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Henriques WS, Young JM, Nemudryi A, Nemudraia A, Wiedenheft B, Malik HS. The Diverse Evolutionary Histories of Domesticated Metaviral Capsid Genes in Mammals. Mol Biol Evol 2024; 41:msae061. [PMID: 38507667 PMCID: PMC11011659 DOI: 10.1093/molbev/msae061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 02/26/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024] Open
Abstract
Selfish genetic elements comprise significant fractions of mammalian genomes. In rare instances, host genomes domesticate segments of these elements for function. Using a complete human genome assembly and 25 additional vertebrate genomes, we re-analyzed the evolutionary trajectories and functional potential of capsid (CA) genes domesticated from Metaviridae, a lineage of retrovirus-like retrotransposons. Our study expands on previous analyses to unearth several new insights about the evolutionary histories of these ancient genes. We find that at least five independent domestication events occurred from diverse Metaviridae, giving rise to three universally retained single-copy genes evolving under purifying selection and two gene families unique to placental mammals, with multiple members showing evidence of rapid evolution. In the SIRH/RTL family, we find diverse amino-terminal domains, widespread loss of protein-coding capacity in RTL10 despite its retention in several mammalian lineages, and differential utilization of an ancient programmed ribosomal frameshift in RTL3 between the domesticated CA and protease domains. Our analyses also reveal that most members of the PNMA family in mammalian genomes encode a conserved putative amino-terminal RNA-binding domain (RBD) both adjoining and independent from domesticated CA domains. Our analyses lead to a significant correction of previous annotations of the essential CCDC8 gene. We show that this putative RBD is also present in several extant Metaviridae, revealing a novel protein domain configuration in retrotransposons. Collectively, our study reveals the divergent outcomes of multiple domestication events from diverse Metaviridae in the common ancestor of placental mammals.
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Affiliation(s)
- William S Henriques
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Janet M Young
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Artem Nemudryi
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Anna Nemudraia
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Blake Wiedenheft
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Harmit S Malik
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
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2
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Rice ES, Alberdi A, Alfieri J, Athrey G, Balacco JR, Bardou P, Blackmon H, Charles M, Cheng HH, Fedrigo O, Fiddaman SR, Formenti G, Frantz LAF, Gilbert MTP, Hearn CJ, Jarvis ED, Klopp C, Marcos S, Mason AS, Velez-Irizarry D, Xu L, Warren WC. A pangenome graph reference of 30 chicken genomes allows genotyping of large and complex structural variants. BMC Biol 2023; 21:267. [PMID: 37993882 PMCID: PMC10664547 DOI: 10.1186/s12915-023-01758-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/02/2023] [Indexed: 11/24/2023] Open
Abstract
BACKGROUND The red junglefowl, the wild outgroup of domestic chickens, has historically served as a reference for genomic studies of domestic chickens. These studies have provided insight into the etiology of traits of commercial importance. However, the use of a single reference genome does not capture diversity present among modern breeds, many of which have accumulated molecular changes due to drift and selection. While reference-based resequencing is well-suited to cataloging simple variants such as single-nucleotide changes and short insertions and deletions, it is mostly inadequate to discover more complex structural variation in the genome. METHODS We present a pangenome for the domestic chicken consisting of thirty assemblies of chickens from different breeds and research lines. RESULTS We demonstrate how this pangenome can be used to catalog structural variants present in modern breeds and untangle complex nested variation. We show that alignment of short reads from 100 diverse wild and domestic chickens to this pangenome reduces reference bias by 38%, which affects downstream genotyping results. This approach also allows for the accurate genotyping of a large and complex pair of structural variants at the K feathering locus using short reads, which would not be possible using a linear reference. CONCLUSIONS We expect that this new paradigm of genomic reference will allow better pinpointing of exact mutations responsible for specific phenotypes, which will in turn be necessary for breeding chickens that meet new sustainability criteria and are resilient to quickly evolving pathogen threats.
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Affiliation(s)
- Edward S Rice
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
- Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Antton Alberdi
- Center for Evolutionary Hologenomics, Globe Institute, University of Copenhagen (UCPH), Copenhagen, Denmark
| | - James Alfieri
- Department of Ecology & Evolutionary Biology, Texas A&M University, College Station, TX, USA
| | - Giridhar Athrey
- Department of Poultry Science, Texas A&M University, College Station, TX, USA
| | - Jennifer R Balacco
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | - Philippe Bardou
- Sigenae, GenPhySE, Université de Toulouse, INRAE, ENVT, Castanet Tolosan, 31326, France
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Mathieu Charles
- University Paris-Saclay, INRAE, AgroParisTech, GABI, Sigenae, Jouy-en-Josas, France
| | - Hans H Cheng
- Avian Disease and Oncology Laboratory, USDA, ARS, USNPRC, East Lansing, MI, USA
| | - Olivier Fedrigo
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | | | - Giulio Formenti
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | - Laurent A F Frantz
- Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität, Munich, Germany
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, E1 4DQ, UK
| | - M Thomas P Gilbert
- Center for Evolutionary Hologenomics, Globe Institute, University of Copenhagen (UCPH), Copenhagen, Denmark
| | - Cari J Hearn
- Avian Disease and Oncology Laboratory, USDA, ARS, USNPRC, East Lansing, MI, USA
| | - Erich D Jarvis
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
- The Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Christophe Klopp
- Sigenae, Genotoul Bioinfo, MIAT UR875, INRAE, Castanet Tolosan, France
| | - Sofia Marcos
- Center for Evolutionary Hologenomics, Globe Institute, University of Copenhagen (UCPH), Copenhagen, Denmark
- Applied Genomics and Bioinformatics, University of the Basque Country (UPV/EHU), Leioa, Bilbao, Spain
| | | | | | - Luohao Xu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Wesley C Warren
- Department of Animal Sciences, University of Missouri, Columbia, MO, USA.
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3
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Shimode S. Acquisition and Exaptation of Endogenous Retroviruses in Mammalian Placenta. Biomolecules 2023; 13:1482. [PMID: 37892164 PMCID: PMC10604696 DOI: 10.3390/biom13101482] [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: 08/15/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
Endogenous retroviruses (ERVs) are retrovirus-like sequences that were previously integrated into the host genome. Although most ERVs are inactivated by mutations, deletions, or epigenetic regulation, some remain transcriptionally active and impact host physiology. Several ERV-encoded proteins, such as Syncytins and Suppressyn, contribute to placenta acquisition, a crucial adaptation in mammals that protects the fetus from external threats and other risks while enabling the maternal supply of oxygen, nutrients, and antibodies. In primates, Syncytin-1 and Syncytin-2 facilitate cell-cell fusion for placental formation. Suppressyn is the first ERV-derived protein that inhibits cell fusion by binding to ASCT2, the receptor for Syncytin-1. Furthermore, Syncytin-2 likely inserted into the genome of the common ancestor of Anthropoidea, whereas Syncytin-1 and Suppressyn likely inserted into the ancestor of catarrhines; however, they were inactivated in some lineages, suggesting that multiple exaptation events had occurred. This review discusses the role of ERV-encoded proteins, particularly Syncytins and Suppressyn, in placental development and function, focusing on the integration of ERVs into the host genome and their contribution to the genetic mechanisms underlying placentogenesis. This review provides valuable insights into the molecular and genetic aspects of placentation, potentially shedding light on broader evolutionary and physiological processes in mammals.
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Affiliation(s)
- Sayumi Shimode
- Genome Editing Innovation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-0046, Japan;
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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4
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Henriques WS, Young JM, Nemudryi A, Nemudraia A, Wiedenheft B, Malik HS. The diverse evolutionary histories of domesticated metaviral capsid genes in mammals. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.17.558119. [PMID: 37745568 PMCID: PMC10516033 DOI: 10.1101/2023.09.17.558119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Selfish genetic elements and their remnants comprise at least half of the human genome. Active transposons duplicate by inserting copies at new sites in a host genome. Following insertion, transposons can acquire mutations that render them inactive; the accrual of additional mutations can render them unrecognizable over time. However, in rare instances, segments of transposons become useful for the host, in a process called gene domestication. Using the first complete human genome assembly and 25 additional vertebrate genomes, we analyzed the evolutionary trajectories and functional potential of genes domesticated from the capsid genes of Metaviridae, a retroviral-like retrotransposon family. Our analysis reveals four families of domesticated capsid genes in placental mammals with varied evolutionary outcomes, ranging from universal retention to lineage-specific duplications or losses and from purifying selection to lineage-specific rapid evolution. The four families of domesticated capsid genes have divergent amino-terminal domains, inherited from four distinct ancestral metaviruses. Structural predictions reveal that many domesticated genes encode a previously unrecognized RNA-binding domain retained in multiple paralogs in mammalian genomes both adjacent to and independent from the capsid domain. Collectively, our study reveals diverse outcomes of domestication of diverse metaviruses, which led to structurally and evolutionarily diverse genes that encode important, but still largely-unknown functions in placental mammals. (207).
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Affiliation(s)
- William S. Henriques
- Department of Microbiology and Cell Biology, Montana State University, Bozeman MT 59717
| | - Janet M. Young
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109
| | - Artem Nemudryi
- Department of Microbiology and Cell Biology, Montana State University, Bozeman MT 59717
| | - Anna Nemudraia
- Department of Microbiology and Cell Biology, Montana State University, Bozeman MT 59717
| | - Blake Wiedenheft
- Department of Microbiology and Cell Biology, Montana State University, Bozeman MT 59717
| | - Harmit S. Malik
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109
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5
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Chabukswar S, Grandi N, Lin LT, Tramontano E. Envelope Recombination: A Major Driver in Shaping Retroviral Diversification and Evolution within the Host Genome. Viruses 2023; 15:1856. [PMID: 37766262 PMCID: PMC10536682 DOI: 10.3390/v15091856] [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: 07/06/2023] [Revised: 08/21/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Endogenous retroviruses (ERVs) are integrated into host DNA as the result of ancient germ line infections, primarily by extinct exogenous retroviruses. Thus, vertebrates' genomes contain thousands of ERV copies, providing a "fossil" record for ancestral retroviral diversity and its evolution within the host genome. Like other retroviruses, the ERV proviral sequence consists of gag, pro, pol, and env genes flanked by long terminal repeats (LTRs). Particularly, the env gene encodes for the envelope proteins that initiate the infection process by binding to the host cellular receptor(s), causing membrane fusion. For this reason, a major element in understanding ERVs' evolutionary trajectory is the characterization of env changes over time. Most of the studies dedicated to ERVs' env have been aimed at finding an "actual" physiological or pathological function, while few of them have focused on how these genes were once acquired and modified within the host. Once acquired into the organism, genome ERVs undergo common cellular events, including recombination. Indeed, genome recombination plays a role in ERV evolutionary dynamics. Retroviral recombination events that might have been involved in env divergence include the acquisition of env genes from distantly related retroviruses, env swapping facilitating multiple cross-species transmission over millions of years, ectopic recombination between the homologous sequences present in different positions in the chromosomes, and template switching during transcriptional events. The occurrence of these recombinational events might have aided in shaping retroviral diversification and evolution until the present day. Hence, this review describes and discusses in detail the reported recombination events involving ERV env to provide the basis for further studies in the field.
