1
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Okhovat M, VanCampen J, Nevonen KA, Harshman L, Li W, Layman CE, Ward S, Herrera J, Wells J, Sheng RR, Mao Y, Ndjamen B, Lima AC, Vigh-Conrad KA, Stendahl AM, Yang R, Fedorov L, Matthews IR, Easow SA, Chan DK, Jan TA, Eichler EE, Rugonyi S, Conrad DF, Ahituv N, Carbone L. TAD evolutionary and functional characterization reveals diversity in mammalian TAD boundary properties and function. Nat Commun 2023; 14:8111. [PMID: 38062027 PMCID: PMC10703881 DOI: 10.1038/s41467-023-43841-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Topological associating domains (TADs) are self-interacting genomic units crucial for shaping gene regulation patterns. Despite their importance, the extent of their evolutionary conservation and its functional implications remain largely unknown. In this study, we generate Hi-C and ChIP-seq data and compare TAD organization across four primate and four rodent species and characterize the genetic and epigenetic properties of TAD boundaries in correspondence to their evolutionary conservation. We find 14% of all human TAD boundaries to be shared among all eight species (ultraconserved), while 15% are human-specific. Ultraconserved TAD boundaries have stronger insulation strength, CTCF binding, and enrichment of older retrotransposons compared to species-specific boundaries. CRISPR-Cas9 knockouts of an ultraconserved boundary in a mouse model lead to tissue-specific gene expression changes and morphological phenotypes. Deletion of a human-specific boundary near the autism-related AUTS2 gene results in the upregulation of this gene in neurons. Overall, our study provides pertinent TAD boundary evolutionary conservation annotations and showcases the functional importance of TAD evolution.
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Affiliation(s)
- Mariam Okhovat
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA.
| | - Jake VanCampen
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Kimberly A Nevonen
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Lana Harshman
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Weiyu Li
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Cora E Layman
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Samantha Ward
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Jarod Herrera
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Jackson Wells
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Rory R Sheng
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Yafei Mao
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Blaise Ndjamen
- Histology and Light Microscopy Core Facility, Gladstone Institutes, San Francisco, CA, USA
| | - Ana C Lima
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
| | | | - Alexandra M Stendahl
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
| | - Ran Yang
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
| | - Lev Fedorov
- OHSU Transgenic Mouse Models Core Lab, Oregon Health and Science University, Portland, OR, USA
| | - Ian R Matthews
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, CA, USA
| | - Sarah A Easow
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, CA, USA
| | - Dylan K Chan
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, CA, USA
| | - Taha A Jan
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA
| | - Sandra Rugonyi
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR, USA
| | - Donald F Conrad
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA.
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA.
| | - Lucia Carbone
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA.
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA.
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA.
- Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, OR, USA.
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2
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Liu M, Jia L, Guo X, Zhai X, Li H, Liu Y, Han J, Zhang B, Wang X, Li T, Wang Y, Li J, Yu C, Li L. Identification and Characterization of the HERV-K (HML-8) Group of Human Endogenous Retroviruses in the Genome. AIDS Res Hum Retroviruses 2023; 39:176-194. [PMID: 36656667 DOI: 10.1089/aid.2022.0084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Human endogenous retroviruses (HERVs) can be vertically transmitted in a Mendelian fashion, are stably maintained in the human genome, and are estimated to constitute ∼8% of the genome. HERVs affect human physiology and pathology through their provirus-encoded protein or long terminal repeat (LTR) element effect. Characterization of the genomic distribution is an essential step to understanding the relationships between endogenous retrovirus expression and diseases. However, the poor characterization of human MMTV-like (HML)-8 prevents a detailed understanding of the regulation of the expression of this family in humans and its impact on the host genome. In light of this, the definition of an accurate and updated HERV-K HML-8 genomic map is urgently needed. In this study, we report the results of a comprehensive analysis of HERV-K HML-8 sequence presence and distribution within the human genome and hominoids, with a detailed description of the different structural and phylogenetic aspects characterizing the group. A total of 40 proviruses and 5 solo LTR elements for human were characterized, which included a detailed description of provirus structure, integration time, potentially regulated genes, transcription factor-binding sites, and primer-binding site features. Besides, 9 chimpanzee sequences, 8 gorilla sequences, and 10 orangutan sequences belonging to the HML-8 subgroup were identified. The integration time results showed that the HML-8 elements were integrated into the primate lineage around 35 and 42 million years ago (mya), during primates evolutionary speciation. Overall, the results clarified the composition of the HML-8 groups, providing an exhaustive background for subsequent functional studies.
