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Bravo A, Fernández-García L, Ibarra-Karmy R, Mardones GA, Mercado L, Bustos FJ, Gifford RJ, Arriagada G. Antiviral Activity of an Endogenous Parvoviral Element. Viruses 2023; 15:1420. [PMID: 37515112 PMCID: PMC10384997 DOI: 10.3390/v15071420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Endogenous viral elements (EVEs) are genomic DNA sequences derived from viruses. Some EVEs have open reading frames (ORFs) that can express proteins with physiological roles in their host. Furthermore, some EVEs exhibit a protective role against exogenous viral infection in their host. Endogenous parvoviral elements (EPVs) are highly represented in mammalian genomes, and although some of them contain ORFs, their function is unknown. We have shown that the locus EPV-Dependo.43-ODegus, an EPV with an intact ORF, is transcribed in Octodon degus (degu). Here we examine the antiviral activity of the protein encoded in this EPV, named DeRep. DeRep was produced in bacteria and used to generate antibodies that recognize DeRep in western blots of degu tissue. To test if DeRep could protect against exogenous parvovirus, we challenged cells with the minute virus of mice (MVM), a model autonomous parvovirus. We observed that MVM protein expression, DNA damage induced by replication, viral DNA, and cytopathic effects are reduced when DeRep is expressed in cells. The results of this study demonstrate that DeRep is expressed in degu and can inhibit parvovirus replication. This is the first time that an EPV has been shown to have antiviral activity against an exogenous virus.
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Affiliation(s)
- Angelica Bravo
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
| | - Leandro Fernández-García
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
| | - Rodrigo Ibarra-Karmy
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
| | - Gonzalo A Mardones
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia 5110466, Chile
| | - Luis Mercado
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile
| | - Fernando J Bustos
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
| | - Robert J Gifford
- Centre for Virus Research, MRC-University of Glasgow, 464 Bearsden Rd, Bearsden, Glasgow G61 1QH, UK
| | - Gloria Arriagada
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
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Garcia BCB, Mukai Y, Tomonaga K, Horie M. The hidden diversity of ancient bornaviral sequences from X and P genes in vertebrate genomes. Virus Evol 2023; 9:vead038. [PMID: 37360682 PMCID: PMC10288550 DOI: 10.1093/ve/vead038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/10/2023] [Accepted: 05/31/2023] [Indexed: 06/28/2023] Open
Abstract
Endogenous bornavirus-like elements (EBLs) are heritable sequences derived from bornaviruses in vertebrate genomes that originate from transcripts of ancient bornaviruses. EBLs have been detected using sequence similarity searches such as tBLASTn, whose technical limitations may hinder the detection of EBLs derived from small and/or rapidly evolving viral X and P genes. Indeed, no EBLs derived from the X and P genes of orthobornaviruses have been detected to date in vertebrate genomes. Here, we aimed to develop a novel strategy to detect such 'hidden' EBLs. To this aim, we focused on the 1.9-kb read-through transcript of orthobornaviruses, which encodes a well-conserved N gene and small and rapidly evolving X and P genes. We show a series of evidence supporting the existence of EBLs derived from orthobornaviral X and P genes (EBLX/Ps) in mammalian genomes. Furthermore, we found that an EBLX/P is expressed as a fusion transcript with the cellular gene, ZNF451, which potentially encodes the ZNF451/EBLP fusion protein in miniopterid bat cells. This study contributes to a deeper understanding of ancient bornaviruses and co-evolution between bornaviruses and their hosts. Furthermore, our data suggest that endogenous viral elements are more abundant than those previously appreciated using BLAST searches alone, and further studies are required to understand ancient viruses more accurately.