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Affiliation(s)
- Saili Chabukswar
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (S.C.); (N.G.)
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (S.C.); (N.G.)
| | - Liang-Tzung Lin
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (S.C.); (N.G.)
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6
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Ansari S, Gupta N, Verma R, Singh ON, Gupta J, Kumar A, Yadav MK, Binayke A, Tiwari M, Periwal N, Sood V, Mani S, Awasthi A, Shalimar, Nayak B, Ranjith‐Kumar CT, Surjit M. Antiviral activity of the human endogenous retrovirus‐R envelope protein against SARS‐CoV‐2. EMBO Rep 2023; 24:e55900. [PMCID: PMC10328075 DOI: 10.15252/embr.202255900] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 03/31/2023] [Accepted: 04/26/2023] [Indexed: 09/29/2023] Open
Abstract
Coronavirus‐induced disease‐19 (COVID‐19), caused by SARS‐CoV‐2, is still a major global health challenge. Human endogenous retroviruses (HERVs) represent retroviral elements that were integrated into the ancestral human genome. HERVs are important in embryonic development as well as in the manifestation of diseases, including cancer, inflammation, and viral infections. Here, we analyze the expression of several HERVs in SARS‐CoV‐2‐infected cells and observe increased activity of HERV‐E, HERV‐V, HERV‐FRD, HERV‐MER34, HERV‐W, and HERV‐K‐HML2. In contrast, the HERV‐R envelope is downregulated in cell‐based models and PBMCs of COVID‐19 patients. Overexpression of HERV‐R inhibits SARS‐CoV‐2 replication, suggesting its antiviral activity. Further analyses demonstrate the role of the extracellular signal‐regulated kinase (ERK) in regulating HERV‐R antiviral activity. Lastly, our data indicate that the crosstalk between ERK and p38 MAPK controls the synthesis of the HERV‐R envelope protein, which in turn modulates SARS‐CoV‐2 replication. These findings suggest the role of the HERV‐R envelope as a prosurvival host factor against SARS‐CoV‐2 and illustrate a possible advantage of integration and evolutionary maintenance of retroviral elements in the human genome.
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Affiliation(s)
- Shabnam Ansari
- Virology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Nidhi Gupta
- Virology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
- Present address:
Department of BiochemistryAll India Institute of Medical SciencesNew DelhiIndia
| | - Rohit Verma
- Virology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Oinam N Singh
- Virology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Jyoti Gupta
- Virology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Amit Kumar
- Virology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Mukesh Kumar Yadav
- Virology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Akshay Binayke
- Immunobiology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Mahima Tiwari
- Translational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Neha Periwal
- Department of Biochemistry, School of Chemical and Life SciencesJamia Hamdard UniversityNew DelhiIndia
| | - Vikas Sood
- Department of Biochemistry, School of Chemical and Life SciencesJamia Hamdard UniversityNew DelhiIndia
| | - Shailendra Mani
- Translational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Amit Awasthi
- Immunobiology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
| | - Shalimar
- Department of GastroenterologyAll India Institute of Medical SciencesNew DelhiIndia
| | - Baibaswata Nayak
- Department of GastroenterologyAll India Institute of Medical SciencesNew DelhiIndia
| | - CT Ranjith‐Kumar
- University School of Biotechnology, Guru Gobind Singh Indraprastha UniversityNew DelhiIndia
| | - Milan Surjit
- Virology LaboratoryTranslational Health Science and Technology Institute, NCR Biotech Science ClusterFaridabadIndia
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7
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Evolutionary Analysis of Placental Orthologues Reveals Two Ancient DNA Virus Integrations. J Virol 2022; 96:e0093322. [DOI: 10.1128/jvi.00933-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genomes of vertebrates preserve a large diversity of endogenous viral elements (remnants of ancient viruses that accumulate in host genomes over evolutionary time). Although retroviruses account for the vast majority of these elements, diverse DNA viruses have also been found and novel lineages are being described.
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8
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Burn A, Roy F, Freeman M, Coffin JM. Widespread expression of the ancient HERV-K (HML-2) provirus group in normal human tissues. PLoS Biol 2022; 20:e3001826. [PMID: 36256614 PMCID: PMC9578601 DOI: 10.1371/journal.pbio.3001826] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/13/2022] [Indexed: 11/11/2022] Open
Abstract
Human endogenous retrovirus (HERV) transcripts are known to be highly expressed in cancers, yet their activity in nondiseased tissue is largely unknown. Using the GTEx RNA-seq dataset from normal tissue sampled at autopsy, we characterized individual expression of the recent HERV-K (HML-2) provirus group across 13,000 different samples of 54 different tissues from 948 individuals. HML-2 transcripts could be identified in every tissue sampled and were elevated in the cerebellum, pituitary, testis, and thyroid. A total of 37 different individual proviruses were expressed in 1 or more tissues, representing all 3 LTR5 subgroups. Nine proviruses were identified as having long terminal repeat (LTR)-driven transcription, 7 of which belonged to the most recent LTR5HS subgroup. Proviruses of different subgroups displayed a bias in tissue expression, which may be associated with differences in transcription factor binding sites in their LTRs. Provirus expression was greater in evolutionarily older proviruses with an earliest shared ancestor of gorilla or older. HML-2 expression was significantly affected by biological sex in 1 tissue, while age and timing of death (Hardy score) had little effect. Proviruses containing intact gag, pro, and env open reading frames (ORFs) were expressed in the dataset, with almost every tissue measured potentially expressing at least 1 intact ORF (gag). Human endogenous retrovirus (HERV) transcripts are known to be highly expressed in cancers, but what is their activity in normal tissue? This study uses unique patterns of HERV-K RNA expression in the large GEx dataset from non-diseased tissue sites to provide new insights into both the coevolution of HERV-K with our primate ancestors and their current role in human biology.
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Affiliation(s)
- Aidan Burn
- Program in Genetics, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
| | - Farrah Roy
- Immuneering Corporation, Cambridge, Massachusetts, United States of America
| | - Michael Freeman
- Program in Genetics, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
| | - John M. Coffin
- Program in Genetics, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
- * E-mail:
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9
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Mo G, Wei P, Hu B, Nie Q, Zhang X. Advances on genetic and genomic studies of ALV resistance. J Anim Sci Biotechnol 2022; 13:123. [PMID: 36217167 PMCID: PMC9550310 DOI: 10.1186/s40104-022-00769-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 08/14/2022] [Indexed: 12/01/2022] Open
Abstract
Avian leukosis (AL) is a general term for a variety of neoplastic diseases in avian caused by avian leukosis virus (ALV). No vaccine or drug is currently available for the disease. Therefore, the disease can result in severe economic losses in poultry flocks. Increasing the resistance of poultry to ALV may be one effective strategy. In this review, we provide an overview of the roles of genes associated with ALV infection in the poultry genome, including endogenous retroviruses, virus receptors, interferon-stimulated genes, and other immune-related genes. Furthermore, some methods and techniques that can improve ALV resistance in poultry are discussed. The objectives are willing to provide some valuable references for disease resistance breeding in poultry.
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Affiliation(s)
- Guodong Mo
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China.,Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, 510642, Guangdong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Ping Wei
- Institute for Poultry Science and Health, Guangxi University, Nanning, 530001, Guangxi, China
| | - Bowen Hu
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China.,Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, 510642, Guangdong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Qinghua Nie
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China.,Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, 510642, Guangdong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Xiquan Zhang
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China. .,Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, 510642, Guangdong, China. .,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
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10
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Srinivasachar Badarinarayan S, Sauter D. Switching Sides: How Endogenous Retroviruses Protect Us from Viral Infections. J Virol 2021; 95:e02299-20. [PMID: 33883223 PMCID: PMC8315955 DOI: 10.1128/jvi.02299-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 03/30/2021] [Indexed: 01/15/2023] Open
Abstract
Long disregarded as junk DNA or genomic dark matter, endogenous retroviruses (ERVs) have turned out to represent important components of the antiviral immune response. These remnants of once-infectious retroviruses not only regulate cellular immune activation, but may even directly target invading viral pathogens. In this Gem, we summarize mechanisms by which retroviral fossils protect us from viral infections. One focus will be on recent advances in the role of ERVs as regulators of antiviral gene expression.
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MESH Headings
- Animals
- Endogenous Retroviruses/genetics
- Endogenous Retroviruses/physiology
- Enhancer Elements, Genetic
- Gene Expression Regulation
- Humans
- Immunity, Cellular
- Promoter Regions, Genetic
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/metabolism
- RNA, Long Noncoding/genetics
- RNA, Long Noncoding/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Receptors, Pattern Recognition/metabolism
- Receptors, Virus/antagonists & inhibitors
- Receptors, Virus/metabolism
- Retroelements
- Viral Proteins/metabolism
- Virion/metabolism
- Virus Diseases/genetics
- Virus Diseases/immunology
- Virus Diseases/virology
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Affiliation(s)
- Smitha Srinivasachar Badarinarayan
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Germany
| | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Germany
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11
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Fulton JE, Mason AS, Wolc A, Arango J, Settar P, Lund AR, Burt DW. The impact of endogenous Avian Leukosis Viruses (ALVE) on production traits in elite layer lines. Poult Sci 2021; 100:101121. [PMID: 33975038 PMCID: PMC8131724 DOI: 10.1016/j.psj.2021.101121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/26/2021] [Accepted: 02/26/2021] [Indexed: 11/28/2022] Open
Abstract
Avian Leukosis Virus subgroup E (ALVE) integrations are endogenous retroviral elements found in the chicken genome. The presence of ALVE has been reported to have negative impacts on multiple traits, including egg production and body weight. The recent development of rapid, inexpensive and specific ALVE detection methods has facilitated their characterization in elite commercial egg production lines across multiple generations. The presence of 20 ALVE was examined in 8 elite lines, from 3 different breeds. Seventeen of these ALVE (85%) were informative and found to be segregating in at least one of the lines. To test for an association between specific ALVE inserts and traits, a large genotype by phenotype study was undertaken. Genotypes were obtained for 500 to 1500 males per line, and the phenotypes used were sire-daughter averages. Phenotype data were analyzed by line with a linear model that included the effects of generation, ALVE genotype and their interaction. If genotype effect was significant, the number of ALVE copies was fitted as a regression to estimate additive ALVE gene substitution effect. Significant associations between the presence of specific ALVE inserts and 18 commercially relevant performance and egg quality traits, including egg production, egg weight and albumen height, were observed. When an ALVE was segregating in more than one line, these associations did not always have the same impact (negative, positive or none) in each line. It is hypothesized that the presence of ALVE in the chicken genome may influence production traits by 3 mechanisms: viral protein production may modulate the immune system and impact overall production performance (virus effect); insertional mutagenesis caused by viral integration may cause direct gene alterations or affect gene regulation (gene effect); or the integration site may be within or adjacent to a quantitative trait region which impacts a performance trait (linkage disequilibrium, marker effect).
