1
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Tembrock LR, Zink FA, Gilligan TM. Viral Prevalence and Genomic Xenology in the Coevolution of HzNV-2 (Nudiviridae) with Host Helicoverpa zea (Lepidoptera: Noctuidae). INSECTS 2023; 14:797. [PMID: 37887809 PMCID: PMC10607169 DOI: 10.3390/insects14100797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/16/2023] [Accepted: 09/24/2023] [Indexed: 10/28/2023]
Abstract
Insect viruses have been described from numerous lineages, yet patterns of genetic exchange and viral prevalence, which are essential to understanding host-virus coevolution, are rarely studied. In Helicoverpa zea, the virus HzNV-2 can cause deformity of male and female genitalia, resulting in sterility. Using ddPCR, we found that male H. zea with malformed genitalia (agonadal) contained high levels of HzNV-2 DNA, confirming previous work. HzNV-2 was found to be prevalent throughout the United States, at more than twice the rate of the baculovirus HaSNPV, and that it contained several host-acquired DNA sequences. HzNV-2 possesses four recently endogenized lepidopteran genes and several more distantly related genes, including one gene with a bacteria-like sequence found in both host and virus. Among the recently acquired genes is cytosolic serine hydroxymethyltransferase (cSHMT). In nearly all tested H. zea, cSHMT contained a 200 bp transposable element (TE) that was not found in cSHMT of the sister species H. armigera. No other virus has been found with host cSHMT, and the study of this shared copy, including possible interactions, may yield new insights into the function of this gene with possible applications to insect biological control, and gene editing.
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Affiliation(s)
- Luke R. Tembrock
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Frida A. Zink
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Todd M. Gilligan
- USDA-APHIS-PPQ-Science & Technology, Identification Technology Program, Fort Collins, CO 80526, USA
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2
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Gaïa M, Forterre P. From Mimivirus to Mirusvirus: The Quest for Hidden Giants. Viruses 2023; 15:1758. [PMID: 37632100 PMCID: PMC10458455 DOI: 10.3390/v15081758] [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: 07/26/2023] [Revised: 08/14/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
Our perception of viruses has been drastically evolving since the inception of the field of virology over a century ago. In particular, the discovery of giant viruses from the Nucleocytoviricota phylum marked a pivotal moment. Their previously concealed diversity and abundance unearthed an unprecedented complexity in the virus world, a complexity that called for new definitions and concepts. These giant viruses underscore the intricate interactions that unfold over time between viruses and their hosts, and are themselves suspected to have played a significant role as a driving force in the evolution of eukaryotes since the dawn of this cellular domain. Whether they possess exceptional relationships with their hosts or whether they unveil the actual depths of evolutionary connections between viruses and cells otherwise hidden in smaller viruses, the attraction giant viruses exert on the scientific community and beyond continues to grow. Yet, they still hold surprises. Indeed, the recent identification of mirusviruses connects giant viruses to herpesviruses, each belonging to distinct viral realms. This discovery substantially broadens the evolutionary landscape of Nucleocytoviricota. Undoubtedly, the years to come will reveal their share of surprises.
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Affiliation(s)
- Morgan Gaïa
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ. Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara GOSEE, 75012 Paris, France
| | - Patrick Forterre
- Institut de Biologie Intégrative de la Cellule (I2BC), CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
- Département de Microbiologie, Institut Pasteur, 75015 Paris, France
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3
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López-García P, Moreira D. The symbiotic origin of the eukaryotic cell. C R Biol 2023; 346:55-73. [PMID: 37254790 DOI: 10.5802/crbiol.118] [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: 01/26/2023] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 06/01/2023]
Abstract
Eukaryogenesis represented a major evolutionary transition that led to the emergence of complex cells from simpler ancestors. For several decades, the most accepted scenario involved the evolution of an independent lineage of proto-eukaryotes endowed with an endomembrane system, including a nuclear compartment, a developed cytoskeleton and phagocytosis, which engulfed the alphaproteobacterial ancestor of mitochondria. However, the recent discovery by metagenomic and cultural approaches of Asgard archaea, which harbour many genes in common with eukaryotes and are their closest relatives in phylogenomic trees, rather supports scenarios based on the symbiosis of one Asgard-like archaeon and one or more bacteria at the origin of the eukaryotic cell. Here, we review the recent discoveries that led to this conceptual shift, briefly evoking current models of eukaryogenesis and the challenges ahead to discriminate between them and to establish a detailed, plausible scenario that accounts for the evolution of eukaryotic traits from those of their prokaryotic ancestors.
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4
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Spang A, Mahendrarajah TA, Offre P, Stairs CW. Evolving perspective on the origin and diversification of cellular life and the virosphere. Genome Biol Evol 2022; 14:6537539. [PMID: 35218347 PMCID: PMC9169541 DOI: 10.1093/gbe/evac034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2022] [Indexed: 11/14/2022] Open
Abstract
The tree of life (TOL) is a powerful framework to depict the evolutionary history of cellular organisms through time, from our microbial origins to the diversification of multicellular eukaryotes that shape the visible biosphere today. During the past decades, our perception of the TOL has fundamentally changed, in part, due to profound methodological advances, which allowed a more objective approach to studying organismal and viral diversity and led to the discovery of major new branches in the TOL as well as viral lineages. Phylogenetic and comparative genomics analyses of these data have, among others, revolutionized our understanding of the deep roots and diversity of microbial life, the origin of the eukaryotic cell, eukaryotic diversity, as well as the origin, and diversification of viruses. In this review, we provide an overview of some of the recent discoveries on the evolutionary history of cellular organisms and their viruses and discuss a variety of complementary techniques that we consider crucial for making further progress in our understanding of the TOL and its interconnection with the virosphere.
