giant viruses, such as the members of the Mimiviridae family or their distant relatives, which produce within the cytoplasm of their host cells a viral factory harboring a complex biochemistry propitious to the growth of the smaller parasites. In this paper, we describe the isolation and the characterization of a new virophage, the eighth, that we named Guarani. We observed that Guarani exhibits a late replication cycle compared to its giant virus host. In addition, like all Sputnik strains, Guarani is able to infect the three lineages A, B and C of the Mimiviridae family, and affects the replication and the infectivity of its host virus. In terms of genetic content, Guarani has a 18,967 bp long double-stranded DNA genome encoding 22 predicted genes very similar to Sputnik genes, except for ORF19 and ORF12. The former is more related to Zamilon while the latter seems to be novel. The architecture of the Guarani genome is closely related to Sputnik and Zamilon strains, suggesting a common origin for all these virophages.
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Affiliation(s)
- Said Mougari
- MEPHI, APHM, IRD 198, Department of Medicine, IHU-Méditerranée Infection, Aix-Marseille University, Marseille, France
| | - Meriem Bekliz
- MEPHI, APHM, IRD 198, Department of Medicine, IHU-Méditerranée Infection, Aix-Marseille University, Marseille, France
| | - Jonatas Abrahao
- MEPHI, APHM, IRD 198, Department of Medicine, IHU-Méditerranée Infection, Aix-Marseille University, Marseille, France.,Laboratório de Vírus, Instituto de Ciências Biológicas, Departamento de Microbiologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Fabrizio Di Pinto
- MEPHI, APHM, IRD 198, Department of Medicine, IHU-Méditerranée Infection, Aix-Marseille University, Marseille, France
| | - Anthony Levasseur
- MEPHI, APHM, IRD 198, Department of Medicine, IHU-Méditerranée Infection, Aix-Marseille University, Marseille, France
| | - Bernard La Scola
- MEPHI, APHM, IRD 198, Department of Medicine, IHU-Méditerranée Infection, Aix-Marseille University, Marseille, France
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30
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Mougari S, Abrahao J, Oliveira GP, Bou Khalil JY, La Scola B. Role of the R349 Gene and Its Repeats in the MIMIVIRE Defense System. Front Microbiol 2019; 10:1147. [PMID: 31178847 PMCID: PMC6538805 DOI: 10.3389/fmicb.2019.01147] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/06/2019] [Indexed: 01/16/2023] Open
Abstract
MIMIVIRE is a defense system described in lineage A Mimivirus (Mimiviridae family) that mediates resistance against Zamilon virophage. It is composed of putative helicase and nuclease associated with a gene of unknown function called R349, which contains four 15 bp repeats homologous to the virophage sequence. In a previous study, the silencing of such genes restored virophage susceptibility. Moreover, the CRISPR Cas-4 like activity of the nuclease has recently been characterized. In this study, a recently isolated Mimivirus of lineage A with R349 gene lacking 3 of 4 repeats was demonstrated to be susceptible to Zamilon. To reinforce the importance of the R349 gene in the MIMIVIRE system, we developed and presented, for the first time to our knowledge, a protocol for Mimivirus genomic editing. By knocking out R349 gene in a Mimivirus lineage A, we observed the replication of Zamilon, indicating that this gene is critical in the resistance against this specific group of virophages.