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Affiliation(s)
- Janet E Fulton
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA.
| | - Andrew S Mason
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology and The York Biomedical Research Institute, The University of York, York, YO10 5DD, United Kingdom
| | - Anna Wolc
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA; Department of Animal Science, Iowa State University, Ames, IA 50011, USA
| | - Jesus Arango
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA
| | - Petek Settar
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA
| | - Ashlee R Lund
- Department of Research and Development, Hy-Line International, Dallas Center, IA 50063, USA
| | - David W Burt
- The University of Queensland, Brisbane, Queensland, 4072, Australia
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Dezordi FZ, Vasconcelos CRDS, Rezende AM, Wallau GL. In and Outs of Chuviridae Endogenous Viral Elements: Origin of a Potentially New Retrovirus and Signature of Ancient and Ongoing Arms Race in Mosquito Genomes. Front Genet 2020; 11:542437. [PMID: 33193616 PMCID: PMC7642597 DOI: 10.3389/fgene.2020.542437] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 09/28/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Endogenous viral elements (EVEs) are sequences of viral origin integrated into the host genome. EVEs have been characterized in various insect genomes, including mosquitoes. A large EVE content has been found in Aedes aegypti and Aedes albopictus genomes among which a recently described Chuviridae viral family is of particular interest, owing to the abundance of EVEs derived from it, the discrepancy among the chuvirus endogenized gene regions and the frequent association with retrotransposons from the BEL-Pao superfamily. In order to better understand the endogenization process of chuviruses and the association between chuvirus glycoproteins and BEL-Pao retrotransposons, we performed a comparative genomics and evolutionary analysis of chuvirus-derived EVEs found in 37 mosquito genomes. RESULTS We identified 428 EVEs belonging to the Chuviridae family confirming the wide discrepancy among the chuvirus genomic regions endogenized: 409 glycoproteins, 18 RNA-dependent RNA polymerases and one nucleoprotein region. Most of the glycoproteins (263 out of 409) are associated specifically with retroelements from the Pao family. Focusing only on well-assembled Pao retroelement copies, we estimated that 263 out of 379 Pao elements are associated with chuvirus-derived glycoproteins. Seventy-three potentially active Pao copies were found to contain glycoproteins into their LTR boundaries. Thirteen out of these were classified as complete and likely autonomous copies, with a full LTR structure and protein domains. We also found 116 Pao copies with no trace of glycoproteins and 37 solo glycoproteins. All potential autonomous Pao copies, contained highly similar LTRs, suggesting a recent/current activity of these elements in the mosquito genomes. CONCLUSION Evolutionary analysis revealed that most of the glycoproteins found are likely derived from a single or few glycoprotein endogenization events associated with a recombination event with a Pao ancestral element. A potential functional Pao-chuvirus hybrid (named Anakin) emerged and the glycoprotein was further replicated through retrotransposition. However, a number of solo glycoproteins, not associated with Pao elements, can be found in some mosquito genomes suggesting that these glycoproteins were likely domesticated by the host genome and may participate in an antiviral defense mechanism against both chuvirus and Anakin retrovirus.
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Affiliation(s)
- Filipe Zimmer Dezordi
- Departamento de Entomologia, Instituto Aggeu Magalhães (IAM), Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
| | | | - Antonio Mauro Rezende
- Departamento de Microbiologia, Instituto Aggeu Magalhães (IAM), Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
| | - Gabriel Luz Wallau
- Departamento de Entomologia, Instituto Aggeu Magalhães (IAM), Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
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13
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Mason AS, Miedzinska K, Kebede A, Bamidele O, Al-Jumaili AS, Dessie T, Hanotte O, Smith J. Diversity of endogenous avian leukosis virus subgroup E (ALVE) insertions in indigenous chickens. Genet Sel Evol 2020; 52:29. [PMID: 32487054 PMCID: PMC7268647 DOI: 10.1186/s12711-020-00548-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 05/26/2020] [Indexed: 12/05/2022] Open
Abstract
Background Avian leukosis virus subgroup E (ALVE) insertions are endogenous retroviruses (ERV) that are restricted to the domestic chicken and its wild progenitor. In commercial chickens, ALVE are known to have a detrimental effect on productivity and provide a source for recombination with exogenous retroviruses. The wider diversity of ALVE in non-commercial chickens and the role of these elements in ERV-derived immunity (EDI) are yet to be investigated. Results In total, 974 different ALVE were identified from 407 chickens sampled from village populations in Ethiopia, Iraq, and Nigeria, using the recently developed obsERVer bioinformatics identification pipeline. Eighty-eight percent of all identified ALVE were novel, bringing the known number of ALVE integrations to more than 1300 across all analysed chickens. ALVE content was highly lineage-specific and populations generally exhibited a large diversity of ALVE at low frequencies, which is typical for ERV involved in EDI. A significantly larger number of ALVE was found within or near coding regions than expected by chance, although a relative depletion of ALVE was observed within coding regions, which likely reflects selection against deleterious integrations. These effects were less pronounced than in previous analyses of chickens from commercial lines. Conclusions Identification of more than 850 novel ALVE has trebled the known diversity of these retroviral elements. This work provides the basis for future studies to fully quantify the role of ALVE in immunity against exogenous ALV, and development of programmes to improve the productivity and welfare of chickens in developing economies.
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Affiliation(s)
- Andrew S Mason
- The University of York, York, YO10 5DD, UK. .,The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
| | - Katarzyna Miedzinska
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Adebabay Kebede
- LiveGene-CTLGH, International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia.,Addis Ababa University, Addis Ababa, Ethiopia
| | - Oladeji Bamidele
- African Chicken Genetic Gains, Department of Animal Sciences, Obafemi Awolowo, Ile Ife, Osun, Nigeria
| | - Ahmed S Al-Jumaili
- School of Life Sciences, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK.,University of Anbar, Ramadi, Anbar, Iraq
| | - Tadelle Dessie
- LiveGene-CTLGH, International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
| | - Olivier Hanotte
- LiveGene-CTLGH, International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia.,School of Life Sciences, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK.,University of Anbar, Ramadi, Anbar, Iraq
| | - Jacqueline Smith
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
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Mason AS, Fulton JE, Smith J. Endogenous avian leukosis virus subgroup E elements of the chicken reference genome. Poult Sci 2020; 99:2911-2915. [PMID: 32475424 PMCID: PMC7597685 DOI: 10.1016/j.psj.2019.12.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/08/2019] [Accepted: 12/31/2019] [Indexed: 11/29/2022] Open
Abstract
The chicken reference genome contains 2 endogenous avian leukosis virus subgroup E (ALVE) insertions, but gaps and unresolved repetitive sequences in previous assemblies have hindered their precise characterization. Detailed analysis of the most recent reference genome (GRCg6a) now shows both ALVEs within contiguous chromosome assemblies for the first time. ALVE6 (ALVE-JFevA) and ALVE-JFevB are both located on chromosome 1, with ALVE6 close to the p-arm telomere. ALVE-JFevB is a structurally intact element containing the ALVE gag, pol, and env genes and is capable of forming replication competent viruses. In contrast, ALVE6 contains a 3,352 bp 5′ truncation and lacks the entire 5′ long terminal repeat and gag gene. Despite this, ALVE6 remains able to produce intact envelope protein, likely due to a mutation in the recognition site for a known inhibitory miRNA (miR-155). Whole genome resequencing data sets from layers, broilers, and 3 independent sources of wild-caught red junglefowl were surveyed for the presence of each of these reference genome ALVEs. ALVE-JFevB was found in no other chicken or red junglefowl genomes, whereas ALVE6 was identified in some layers, broilers, and native breeds but not within any other red junglefowl genome. Improved assembly contiguity has facilitated better characterization of the 2 ALVEs of the chicken reference genome. However, both the limited ALVE content and unique presence of ALVE-JFevB suggests that the reference individual is unrepresentative of ancestral Gallus gallus ALVE diversity.
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Affiliation(s)
- Andrew S Mason
- Department of Biology, The University of York, York YO10 5DD, UK; The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian EH25 9RG, UK.
| | | | - Jacqueline Smith
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian EH25 9RG, UK
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15
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Abstract
Retroviruses infect a broad range of vertebrate hosts that includes amphibians, reptiles, fish, birds and mammals. In addition, a typical vertebrate genome contains thousands of loci composed of ancient retroviral sequences known as endogenous retroviruses (ERVs). ERVs are molecular remnants of ancient retroviruses and proof that the ongoing relationship between retroviruses and their vertebrate hosts began hundreds of millions of years ago. The long-term impact of retroviruses on vertebrate evolution is twofold: first, as with other viruses, retroviruses act as agents of selection, driving the evolution of host genes that block viral infection or that mitigate pathogenesis, and second, through the phenomenon of endogenization, retroviruses contribute an abundance of genetic novelty to host genomes, including unique protein-coding genes and cis-acting regulatory elements. This Review describes ERV origins, their diversity and their relationships to retroviruses and discusses the potential for ERVs to reveal virus-host interactions on evolutionary timescales. It also describes some of the many examples of cellular functions, including protein-coding genes and regulatory elements, that have evolved from ERVs.