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Affiliation(s)
- Anja Spang
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, The Netherlands and 1790 AB Den Burg.,Department of Cell- and Molecular Biology, Science for Life Laboratory, Uppsala University, Sweden SE-75123, Uppsala
| | - Tara A Mahendrarajah
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, The Netherlands and 1790 AB Den Burg
| | - Pierre Offre
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, The Netherlands and 1790 AB Den Burg
| | - Courtney W Stairs
- Department of Biology, Lund University, Sweden Sölvegatan 35, 223 62 Lund
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5
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Sun TW, Ku C. Unraveling gene content variation across eukaryotic giant viruses based on network analyses and host associations. Virus Evol 2021; 7:veab081. [PMID: 34754514 PMCID: PMC8570155 DOI: 10.1093/ve/veab081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/31/2021] [Accepted: 09/15/2021] [Indexed: 12/31/2022] Open
Abstract
The nucleocytoplasmic large DNA viruses (NCLDVs, phylum Nucleocytoviricota) infect vertebrates, invertebrates, algae, amoebae, and other unicellular organisms across supergroups of eukaryotes and in various ecosystems. The expanding collection of their genome sequences has revolutionized our view of virus genome size and coding capacity. Phylogenetic trees based on a few core genes are commonly used as a model to understand their evolution. However, the tree topology can differ between analyses, and the vast majority of encoded genes might not share a common evolutionary history. To explore the whole-genome variation and evolution of NCLDVs, we dissected their gene contents using clustering, network, and comparative analyses. Our updated core-gene tree served as a framework to classify NCLDVs into families and intrafamilial lineages, but networks of individual genomes and family pangenomes showed patterns of gene sharing that contradict with the tree topology, in particular at higher taxonomic levels. Clustering of NCLDV genomes revealed variable granularity and degrees of gene sharing within each family, which cannot be inferred from the tree. At the level of NCLDV families, a correlation exists between gene content variation, but not core-gene sequence divergence, and host supergroup diversity. In addition, there is significantly higher gene sharing between divergent viruses that infect similar host types. The identified shared genes would be a useful resource for further functional analyses of NCLDV–host interactions. Overall this study provides a comprehensive view of gene repertoire variation in NCLDVs at different taxonomic levels, as well as a novel approach to studying the extremely diverse giant virus genomes.
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Affiliation(s)
- Tsu-Wang Sun
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Chuan Ku
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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6
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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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7
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Forterre P, Gaia M. [Giant viruses and the origin of eukaryotic RNA polymerases]. Med Sci (Paris) 2021; 37:230-233. [PMID: 33739269 DOI: 10.1051/medsci/2021007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Patrick Forterre
- Département de microbiologie, Institut Pasteur, 25 rue du Docteur-Roux, 75015 Paris, France. - Institut de biologie intégrative de la cellule (I2BC), Département de microbiologie, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Morgan Gaia
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ. Évry, Université Paris-Saclay, 91057 Évry, France
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8
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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: 33] [Impact Index Per Article: 8.3] [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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9
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Rey C. The hunt for plant viruses in South Africa: The early days. S AFR J SCI 2020. [DOI: 10.17159/sajs.2020/7916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Plant viruses cause widespread disease in agriculturally important crops, resulting in a reduction in both quality and quantity of produce. The introduction of intensive crop monoculture has resulted in an exponential increase in viral diseases which can cross over from wild indigenous plants. Viral pathogens also can occur in mixed infections, and rapid, sensitive and reliable diagnostic methods are required to identify and characterise the viruses responsible for the field diseases. In comparison to bacterial and fungal diseases, viral diseases are more difficult to diagnose. This review covers a period (1985–2011) in the history of virus discovery in South Africa during which several plant viruses from commercial and smallscale farms were identified and characterised. Interestingly, novel viruses were discovered in three crops, namely guar and cassava grown by small-scale farmers in Mpumalanga, and in commercial tobacco. The implication of these plant diseases is potential yield loss to farmers which can affect their livelihoods, and result in severe economic loss for the food and agriculture industries. Accurate identification of the causal viral agents of these viral diseases is a prerequisite for development of effective management strategies.