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Affiliation(s)
- Said Mougari
- Unité MEPHI, Aix Marseille Université, IHU Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Jonatas Abrahao
- Unité MEPHI, Aix Marseille Université, IHU Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France.,Laboratório de Vírus, Departamento de Microbiologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Graziele P Oliveira
- Laboratório de Vírus, Departamento de Microbiologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Jacques Y Bou Khalil
- Unité MEPHI, Aix Marseille Université, IHU Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Bernard La Scola
- Unité MEPHI, Aix Marseille Université, IHU Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
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31
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Seligmann H. Giant viruses: spore‐like missing links betweenRickettsiaand mitochondria? Ann N Y Acad Sci 2019; 1447:69-79. [DOI: 10.1111/nyas.14022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/10/2019] [Accepted: 01/16/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Hervé Seligmann
- The National Natural History Collectionsthe Hebrew University of Jerusalem Jerusalem Israel
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32
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Duponchel S, Fischer MG. Viva lavidaviruses! Five features of virophages that parasitize giant DNA viruses. PLoS Pathog 2019; 15:e1007592. [PMID: 30897185 PMCID: PMC6428243 DOI: 10.1371/journal.ppat.1007592] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Sarah Duponchel
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Matthias G. Fischer
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Heidelberg, Germany
- * E-mail:
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33
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Koonin EV, Yutin N. Evolution of the Large Nucleocytoplasmic DNA Viruses of Eukaryotes and Convergent Origins of Viral Gigantism. Adv Virus Res 2019; 103:167-202. [PMID: 30635076 DOI: 10.1016/bs.aivir.2018.09.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Nucleocytoplasmic Large DNA Viruses (NCLDV) of eukaryotes (proposed order "Megavirales") comprise an expansive group of eukaryotic viruses that consists of the families Poxviridae, Asfarviridae, Iridoviridae, Ascoviridae, Phycodnaviridae, Marseilleviridae, Pithoviridae, and Mimiviridae, as well as Pandoraviruses, Molliviruses, and Faustoviruses that so far remain unaccounted by the official virus taxonomy. All these viruses have double-stranded DNA genomes that range in size from about 100 kilobases (kb) to more than 2.5 megabases. The viruses with genomes larger than 500kb are informally considered "giant," and the largest giant viruses surpass numerous bacteria and archaea in both particle and genome size. The discovery of giant viruses has been highly unexpected and has changed the perception of viral size and complexity, and even, arguably, the entire concept of a virus. Given that giant viruses encode multiple proteins that are universal among cellular life forms and are components of the translation system, the quintessential cellular molecular machinery, attempts have been made to incorporate these viruses in the evolutionary tree of cellular life. Moreover, evolutionary scenarios of the origin of giant viruses from a fourth, supposedly extinct domain of cellular life have been proposed. However, despite all the differences in the genome size and gene repertoire, the NCLDV can be confidently defined as monophyletic group, on the strength of the presence of about 40 genes that can be traced back to their last common ancestor. Using several most strongly conserved genes from this ancestral set, a well-resolved phylogenetic tree of the NCLDV was built and employed as the scaffold to reconstruct the history of gene gain and loss throughout the course of the evolution of this group of viruses. This reconstruction reveals extremely dynamic evolution that involved extensive gene gain and loss in many groups of viruses and indicates that giant viruses emerged independently in several clades of the NCLDV. Thus, these giants of the virus world evolved repeatedly from smaller and simpler viruses, rather than from a fourth domain of cellular life, and captured numerous genes, including those for translation system components, from eukaryotes, along with some bacterial genes. Even deeper evolutionary reconstructions reveal apparent links between the NCLDV and smaller viruses of eukaryotes, such as adenoviruses, and ultimately, derive all these viruses from tailless bacteriophages.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States.
| | - Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States
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Abstract
Organisms display astonishing levels of cell and molecular diversity, including genome size, shape, and architecture. In this chapter, we review how the genome can be viewed as both a structural and an informational unit of biological diversity and explicitly define our intended meaning of genetic information. A brief overview of the characteristic features of bacterial, archaeal, and eukaryotic cell types and viruses sets the stage for a review of the differences in organization, size, and packaging strategies of their genomes. We include a detailed review of genetic elements found outside the primary chromosomal structures, as these provide insights into how genomes are sometimes viewed as incomplete informational entities. Lastly, we reassess the definition of the genome in light of recent advancements in our understanding of the diversity of genomic structures and the mechanisms by which genetic information is expressed within the cell. Collectively, these topics comprise a good introduction to genome biology for the newcomer to the field and provide a valuable reference for those developing new statistical or computation methods in genomics. This review also prepares the reader for anticipated transformations in thinking as the field of genome biology progresses.