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Endogenous Avian Leukosis Virus in Combination with Serotype 2 Marek's Disease Virus Significantly Boosted the Incidence of Lymphoid Leukosis-Like Bursal Lymphomas in Susceptible Chickens. J Virol 2019; 93:JVI.00861-19. [PMID: 31554689 PMCID: PMC6854487 DOI: 10.1128/jvi.00861-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/10/2019] [Indexed: 01/05/2023] Open
Abstract
Lymphoid leukosis (LL)-like lymphoma is a low-incidence yet costly and poorly understood disease of domestic chickens. The observed unique characteristics of LL-like lymphomas are that the incidence of the disease is chicken line dependent; pathologically, it appeared to mimic avian leukosis but is free of exogenous ALV infection; inoculation of the nonpathogenic ALV-E or MDV-2 (SB-1) boosts the incidence of the disease; and inoculation of both the nonpathogenic ALV-E and SB-1 escalates it to much higher levels. This study was designed to test the impact of two new ALV-E isolates, recently derived from commercial broiler breeder flocks, in combination with the nonpathogenic SB-1 on LL-like lymphoma incidences in both an experimental egg layer line of chickens and a commercial broiler breeder line of chickens under a controlled condition. Data from this study provided an additional piece of experimental evidence on the potency of nonpathogenic ALV-E, MDV-2, and ALV-E plus MDV-2 in boosting the incidence of LL-like lymphomas in susceptible chickens. This study also generated the first piece of genomic evidence that suggests host transcriptomic variation plays an important role in modulating LL-like lymphoma formation. In 2010, sporadic cases of avian leukosis virus (ALV)-like bursal lymphoma, also known as spontaneous lymphoid leukosis (LL)-like tumors, were identified in two commercial broiler breeder flocks in the absence of exogenous ALV infection. Two individual ALV subgroup E (ALV-E) field strains, designated AF227 and AF229, were isolated from two different breeder farms. The role of these ALV-E field isolates in development of and the potential joint impact in conjunction with a Marek’s disease virus (MDV) vaccine (SB-1) were further characterized in chickens of an experimental line and commercial broiler breeders. The experimental line 0.TVB*S1, commonly known as the rapid feathering-susceptible (RFS) line, of chickens lacks all endogenous ALV and is fully susceptible to all subgroups of ALV, including ALV-E. Spontaneous LL-like tumors occurred following infection with AF227, AF229, and a reference ALV-E strain, RAV60, in RFS chickens. Vaccination with serotype 2 MDV, SB-1, in addition to AF227 or AF229 inoculation, significantly enhanced the spontaneous LL-like tumor incidence in the RFS chickens. The spontaneous LL-like tumor incidence jumped from 14% by AF227 alone to 42 to 43% by AF227 in combination with SB-1 in the RFS chickens under controlled conditions. RNA-sequencing analysis of the LL-like lymphomas and nonmalignant bursa tissues of the RFS line of birds identified hundreds of differentially expressed genes that are reportedly involved in key biological processes and pathways, including signaling and signal transduction pathways. The data from this study suggested that both ALV-E and MDV-2 play an important role in enhancement of the spontaneous LL-like tumors in susceptible chickens. The underlying mechanism may be complex and involved in many chicken genes and pathways, including signal transduction pathways and immune system processes, in addition to reported viral genes. IMPORTANCE Lymphoid leukosis (LL)-like lymphoma is a low-incidence yet costly and poorly understood disease of domestic chickens. The observed unique characteristics of LL-like lymphomas are that the incidence of the disease is chicken line dependent; pathologically, it appeared to mimic avian leukosis but is free of exogenous ALV infection; inoculation of the nonpathogenic ALV-E or MDV-2 (SB-1) boosts the incidence of the disease; and inoculation of both the nonpathogenic ALV-E and SB-1 escalates it to much higher levels. This study was designed to test the impact of two new ALV-E isolates, recently derived from commercial broiler breeder flocks, in combination with the nonpathogenic SB-1 on LL-like lymphoma incidences in both an experimental egg layer line of chickens and a commercial broiler breeder line of chickens under a controlled condition. Data from this study provided an additional piece of experimental evidence on the potency of nonpathogenic ALV-E, MDV-2, and ALV-E plus MDV-2 in boosting the incidence of LL-like lymphomas in susceptible chickens. This study also generated the first piece of genomic evidence that suggests host transcriptomic variation plays an important role in modulating LL-like lymphoma formation.
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17
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piRNA-Guided CRISPR-like Immunity in Eukaryotes. Trends Immunol 2019; 40:998-1010. [DOI: 10.1016/j.it.2019.09.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 09/17/2019] [Accepted: 09/17/2019] [Indexed: 02/07/2023]
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18
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Abstract
Transposable elements (TEs) are mobile DNA sequences that colonize genomes and threaten genome integrity. As a result, several mechanisms appear to have emerged during eukaryotic evolution to suppress TE activity. However, TEs are ubiquitous and account for a prominent fraction of most eukaryotic genomes. We argue that the evolutionary success of TEs cannot be explained solely by evasion from host control mechanisms. Rather, some TEs have evolved commensal and even mutualistic strategies that mitigate the cost of their propagation. These coevolutionary processes promote the emergence of complex cellular activities, which in turn pave the way for cooption of TE sequences for organismal function.
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Affiliation(s)
- Rachel L Cosby
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Ni-Chen Chang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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Sun YH, Xie LH, Zhuo X, Chen Q, Ghoneim D, Zhang B, Jagne J, Yang C, Li XZ. Domestic chickens activate a piRNA defense against avian leukosis virus. eLife 2017; 6. [PMID: 28384097 PMCID: PMC5383398 DOI: 10.7554/elife.24695] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/04/2017] [Indexed: 12/12/2022] Open
Abstract
PIWI-interacting RNAs (piRNAs) protect the germ line by targeting transposable elements (TEs) through the base-pair complementarity. We do not know how piRNAs co-evolve with TEs in chickens. Here we reported that all active TEs in the chicken germ line are targeted by piRNAs, and as TEs lose their activity, the corresponding piRNAs erode away. We observed de novo piRNA birth as host responds to a recent retroviral invasion. Avian leukosis virus (ALV) has endogenized prior to chicken domestication, remains infectious, and threatens poultry industry. Domestic fowl produce piRNAs targeting ALV from one ALV provirus that was known to render its host ALV resistant. This proviral locus does not produce piRNAs in undomesticated wild chickens. Our findings uncover rapid piRNA evolution reflecting contemporary TE activity, identify a new piRNA acquisition modality by activating a pre-existing genomic locus, and extend piRNA defense roles to include the period when endogenous retroviruses are still infectious. DOI:http://dx.doi.org/10.7554/eLife.24695.001 Viruses called retroviruses can infect animal cells and merge their genetic information with those of the animal causing damage to the animal’s genetic blueprints. Once retroviruses are integrated into a cell they can sometimes get passed down through the generations over the centuries. Almost half of the human genetic code, for example, is made from ancient retroviruses and other foreign sequences. Over time many of these ancient viruses lost the ability to infect other cells and became trapped within cells but they can still jump out and damage the animal’s genetic code under certain circumstances. These trapped foreign sequences are called transposable elements. Animal cells produce molecules called piRNAs to shut down transposable elements. Most piRNAs are produced from genetic information that originally came from integrated retroviruses and that has been hijacked to defend the cell, a similar strategy as Crisper system in bacteria. Domestic chickens produce piRNAs against a virus called avian leukosis virus (or ALV for short) – which commonly infects domestic fowl. The virus also infected the wild ancestors of chickens, known as red jungle fowl, but these birds do not produce piRNAs. This provides an ideal setting to study the evolution of piRNAs in an animal that is not too distantly related to humans (chickens and humans both have backbones, and are therefore both warm-blooded vertebrates). Sun et al. examined cells from the testicles of domestic chickens and red jungle fowl as an example of the role of piRNAs in protecting genetic information in vertebrates. The investigation revealed that piRNAs against all previously trapped viruses in the chicken’s genetic code are produced in chickens to stop them from causing more damage. Sun et al. also observed the creation of piRNAs in chickens in response to ALV that had not yet become trapped in the chicken’s genetic code. Importantly, the piRNAs could control these retroviruses while they were still infectious. The experiments also revealed that piRNAs against ALV are produced from a single copy of ALV that is found in both domestic and wild chickens. The results showed that cells can produce new piRNAs using these pre-existing viral copies within their own genetics. This illustrates that production of piRNA from existing genetic material can be activated in response to certain cues. Further work will seek to discover how existing genetic information becomes a source of piRNAs. In the United States, 8 billion domestic chickens are consumed each year, and a better understanding of how these birds defend themselves against viral infections could increase the productivity of the poultry industry around the world. Moreover, because other viruses trapped in the chicken’s genetic code are related to similar viruses in humans, future discoveries made in this area could help to guide research that will benefit human health as well. DOI:http://dx.doi.org/10.7554/eLife.24695.002
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Affiliation(s)
- Yu Huining Sun
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, Department of Urology, University of Rochester Medical Center, Rochester, United States
| | - Li Huitong Xie
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, Department of Urology, University of Rochester Medical Center, Rochester, United States
| | - Xiaoyu Zhuo
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, United States
| | - Qiang Chen
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, Department of Urology, University of Rochester Medical Center, Rochester, United States
| | - Dalia Ghoneim
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, Department of Urology, University of Rochester Medical Center, Rochester, United States
| | - Bin Zhang
- Department of Pathology and Laboratory Medicine, Department of Pediatrics, University of Rochester Medical Center, Rochester, United States
| | - Jarra Jagne
- Animal Health Diagnostic Center, Cornell University College of Veterinary Medicine, Ithaca, United States
| | - Chengbo Yang
- Department of Animal Science, University of Manitoba, Winnipeg, Canada
| | - Xin Zhiguo Li
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, Department of Urology, University of Rochester Medical Center, Rochester, United States
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Liu Q, Yan Y, Kozak CA. Permissive XPR1 gammaretrovirus receptors in four mammalian species are functionally distinct in interference tests. Virology 2016; 497:53-58. [PMID: 27423269 DOI: 10.1016/j.virol.2016.06.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 06/29/2016] [Accepted: 06/30/2016] [Indexed: 01/29/2023]
Abstract
Xenotropic/polytropic mouse leukemia viruses (X/P-MLVs) use the XPR1 gammaretrovirus receptor for entry. X/P-MLV host range is defined by usage of naturally occurring restrictive XPR1 receptors, and is governed by polymorphisms in the virus envelope glycoprotein and in XPR1. Here, we examined receptors of four mammalian species permissive to all X/P-MLVs (Mus dunni, human, rabbit, mink). Interference assays showed the four to be functionally distinct. Preinfection with X-MLVs consistently blocked all nine XPR1-dependent viruses, while preinfection with P-MLVs and wild mouse X/P-MLVs produced distinctive interference patterns in the four cells. These patterns indicate shared usage of independent, but not always fully functional, receptor sites. XPR1 sequence comparisons identified candidate sites in receptor-determining regions that correlate with some interference patterns. The evolutionary record suggests that the X/P-MLV tropism variants evolved to adapt to host receptor polymorphisms, to circumvent blocks by competing viruses or to avoid host-encoded envelope glycoproteins acquired for defense.
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Affiliation(s)
- Qingping Liu
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Yuhe Yan
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Christine A Kozak
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA.
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Rutherford K, Meehan CJ, Langille MGI, Tyack SG, McKay JC, McLean NL, Benkel K, Beiko RG, Benkel B. Discovery of an expanded set of avian leukosis subgroup E proviruses in chickens using Vermillion, a novel sequence capture and analysis pipeline [corrected]. Poult Sci 2016; 95:2250-8. [PMID: 27354549 DOI: 10.3382/ps/pew194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/08/2016] [Indexed: 01/26/2023] Open
Abstract
Transposable elements (TEs), such as endogenous retroviruses (ERVs), are common in the genomes of vertebrates. ERVs result from retroviral infections of germ-line cells, and once integrated into host DNA they become part of the host's heritable genetic material. ERVs have been ascribed positive effects on host physiology such as the generation of novel, adaptive genetic variation and resistance to infection, as well as negative effects as agents of tumorigenesis and disease. The avian leukosis virus subgroup E family (ALVE) of endogenous viruses of chickens has been used as a model system for studying the effects of ERVs on host physiology, and approximately 30 distinct ALVE proviruses have been described in the Gallus gallus genome. In this report we describe the development of a software tool, which we call Vermillion, and the use of this tool in combination with targeted next-generation sequencing (NGS) to increase the number of known proviruses belonging to the ALVE family of ERVs in the chicken genome by 4-fold, including expanding the number of known ALVE elements on chromosome 1 (Gga1) from the current 9 to a total of 40. Although we focused on the discovery of ALVE elements in chickens, with appropriate selection of target sequences Vermillion can be used to develop profiles of other families of ERVs and TEs in chickens as well as in species other than the chicken.