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Affiliation(s)
- Chrissie Rey
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
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10
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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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11
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Pereira-Santana A, Gamboa-Tuz SD, Zhao T, Schranz ME, Vinuesa P, Bayona A, Rodríguez-Zapata LC, Castano E. Fibrillarin evolution through the Tree of Life: Comparative genomics and microsynteny network analyses provide new insights into the evolutionary history of Fibrillarin. PLoS Comput Biol 2020; 16:e1008318. [PMID: 33075080 PMCID: PMC7608942 DOI: 10.1371/journal.pcbi.1008318] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 11/03/2020] [Accepted: 09/07/2020] [Indexed: 12/26/2022] Open
Abstract
Fibrillarin (FIB), a methyltransferase essential for life in the vast majority of eukaryotes, is involved in methylation of rRNA required for proper ribosome assembly, as well as methylation of histone H2A of promoter regions of rRNA genes. RNA viral progression that affects both plants and animals requires FIB proteins. Despite the importance and high conservation of fibrillarins, there little is known about the evolutionary dynamics of this small gene family. We applied a phylogenomic microsynteny-network approach to elucidate the evolutionary history of FIB proteins across the Tree of Life. We identified 1063 non-redundant FIB sequences across 1049 completely sequenced genomes from Viruses, Bacteria, Archaea, and Eukarya. FIB is a highly conserved single-copy gene through Archaea and Eukarya lineages, except for plants, which have a gene family expansion due to paleopolyploidy and tandem duplications. We found a high conservation of the FIB genomic context during plant evolution. Surprisingly, FIB in mammals duplicated after the Eutheria split (e.g., ruminants, felines, primates) from therian mammals (e.g., marsupials) to form two main groups of sequences, the FIB and FIB-like groups. The FIB-like group transposed to another genomic context and remained syntenic in all the eutherian mammals. This transposition correlates with differences in the expression patterns of FIB-like proteins and with elevated Ks values potentially due to reduced evolutionary constraints of the duplicated copy. Our results point to a unique evolutionary event in mammals, between FIB and FIB-like genes, that led to non-redundant roles of the vital processes in which this protein is involved.
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Affiliation(s)
- Alejandro Pereira-Santana
- Unidad de Bioquímica y Biología molecular de plantas, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
- Unidad de Biotecnología Industrial, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Zapopan, Jalisco, México
- Dirección de Cátedras, Consejo Nacional de Ciencia y Tecnología, Ciudad de México, México
| | - Samuel David Gamboa-Tuz
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | - Tao Zhao
- Bioinformatics and Evolutionary Genomics, VIB-UGent Center for Plant Systems Biology, Gent, Belgium
- Biosystematics Group, Wageningen University and Research, Wageningen, Netherlands
| | - M. Eric Schranz
- Biosystematics Group, Wageningen University and Research, Wageningen, Netherlands
| | - Pablo Vinuesa
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, México
| | - Andrea Bayona
- Unidad de Bioquímica y Biología molecular de plantas, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | | | - Enrique Castano
- Unidad de Bioquímica y Biología molecular de plantas, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
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12
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de Farias ST, Jheeta S, Prosdocimi F. Viruses as a survival strategy in the armory of life. HISTORY AND PHILOSOPHY OF THE LIFE SCIENCES 2019; 41:45. [PMID: 31612293 DOI: 10.1007/s40656-019-0287-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
Viruses have generally been thought of as infectious agents. New data on mimivirus, however, suggests a reinterpretation of this thought. Earth's biosphere seems to contain many more viruses than previously thought and they are relevant in the maintenance of ecosystems and biodiversity. Viruses are not considered to be alive because they are not free-living entities and do not have cellular units. Current hypotheses indicate that some viruses may have been the result of genomic reduction of cellular life forms. However, new studies relating to the origins of biological systems suggest that viruses could also have originated during the transition from First to the Last Universal Common Ancestor (from FUCA to LUCA). Within this setting, life has been established as chemical informational system and could be interpreted as a macrocode of multiple layers. The first entity to acquire these features was the First Universal Common Ancestor (FUCA) that evolved to an intermediate ancestral that could be named T-LUCA (Transitional-LUCA) and be equated to Woese's concept of progenotes. T-LUCA may have remained as undifferentiated subsystems with viruses-like structures. The net result is that both cellular life forms and viruses shared protein synthesis apparatuses. In short, virus is a strategy of life reached by two paths: T-LUCAs like entities and the reduction of cellular life forms.
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Affiliation(s)
- Sávio Torres de Farias
- Laboratório de Genética Evolutiva Paulo Leminsk, Departamento de Biologia Molecular, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil.
- Departamento de Filosofia, Programa de Pós-Graduação em Filosofia, Universidade Federal de Santa Catarina, Florianopólis, Santa Catarina, Brazil.
| | - Sohan Jheeta
- Network of Researchers on the Chemical Evolution of Life, Leeds, UK
| | - Francisco Prosdocimi
- Laboratório de Biologia Teórica e de Sistemas, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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13
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Diversification of giant and large eukaryotic dsDNA viruses predated the origin of modern eukaryotes. Proc Natl Acad Sci U S A 2019; 116:19585-19592. [PMID: 31506349 DOI: 10.1073/pnas.1912006116] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Giant and large eukaryotic double-stranded DNA viruses from the Nucleo-Cytoplasmic Large DNA Virus (NCLDV) assemblage represent a remarkably diverse and potentially ancient component of the eukaryotic virome. However, their origin(s), evolution, and potential roles in the emergence of modern eukaryotes remain subjects of intense debate. Here we present robust phylogenetic trees of NCLDVs, based on the 8 most conserved proteins responsible for virion morphogenesis and informational processes. Our results uncover the evolutionary relationships between different NCLDV families and support the existence of 2 superclades of NCLDVs, each encompassing several families. We present evidence strongly suggesting that the NCLDV core genes, which are involved in both informational processes and virion formation, were acquired vertically from a common ancestor. Among them, the largest subunits of the DNA-dependent RNA polymerase were transferred between 2 clades of NCLDVs and proto-eukaryotes, giving rise to 2 of the 3 eukaryotic DNA-dependent RNA polymerases. Our results strongly suggest that these transfers and the diversification of NCLDVs predated the emergence of modern eukaryotes, emphasizing the major role of viruses in the evolution of cellular domains.