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Colson P, Levasseur A, La Scola B, Sharma V, Nasir A, Pontarotti P, Caetano-Anollés G, Raoult D. Ancestrality and Mosaicism of Giant Viruses Supporting the Definition of the Fourth TRUC of Microbes. Front Microbiol 2018; 9:2668. [PMID: 30538677 PMCID: PMC6277510 DOI: 10.3389/fmicb.2018.02668] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 10/18/2018] [Indexed: 12/20/2022] Open
Abstract
Giant viruses of amoebae were discovered in 2003. Since then, their diversity has greatly expanded. They were suggested to form a fourth branch of life, collectively named ‘TRUC’ (for “Things Resisting Uncompleted Classifications”) alongside Bacteria, Archaea, and Eukarya. Their origin and ancestrality remain controversial. Here, we specify the evolution and definition of giant viruses. Phylogenetic and phenetic analyses of informational gene repertoires of giant viruses and selected bacteria, archaea and eukaryota were performed, including structural phylogenomics based on protein structural domains grouped into 289 universal fold superfamilies (FSFs). Hierarchical clustering analysis was performed based on a binary presence/absence matrix constructed using 727 informational COGs from cellular organisms. The presence/absence of ‘universal’ FSF domains was used to generate an unrooted maximum parsimony phylogenomic tree. Comparison of the gene content of a giant virus with those of a bacterium, an archaeon, and a eukaryote with small genomes was also performed. Overall, both cladistic analyses based on gene sequences of very central and ancient proteins and on highly conserved protein fold structures as well as phenetic analyses were congruent regarding the delineation of a fourth branch of microbes comprised by giant viruses. Giant viruses appeared as a basal group in the tree of all proteomes. A pangenome and core genome determined for Rickettsia bellii (bacteria), Methanomassiliicoccus luminyensis (archaeon), Encephalitozoon intestinalis (eukaryote), and Tupanvirus (giant virus) showed a substantial proportion of Tupanvirus genes that overlap with those of the cellular microbes. In addition, a substantial genome mosaicism was observed, with 51, 11, 8, and 0.2% of Tupanvirus genes best matching with viruses, eukaryota, bacteria, and archaea, respectively. Finally, we found that genes themselves may be subject to lateral sequence transfers. In summary, our data highlight the quantum leap between classical and giant viruses. Phylogenetic and phyletic analyses and the study of protein fold superfamilies confirm previous evidence of the existence of a fourth TRUC of life that includes giant viruses, and highlight its ancestrality and mosaicism. They also point out that best evolutionary representations for giant viruses and cellular microorganisms are rhizomes, and that sequence transfers rather than gene transfers have to be considered.
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Affiliation(s)
- Philippe Colson
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM); Microbes, Evolution, Phylogeny and Infection (MEΦI); Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, Marseille, France
| | - Anthony Levasseur
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM); Microbes, Evolution, Phylogeny and Infection (MEΦI); Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, Marseille, France
| | - Bernard La Scola
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM); Microbes, Evolution, Phylogeny and Infection (MEΦI); Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, Marseille, France
| | - Vikas Sharma
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM); Microbes, Evolution, Phylogeny and Infection (MEΦI); Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, Marseille, France.,Centre National de la Recherche Scientifique, Marseille, France
| | - Arshan Nasir
- Evolutionary Bioinformatics Laboratory, Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States.,Department of Biosciences, COMSATS University Islamabad, Islamabad, Pakistan
| | - Pierre Pontarotti
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM); Microbes, Evolution, Phylogeny and Infection (MEΦI); Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, Marseille, France.,Centre National de la Recherche Scientifique, Marseille, France
| | - Gustavo Caetano-Anollés
- Evolutionary Bioinformatics Laboratory, Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Didier Raoult
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM); Microbes, Evolution, Phylogeny and Infection (MEΦI); Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, Marseille, France
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Abstract
The nucleocytoplasmic large DNA viruses (NCLDVs) are a monophyletic group of diverse eukaryotic viruses that reproduce primarily in the cytoplasm of the infected cells and include the largest viruses currently known: the giant mimiviruses, pandoraviruses, and pithoviruses. With virions measuring up to 1.5 μm and genomes of up to 2.5 Mb, the giant viruses break the now-outdated definition of a virus and extend deep into the genome size range typical of bacteria and archaea. Additionally, giant viruses encode multiple proteins that are universal among cellular life forms, particularly components of the translation system, the signature cellular molecular machinery. These findings triggered hypotheses on the origin of giant viruses from cells, likely of an extinct fourth domain of cellular life, via reductive evolution. However, phylogenomic analyses reveal a different picture, namely multiple origins of giant viruses from smaller NCLDVs via acquisition of multiple genes from the eukaryotic hosts and bacteria, along with gene duplication. Thus, with regard to their origin, the giant viruses do not appear to qualitatively differ from the rest of the virosphere. However, the evolutionary forces that led to the emergence of virus gigantism remain enigmatic.