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Affiliation(s)
- Bea Clarise B Garcia
- Laboratory of Veterinary Microbiology, Graduate School of Veterinary Science, Osaka Metropolitan University, 1-58 Rinku Orai-kita, Izumisano, Osaka 598-8531, Japan
| | - Yahiro Mukai
- Laboratory of RNA Viruses, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan
- Laboratory of RNA Viruses, Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan
| | - Keizo Tomonaga
- Laboratory of RNA Viruses, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan
- Laboratory of RNA Viruses, Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan
- Department of Molecular Virology, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan
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Du Q, Peng F, Xiong Q, Xu K, Yang KY, Wang M, Wu Z, Li S, Cheng X, Rao X, Wang Y, Tsui SKW, Zeng X. Genomic Analysis of Amphioxus Reveals a Wide Range of Fragments Homologous to Viral Sequences. Viruses 2023; 15:v15040909. [PMID: 37112889 PMCID: PMC10145014 DOI: 10.3390/v15040909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/11/2023] [Accepted: 03/28/2023] [Indexed: 04/05/2023] Open
Abstract
Amphioxus species are considered living fossils and are important in the evolutionary study of chordates and vertebrates. To explore viral homologous sequences, a high-quality annotated genome of the Beihai amphioxus (Branchiostoma belcheri beihai) was examined using virus sequence queries. In this study, 347 homologous fragments (HFs) of viruses were identified in the genome of B. belcheri beihai, of which most were observed on 21 genome assembly scaffolds. HFs were preferentially located within protein-coding genes, particularly in their CDS regions and promoters. A range of amphioxus genes with a high frequency of HFs is proposed, including histone-related genes that are homologous to the Histone H4 or Histone H2B domains of viruses. Together, this comprehensive analysis of viral HFs provides insights into the neglected role of viral integration in the evolution of amphioxus.
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Affiliation(s)
- Qiao Du
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Fang Peng
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Qing Xiong
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Hong Kong Bioinformatics Centre, The Chinese University of Hong Kong, Hong Kong, China
| | - Kejin Xu
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Kevin Yi Yang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Hong Kong Bioinformatics Centre, The Chinese University of Hong Kong, Hong Kong, China
| | - Mingqiang Wang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Zhitian Wu
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Shanying Li
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiaorui Cheng
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Xinjie Rao
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Yuyouye Wang
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Stephen Kwok-Wing Tsui
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Hong Kong Bioinformatics Centre, The Chinese University of Hong Kong, Hong Kong, China
| | - Xi Zeng
- Agricultural Bioinformatics Key Laboratory of Hubei Province and 3D Genomics Research Centre, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
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4
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Mukai Y, Horie M, Kojima S, Kawasaki J, Maeda K, Tomonaga K. An endogenous bornavirus-like nucleoprotein in miniopterid bats retains the RNA-binding properties of the original viral protein. FEBS Lett 2022; 596:323-337. [PMID: 35043395 DOI: 10.1002/1873-3468.14290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/06/2021] [Accepted: 12/10/2021] [Indexed: 11/11/2022]
Abstract
Endogenous bornavirus-like nucleoprotein elements (EBLNs) are sequences derived from bornaviral N genes in vertebrate genomes. Some EBLNs have been suggested to encode functional proteins in host cells; however, little is known about their evolution and functional relationship to the viral genes from which EBLNs originate. Here, we predicted functionality of EBLNs based on the properties of N as an RNA-binding protein. We showed an EBLN in miniopterid bats (miEBLN-1) has evolved under purifying selection and encodes an RNA-binding protein (miEBLN-1p) with biochemical properties similar to bornaviral N. Furthermore, we revealed miEBLN-1p interacts with host RNA-binding proteins, such as MOV10. These data suggest that miEBLN-1p has been exapted as an RNA-binding protein with similar properties to exogenous bornaviral N in miniopterid bats.