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14
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de Mendoza A, Sebé-Pedrós A. Origin and evolution of eukaryotic transcription factors. Curr Opin Genet Dev 2019; 58-59:25-32. [PMID: 31466037 DOI: 10.1016/j.gde.2019.07.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/14/2019] [Accepted: 07/20/2019] [Indexed: 12/17/2022]
Abstract
Transcription factors (TFs) have a central role in genome regulation directing gene transcription through binding specific DNA sequences. Eukaryotic genomes encode a large diversity of TF classes, each defined by unique DNA-interaction domains. Recent advances in genome sequencing and phylogenetic placement of diverse eukaryotic and archaeal species are re-defining the evolutionary history of eukaryotic TFs. The emerging view from a comparative genomics perspective is that the Last Eukaryotic Common Ancestor (LECA) had an extensive repertoire of TFs, most of which represent eukaryotic evolutionary novelties. This burst of TF innovation coincides with the emergence of genomic nuclear segregation and complex chromatin organization.
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Affiliation(s)
- Alex de Mendoza
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia; Harry Perkins Institute of Medical Research, Perth, WA, 6009, Australia
| | - Arnau Sebé-Pedrós
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra, Barcelona, Spain.
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15
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Shukla A, López-González S, Hoffmann G, Hafrén A. Diverse plant viruses: a toolbox for dissection of cellular pathways. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3029-3034. [PMID: 30882863 PMCID: PMC6598076 DOI: 10.1093/jxb/erz122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/11/2019] [Indexed: 05/12/2023]
Abstract
Research in virology has usually focused on one selected host-virus pathosystem to examine the mechanisms underlying a particular disease. However, as exemplified by the mechanistically versatile suppression of antiviral RNA silencing by plant viruses, there may be functionally convergent evolution. Assuming this is a widespread feature, we propose that effector proteins from diverse plant viruses can be a powerful resource for discovering new regulatory mechanisms of distinct cellular pathways. The efficiency of this approach will depend on how deeply and widely the studied pathway is integrated into viral infections. Beyond this, comparative studies using broad virus diversity should increase our global understanding of plant-virus interactions.
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Affiliation(s)
- Aayushi Shukla
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Silvia López-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Gesa Hoffmann
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Anders Hafrén
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
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Rolland C, Andreani J, Louazani AC, Aherfi S, Francis R, Rodrigues R, Silva LS, Sahmi D, Mougari S, Chelkha N, Bekliz M, Silva L, Assis F, Dornas F, Khalil JYB, Pagnier I, Desnues C, Levasseur A, Colson P, Abrahão J, La Scola B. Discovery and Further Studies on Giant Viruses at the IHU Mediterranee Infection That Modified the Perception of the Virosphere. Viruses 2019; 11:E312. [PMID: 30935049 PMCID: PMC6520786 DOI: 10.3390/v11040312] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 12/17/2022] Open
Abstract
The history of giant viruses began in 2003 with the identification of Acanthamoeba polyphaga mimivirus. Since then, giant viruses of amoeba enlightened an unknown part of the viral world, and every discovery and characterization of a new giant virus modifies our perception of the virosphere. This notably includes their exceptional virion sizes from 200 nm to 2 µm and their genomic complexity with length, number of genes, and functions such as translational components never seen before. Even more surprising, Mimivirus possesses a unique mobilome composed of virophages, transpovirons, and a defense system against virophages named Mimivirus virophage resistance element (MIMIVIRE). From the discovery and isolation of new giant viruses to their possible roles in humans, this review shows the active contribution of the University Hospital Institute (IHU) Mediterranee Infection to the growing knowledge of the giant viruses' field.
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Affiliation(s)
- Clara Rolland
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Julien Andreani
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Amina Cherif Louazani
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Sarah Aherfi
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
- IHU IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Rania Francis
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Rodrigo Rodrigues
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
- Laboratório de Vírus, Instituto de Ciêncas Biológicas, Departamento de Microbiologia, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil.
| | - Ludmila Santos Silva
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Dehia Sahmi
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Said Mougari
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Nisrine Chelkha
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Meriem Bekliz
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Lorena Silva
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
- Laboratório de Vírus, Instituto de Ciêncas Biológicas, Departamento de Microbiologia, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil.
| | - Felipe Assis
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Fábio Dornas
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | | | - Isabelle Pagnier
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
- IHU IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Christelle Desnues
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Anthony Levasseur
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
- IHU IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Philippe Colson
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
- IHU IHU-Méditerranée Infection, 13005 Marseille, France.
| | - Jônatas Abrahão
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
- Laboratório de Vírus, Instituto de Ciêncas Biológicas, Departamento de Microbiologia, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil.
| | - Bernard La Scola
- MEPHI, APHM, IRD 198, Aix Marseille Univ, Department of Medicine, IHU-Méditerranée Infection, 13005 Marseille, France.