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Affiliation(s)
- K Rutherford
- Dalhousie University, Faculty of Computer Science, 6050 University Avenue, Halifax, NS, Canada, B3H 4R2
| | - C J Meehan
- Dalhousie University, Faculty of Computer Science, 6050 University Avenue, Halifax, NS, Canada, B3H 4R2 Institute of Tropical Medicine, Department of Biomedical Sciences, Antwerp 2000, Belgium
| | - M G I Langille
- Dalhousie University, Faculty of Computer Science, 6050 University Avenue, Halifax, NS, Canada, B3H 4R2 Dalhousie University, Faculty of Medicine, Department of Pharmacology, 5850 College St, Halifax, NS, Canada, B3H 4R2
| | - S G Tyack
- EW GROUP, 1 Hogenboegen, Visbek, Germany
| | - J C McKay
- EW GROUP, 1 Hogenboegen, Visbek, Germany
| | - N L McLean
- Dalhousie University, Faculty of Agriculture, Department of Plant and Animal Sciences, Box 550, Truro, NS, B2N 5E3
| | - K Benkel
- Dalhousie University, Faculty of Agriculture, Department of Plant and Animal Sciences, Box 550, Truro, NS, B2N 5E3
| | - R G Beiko
- Dalhousie University, Faculty of Computer Science, 6050 University Avenue, Halifax, NS, Canada, B3H 4R2
| | - B Benkel
- Dalhousie University, Faculty of Agriculture, Department of Plant and Animal Sciences, Box 550, Truro, NS, B2N 5E3
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Villarreal LP. Viruses and the placenta: the essential virus first view. APMIS 2016; 124:20-30. [PMID: 26818259 DOI: 10.1111/apm.12485] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/26/2015] [Indexed: 01/05/2023]
Abstract
A virus first perspective is presented as an alternative hypothesis to explain the role of various endogenized retroviruses in the origin of the mammalian placenta. It is argued that virus-host persistence is a key determinant of host survival and the various ERVs involved have directly affected virus-host persistence.
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Affiliation(s)
- Luis P Villarreal
- Center for Virus Research, Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA, USA
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Expression of the env gene from the avian endogenous retrovirus ALVE and regulation by miR-155. Arch Virol 2016; 161:1623-32. [PMID: 27016933 DOI: 10.1007/s00705-016-2833-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/16/2016] [Indexed: 01/17/2023]
Abstract
Endogenous retroviruses (ERVs) are important retroelements that reside in host genomes. However, ERV expression patterns and regulatory mechanisms are poorly understood. In this study, chicken embryo fibroblasts (CEFs) and MSB1 cells infected with Marek's disease virus (MDV) exhibited significantly increased expression of env from the endogenous retrovirus ALVE. In contrast, env expression was significantly lower in CEF and MSB1 cells infected with exogenous avian leukosis virus J (ALVJ) at the early infection stage. Furthermore, env was found to be ubiquitously expressed in various chicken tissues, with high expression in certain tissues at 2 days of age and low levels in most tissues, including immune organs (thymus, spleen and bursa) as well as the brain and heart, at 35 days of age. Sequence analysis revealed miR-155 target sites in env transcripts, which was verified using a firefly luciferase reporter assay, and treatment with miR-155 agomir significantly decreased levels of env transcripts in MSB1 and CEF cells. Together, these findings suggest that the env gene from the endogenous retrovirus ALVE is regulated by miR-155.
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Naville M, Warren IA, Haftek-Terreau Z, Chalopin D, Brunet F, Levin P, Galiana D, Volff JN. Not so bad after all: retroviruses and long terminal repeat retrotransposons as a source of new genes in vertebrates. Clin Microbiol Infect 2016; 22:312-323. [PMID: 26899828 DOI: 10.1016/j.cmi.2016.02.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/05/2016] [Accepted: 02/06/2016] [Indexed: 12/24/2022]
Abstract
Viruses and transposable elements, once considered as purely junk and selfish sequences, have repeatedly been used as a source of novel protein-coding genes during the evolution of most eukaryotic lineages, a phenomenon called 'molecular domestication'. This is exemplified perfectly in mammals and other vertebrates, where many genes derived from long terminal repeat (LTR) retroelements (retroviruses and LTR retrotransposons) have been identified through comparative genomics and functional analyses. In particular, genes derived from gag structural protein and envelope (env) genes, as well as from the integrase-coding and protease-coding sequences, have been identified in humans and other vertebrates. Retroelement-derived genes are involved in many important biological processes including placenta formation, cognitive functions in the brain and immunity against retroelements, as well as in cell proliferation, apoptosis and cancer. These observations support an important role of retroelement-derived genes in the evolution and diversification of the vertebrate lineage.
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Affiliation(s)
- M Naville
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR5242, Université Lyon 1, Lyon, France
| | - I A Warren
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR5242, Université Lyon 1, Lyon, France
| | - Z Haftek-Terreau
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR5242, Université Lyon 1, Lyon, France
| | - D Chalopin
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR5242, Université Lyon 1, Lyon, France; Department of Genetics, University of Georgia, Athens, GA, USA
| | - F Brunet
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR5242, Université Lyon 1, Lyon, France
| | - P Levin
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR5242, Université Lyon 1, Lyon, France
| | - D Galiana
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR5242, Université Lyon 1, Lyon, France
| | - J-N Volff
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS UMR5242, Université Lyon 1, Lyon, France.
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Abstract
A considerable portion of vertebrate genomes are made up of endogenous retroviruses (ERVs). While aberrant or uncontrolled ERV expression has been perceived as a potential cause of disease, there is mounting evidence that some ERVs have become integral components of normal host development and physiology. Here, we revisit the longstanding concept that some of the gene products encoded by ERVs and other endogenous viral elements may offer to the host protection against viral infection. Notably, proteins produced from envelope (env) genes have been shown to act as restriction factors against related exogenous retroviruses in chickens, sheep, mice, and cats. Based on the proposed mode of restriction and the domain architecture of known antiretroviral env, we argue that many more env gene-derived restriction factors await discovery in vertebrate genomes, including the human genome.
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Kozak CA. Origins of the endogenous and infectious laboratory mouse gammaretroviruses. Viruses 2014; 7:1-26. [PMID: 25549291 PMCID: PMC4306825 DOI: 10.3390/v7010001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 12/18/2014] [Indexed: 01/07/2023] Open
Abstract
The mouse gammaretroviruses associated with leukemogenesis are found in the classical inbred mouse strains and in house mouse subspecies as infectious exogenous viruses (XRVs) and as endogenous retroviruses (ERVs) inserted into their host genomes. There are three major mouse leukemia virus (MuLV) subgroups in laboratory mice: ecotropic, xenotropic, and polytropic. These MuLV subgroups differ in host range, pathogenicity, receptor usage and subspecies of origin. The MuLV ERVs are recent acquisitions in the mouse genome as demonstrated by the presence of many full-length nondefective MuLV ERVs that produce XRVs, the segregation of these MuLV subgroups into different house mouse subspecies, and by the positional polymorphism of these loci among inbred strains and individual wild mice. While some ecotropic and xenotropic ERVs can produce XRVs directly, others, especially the pathogenic polytropic ERVs, do so only after recombinations that can involve all three ERV subgroups. Here, I describe individual MuLV ERVs found in the laboratory mice, their origins and geographic distribution in wild mouse subspecies, their varying ability to produce infectious virus and the biological consequences of this expression.
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Demogines A, Abraham J, Choe H, Farzan M, Sawyer SL. Dual host-virus arms races shape an essential housekeeping protein. PLoS Biol 2013; 11:e1001571. [PMID: 23723737 PMCID: PMC3665890 DOI: 10.1371/journal.pbio.1001571] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 04/17/2013] [Indexed: 02/07/2023] Open
Abstract
Relentless selective pressures exerted by viruses trigger arms race dynamics that shape the evolution of even critical host genes like those involved in iron homeostasis. Transferrin Receptor (TfR1) is the cell-surface receptor that regulates iron uptake into cells, a process that is fundamental to life. However, TfR1 also facilitates the cellular entry of multiple mammalian viruses. We use evolutionary and functional analyses of TfR1 in the rodent clade, where two families of viruses bind this receptor, to mechanistically dissect how essential housekeeping genes like TFR1 successfully balance the opposing selective pressures exerted by host and virus. We find that while the sequence of rodent TfR1 is generally conserved, a small set of TfR1 residue positions has evolved rapidly over the speciation of rodents. Remarkably, all of these residues correspond to the two virus binding surfaces of TfR1. We show that naturally occurring mutations at these positions block virus entry while simultaneously preserving iron-uptake functionalities, both in rodent and human TfR1. Thus, by constantly replacing the amino acids encoded at just a few residue positions, TFR1 divorces adaptation to ever-changing viruses from preservation of key cellular functions. These dynamics have driven genetic divergence at the TFR1 locus that now enforces species-specific barriers to virus transmission, limiting both the cross-species and zoonotic transmission of these viruses. Genetic differences between mammalian species dictate the patterns of viral infection observed in nature. They also define how viruses must evolve in order to infect new mammalian hosts, giving rise to new and sometimes pandemic diseases. Because viruses must enter cells before they can replicate, new diseases often emerge when existing viruses evolve the ability to bind to the cell-surface receptor of a new species. At the same time, host cell receptors also evolve to counteract virus attacks. This back-and-forth evolution between virus and host can lead to an arms race that shapes the sequences of the proteins involved. In wild rodent populations, the retrovirus MMTV and New World arenaviruses both exploit Transferrin Receptor 1 (TfR1) to enter the cells of their hosts. Here we show that the physical interactions between these viruses and TfR1 have triggered evolutionary arms race dynamics that have directly modified the sequence of TfR1 and at least one of the viruses involved. Computational evolutionary analysis allowed us to identify specific residues in TfR1 that define patterns of viral infection in nature. The approach presented here can theoretically be applied to the study of any virus, through analysis of host genes known to be key to controlling viral infection. As such, this approach can expand our understanding of how viruses emerge from wildlife reservoirs, and how they drive the evolution of host genes.
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Affiliation(s)
- Ann Demogines
- Department of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Jonathan Abraham
- Department of Medicine, Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hyeryun Choe
- Department of Medicine, Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael Farzan
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sara L. Sawyer
- Department of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
- * E-mail:
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Johnson WE. Rapid adversarial co-evolution of viruses and cellular restriction factors. Curr Top Microbiol Immunol 2013; 371:123-51. [PMID: 23686234 DOI: 10.1007/978-3-642-37765-5_5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Since the discovery of viruses over a century ago, virologists have recognized that host genetics plays a major role in viral tropism and the distribution of viruses in nature. Traditionally, studies of tropism have centered on identification of cellular factors required for viral replication, such as cell-surface entry receptors. However, over the past 20 years, there has been a steady increase in the identification and characterization of restriction factors (RFs), here defined as dominant cellular factors that have evolved specifically to interfere with viral replication. Genetic studies suggest that restriction factors impose significant barriers to interspecies movement of viruses and are therefore critical determinants of viral tropism. Furthermore, the scope of the ever-expanding list of restriction factors, and the variety of antiviral mechanisms they represent, testifies to the extraordinary impact viruses have had on organismal evolution-an impact hitherto underappreciated by evolutionary biologists and virologists alike. Recent studies of RF-encoding genes that combine molecular evolutionary analysis with functional assays illustrate the potential for asking questions about virus-host interactions as they play out in natural populations and across evolutionary timescales. Most notably, it has become common to apply tests of positive selection to RF genes and couple these analyses with virological assays, to reveal evidence for antagonistic virus-host co-evolution. Herein, I summarize recent work on the evolutionary genetics of mammalian RFs, particularly those of humans, non-human primates, and model organisms, and how RFs can reveal the influence of virus-host interactions on organismal evolution. Because intensive investigation of RF evolution is fairly new (and because there is still much to learn), the discussion is organized around five broad, outstanding questions that will need to be answered before we can fully appreciate the evolutionary biology of restriction.