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Affiliation(s)
- Yahiro Mukai
- Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), Kyoto University, Japan
- Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Japan
| | - Masayuki Horie
- Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), Kyoto University, Japan
- Hakubi Center for Advanced Research, Kyoto University, Japan
- Laboratory of Veterinary Microbiology, Division of Veterinary Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Japan
- Osaka International Research Center for Infectious Diseases, Japan
| | - Shohei Kojima
- Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), Kyoto University, Japan
- Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Japan
| | - Junna Kawasaki
- Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), Kyoto University, Japan
- Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Japan
| | - Ken Maeda
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo, Japan
| | - Keizo Tomonaga
- Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), Kyoto University, Japan
- Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Japan
- Department of Molecular Virology, Graduate School of Medicine, Kyoto University, Japan
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5
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Horie M. [One hundred million years history of bornavirus infection]. Uirusu 2022; 72:47-54. [PMID: 37899229 DOI: 10.2222/jsv.72.47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
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Abstract
The innate immune system has numerous signal transduction pathways that lead to the production of type I interferons in response to exposure of cells to external stimuli. One of these pathways comprises RNA polymerase (Pol) III that senses common DNA viruses, such as cytomegalovirus, vaccinia, herpes simplex virus-1 and varicella zoster virus. This polymerase detects and transcribes viral genomic regions to generate AU-rich transcripts that bring to the induction of type I interferons. Remarkably, Pol III is also stimulated by foreign non-viral DNAs and expression of one of its subunits is induced by an RNA virus, the Sindbis virus. Moreover, a protein subunit of RNase P, which is known to associate with Pol III in initiation complexes, is induced by viral infection. Accordingly, alliance of the two tRNA enzymes in innate immunity merits a consideration.
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Affiliation(s)
- Nayef Jarrous
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Israel-Canada
| | - Alexander Rouvinski
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Israel-Canada.,The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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7
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Modeling Borna Disease Virus In Vitro Spread Reveals the Mode of Antiviral Effect Conferred by an Endogenous Bornavirus-Like Element. J Virol 2020; 94:JVI.01204-20. [PMID: 32817215 DOI: 10.1128/jvi.01204-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/12/2020] [Indexed: 02/07/2023] Open
Abstract
Endogenous retroviruses have demonstrated exaptation during long-term evolution with hosts, e.g., resulting in acquisition of antiviral effect on related extant viral infections. While empirical studies have found that an endogenous bornavirus-like element derived from viral nucleoprotein (itEBLN) in the ground squirrel genome shows antiviral effect on virus replication and de novo infection, the antiviral mechanism, dynamics, and quantitative effect of itEBLN remain unknown. In this study, we experimentally and theoretically investigated the dynamics of how an extant bornavirus, Borna disease virus 1 (BoDV-1), spreads and replicates in uninfected, BoDV-1-infected, and itEBLN-expressing cultured cells. Quantifying antiviral effect based on time course data sets, we found that the antiviral effects of itEBLN are estimated to be 75% and 34% on intercellular virus spread and intracellular virus replication, respectively. This discrepancy between intercellular virus spread and intracellular viral replication suggests that viral processes other than the replication of viral ribonucleoprotein complex (RNP) contributed to the suppression of virus spread in itEBLN-expressing cells. Because itEBLN binds to the BoDV-1 RNP, the suppression of viral RNP trafficking can be an attractive candidate explaining this discrepancy.IMPORTANCE Accumulating evidence suggests that some endogenous viral elements (EVEs), including endogenous retroviruses and endogenous nonretroviral virus elements, have acquired functions in the host as a result of long-term coevolution. Recently, an endogenous bornavirus-like element (itEBLN) found in the ground squirrel genome has been shown to have antiviral activity against exogenous bornavirus infection. In this study, we first quantified bornavirus spread in cultured cells and then calculated the antiviral activity of itEBLN on bornavirus infection. The calculated antiviral activity of itEBLN suggests its suppression of multiple processes in the viral life cycle. To our knowledge, this is the first study quantifying the antiviral activity of EVEs and speculating on a model of how some EVEs have acquired antiviral activity during host-virus arms races.