- IHU IHU-Méditerranée Infection, 13005 Marseille, France.
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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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18
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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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19
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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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20
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Rodrigues RAL, Mougari S, Colson P, La Scola B, Abrahão JS. “Tupanvirus”, a new genus in the family Mimiviridae. Arch Virol 2018; 164:325-331. [DOI: 10.1007/s00705-018-4067-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 09/30/2018] [Indexed: 12/31/2022]
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21
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Bernard G, Pathmanathan JS, Lannes R, Lopez P, Bapteste E. Microbial Dark Matter Investigations: How Microbial Studies Transform Biological Knowledge and Empirically Sketch a Logic of Scientific Discovery. Genome Biol Evol 2018; 10:707-715. [PMID: 29420719 PMCID: PMC5830969 DOI: 10.1093/gbe/evy031] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2018] [Indexed: 02/07/2023] Open
Abstract
Microbes are the oldest and most widespread, phylogenetically and metabolically diverse life forms on Earth. However, they have been discovered only 334 years ago, and their diversity started to become seriously investigated even later. For these reasons, microbial studies that unveil novel microbial lineages and processes affecting or involving microbes deeply (and repeatedly) transform knowledge in biology. Considering the quantitative prevalence of taxonomically and functionally unassigned sequences in environmental genomics data sets, and that of uncultured microbes on the planet, we propose that unraveling the microbial dark matter should be identified as a central priority for biologists. Based on former empirical findings of microbial studies, we sketch a logic of discovery with the potential to further highlight the microbial unknowns.
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Affiliation(s)
- Guillaume Bernard
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris-Seine (IBPS), France
| | - Jananan S Pathmanathan
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris-Seine (IBPS), France
| | - Romain Lannes
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris-Seine (IBPS), France
| | - Philippe Lopez
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris-Seine (IBPS), France
| | - Eric Bapteste
- Sorbonne Universités, UPMC Université Paris 06, Institut de Biologie Paris-Seine (IBPS), France
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22
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Mihara T, Koyano H, Hingamp P, Grimsley N, Goto S, Ogata H. Taxon Richness of "Megaviridae" Exceeds those of Bacteria and Archaea in the Ocean. Microbes Environ 2018; 33:162-171. [PMID: 29806626 PMCID: PMC6031395 DOI: 10.1264/jsme2.me17203] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Since the discovery of the giant mimivirus, evolutionarily related viruses have been isolated or identified from various environments. Phylogenetic analyses of this group of viruses, tentatively referred to as the family “Megaviridae”, suggest that it has an ancient origin that may predate the emergence of major eukaryotic lineages. Environmental genomics has since revealed that Megaviridae represents one of the most abundant and diverse groups of viruses in the ocean. In the present study, we compared the taxon richness and phylogenetic diversity of Megaviridae, Bacteria, and Archaea using DNA-dependent RNA polymerase as a common marker gene. By leveraging existing microbial metagenomic data, we found higher richness and phylogenetic diversity in this single viral family than in the two prokaryotic domains. We also obtained results showing that the evolutionary rate alone cannot account for the observed high diversity of Megaviridae lineages. These results suggest that the Megaviridae family has a deep co-evolutionary history with diverse marine protists since the early “Big-Bang” radiation of the eukaryotic tree of life.
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Affiliation(s)
- Tomoko Mihara
- Bioinformatics Center, Institute for Chemical Research, Kyoto University
| | - Hitoshi Koyano
- School of Life Science and Technology, Laboratory of Genome Informatics, Tokyo Institute of Technology
| | | | - Nigel Grimsley
- Integrative Marine Biology Laboratory (BIOM), CNRS UMR7232, Sorbonne Universities
| | - Susumu Goto
- Database Center for Life Science, Joint-Support Center for Data Science Research, Research Organization of Information and Systems
| | - Hiroyuki Ogata
- Bioinformatics Center, Institute for Chemical Research, Kyoto University
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23
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Classification of Complete Proteomes of Different Organisms and Protein Sets Based on Their Protein Distributions in Terms of Some Key Attributes of Proteins. Int J Genomics 2018; 2018:9784161. [PMID: 29686995 PMCID: PMC5857298 DOI: 10.1155/2018/9784161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/12/2017] [Accepted: 11/20/2017] [Indexed: 01/01/2023] Open
Abstract
The existence of complete genome sequences makes it important to develop different approaches for classification of large-scale data sets and to make extraction of biological insights easier. Here, we propose an approach for classification of complete proteomes/protein sets based on protein distributions on some basic attributes. We demonstrate the usefulness of this approach by determining protein distributions in terms of two attributes: protein lengths and protein intrinsic disorder contents (ID). The protein distributions based on L and ID are surveyed for representative proteome organisms and protein sets from the three domains of life. The two-dimensional maps (designated as fingerprints here) from the protein distribution densities in the LD space defined by ln(L) and ID are then constructed. The fingerprints for different organisms and protein sets are found to be distinct with each other, and they can therefore be used for comparative studies. As a test case, phylogenetic trees have been constructed based on the protein distribution densities in the fingerprints of proteomes of organisms without performing any protein sequence comparison and alignments. The phylogenetic trees generated are biologically meaningful, demonstrating that the protein distributions in the LD space may serve as unique phylogenetic signals of the organisms at the proteome level.