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Affiliation(s)
- Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
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37
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Zhang QY, Gui JF. Diversity, evolutionary contribution and ecological roles of aquatic viruses. SCIENCE CHINA-LIFE SCIENCES 2018; 61:1486-1502. [DOI: 10.1007/s11427-018-9414-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 09/26/2018] [Indexed: 01/21/2023]
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Zara V, Ferramosca A, Günnewig K, Kreimendahl S, Schwichtenberg J, Sträter D, Çakar M, Emmrich K, Guidato P, Palmieri F, Rassow J. Mimivirus-Encoded Nucleotide Translocator VMC1 Targets the Mitochondrial Inner Membrane. J Mol Biol 2018; 430:5233-5245. [PMID: 30261167 DOI: 10.1016/j.jmb.2018.09.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/18/2018] [Accepted: 09/18/2018] [Indexed: 01/08/2023]
Abstract
Mimivirus (Acanthamoeba polyphaga mimivirus) was the first giant DNA virus identified in an amoeba species. Its genome contains at least 979 genes. One of these, L276, encodes a nucleotide translocator with similarities to mitochondrial metabolite carriers, provisionally named viral mitochondrial carrier 1 (VMC1). In this study, we investigated the intracellular distribution of VMC1 upon expression in HeLa cells and in the yeast Saccharomyces cerevisiae. We found that VMC1 is specifically targeted to mitochondria and to the inner mitochondrial membrane. Newly synthesized VMC1 binds to the mitochondrial outer-membrane protein Tom70 and translocates through the import channel formed by the β-barrel protein Tom40. Derivatization of the four cysteine residues inside Tom40 by N-ethylmaleimide caused a delay in translocation but not a complete occlusion. Cell viability was not reduced by VMC1. Neither the mitochondrial membrane potential nor the intracellular production of reactive oxygen species was affected. Similar to endogenous metabolite carriers, mimivirus-encoded VMC1 appears to act as a specific translocator in the mitochondrial inner membrane. Due to its permeability for deoxyribonucleotides, VMC1 confers to the mitochondria an opportunity to contribute nucleotides for the replication of the large DNA genome of the virus.
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Affiliation(s)
- Vincenzo Zara
- Department of Environmental and Biological Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Alessandra Ferramosca
- Department of Environmental and Biological Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Kathrin Günnewig
- Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Sebastian Kreimendahl
- Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Jan Schwichtenberg
- Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Dina Sträter
- Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Mahmut Çakar
- Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Kerstin Emmrich
- Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Patrick Guidato
- Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Joachim Rassow
- Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44780 Bochum, Germany.
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Mimiviridae: An Expanding Family of Highly Diverse Large dsDNA Viruses Infecting a Wide Phylogenetic Range of Aquatic Eukaryotes. Viruses 2018; 10:v10090506. [PMID: 30231528 PMCID: PMC6163669 DOI: 10.3390/v10090506] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/13/2018] [Accepted: 09/15/2018] [Indexed: 01/22/2023] Open
Abstract
Since 1998, when Jim van Etten’s team initiated its characterization, Paramecium bursaria Chlorella virus 1 (PBCV-1) had been the largest known DNA virus, both in terms of particle size and genome complexity. In 2003, the Acanthamoeba-infecting Mimivirus unexpectedly superseded PBCV-1, opening the era of giant viruses, i.e., with virions large enough to be visible by light microscopy and genomes encoding more proteins than many bacteria. During the following 15 years, the isolation of many Mimivirus relatives has made Mimiviridae one of the largest and most diverse families of eukaryotic viruses, most of which have been isolated from aquatic environments. Metagenomic studies of various ecosystems (including soils) suggest that many more remain to be isolated. As Mimiviridae members are found to infect an increasing range of phytoplankton species, their taxonomic position compared to the traditional Phycodnaviridae (i.e., etymologically “algal viruses”) became a source of confusion in the literature. Following a quick historical review of the key discoveries that established the Mimiviridae family, we describe its current taxonomic structure and propose a set of operational criteria to help in the classification of future isolates.