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Nobach D, Müller J, Tappe D, Herden C. Update on immunopathology of bornavirus infections in humans and animals. Adv Virus Res 2020; 107:159-222. [PMID: 32711729 DOI: 10.1016/bs.aivir.2020.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Knowledge on bornaviruses has expanded tremendously during the last decade through detection of novel bornaviruses and endogenous bornavirus-like elements in many eukaryote genomes, as well as by confirmation of insectivores as reservoir species for classical Borna disease virus 1 (BoDV-1). The most intriguing finding was the demonstration of the zoonotic potential of lethal human bornavirus infections caused by a novel bornavirus of different squirrel species (variegated squirrel 1 bornavirus, VSBV-1) and by BoDV-1 known as the causative agent for the classical Borna disease in horses and sheep. Whereas a T cell-mediated immunopathology has already been confirmed as key disease mechanism for infection with BoDV-1 by experimental studies in rodents, the underlying pathomechanisms remain less clear for human bornavirus infections, infection with other bornaviruses or infection of reservoir species. Thus, an overview of current knowledge on the pathogenesis of bornavirus infections focusing on immunopathology is given.
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Affiliation(s)
- Daniel Nobach
- Institute of Veterinary Pathology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Jana Müller
- Institute of Veterinary Pathology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Dennis Tappe
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Christiane Herden
- Institute of Veterinary Pathology, Justus-Liebig-University Giessen, Giessen, Germany; Center for Brain, Mind and Behavior, Justus-Liebig-University Giessen, Giessen, Germany.
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Nobach D, Herden C. No evidence for European bats serving as reservoir for Borna disease virus 1 or other known mammalian orthobornaviruses. Virol J 2020; 17:11. [PMID: 32000801 PMCID: PMC6993374 DOI: 10.1186/s12985-020-1289-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 01/22/2020] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The majority of emerging infectious diseases are zoonotic in nature and originate from wildlife reservoirs. Borna disease, caused by Borna disease virus 1 (BoDV-1), is an infectious disease affecting mammals, but recently it has also been shown to cause fatal encephalitis in humans. The endemic character of Borna disease points towards a nature-bound reservoir, with only one shrew species identified as reservoir host to date. Bats have been identified as reservoirs of a variety of zoonotic infectious agents. Endogenous borna-like elements in the genome of certain bat species additionally point towards co-evolution of bats with bornaviruses and therefore raise the question whether bats could serve as a potential reservoir of orthobornaviruses. METHODS Frozen brain samples (n = 257) of bats of seven different genera from Germany were investigated by orthobornaviral RT-PCR. Additionally, tissue slides of formalin-fixed paraffin-embedded material of a subset of these bats (n = 140) were investigated for orthobornaviral phosphoprotein by immunohistochemistry. RESULTS The brain samples were tested by RT-PCR without any evidence of orthobornavirus specific amplicons. Immunohistochemistry revealed a faint immunoreaction in 3/140 bats but with an untypical staining pattern for viral antigen. CONCLUSIONS RT-PCR-screening showed no evidence for orthobornaviral RNA in the investigated bats. However, immunohistochemistry results should be investigated further to elucidate whether the reaction might be associated with expressed endogenous bornaviral elements or other so far unknown bornaviruses.
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Affiliation(s)
- Daniel Nobach
- Institute of Veterinary Pathology, Justus Liebig University, Giessen, Germany.
| | - Christiane Herden
- Institute of Veterinary Pathology, Justus Liebig University, Giessen, Germany
- Center for Mind, Brain and Behavior, Justus Liebig University, Giessen, Germany
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10
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Kanduc D. The comparative biochemistry of viruses and humans: an evolutionary path towards autoimmunity. Biol Chem 2019; 400:629-638. [PMID: 30504522 DOI: 10.1515/hsz-2018-0271] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 11/07/2018] [Indexed: 11/15/2022]
Abstract
Analyses of the peptide sharing between five common human viruses (Borna disease virus, influenza A virus, measles virus, mumps virus and rubella virus) and the human proteome highlight a massive viral vs. human peptide overlap that is mathematically unexpected. Evolutionarily, the data underscore a strict relationship between viruses and the origin of eukaryotic cells. Indeed, according to the viral eukaryogenesis hypothesis and in light of the endosymbiotic theory, the first eukaryotic cell (our lineage) originated as a consortium consisting of an archaeal ancestor of the eukaryotic cytoplasm, a bacterial ancestor of the mitochondria and a viral ancestor of the nucleus. From a pathologic point of view, the peptide sequence similarity between viruses and humans may provide a molecular platform for autoimmune crossreactions during immune responses following viral infections/immunizations.