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24
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Berliner AJ, Mochizuki T, Stedman KM. Astrovirology: Viruses at Large in the Universe. ASTROBIOLOGY 2018; 18:207-223. [PMID: 29319335 DOI: 10.1089/ast.2017.1649] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Viruses are the most abundant biological entities on modern Earth. They are highly diverse both in structure and genomic sequence, play critical roles in evolution, strongly influence terran biogeochemistry, and are believed to have played important roles in the origin and evolution of life. However, there is yet very little focus on viruses in astrobiology. Viruses arguably have coexisted with cellular life-forms since the earliest stages of life, may have been directly involved therein, and have profoundly influenced cellular evolution. Viruses are the only entities on modern Earth to use either RNA or DNA in both single- and double-stranded forms for their genetic material and thus may provide a model for the putative RNA-protein world. With this review, we hope to inspire integration of virus research into astrobiology and also point out pressing unanswered questions in astrovirology, particularly regarding the detection of virus biosignatures and whether viruses could be spread extraterrestrially. We present basic virology principles, an inclusive definition of viruses, review current virology research pertinent to astrobiology, and propose ideas for future astrovirology research foci. Key Words: Astrobiology-Virology-Biosignatures-Origin of life-Roadmap. Astrobiology 18, 207-223.
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Affiliation(s)
| | | | - Kenneth M Stedman
- 3 Center for Life in Extreme Environments and Biology Department, Portland State University , Oregon, USA
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25
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Andreani J, Khalil JYB, Baptiste E, Hasni I, Michelle C, Raoult D, Levasseur A, La Scola B. Orpheovirus IHUMI-LCC2: A New Virus among the Giant Viruses. Front Microbiol 2018; 8:2643. [PMID: 29403444 PMCID: PMC5786535 DOI: 10.3389/fmicb.2017.02643] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/19/2017] [Indexed: 02/06/2023] Open
Abstract
Giant viruses continue to invade the world of virology, in gigantic genome sizes and various particles shapes. Strains discoveries and metagenomic studies make it possible to reveal the complexity of these microorganisms, their origins, ecosystems and putative roles. We isolated from a rat stool sample a new giant virus “Orpheovirus IHUMI-LCC2,” using Vermamoeba vermiformis as host cell. In this paper, we describe the main genomic features and replicative cycle of Orpheovirus IHUMI-LCC2. It possesses a circular genome exceeding 1.4 Megabases with 25% G+C content and ovoidal-shaped particles ranging from 900 to 1300 nm. Particles are closed by at least one thick membrane in a single ostiole-like shape in their apex. Phylogenetic analysis and the reciprocal best hit for Orpheovirus show a connection to the proposed Pithoviridae family. However, some genomic characteristics bear witness to a completely divergent evolution for Orpheovirus IHUMI-LCC2 when compared to Cedratviruses or Pithoviruses.
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Affiliation(s)
- Julien Andreani
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
| | - Jacques Y B Khalil
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France.,Centre National de la Recherche Scientifique, Marseille, France
| | - Emeline Baptiste
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
| | - Issam Hasni
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
| | - Caroline Michelle
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
| | - Didier Raoult
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
| | - Anthony Levasseur
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
| | - Bernard La Scola
- Aix Marseille Université, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
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26
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27
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Schulz F, Yutin N, Ivanova NN, Ortega DR, Lee TK, Vierheilig J, Daims H, Horn M, Wagner M, Jensen GJ, Kyrpides NC, Koonin EV, Woyke T. Giant viruses with an expanded complement of translation system components. Science 2017; 356:82-85. [PMID: 28386012 DOI: 10.1126/science.aal4657] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/18/2017] [Accepted: 03/15/2017] [Indexed: 12/24/2022]
Abstract
The discovery of giant viruses blurred the sharp division between viruses and cellular life. Giant virus genomes encode proteins considered as signatures of cellular organisms, particularly translation system components, prompting hypotheses that these viruses derived from a fourth domain of cellular life. Here we report the discovery of a group of giant viruses (Klosneuviruses) in metagenomic data. Compared with other giant viruses, the Klosneuviruses encode an expanded translation machinery, including aminoacyl transfer RNA synthetases with specificities for all 20 amino acids. Notwithstanding the prevalence of translation system components, comprehensive phylogenomic analysis of these genes indicates that Klosneuviruses did not evolve from a cellular ancestor but rather are derived from a much smaller virus through extensive gain of host genes.
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Affiliation(s)
- Frederik Schulz
- Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA.
| | - Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Natalia N Ivanova
- Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Davi R Ortega
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Tae Kwon Lee
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, "Chemistry Meets Microbiology" Research Network, University of Vienna, 1090 Vienna, Austria
| | - Julia Vierheilig
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, "Chemistry Meets Microbiology" Research Network, University of Vienna, 1090 Vienna, Austria
| | - Holger Daims
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, "Chemistry Meets Microbiology" Research Network, University of Vienna, 1090 Vienna, Austria
| | - Matthias Horn
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, "Chemistry Meets Microbiology" Research Network, University of Vienna, 1090 Vienna, Austria
| | - Michael Wagner
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, "Chemistry Meets Microbiology" Research Network, University of Vienna, 1090 Vienna, Austria
| | - Grant J Jensen
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena, CA 91125, USA.,Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Nikos C Kyrpides
- Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
| | - Tanja Woyke
- Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA.