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Naturally Occurring Polymorphisms of the Mouse Gammaretrovirus Receptors CAT-1 and XPR1 Alter Virus Tropism and Pathogenicity. Adv Virol 2011; 2011:975801. [PMID: 22312361 PMCID: PMC3265322 DOI: 10.1155/2011/975801] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 07/12/2011] [Indexed: 01/29/2023] Open
Abstract
Gammaretroviruses of several different host range subgroups have been isolated from laboratory mice. The ecotropic viruses infect mouse cells and rely on the host CAT-1 receptor. The xenotropic/polytropic viruses, and the related human-derived XMRV, can infect cells of other mammalian species and use the XPR1 receptor for entry. The coevolution of these viruses and their receptors in infected mouse populations provides a good example of how genetic conflicts can drive diversifying selection. Genetic and epigenetic variations in the virus envelope glycoproteins can result in altered host range and pathogenicity, and changes in the virus binding sites of the receptors are responsible for host restrictions that reduce virus entry or block it altogether. These battleground regions are marked by mutational changes that have produced 2 functionally distinct variants of the CAT-1 receptor and 5 variants of the XPR1 receptor in mice, as well as a diverse set of infectious viruses, and several endogenous retroviruses coopted by the host to interfere with entry.
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30
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Urbani N, Hartmann W, Kuhnlein U, Zadworny D, Heil G. Incidence of endogenous viral genes in Leghorn strains of different origin, each with sublines of a different genotype for resistance to avian leukosis virus infection. J Anim Breed Genet 2011. [DOI: 10.1111/j.1439-0388.1995.tb00581.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Kozak CA. The mouse "xenotropic" gammaretroviruses and their XPR1 receptor. Retrovirology 2010; 7:101. [PMID: 21118532 PMCID: PMC3009702 DOI: 10.1186/1742-4690-7-101] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 11/30/2010] [Indexed: 11/29/2022] Open
Abstract
The xenotropic/polytropic subgroup of mouse leukemia viruses (MLVs) all rely on the XPR1 receptor for entry, but these viruses vary in tropism, distribution among wild and laboratory mice, pathogenicity, strategies used for transmission, and sensitivity to host restriction factors. Most, but not all, isolates have typical xenotropic or polytropic host range, and these two MLV tropism types have now been detected in humans as viral sequences or as infectious virus, termed XMRV, or xenotropic murine leukemia virus-related virus. The mouse xenotropic MLVs (X-MLVs) were originally defined by their inability to infect cells of their natural mouse hosts. It is now clear, however, that X-MLVs actually have the broadest host range of the MLVs. Nearly all nonrodent mammals are susceptible to X-MLVs, and all species of wild mice and several common strains of laboratory mice are X-MLV susceptible. The polytropic MLVs, named for their apparent broad host range, show a more limited host range than the X-MLVs in that they fail to infect cells of many mouse species as well as many nonrodent mammals. The co-evolution of these viruses with their receptor and other host factors that affect their replication has produced a heterogeneous group of viruses capable of inducing various diseases, as well as endogenized viral genomes, some of which have been domesticated by their hosts to serve in antiviral defense.
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Affiliation(s)
- Christine A Kozak
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892-0460, USA.
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32
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Bacon LD, Smith EJ, Fadly AM, Crittenden LB. Development of an alloantiserum (R2) that detects susceptibility of chickens to subgroup E endogenous avian leukosis virus. Avian Pathol 2009; 25:551-68. [PMID: 18645878 DOI: 10.1080/03079459608419161] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
An alloantiserum, termed R2, specifically agglutinates red blood cells (RBC) from line 100B chickens that are susceptible to avian leukosis viruses (ALV) belonging to subgroups B and E, but does not agglutinate RBC from congenic inbred line 7(2) chickens that are resistant to ALV B and E. The R2 antigen was also detected on lymphocytes and thrombocytes. Using chickens from a special cross, it was found that R2 reactivity requires that the chickens must: (1) be susceptible to infection by ALV-E; and (2) express a viral envelope gene with subgroup E specificity. With R2 antiserum, a nearly perfect association was observed between agglutination and susceptibility to ALV-B in F2 chickens containing endogenous viral genes ev2 and/or ev3. These results support earlier evidence that ALV-B and ALV-E share receptors. Moreover, the R2 antiserum was shown to neutralize ALV-E. The R2 antigen showed Mendelian segregation in chickens of a commercial White Leghorn strain-cross containing ev3, ev6 and ev9. However, commercial chickens with or without the R2 antigen did not differ in susceptibility to lymphoid leukosis induction or immune response on infection with ALV of subgroup A for complex reasons we discuss.
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Affiliation(s)
- L D Bacon
- US Department of Agriculture, Agricultural Research Service, Avian Disease and Oncology Laboratory, East Lansing, Michigan, USA
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33
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Wu T, Yan Y, Kozak CA. Rmcf2, a xenotropic provirus in the Asian mouse species Mus castaneus, blocks infection by polytropic mouse gammaretroviruses. J Virol 2005; 79:9677-84. [PMID: 16014929 PMCID: PMC1181588 DOI: 10.1128/jvi.79.15.9677-9684.2005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cells from the Asian wild mouse species Mus castaneus are resistant to infection by the polytropic host range group of mouse gammaretroviruses. Two factors are responsible for this resistance: a defective XPR1 cell surface receptor for polytropic murine leukemia viruses (P-MLVs), and a resistance factor detectable only in interspecies hybrids between M. castaneus and mice with an XPR1 variant that permits infection by xenotropic MLVs (X-MLVs) as well as P-MLVs. This second novel virus resistance phenotype has been associated with expression of viral Env glycoprotein; Northern blotting with specific hybridization probes identified a spliced X-MLV env message unique to virus-resistant mice. These observations suggest that resistance is due to expression of one or more endogenous X-MLV envelope genes that interfere with infection by exogenous P-MLVs. M. castaneus contains multiple X-MLV proviruses, but serial backcrosses reduced this proviral content and permitted identification of a single proviral env sequence inherited with resistance. The resistance phenotype and the provirus were mapped to the same site on distal chromosome 18. The provirus was shown to be a full-length provirus highly homologous to previously described X-MLVs. Use of viral pseudotypes confirmed that this resistance gene, termed Rmcf2, prevents entry of P-MLVs. Rmcf2 resembles the virus resistance genes Fv4 and Rmcf in that it produces Env glycoprotein but fails to produce infectious virus; the proviruses associated with all three resistance genes have fatal defects. This type of provirus Env-mediated resistance represents an important defense mechanism in wild mouse populations exposed to endemic infections.
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Affiliation(s)
- Tiyun Wu
- Laboratory of Molecular Microbiology, National Institute and Allergy and Infectious Diseases, Bethesda, MD 20892-0460, USA
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Collins WJ, Johnson DC. Herpes simplex virus gE/gI expressed in epithelial cells interferes with cell-to-cell spread. J Virol 2003; 77:2686-95. [PMID: 12552008 PMCID: PMC141120 DOI: 10.1128/jvi.77.4.2686-2695.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The herpes simplex virus (HSV) glycoprotein heterodimer gE/gI plays an important role in virus cell-to-cell spread in epithelial and neuronal tissues. In an analogous fashion, gE/gI promotes virus spread between certain cell types in culture, e.g., keratinocytes and epithelial cells, cells that are polarized or that form extensive cell junctions. One mechanism by which gE/gI facilitates cell-to-cell spread involves selective sorting of nascent virions to cell junctions, a process that requires the cytoplasmic domain of gE. However, the large extracellular domains of gE/gI also appear to be involved in cell-to-cell spread. Here, we show that coexpression of a truncated form of gE and gI in a human keratinocyte line, HaCaT cells, decreased the spread of HSV between cells. This truncated gE/gI was found extensively at cell junctions. Expression of wild-type gE/gI that accumulates at intracellular sites, in the trans-Golgi network, did not reduce cell-to-cell spread. There was no obvious reduction in production of infectious HSV in cells expressing gE/gI, and virus particles accumulated at cell junctions, not at intracellular sites. Expression of HSV gD, which is known to bind virus receptors, also blocked cell-to-cell spread. Therefore, like gD, gE/gI appears to be able to interact with cellular components of cell junctions, gE/gI receptors which can promote HSV cell-to-cell spread.
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Affiliation(s)
- Wendy J Collins
- Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, OR 97239, USA
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35
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Jung YT, Lyu MS, Buckler-White A, Kozak CA. Characterization of a polytropic murine leukemia virus proviral sequence associated with the virus resistance gene Rmcf of DBA/2 mice. J Virol 2002; 76:8218-24. [PMID: 12134027 PMCID: PMC155147 DOI: 10.1128/jvi.76.16.8218-8224.2002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The DBA/2 mouse Rmcf gene is responsible for in vivo and in vitro resistance to infection by the polytropic mink cell focus-forming (MCF) virus subgroup of murine leukemia viruses (MLVs). Previous studies suggested that Rmcf resistance is mediated by expression of an interfering MCF MLV envelope (Env) gene. To characterize this env gene, we examined resistance in crosses between Rmcf(r) DBA/2 mice and Mus castaneus, a species that lacks endogenous MCF env sequences. In backcross progeny, inheritance of Rmcf resistance correlated with inheritance of a specific endogenous MCF virus env-containing 4.6-kb EcoRI fragment. This fragment was present in the DBA/2N substrain with Rmcf-mediated resistance but not in virus-susceptible DBA/2J substrain mice. This fragment contains a provirus with a 5' long terminal repeat and the 5' half of env; the gag and pol genes have been partially deleted. The Env sequence is identical to that of a highly immunogenic viral glycoprotein expressed in the DBA/2 cell line L5178Y and closely resembles the env genes of modified polytropic proviruses. The coding sequence for the full-length Rmcf Env surface subunit was amplified from DNAs from virus-resistant backcross mice and was cloned into an expression vector. NIH 3T3 and BALB 3T3 cells stably transfected with this construct showed significant resistance to infection by MCF MLV but not by amphotropic MLV. This study identifies an Rmcf-linked MCF provirus and indicates that, like the ecotropic virus resistance gene Fv4, Rmcf may mediate resistance through an interference mechanism.