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Giant viruses as protein-coated amoeban mitochondria? Virus Res 2018; 253:77-86. [DOI: 10.1016/j.virusres.2018.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/13/2018] [Accepted: 06/14/2018] [Indexed: 01/18/2023]
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41
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Quemin ER, Corroyer-Dulmont S, Krijnse-Locker J. Entry and Disassembly of Large DNA Viruses: Electron Microscopy Leads the Way. J Mol Biol 2018; 430:1714-1724. [DOI: 10.1016/j.jmb.2018.04.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/11/2018] [Accepted: 04/17/2018] [Indexed: 12/17/2022]
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42
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Seligmann H, Raoult D. Stem-Loop RNA Hairpins in Giant Viruses: Invading rRNA-Like Repeats and a Template Free RNA. Front Microbiol 2018; 9:101. [PMID: 29449833 PMCID: PMC5799277 DOI: 10.3389/fmicb.2018.00101] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 01/16/2018] [Indexed: 12/31/2022] Open
Abstract
We examine the hypothesis that de novo template-free RNAs still form spontaneously, as they did at the origins of life, invade modern genomes, contribute new genetic material. Previously, analyses of RNA secondary structures suggested that some RNAs resembling ancestral (t)RNAs formed recently de novo, other parasitic sequences cluster with rRNAs. Here positive control analyses of additional RNA secondary structures confirm ancestral and de novo statuses of RNA grouped according to secondary structure. Viroids with branched stems resemble de novo RNAs, rod-shaped viroids resemble rRNA secondary structures, independently of GC contents. 5' UTR leading regions of West Nile and Dengue flavivirid viruses resemble de novo and rRNA structures, respectively. An RNA homologous with Megavirus, Dengue and West Nile genomes, copperhead snake microsatellites and levant cotton repeats, not templated by Mimivirus' genome, persists throughout Mimivirus' infection. Its secondary structure clusters with candidate de novo RNAs. The saltatory phyletic distribution and secondary structure of Mimivirus' peculiar RNA suggest occasional template-free polymerization of this sequence, rather than noncanonical transcriptions (swinger polymerization, posttranscriptional editing).
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Affiliation(s)
- Hervé Seligmann
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR MEPHI, Aix-Marseille Université, IRD, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Didier Raoult
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR MEPHI, Aix-Marseille Université, IRD, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
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43
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Love LG. Does the discovery of the mimivirus call into question attempts to define life? BIOSCIENCE HORIZONS: THE INTERNATIONAL JOURNAL OF STUDENT RESEARCH 2018. [PMCID: PMC7149470 DOI: 10.1093/biohorizons/hzy006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Despite biology being ‘The study of living organisms’ (Proffitt, 2017), there is no consensus between biologists on the definition of life (Bedau, 2010). Defining life has challenged and divided biologists and philosophers alike ever since Aristotle proposed the first definition. Emerging fields like synthetic biology and exobiology have rekindled attempts at establishing a definition of life for practical purposes. The question presents many challenges with each attempt thus far leading to unintended implications and strong counterexamples. It is an inherently multidisciplinary challenge with each approach giving wildly varying and often irreconcilable definitions. The given definitions of life are numerous with over 300 definitions published in books and journals. The unique characteristics of the mimivirus, discovered in 2003, and later giant viruses, rekindled the discussion in defining life, indicating other complications in a definition.
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Affiliation(s)
- Luca Gregory Love
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
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Okamoto K, Miyazaki N, Song C, Maia FRNC, Reddy HKN, Abergel C, Claverie JM, Hajdu J, Svenda M, Murata K. Structural variability and complexity of the giant Pithovirus sibericum particle revealed by high-voltage electron cryo-tomography and energy-filtered electron cryo-microscopy. Sci Rep 2017; 7:13291. [PMID: 29038566 PMCID: PMC5643343 DOI: 10.1038/s41598-017-13390-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 09/22/2017] [Indexed: 12/23/2022] Open
Abstract
The Pithoviridae giant virus family exhibits the largest viral particle known so far, a prolate spheroid up to 2.5 μm in length and 0.9 μm in diameter. These particles show significant variations in size. Little is known about the structure of the intact virion due to technical limitations with conventional electron cryo-microscopy (cryo-EM) when imaging thick specimens. Here we present the intact structure of the giant Pithovirus sibericum particle at near native conditions using high-voltage electron cryo-tomography (cryo-ET) and energy-filtered cryo-EM. We detected a previously undescribed low-density outer layer covering the tegument and a periodical structuring of the fibres in the striated apical cork. Energy-filtered Zernike phase-contrast cryo-EM images show distinct substructures inside the particles, implicating an internal compartmentalisation. The density of the interior volume of Pithovirus particles is three quarters lower than that of the Mimivirus. However, it is remarkably high given that the 600 kbp Pithovirus genome is only half the size of the Mimivirus genome and is packaged in a volume up to 100 times larger. These observations suggest that the interior is densely packed with macromolecules in addition to the genomic nucleic acid.