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van der Gulik PTS, Hoff WD, Speijer D. In defence of the three-domains of life paradigm. BMC Evol Biol 2017; 17:218. [PMID: 28927381 PMCID: PMC5604501 DOI: 10.1186/s12862-017-1059-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 09/01/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Recently, important discoveries regarding the archaeon that functioned as the "host" in the merger with a bacterium that led to the eukaryotes, its "complex" nature, and its phylogenetic relationship to eukaryotes, have been reported. Based on these new insights proposals have been put forward to get rid of the three-domain Model of life, and replace it with a two-domain model. RESULTS We present arguments (both regarding timing, complexity, and chemical nature of specific evolutionary processes, as well as regarding genetic structure) to resist such proposals. The three-domain Model represents an accurate description of the differences at the most fundamental level of living organisms, as the eukaryotic lineage that arose from this unique merging event is distinct from both Archaea and Bacteria in a myriad of crucial ways. CONCLUSIONS We maintain that "a natural system of organisms", as proposed when the three-domain Model of life was introduced, should not be revised when considering the recent discoveries, however exciting they may be.
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Affiliation(s)
- P T S van der Gulik
- Centrum Wiskunde & Informatica, P.O. Box 94079, 1090 GB Amsterdam, Amsterdam, The Netherlands.
| | - W D Hoff
- Department of Microbiology and Molecular Genetics and Department of Chemistry, Oklahoma State University, Stillwater, OK, 74078, USA
| | - D Speijer
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, Amsterdam, The Netherlands.
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Colson P, La Scola B, Raoult D. Giant Viruses of Amoebae: A Journey Through Innovative Research and Paradigm Changes. Annu Rev Virol 2017; 4:61-85. [PMID: 28759330 DOI: 10.1146/annurev-virology-101416-041816] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Giant viruses of amoebae were discovered serendipitously in 2003; they are visible via optical microscopy, making them bona fide microbes. Their lifestyle, structure, and genomes break the mold of classical viruses. Giant viruses of amoebae are complex microorganisms. Their genomes harbor between 444 and 2,544 genes, including many that are unique to viruses, and encode translation components; their virions contain >100 proteins as well as mRNAs. Mimiviruses have a specific mobilome, including virophages, provirophages, and transpovirons, and can resist virophages through a system known as MIMIVIRE (mimivirus virophage resistance element). Giant viruses of amoebae bring upheaval to the definition of viruses and tend to separate the current virosphere into two categories: very simple viruses and viruses with complexity similar to that of other microbes. This new paradigm is propitious for enhanced detection and characterization of giant viruses of amoebae, and a particular focus on their role in humans is warranted.
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Affiliation(s)
- Philippe Colson
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Assistance Publique-Hôpitaux de Marseille (AP-HM), 13005 Marseille, France;
| | - Bernard La Scola
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Assistance Publique-Hôpitaux de Marseille (AP-HM), 13005 Marseille, France;
| | - Didier Raoult
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Assistance Publique-Hôpitaux de Marseille (AP-HM), 13005 Marseille, France;
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Lusi EA, Maloney D, Caicci F, Guarascio P. Questions on unusual Mimivirus-like structures observed in human cells. F1000Res 2017; 6:262. [PMID: 28663783 PMCID: PMC5473404 DOI: 10.12688/f1000research.11007.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/13/2017] [Indexed: 12/15/2022] Open
Abstract
Background: Mimiviruses or giant viruses that infect amoebas have the ability to retain the Gram stain, which is usually used to colour bacteria. There is some evidence suggesting that Mimiviruses can also infect human cells. Guided by these premises, we performed a routine Gram stain on a variety of human specimens to see if we could detect the same Gram positive blue granules that identify Mimiviruses in the amoebas.
Methods: We analysed 24 different human specimens (liver, brain, kidney, lymph node and ovary) using Gram stain histochemistry, electron microscopy immunogold, high resolution mass spectrometry and protein identification.
Results: We detected in the human cells Gram positive granules that were distinct from bacteria. The fine blue granules displayed the same pattern of the Gram positive granules that diagnose Mimiviruses in the cytoplasm of the amoebas. Electron microscopy confirmed the presence of human Mimiviruses-like structures and mass spectrometry identified histone H4 peptides, which had the same footprints as giant viruses. However, some differences were noted: the Mimivirus-like structures identified in the human cells were ubiquitous and manifested a distinct mammalian retroviral antigenicity.
Conclusions: Our main hypotheses are that the structures could be either giant viruses having a retroviral antigenicity or ancestral cellular components having a viral origin. However, other possible alternatives have been proposed to explain the nature and function of the newly identified structures.