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Affiliation(s)
- Yong Tae Jung
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0460, USA
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36
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Ikeda H, Kato K, Kitani H, Suzuki T, Yoshida T, Inaguma Y, Yamamoto N, Suh JG, Hyun BH, Yamagata T, Namikawa T, Tomita T. Virological properties and nucleotide sequences of Cas-E-type endogenous ecotropic murine leukemia viruses in South Asian wild mice, Mus musculus castaneus. J Virol 2001; 75:5049-58. [PMID: 11333885 PMCID: PMC114909 DOI: 10.1128/jvi.75.11.5049-5058.2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two types of endogenous ecotropic murine leukemia viruses (MuLVs), termed AKV- and Cas-E-type MuLVs, differ in nucleotide sequence and distribution in wild mouse subspecies. In contrast to AKV-type MuLV, Cas-E-type MuLV is not carried by common laboratory mice. Wild mice of Mus musculus (M. m.) castaneus carry multiple copies of Cas-E-type endogenous MuLV, including the Fv-4(r) gene that is a truncated form of integrated MuLV and functions as a host's resistance gene against ecotropic MuLV infection. Our genetic cross experiments showed that only the Fv-4(r) gene was associated with resistance to ecotropic F-MuLV infection. Because the spontaneous expression of infectious virus was not detected in M. m. castaneus, we generated mice that did not carry the Fv-4(r) gene but did carry a single or a few endogenous MuLV loci. In mice not carrying the Fv-4(r) gene, infectious MuLVs were isolated in association with three of six Cas-E-type endogenous MuLV loci. The isolated viruses showed a weak syncytium-forming activity for XC cells, an interfering property of ecotropic MuLV, and a slight antigenic variation. Two genomic DNAs containing endogenous Cas-E-type MuLV were cloned and partially sequenced. All of the Cas-E-type endogenous MuLVs were closely related, hybrid-type viruses with an ecotropic env gene and a xenotropic long terminal repeat. Duplications and a deletion were found in a restricted region of the hypervariable proline-rich region of Env glycoprotein.
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Affiliation(s)
- H Ikeda
- National Institute of Animal Health, Tsukuba, Ibaraki-ken, Japan.
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37
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Holmen SL, Salter DW, Payne WS, Dodgson JB, Hughes SH, Federspiel MJ. Soluble forms of the subgroup A avian leukosis virus [ALV(A)] receptor Tva significantly inhibit ALV(A) infection in vitro and in vivo. J Virol 1999; 73:10051-60. [PMID: 10559319 PMCID: PMC113056 DOI: 10.1128/jvi.73.12.10051-10060.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interactions between the subgroup A avian leukosis virus [ALV(A)] envelope glycoproteins and soluble forms of the ALV(A) receptor Tva were analyzed both in vitro and in vivo by quantitating the ability of the soluble Tva proteins to inhibit ALV(A) entry into susceptible cells. Two soluble Tva proteins were tested: the 83-amino-acid Tva extracellular region fused to two epitope tags (sTva) or fused to the constant region of the mouse immunoglobulin G heavy chain (sTva-mIgG). Replication-competent ALV-based retroviral vectors with subgroup B or C env were used to deliver and express the two soluble tv-a (stva) genes in avian cells. In vitro, chicken embryo fibroblasts or DF-1 cells expressing sTva or sTva-mIgG proteins were much more resistant to infection by ALV(A) ( approximately 200-fold) than were control cells infected by only the vector. The antiviral effect was specific for ALV(A), which is consistent with a receptor interference mechanism. The antiviral effect of sTva-mIgG was positively correlated with the amount of sTva-mIgG protein. In vivo, the stva genes were delivered and expressed in line 0 chicken embryos by the ALV(B)-based vector RCASBP(B). Viremic chickens expressed relatively high levels of stva and stva-mIgG RNA in a broad range of tissues. High levels of sTva-mIgG protein were detected in the sera of chickens infected with RCASBP(B)stva-mIgG. Viremic chickens infected with RCASBP(B) alone, RCASBP(B)stva, or RCASBP(B)stva-mIgG were challenged separately with ALV(A) and ALV(C). Both sTva and sTva-mIgG significantly inhibited infection by ALV(A) (95 and 100% respectively) but had no measurable effect on ALV(C) infection. The results of this study indicate that a soluble receptor can effectively block infection of at least some retroviruses and demonstrates the utility of the ALV experimental system in characterizing the mechanism(s) of viral entry.
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Affiliation(s)
- S L Holmen
- Molecular Medicine Program, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA
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38
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Abstract
The study of viral interference in HIV-1 infected cells has revealed several different means whereby infected cells resist superinfection. The most familiar of these, down-modulation of cellular receptors for virus, can be accomplished through the independent action of at least three HIV-1 proteins. Both the principal viral receptor CD4 and the chemokine receptors which serve as co-receptors are subject to down-modulation as a consequence of infection. Elucidation of the specificity of co-receptor utilisation by HIV-1 strains is an exciting, ongoing task which has opened new avenues to the understanding of viral replication and pathogenesis. Novel routes to resistance to superinfection have been discovered during HIV-1 infection and their investigation may reveal new pathways to control HIV-1 and the loss of immunological function with AIDS. Copyright 1998 John Wiley & Sons, Ltd.
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Affiliation(s)
- MJ Potash
- Molecular Virology Laboratory, St. Luke's-Roosevelt Hospital, Columbia University, 432 West 58th Street, New York, NY 10019, USA
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Gorbovitskaia M, Coville JL, Tixier-Boichard M. Molecular characterization of endogenous viral genes of the avian leukosis virus family in an experimental population of brown-egg layers. Poult Sci 1998; 77:605-14. [PMID: 9565246 DOI: 10.1093/ps/77.4.605] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Retroviral DNA sequences similar to the exogenous avian leukosis virus can be found in the genome of many chicken breeds and have been identified as the ALVE family of endogenous viral (ev) genes. Most of them have been described by a restriction fragment length polymorphism (RFLP) procedure with two restriction enzymes and a full length viral probe. In order to facilitate the comparison of ALVE genes between strains, the nomenclature workshop held at the XXIV International Society for Animal Genetics Congress recommended that four enzymes and several viral subprobes be used to characterize each locus. This approach has been followed in the present study of a Rhode Island Red experimental population. A previous study had identified ev genes with the SacI and BamHI enzymes and the Rous-associated virus-2 probe (RAV-2). Chickens carrying only one ALVE locus at a time have been produced to facilitate the analysis. Additional enzymes (EcoRI, HindIII, and KpnI), the full probe RAV-2 and three viral subprobes for the gag, pol, and LTR regions have been used. In addition, a PCR diagnostic test has been used to search for homologies with the ALVE1 (= ev1), ALVE6 (= ev6) and evA loci. Currently, 12 loci have been identified precisely: three were identical to ALVE loci described previously, either in White Leghorns, ALVE6 and ALVE18 (= ev18) or in broilers (evB8). In addition, the evB8 locus was found to be identical to the evA locus previously described in brown-egg layers. Nine loci appeared specific to this Rhode Island Red population. Four of these specific loci were complete and one of them could be considered of characteristic of this population, because of its very high frequency. The remaining five specific loci showed small deletions, either in the pol region for one of them or in the env region for three of them or at the 3' long terminal repeat for one of them. Altogether, 5 out of 12 loci were structurally complete, which could suggest that deleted proviruses may have been preferentially retained.
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Affiliation(s)
- M Gorbovitskaia
- Laboratoire de Génétique Factorielle, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
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Mayer J, Meese E, Mueller-Lantzsch N. Human endogenous retrovirus K homologous sequences and their coding capacity in Old World primates. J Virol 1998; 72:1870-5. [PMID: 9499038 PMCID: PMC109477 DOI: 10.1128/jvi.72.3.1870-1875.1998] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/1997] [Accepted: 12/03/1997] [Indexed: 02/06/2023] Open
Abstract
The coding capacity for retroviral Gag and Env proteins has been maintained in human endogenous retroviruses of the HERV-K family. HERV-K homologous sequences have been found in all Old World primates. Here, we examined Old World primate species for the presence of full-length HERV-K gag and env genes and the presence of gag and env open reading frames as determined by the protein truncation test. Full-length HERV-K env genes were found in DNAs of all Old World primate species, whereas open reading frames for Env protein were found solely in human, chimpanzee, and gorilla DNAs. The mutational event leading to two HERV-K types was found to have occurred after the separation of hominids from lower Old World primates and before the expansion of hominids. Full-length HERV-K gag genes in hominids displayed a 96-bp deletion compared to those in lower Old World primates. The ancient gag variant has not been maintained during hominid evolution. Open reading frames for HERV-K Gag have been found in all Old World primates except chimpanzees. Our study of the HERV-K family during Old World primate evolution contributes to the understanding of their possible biological functions in the host genomes.
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Affiliation(s)
- J Mayer
- Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universitätskliniken des Saarlandes, Homburg/Saar, Germany
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Best S, Le Tissier PR, Stoye JP. Endogenous retroviruses and the evolution of resistance to retroviral infection. Trends Microbiol 1997; 5:313-8. [PMID: 9263409 DOI: 10.1016/s0966-842x(97)01086-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The current AIDS epidemic has rekindled interest in the evolution of retroviruses and the development of resistance to infection. Retroviruses and their vertebrate hosts have coexisted for millions of years, during which time a variety of host defence mechanisms has evolved. One repeated strategy is to use endogenous retroviruses to combat infection by their exogenous relatives.
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Affiliation(s)
- S Best
- Wellcome Trust Centre for Human Genetics, Oxford, UK.
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Tixier-Boichard M, Boulliou-Robic A, Morisson M, Coquerelle G, Horst P, Benkel B. A deleted retroviral insertion at the ev21-K complex locus in Indonesian chickens. Poult Sci 1997; 76:733-42. [PMID: 9154627 DOI: 10.1093/ps/76.5.733] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Very poor feather development has been observed in chickens of the Nunukan strain, originating from Indonesia. The wing of the newly hatched chick does not show any primary or covert feathers; this phenotype will be referred to as very-late feathering (VLF). As adults, chickens are feathered but tail feathers are short and fragile. An experimental population was set up at the National Institute of Agronomic Research (INRA), Jouy-en-Josas, from one Nunukan male and four Nunukan females. Preliminary observations did not support the hypothesis of a sex-linked dominant mode of inheritance for the VLF phenotype. A restriction fragment length polymorphism (RFLP) study using five restriction enzymes and two probes, RAV-2 and endogenous virus (ev) ev21-int specific for the endogenous viral locus ALVE21, showed the presence of the expected 3' junction fragments for the ev21 occupied site but failed to reveal the expected 5' junction fragments for ev21 in Nunukan chickens. The unoccupied site corresponded to the ev21 unoccupied repeat (UR) of type a (URa). A deletion in the 5' region of the provirus and of the insertion site was indicated by the RFLP analysis and confirmed by a PCR study. Primers were designed in order to amplify a 5' junction fragment specific to the modified ev21 found in the Nunukan chickens. The sequence of this amplified product showed that the deletion started 652 bp upstream of the insertion site of ev21 and ended within the pol gene of the viral genome. This deletion represents a new allele, OSD, at the ev21 insertion site (locus ALVE21), that appears insufficient to produce a complete virus. Current data do not show a clear causal relationship between OSD and the VLF phenotype. The presence of OSD may be required but is not in itself sufficient to obtain the VLF phenotype. The genetic relationships between OSD and the altered feathering phenotype of Nunukan chickens will be investigated further in families segregating for the VLF phenotype, using the locus-specific PCR test developed as part of this study.