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Affiliation(s)
- Kenta Okamoto
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3 (Box 596), SE-75124, Uppsala, Sweden.
| | - Naoyuki Miyazaki
- National Institute for Physiological Sciences (NIPS), Okazaki, Aichi, 444-8585, Japan
| | - Chihong Song
- National Institute for Physiological Sciences (NIPS), Okazaki, Aichi, 444-8585, Japan
| | - Filipe R N C Maia
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3 (Box 596), SE-75124, Uppsala, Sweden
| | - Hemanth K N Reddy
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3 (Box 596), SE-75124, Uppsala, Sweden
| | - Chantal Abergel
- Structural and Genomic Information Laboratory, UMR 7256 (IMM FR 3479) Centre National de la Recherche Scientifique & Aix-Marseille University, Marseille, 13288, France
| | - Jean-Michel Claverie
- Structural and Genomic Information Laboratory, UMR 7256 (IMM FR 3479) Centre National de la Recherche Scientifique & Aix-Marseille University, Marseille, 13288, France.,Assistance Publique des Hôpitaux de Marseille. La Timone, 13005, Marseille, France
| | - Janos Hajdu
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3 (Box 596), SE-75124, Uppsala, Sweden.,Institute of Physics AS CR, v.v.i., Na Slovance 2, 18221, Prague 8, Czech Republic
| | - Martin Svenda
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3 (Box 596), SE-75124, Uppsala, Sweden
| | - Kazuyoshi Murata
- National Institute for Physiological Sciences (NIPS), Okazaki, Aichi, 444-8585, Japan.
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Ecogenomics of virophages and their giant virus hosts assessed through time series metagenomics. Nat Commun 2017; 8:858. [PMID: 29021524 PMCID: PMC5636890 DOI: 10.1038/s41467-017-01086-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/16/2017] [Indexed: 11/30/2022] Open
Abstract
Virophages are small viruses that co-infect eukaryotic cells alongside giant viruses (Mimiviridae) and hijack their machinery to replicate. While two types of virophages have been isolated, their genomic diversity and ecology remain largely unknown. Here we use time series metagenomics to identify and study the dynamics of 25 uncultivated virophage populations, 17 of which represented by complete or near-complete genomes, in two North American freshwater lakes. Taxonomic analysis suggests that these freshwater virophages represent at least three new candidate genera. Ecologically, virophage populations are repeatedly detected over years and evolutionary stable, yet their distinct abundance profiles and gene content suggest that virophage genera occupy different ecological niches. Co-occurrence analyses reveal 11 virophages strongly associated with uncultivated Mimiviridae, and three associated with eukaryotes among the Dinophyceae, Rhizaria, Alveolata, and Cryptophyceae groups. Together, these findings significantly augment virophage databases, help refine virophage taxonomy, and establish baseline ecological hypotheses and tools to study virophages in nature. Virophages are recently-identified small viruses that infect larger viruses, yet their diversity and ecological roles are poorly understood. Here, Roux and colleagues present time series metagenomics data revealing new virophage genera and their putative ecological interactions in two freshwater lakes.
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46
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Claverie JM, Abergel C. CRISPR-Cas-like system in giant viruses: why MIMIVIRE is not likely to be an adaptive immune system. Virol Sin 2017; 31:193-6. [PMID: 27315813 DOI: 10.1007/s12250-016-3801-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Jean-Michel Claverie
- Structural and Genomic Information Laboratory (UMR7256), CNRS Aix Marseille University, Mediterranean Institute of Microbiology (FR 3479), Marseille, France.
| | - Chantal Abergel
- Structural and Genomic Information Laboratory (UMR7256), CNRS Aix Marseille University, Mediterranean Institute of Microbiology (FR 3479), Marseille, France.
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47
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El Houmami N, Seligmann H. Evolution of Nucleotide Punctuation Marks: From Structural to Linear Signals. Front Genet 2017; 8:36. [PMID: 28396681 PMCID: PMC5366352 DOI: 10.3389/fgene.2017.00036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 03/13/2017] [Indexed: 01/13/2023] Open
Abstract
We present an evolutionary hypothesis assuming that signals marking nucleotide synthesis (DNA replication and RNA transcription) evolved from multi- to unidimensional structures, and were carried over from transcription to translation. This evolutionary scenario presumes that signals combining secondary and primary nucleotide structures are evolutionary transitions. Mitochondrial replication initiation fits this scenario. Some observations reported in the literature corroborate that several signals for nucleotide synthesis function in translation, and vice versa. (a) Polymerase-induced frameshift mutations occur preferentially at translational termination signals (nucleotide deletion is interpreted as termination of nucleotide polymerization, paralleling the role of stop codons in translation). (b) Stem-loop hairpin presence/absence modulates codon-amino acid assignments, showing that translational signals sometimes combine primary and secondary nucleotide structures (here codon and stem-loop). (c) Homopolymer nucleotide triplets (AAA, CCC, GGG, TTT) cause transcriptional and ribosomal frameshifts. Here we find in recently described human mitochondrial RNAs that systematically lack mono-, dinucleotides after each trinucleotide (delRNAs) that delRNA triplets include 2x more homopolymers than mitogenome regions not covered by delRNA. Further analyses of delRNAs show that the natural circular code X (a little-known group of 20 translational signals enabling ribosomal frame retrieval consisting of 20 codons {AAC, AAT, ACC, ATC, ATT, CAG, CTC, CTG, GAA, GAC, GAG, GAT, GCC, GGC, GGT, GTA, GTC, GTT, TAC, TTC} universally overrepresented in coding versus other frames of gene sequences), regulates frameshift in transcription and translation. This dual transcription and translation role confirms for X the hypothesis that translational signals were carried over from transcriptional signals.