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Affiliation(s)
- Elena Angela Lusi
- St Vincent Health Care Group, University College of Dublin, Dublin 4, Ireland
| | - Dan Maloney
- Bioinformatics Solutions Inc., Waterloo, ON, N2L 6J2, Canada
| | - Federico Caicci
- Department of Biology, University of Padua, Padua, 35121, Italy
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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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Harish A, Abroi A, Gough J, Kurland C. Did Viruses Evolve As a Distinct Supergroup from Common Ancestors of Cells? Genome Biol Evol 2016; 8:2474-81. [PMID: 27497315 PMCID: PMC5010908 DOI: 10.1093/gbe/evw175] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The evolutionary origins of viruses according to marker gene phylogenies, as well as their relationships to the ancestors of host cells remains unclear. In a recent article Nasir and Caetano-Anollés reported that their genome-scale phylogenetic analyses based on genomic composition of protein structural-domains identify an ancient origin of the “viral supergroup” (Nasir et al. 2015. A phylogenomic data-driven exploration of viral origins and evolution. Sci Adv. 1(8):e1500527.). It suggests that viruses and host cells evolved independently from a universal common ancestor. Examination of their data and phylogenetic methods indicates that systematic errors likely affected the results. Reanalysis of the data with additional tests shows that small-genome attraction artifacts distort their phylogenomic analyses, particularly the location of the root of the phylogenetic tree of life that is central to their conclusions. These new results indicate that their suggestion of a distinct ancestry of the viral supergroup is not well supported by the evidence.
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Affiliation(s)
- Ajith Harish
- Structural and Molecular Biology Group, Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Sweden
| | - Aare Abroi
- Estonian Biocentre, Riia 23, Tartu 51010, Estonia
| | - Julian Gough
- Computational Genomics Group, Department of Computer Science, University of Bristol, The Merchant Venturers Building, UK
| | - Charles Kurland
- Microbial Ecology, Department of Biology, Lund University, Sweden
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Giant viruses come of age. Curr Opin Microbiol 2016; 31:50-57. [DOI: 10.1016/j.mib.2016.03.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/04/2016] [Accepted: 03/07/2016] [Indexed: 12/18/2022]
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DNA repair genes in the Megavirales pangenome. Curr Opin Microbiol 2016; 31:94-100. [PMID: 27042991 DOI: 10.1016/j.mib.2016.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/21/2016] [Accepted: 03/21/2016] [Indexed: 12/12/2022]
Abstract
The order 'Megavirales' represents a group of eukaryotic viruses with a large genome encoding a few hundred up to two thousand five hundred genes. Several members of Megavirales possess genes involved in major DNA repair pathways. Some of these genes were likely inherited from an ancient virus world and some others were derived from the genomes of their hosts. Here we examine molecular phylogenies of key DNA repair enzymes in light of recent hypotheses on the origin of Megavirales, and propose that the last common ancestors of the individual families of the order Megavirales already possessed DNA repair functions to achieve and maintain a moderately large genome and that this repair capacity gradually increased, in a family-dependent manner, during their recent evolution.
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35
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Giant viruses and the origin of modern eukaryotes. Curr Opin Microbiol 2016; 31:44-49. [PMID: 26894379 DOI: 10.1016/j.mib.2016.02.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 01/28/2023]
Abstract
Several authors have suggested that viruses from the NucleoCytoplasmic Large DNA Viruses group (NCLDV) have played an important role in the origin of modern eukaryotes. Notably, the viral eukaryogenesis theory posits that the nucleus originated from an ancient NCLDV-related virus. Focusing on the viral factory instead of the virion adds credit to this hypothesis, but also suggests alternative scenarios. Beside a role in the emergence of the nucleus, ancient NCLDV may have provided new genes and/or chromosomes to the proto-eukaryotic lineage. Phylogenetic analyses suggest that NCLDV informational proteins, related to those of Archaea and Eukarya, were either recruited by ancient NCLDV from proto-eukaryotes and/or transferred to proto-eukaryotes, in agreement with the antiquity of NCLDV and their possible role in eukaryogenesis.
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36
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Williams TA, Embley TM. Changing ideas about eukaryotic origins. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140318. [PMID: 26323752 PMCID: PMC4571560 DOI: 10.1098/rstb.2014.0318] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2015] [Indexed: 11/12/2022] Open
Abstract
The origin of eukaryotic cells is one of the most fascinating challenges in biology, and has inspired decades of controversy and debate. Recent work has led to major upheavals in our understanding of eukaryotic origins and has catalysed new debates about the roles of endosymbiosis and gene flow across the tree of life. Improved methods of phylogenetic analysis support scenarios in which the host cell for the mitochondrial endosymbiont was a member of the Archaea, and new technologies for sampling the genomes of environmental prokaryotes have allowed investigators to home in on closer relatives of founding symbiotic partners. The inference and interpretation of phylogenetic trees from genomic data remains at the centre of many of these debates, and there is increasing recognition that trees built using inadequate methods can prove misleading, whether describing the relationship of eukaryotes to other cells or the root of the universal tree. New statistical approaches show promise for addressing these questions but they come with their own computational challenges. The papers in this theme issue discuss recent progress on the origin of eukaryotic cells and genomes, highlight some of the ongoing debates, and suggest possible routes to future progress.
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Affiliation(s)
- Tom A Williams
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
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