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Affiliation(s)
- Mengying Liu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Lei Jia
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Xing Guo
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China.,Department of Microbiology, School of Basic Medicine, Anhui Medical University, Hefei, China
| | - Xiuli Zhai
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China.,Department of Microbiology, School of Basic Medicine, Anhui Medical University, Hefei, China
| | - Hanping Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Yongjian Liu
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Jingwan Han
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Bohan Zhang
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Xiaolin Wang
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Tianyi Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Yanglan Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Jingyun Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Changyuan Yu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Lin Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
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3
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Okhovat M, VanCampen J, Lima AC, Nevonen KA, Layman CE, Ward S, Herrera J, Stendahl AM, Yang R, Harshman L, Li W, Sheng RR, Mao Y, Fedorov L, Ndjamen B, Vigh-Conrad KA, Matthews IR, Easow SA, Chan DK, Jan TA, Eichler EE, Rugonyi S, Conrad DF, Ahituv N, Carbone L. TAD Evolutionary and functional characterization reveals diversity in mammalian TAD boundary properties and function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.07.531534. [PMID: 36945527 PMCID: PMC10028908 DOI: 10.1101/2023.03.07.531534] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Topological associating domains (TADs) are self-interacting genomic units crucial for shaping gene regulation patterns. Despite their importance, the extent of their evolutionary conservation and its functional implications remain largely unknown. In this study, we generate Hi-C and ChIP-seq data and compare TAD organization across four primate and four rodent species, and characterize the genetic and epigenetic properties of TAD boundaries in correspondence to their evolutionary conservation. We find that only 14% of all human TAD boundaries are shared among all eight species (ultraconserved), while 15% are human-specific. Ultraconserved TAD boundaries have stronger insulation strength, CTCF binding, and enrichment of older retrotransposons, compared to species-specific boundaries. CRISPR-Cas9 knockouts of two ultraconserved boundaries in mouse models leads to tissue-specific gene expression changes and morphological phenotypes. Deletion of a human-specific boundary near the autism-related AUTS2 gene results in upregulation of this gene in neurons. Overall, our study provides pertinent TAD boundary evolutionary conservation annotations, and showcase the functional importance of TAD evolution.
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4
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Scognamiglio S, Grandi N, Pessiu E, Tramontano E. Identification, comprehensive characterization, and comparative genomics of the HERV-K(HML8) integrations in the human genome. Virus Res 2023; 323:198976. [PMID: 36309315 PMCID: PMC10194239 DOI: 10.1016/j.virusres.2022.198976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022]
Abstract
Around 8% of the human genome is composed by Human Endogenous Retroviruses (HERVs), ancient viral sequences inherited from the primate germ line after their infection by now extinct retroviruses. Given the still underexplored physiological and pathological roles of HERVs, it is fundamental to increase our information about the genomic composition of the different groups, to lay reliable foundation for functional studies. Among HERVs, the most characterized elements belong to the beta-like superfamily HERV-K, comprising 10 groups (HML1-10) with HML2 being the most recent and studied one. Among HMLs, the HML8 group is the only one still lacking a comprehensive genomic description. In the present work, we investigated HML8 sequences' distribution in the human genome (GRCh38/hg38), identifying 23 novel proviruses and characterizing the overall 78 HML8 proviruses in terms of genome structure, phylogeny, and integration pattern. HML8 elements were significantly enriched in human chromosomes 8 and X (p<0.005) while chromosomes 17 and 20 showed fewer integrations than expected (p<0.025 and p<0.005, respectively). Phylogenetic analyses classified HML8 members into 3 clusters, corresponding to the three LTR types MER11A, MER11B and MER11C. Besides different LTR types, common signatures in the internal structure suggested the potential existence of three different ancestral HML8 variants. Accordingly, time of integration estimation coupled with comparative genomics revealed that these three clusters have a different time of integration in the primates' genome, with MER11C elements being significantly younger than MER11A- and MER11B associated proviruses (p<0.005 and p<0.05, respectively). Approximately 30% of the HML8 elements were found co-localized within human genes, sometimes in exonic portions and with the same orientation, deserving further studies for their possible effects on gene expression. Overall, we provide the first detailed picture of the HML8 group distribution and variety among the genome, creating the backbone for the specific analysis of their transcriptional activity in healthy and diseased conditions.