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Affiliation(s)
- Nawal El Houmami
- URMITE, Aix Marseille Université UM63, CNRS 7278, IRD 198, INSERM 1095, IHU - Méditerranée Infection Marseille, France
| | - Hervé Seligmann
- URMITE, Aix Marseille Université UM63, CNRS 7278, IRD 198, INSERM 1095, IHU - Méditerranée Infection Marseille, France
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48
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Wilhelm SW, Bird JT, Bonifer KS, Calfee BC, Chen T, Coy SR, Gainer PJ, Gann ER, Heatherly HT, Lee J, Liang X, Liu J, Armes AC, Moniruzzaman M, Rice JH, Stough JMA, Tams RN, Williams EP, LeCleir GR. A Student's Guide to Giant Viruses Infecting Small Eukaryotes: From Acanthamoeba to Zooxanthellae. Viruses 2017; 9:E46. [PMID: 28304329 PMCID: PMC5371801 DOI: 10.3390/v9030046] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/07/2017] [Accepted: 03/09/2017] [Indexed: 12/15/2022] Open
Abstract
The discovery of infectious particles that challenge conventional thoughts concerning "what is a virus" has led to the evolution a new field of study in the past decade. Here, we review knowledge and information concerning "giant viruses", with a focus not only on some of the best studied systems, but also provide an effort to illuminate systems yet to be better resolved. We conclude by demonstrating that there is an abundance of new host-virus systems that fall into this "giant" category, demonstrating that this field of inquiry presents great opportunities for future research.
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Affiliation(s)
- Steven W Wilhelm
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Jordan T Bird
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Kyle S Bonifer
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Benjamin C Calfee
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Tian Chen
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Samantha R Coy
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - P Jackson Gainer
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Eric R Gann
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Huston T Heatherly
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Jasper Lee
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Xiaolong Liang
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Jiang Liu
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - April C Armes
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Mohammad Moniruzzaman
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - J Hunter Rice
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Joshua M A Stough
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Robert N Tams
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Evan P Williams
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
| | - Gary R LeCleir
- The Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
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Colson P, La Scola B, Levasseur A, Caetano-Anollés G, Raoult D. Mimivirus: leading the way in the discovery of giant viruses of amoebae. Nat Rev Microbiol 2017; 15:243-254. [PMID: 28239153 PMCID: PMC7096837 DOI: 10.1038/nrmicro.2016.197] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Acanthamoeba polyphaga mimivirus (APMV) and subsequently discovered giant viruses of amoebae challenge the previous definition of viruses and their classification. The replication cycle, structure, genomic make-up and plasticity of giant viruses differ from those of traditional viruses. They extend the definition of viruses into a broader range of biological entities, some of which are very simple and others of which have a complexity that is comparable to that of other microorganisms. Giant viruses of amoebae have virus particles as large as some microorganisms that are visible by light microscopy and that have a stunning level of complexity. Their genomes are mosaics and contain large repertoires of genes, some of which are hallmarks of cellular organisms, although the majority of which have unknown functions. Mimiviruses are associated with a specific mobilome and are parasitized by viruses that they can defend against. Several hypotheses on the ancient origin and evolutionary relationship between cellular organisms and giant viruses of amoebae have been proposed, and these topics continue to be debated. The detection of giant viruses of amoebae in humans and the study of their potential pathogenicity are emerging fields.