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Affiliation(s)
- Darja Kanduc
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, I-70124 Bari, Italy
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11
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Molecular Properties and Evolutionary Origins of a Parvovirus-Derived Myosin Fusion Gene in Guinea Pigs. J Virol 2019; 93:JVI.00404-19. [PMID: 31217242 DOI: 10.1128/jvi.00404-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/11/2019] [Indexed: 01/11/2023] Open
Abstract
Sequences derived from parvoviruses (family Parvoviridae) are relatively common in animal genomes, but the functional significance of these endogenous parvoviral element (EPV) sequences remains unclear. In this study, we used a combination of in silico and molecular biological approaches to investigate a fusion gene carried by guinea pigs (genus Cavia) that is partially derived from an EPV. This gene, named enRep-M9l, encodes a predicted polypeptide gene product comprising a partial myosin9-like (M9l) gene fused to a 3' truncated, EPV-encoded replicase. We examined the genomic and phylogenetic characteristics of the EPV locus (enRep) that encodes the viral portions of enRep-M9l, revealing that it derives from an ancient dependoparvovirus (genus Dependoparvovirus) that was incorporated into the guinea pig germ line between approximately 22 and 35 million years ago (MYA). Despite these ancient origins, the regions of the enRep locus that are expressed in the enRep-M9l gene are conserved across multiple species in the family Caviidae (guinea pigs and cavies), consistent with a potential function at the amino acid level. Using molecular biological approaches, we further demonstrated that (i) enRep-M9l mRNA is broadly transcribed in guinea pig cells, (ii) the cloned enRep-M9l transcript can express a protein of the expected size in guinea pig cells in vitro, and (iii) the expressed protein localizes to the cytosol. Our findings demonstrate that, consistent with a functional role, the enRep-M9l fusion gene is evolutionarily conserved, broadly transcribed, and capable of expressing protein.IMPORTANCE DNA from viruses has been "horizontally transferred" to mammalian genomes during evolution, but the impact of this process on mammalian biology remains poorly understood. The findings of our study indicate that a novel gene has evolved in guinea pigs through fusion of host and virus genes.
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12
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Heaton SM. Harnessing host-virus evolution in antiviral therapy and immunotherapy. Clin Transl Immunology 2019; 8:e1067. [PMID: 31312450 PMCID: PMC6613463 DOI: 10.1002/cti2.1067] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/07/2019] [Accepted: 06/09/2019] [Indexed: 02/06/2023] Open
Abstract
Pathogen resistance and development costs are major challenges in current approaches to antiviral therapy. The high error rate of RNA synthesis and reverse‐transcription confers genome plasticity, enabling the remarkable adaptability of RNA viruses to antiviral intervention. However, this property is coupled to fundamental constraints including limits on the size of information available to manipulate complex hosts into supporting viral replication. Accordingly, RNA viruses employ various means to extract maximum utility from their informationally limited genomes that, correspondingly, may be leveraged for effective host‐oriented therapies. Host‐oriented approaches are becoming increasingly feasible because of increased availability of bioactive compounds and recent advances in immunotherapy and precision medicine, particularly genome editing, targeted delivery methods and RNAi. In turn, one driving force behind these innovations is the increasingly detailed understanding of evolutionarily diverse host–virus interactions, which is the key concern of an emerging field, neo‐virology. This review examines biotechnological solutions to disease and other sustainability issues of our time that leverage the properties of RNA and DNA viruses as developed through co‐evolution with their hosts.