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Affiliation(s)
- M Tixier-Boichard
- Laboratoire de Génétique Factorielle, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
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Abstract
Retroviruses are distinguished from other viruses by several features. Notably, some retroviruses are present as normal elements in the genomes of virtually all vertebrates (endogenous proviruses). Others are exogenous, i.e. horizontally transmitted agents, many of which cause fatal diseases. The endogenous retroviruses are genetically transmitted and to a large extent their significance is uncertain. However, there is evidence suggesting that they contribute to the development of diseases in several animal species. Most importantly, some endogenous retroviruses are capable of interacting with exogenous counterparts through a variety of different mechanisms with serious consequences to the host. Conversely, others are advantageous in that they protect against exogenous retroviruses. In this review various types of interactions between endogenous and exogenous retroviruses are discussed, including receptor interference, recombination, phenotypic mixing, immunological interactions and heterologous trans-activation. Copyright 1997 S. Karger AG, Basel
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Affiliation(s)
- H.B. Rasmussen
- Department of Life Sciences and Chemistry, Roskilde University, Roskilde, Denmark
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44
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Miller AD. Cell-surface receptors for retroviruses and implications for gene transfer. Proc Natl Acad Sci U S A 1996; 93:11407-13. [PMID: 8876148 PMCID: PMC38070 DOI: 10.1073/pnas.93.21.11407] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Retroviruses can utilize a variety of cell-surface proteins for binding and entry into cells, and the cloning of several of these viral receptors has allowed refinement of models to explain retrovirus tropism. A single receptor appears to be necessary and sufficient for entry of many retroviruses, but exceptions to this simple model are accumulating. For example, HIV requires two proteins for cell entry, neither of which alone is sufficient; 10A1 murine leukemia virus can enter cells by using either of two distinct receptors; two retroviruses can use different receptors in some cells but use the same receptor for entry into other cells; and posttranslational protein modifications and secreted factors can dramatically influence virus entry. These findings greatly complicate the rules governing retrovirus tropism. The mechanism underlying retrovirus evolution to use many receptors for cell entry is not clear, although some evidence supports a mutational model for the evolution of new receptor specificities. Further study of factors that govern retrovirus entry into cells are important for achieving high-efficiency gene transduction to specific cells and for the design of retroviral vectors to target additional receptors for cell entry.
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Affiliation(s)
- A D Miller
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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Volsky DJ, Simm M, Shahabuddin M, Li G, Chao W, Potash MJ. Interference to human immunodeficiency virus type 1 infection in the absence of downmodulation of the principal virus receptor, CD4. J Virol 1996; 70:3823-33. [PMID: 8648718 PMCID: PMC190259 DOI: 10.1128/jvi.70.6.3823-3833.1996] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
It is thought that interference during human immunodeficiency virus type 1 (HIV-1) infection is established by downmodulation of the principal virus receptor, CD4. Here we present evidence to the contrary. At various times after primary infection, we superinfected T cells in vitro by exposure to a genetically distinct viral clone or to a virus carrying the chloramphenicol acetyltransferase gene. Replication of each virus strain was determined by restriction enzyme analysis of total cellular DNA, by PCR amplification of viral DNA, or by assay of cell extracts for chloramphenicol acetyltransferase activity. We found that efficient viral interference is established within 24 h of infection at a multiplicity of infection of 1. At that time, expression of viral structural proteins was low and infected cells displayed undiminished levels of surface CD4 and were fully susceptible to virus binding and fusion. Superinfection by either cell-free HIV-1 or cocultivation was blocked. Cells resistant to superinfection by HIV-1 remained susceptible to Moloney murine leukemia and vaccinia viruses. No interference was observed 4 h after primary infection or in cells infected with either UV-inactivated HIV-1 or a mutant virus defective in virus-cell fusion activity, indicating that binding of primary virus to CD4 is insufficient to prevent superinfection. The minimum viral requirements for this interference are that HIV-1 must be able to enter cells and synthesize viral DNA; Tat-mediated transcription is dispensable. Our results support the existence of a novel pathway to interference to HIV-1 infection, which we term postentry interference, which blocks superinfection during intracellular phases of the virus life cycle.
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Affiliation(s)
- D J Volsky
- Molecular Virology Laboratory, St. Luke's-Roosevelt Hospital Center, New York 10019, USA.
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Granowitz C, Berkowitz RD, Goff SP. Mutations affecting the cytoplasmic domain of the Moloney murine leukemia virus envelope protein: rapid reversion during replication. Virus Res 1996; 41:25-42. [PMID: 8725100 DOI: 10.1016/0168-1702(95)01278-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Five premature termination mutations and five missense mutations were introduced into the portion of cloned Moloney murine leukemia virus (M-MuLV) DNA encoding the Env cytoplasmic domain. All of the mutant DNAs gave rise to replication-competent virus after transfection of NIH/3T3 cells, but several of the mutant DNAs scored as replication-defective when introduced into Rat2 cells. Cell lines stably expressing the mutant DNAs all released virion particles, and in all but one case infectious virus were generated. These viable mutants were all found to have reverted to the wild-type sequence. To generate fully mutant virus stocks, the mutant DNAs were introduced transiently into COS cells, which are resistant to infection with MuLV, thus prohibiting reversion by error-prone mechanisms involving reverse transcription. Virions harvested from the COS cells were confirmed as mutant by analyzing both virion proteins and the viral DNA they generated, and were then tested for infectivity in NIH/3T3 cells. The mutant viruses were infectious, but still rapidly gave rise to revertants. We conclude that the mutations within the cytoplasmic domain do not provide an absolute block to virus replication, but that the mutants replicate more slowly than the wild-type and quickly give rise to revertants with selective advantage for replication.
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Affiliation(s)
- C Granowitz
- Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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47
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Nihrane A, Fujita K, Willey R, Lyu MS, Silver J. Murine leukemia virus envelope protein in transgenic-mouse serum blocks infection in vitro. J Virol 1996; 70:1882-9. [PMID: 8627713 PMCID: PMC190016 DOI: 10.1128/jvi.70.3.1882-1889.1996] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transgenic mice bearing a murine retroviral envelope transgene (Fv4) have Fv4 gp70env (SU) in their serum in amounts sufficient to block infection by ecotropic virus in vitro. Fv4 Env in serum is derived largely but not exclusively from hematopoietic cells. Tail cells from Fv4 mice and cell lines transduced with the Fv4 env transgene synthesize both components of the envelope protein (gp70 SU and p15E TM) but secrete the gp70 moiety, in the absence of retroviral particles. Blocking of the ecotropic viral receptor by secreted gp70 SU may contribute to resistance to retroviral infection in these mice.
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Affiliation(s)
- A Nihrane
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0460, USA
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48
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Aarts HJ, Leenstra FR. Association of endogenous avian viral and endogenous viral genes with feed conversion and six-week body weight in broilers. Poult Sci 1995; 74:1022-8. [PMID: 7543996 DOI: 10.3382/ps.0741022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The consistency of the effect of selection on the frequencies of endogenous avian viral (eav) and endogenous viral (ev) specific restriction fragment length polymorphism (RFLP) bands was studied in two broiler lines selected from a single base population and in an F2 population derived from a reciprocal cross of both lines. One broiler line (FC line) was selected for low feed conversion ratio and the other line (GL line) was selected for high 6-wk body weight. In the F2 population, the band frequencies were determined in groups representing separate tails of the distribution of two production traits, namely, low feed conversion ratio between 29 and 42 d of age and body weight at 42 d of age. The F2 population consisted of 288 females belonging to 24 full-sib families. To rule out family effects, the tails for these production traits were composed by either the best or by the worst female performer for each trait in each full-sib family. In total, 29 HindIII-eav, 34 MspI-eav, and 21 BamHI-ev bands could be distinguished by RFLP analysis. This report describes the influence of selection on 11 potentially interesting bands. Two bands, the 9.5-kb HindIII-eav and the 15-kb MspI-eav band, which were found both in higher frequencies in the parental FC line, were also found in higher (P < or = .05) frequencies in the F2 tail with a favorable feed conversion ratio. A third band, the 6.5-kb HindIII-eav band, present in lower frequencies in the parental GL line, was also present in lower (P < or = .05) frequencies in the F2 tail of birds with heavy body weight.
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Affiliation(s)
- H J Aarts
- DLO-Institute for Animal Science and Health, Beekbergen, The Netherlands
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49
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Bour S, Geleziunas R, Wainberg MA. The human immunodeficiency virus type 1 (HIV-1) CD4 receptor and its central role in promotion of HIV-1 infection. Microbiol Rev 1995; 59:63-93. [PMID: 7708013 PMCID: PMC239355 DOI: 10.1128/mr.59.1.63-93.1995] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Interactions between the viral envelope glycoprotein gp120 and the cell surface receptor CD4 are responsible for the entry of human immunodeficiency virus type 1 (HIV-1) into host cells in the vast majority of cases. HIV-1 replication is commonly followed by the disappearance or receptor downmodulation of cell surface CD4. This potentially renders cells nonsusceptible to subsequent infection by HIV-1, as well as by other viruses that use CD4 as a portal of entry. Disappearance of CD4 from the cell surface is mediated by several different viral proteins that act at various stages through the course of the viral life cycle, and it occurs in T-cell lines, peripheral blood CD4+ lymphocytes, and monocytes of both primary and cell line origin. At the cell surface, gp120 itself and in the form of antigen-antibody complexes can trigger cellular pathways leading to CD4 internalization. Intracellularly, the mechanisms leading to CD4 downmodulation by HIV-1 are multiple and complex; these include degradation of CD4 by Vpu, formation of intracellular complexes between CD4 and the envelope precursor gp160, and internalization by the Nef protein. Each of the above doubtless contributes to the ultimate depletion of cell surface CD4, although the relative contribution of each mechanism and the manner in which they interact remain to be definitively established.
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Affiliation(s)
- S Bour
- McGill AIDS Centre, Lady Davis Institute-Jewish General Hospital, Montreal, Quebec, Canada
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50
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Ronfort C, Chebloune Y, Cosset FL, Faure C, Nigon VM, Verdier G. Structure and expression of endogenous retroviral sequences in the permanent LMH chicken cell line. Poult Sci 1995; 74:127-35. [PMID: 7899200 DOI: 10.3382/ps.0740127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
From DNA mapping data, four endogenous proviral loci have been observed in the chicken permanent cell line LMH. The locus corresponding to endogenous virus (ev) ev1 is present in duplicate whereas the locus corresponding to ev3 is present in one copy. The other loci are probably ev6 and a solitary long terminal repeat. A RNA Northern blot analysis revealed both ev3 and ev6 transcripts but no ev1 transcript was detected. Using avian leukosis virus (ALV)-based vectors, transcomplementing assays were performed. They demonstrate the correct expression and maturation of endogenous env proteins and the absence of production of functional gag and pol components, indicating that these cells are not competent for viral production.
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Affiliation(s)
- C Ronfort
- Centre de Génétique Moléculaire et Cellulaire, CNRS UMR106, Université Claude Bernard, Villeurbanne, France
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