The discovery of the giant amoebal virus mimivirus, in 2003, opened up a new area of virology. Extended studies, including those of mimiviruses, have since revealed that these viruses have genetic, proteomic and structural features that are more complex than those of conventional viruses. The accidental discovery of the giant virus of amoeba — Acanthamoeba polyphaga mimivirus (APMV; more commonly known as mimivirus) — in 2003 changed the field of virology. Viruses were previously defined by their submicroscopic size, which probably prevented the search for giant viruses, which are visible by light microscopy. Extended studies of giant viruses of amoebae revealed that they have genetic, proteomic and structural complexities that were not thought to exist among viruses and that are comparable to those of bacteria, archaea and small eukaryotes. The giant virus particles contain mRNA and more than 100 proteins, they have gene repertoires that are broader than those of other viruses and, notably, some encode translation components. The infection cycles of giant viruses of amoebae involve virus entry by amoebal phagocytosis and replication in viral factories. In addition, mimiviruses are infected by virophages, defend against them through the mimivirus virophage resistance element (MIMIVIRE) system and have a unique mobilome. Overall, giant viruses of amoebae, including mimiviruses, marseilleviruses, pandoraviruses, pithoviruses, faustoviruses and molliviruses, challenge the definition and classification of viruses, and have increasingly been detected in humans.
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Affiliation(s)
- Philippe Colson
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Aix-Marseille University, UM63, CNRS 7278, IRD 198, INSERM 1095, Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, AP-HM, 19-21 Boulevard Jean Moulin, 13385 Marseille, France
| | - Bernard La Scola
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Aix-Marseille University, UM63, CNRS 7278, IRD 198, INSERM 1095, Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, AP-HM, 19-21 Boulevard Jean Moulin, 13385 Marseille, France
| | - Anthony Levasseur
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Aix-Marseille University, UM63, CNRS 7278, IRD 198, INSERM 1095, Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, AP-HM, 19-21 Boulevard Jean Moulin, 13385 Marseille, France
| | - Gustavo Caetano-Anollés
- Evolutionary Bioinformatics Laboratory, Department of Crop Sciences, University of Illinois, 332 National Soybean Research Center, 1101 West Peabody Drive, Urbana, Illinois 61801, USA
| | - Didier Raoult
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Aix-Marseille University, UM63, CNRS 7278, IRD 198, INSERM 1095, Institut Hospitalo-Universitaire (IHU) - Méditerranée Infection, AP-HM, 19-21 Boulevard Jean Moulin, 13385 Marseille, France
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50
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Schrad JR, Young EJ, Abrahão JS, Cortines JR, Parent KN. Microscopic Characterization of the Brazilian Giant Samba Virus. Viruses 2017; 9:v9020030. [PMID: 28216551 PMCID: PMC5332949 DOI: 10.3390/v9020030] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/25/2017] [Accepted: 02/02/2017] [Indexed: 12/13/2022] Open
Abstract
Prior to the discovery of the mimivirus in 2003, viruses were thought to be physically small and genetically simple. Mimivirus, with its ~750-nm particle size and its ~1.2-Mbp genome, shattered these notions and changed what it meant to be a virus. Since this discovery, the isolation and characterization of giant viruses has exploded. One of the more recently discovered giant viruses, Samba virus, is a Mimivirus that was isolated from the Rio Negro in the Brazilian Amazon. Initial characterization of Samba has revealed some structural information, although the preparation techniques used are prone to the generation of structural artifacts. To generate more native-like structural information for Samba, we analyzed the virus through cryo-electron microscopy, cryo-electron tomography, scanning electron microscopy, and fluorescence microscopy. These microscopy techniques demonstrated that Samba particles have a capsid diameter of ~527 nm and a fiber length of ~155 nm, making Samba the largest Mimivirus yet characterized. We also compared Samba to a fiberless mimivirus variant. Samba particles, unlike those of mimivirus, do not appear to be rigid, and quasi-icosahedral, although the two viruses share many common features, including a multi-layered capsid and an asymmetric nucleocapsid, which may be common amongst the Mimiviruses.
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Affiliation(s)
- Jason R Schrad
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, 48824 MI, USA.
| | - Eric J Young
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, 48824 MI, USA.
| | - Jônatas S Abrahão
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901 Minas Gerais, Brazil.
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE) UM63 CNRS 7278 IRD 198 INSERM U1095, Aix-Marseille University, 13385 Marseille Cedex 05, France.
| | - Juliana R Cortines
- Departamento de Virologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil.
| | - Kristin N Parent
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, 48824 MI, USA.
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