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Affiliation(s)
- Steven M Heaton
- Department of Biochemistry & Molecular Biology Monash University Clayton VIC Australia
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13
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Bornavirus. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2019; 62:519-532. [DOI: 10.1007/s00103-019-02904-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Broecker F, Moelling K. Evolution of Immune Systems From Viruses and Transposable Elements. Front Microbiol 2019; 10:51. [PMID: 30761103 PMCID: PMC6361761 DOI: 10.3389/fmicb.2019.00051] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 01/14/2019] [Indexed: 12/20/2022] Open
Abstract
Virus-derived sequences and transposable elements constitute a substantial portion of many cellular genomes. Recent insights reveal the intimate evolutionary relationship between these sequences and various cellular immune pathways. At the most basic level, superinfection exclusion may be considered a prototypical virus-mediated immune system that has been described in both prokaryotes and eukaryotes. More complex immune mechanisms fully or partially derived from mobile genetic elements include CRISPR-Cas of prokaryotes and the RAG1/2 system of vertebrates, which provide immunological memory of foreign genetic elements and generate antibody and T cell receptor diversity, respectively. In this review, we summarize the current knowledge on the contribution of mobile genetic elements to the evolution of cellular immune pathways. A picture is emerging in which the various cellular immune systems originate from and are spread by viruses and transposable elements. Immune systems likely evolved from simple superinfection exclusion to highly complex defense strategies.
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Affiliation(s)
- Felix Broecker
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Karin Moelling
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.,Max Planck Institute for Molecular Genetics, Berlin, Germany
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15
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Horie M, Tomonaga K. Paleovirology of bornaviruses: What can be learned from molecular fossils of bornaviruses. Virus Res 2018; 262:2-9. [PMID: 29630909 DOI: 10.1016/j.virusres.2018.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 02/05/2023]
Abstract
Endogenous viral elements (EVEs) are virus-derived sequences embedded in eukaryotic genomes formed by germline integration of viral sequences. As many EVEs were integrated into eukaryotic genomes millions of years ago, EVEs are considered molecular fossils of viruses. EVEs can be valuable informational sources about ancient viruses, including their time scale, geographical distribution, genetic information, and hosts. Although integration of viral sequences is not required for replications of viruses other than retroviruses, many non-retroviral EVEs have been reported to exist in eukaryotes. Investigation of these EVEs has expanded our knowledge regarding virus-host interactions, as well as provided information on ancient viruses. Among them, EVEs derived from bornaviruses, non-retroviral RNA viruses, have been relatively well studied. Bornavirus-derived EVEs are widely distributed in animal genomes, including the human genome, and the history of bornaviruses can be dated back to more than 65 million years. Although there are several reports focusing on the biological significance of bornavirus-derived sequences in mammals, paleovirology of bornaviruses has not yet been well described and summarized. In this paper, we describe what can be learned about bornaviruses from endogenous bornavirus-like elements from the view of paleovirology using published results and our novel data.
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Affiliation(s)
- Masayuki Horie
- Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan; Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.
| | - Keizo Tomonaga
- Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan; Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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Horizontal acquisition of transposable elements and viral sequences: patterns and consequences. Curr Opin Genet Dev 2018; 49:15-24. [PMID: 29505963 DOI: 10.1016/j.gde.2018.02.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/30/2022]
Abstract
It is becoming clear that most eukaryotic transposable elements (TEs) owe their evolutionary success in part to horizontal transfer events, which enable them to invade new species. Recent large-scale studies are beginning to unravel the mechanisms and ecological factors underlying this mode of transmission. Viruses are increasingly recognized as vectors in the process but also as a direct source of genetic material horizontally acquired by eukaryotic organisms. Because TEs and endogenous viruses are major catalysts of variation and innovation in genomes, we argue that horizontal inheritance has had a more profound impact in eukaryotic evolution than is commonly appreciated. To support this proposal, we compile a list of examples, including some previously unrecognized, whereby new host functions and phenotypes can be directly attributed to horizontally acquired TE or viral sequences. We predict that the number of examples will rapidly grow in the future as the prevalence of horizontal transfer in the life cycle of TEs becomes even more apparent, firmly establishing this form of non-Mendelian inheritance as a consequential facet of eukaryotic evolution.
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