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Affiliation(s)
- Sante Scognamiglio
- Department of Life and Environmental Sciences, Laboratory of Molecular Virology, University of Cagliari, Cittadella Universitaria di Monserrato, SS554, Monserrato, Cagliari 09042, Italy
| | - Nicole Grandi
- Department of Life and Environmental Sciences, Laboratory of Molecular Virology, University of Cagliari, Cittadella Universitaria di Monserrato, SS554, Monserrato, Cagliari 09042, Italy
| | - Eleonora Pessiu
- Department of Life and Environmental Sciences, Laboratory of Molecular Virology, University of Cagliari, Cittadella Universitaria di Monserrato, SS554, Monserrato, Cagliari 09042, Italy
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, Laboratory of Molecular Virology, University of Cagliari, Cittadella Universitaria di Monserrato, SS554, Monserrato, Cagliari 09042, Italy; Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche (CNR), Monserrato, Cagliari 09042, Italy.
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5
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Rangel SC, da Silva MD, da Silva AL, dos Santos JDMB, Neves LM, Pedrosa A, Rodrigues FM, Trettel CDS, Furtado GE, de Barros MP, Bachi ALL, Romano CM, Nali LHDS. Human endogenous retroviruses and the inflammatory response: A vicious circle associated with health and illness. Front Immunol 2022; 13:1057791. [PMID: 36518758 PMCID: PMC9744114 DOI: 10.3389/fimmu.2022.1057791] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/31/2022] [Indexed: 11/24/2022] Open
Abstract
Human Endogenous Retroviruses (HERVs) are derived from ancient exogenous retroviral infections that have infected our ancestors' germline cells, underwent endogenization process, and were passed throughout the generations by retrotransposition and hereditary transmission. HERVs comprise 8% of the human genome and are critical for several physiological activities. Yet, HERVs reactivation is involved in pathological process as cancer and autoimmune diseases. In this review, we summarize the multiple aspects of HERVs' role within the human genome, as well as virological and molecular aspects, and their fusogenic property. We also discuss possibilities of how the HERVs are possibly transactivated and participate in modulating the inflammatory response in health conditions. An update on their role in several autoimmune, inflammatory, and aging-related diseases is also presented.
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Affiliation(s)
- Sara Coelho Rangel
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | | | - Amanda Lopes da Silva
- Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo, Brazil
| | | | - Lucas Melo Neves
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | - Ana Pedrosa
- CNC-Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, (3004-504), Coimbra, Portugal
| | | | - Caio dos Santos Trettel
- Interdisciplinary Program in Health Sciences, Institute of Physical Activity Sciences and Sports (ICAFE), Cruzeiro do Sul University, São Paulo, Brazil
| | - Guilherme Eustáquio Furtado
- Polytechnic Institute of Coimbra, Applied Research Institute, Rua da Misericórdia, Lagar dos Cortiços – S. Martinho do Bispo, Coimbra, Portugal
| | - Marcelo Paes de Barros
- Interdisciplinary Program in Health Sciences, Institute of Physical Activity Sciences and Sports (ICAFE), Cruzeiro do Sul University, São Paulo, Brazil
| | - André Luis Lacerda Bachi
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | - Camila Malta Romano
- Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo, Brazil,Hospital das Clínicas HCFMUSP (LIM52), Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Luiz Henrique Da Silva Nali
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil,*Correspondence: Luiz Henrique Da Silva Nali, ;
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6
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Jia L, Liu M, Yang C, Li H, Liu Y, Han J, Zhai X, Wang X, Li T, Li J, Zhang B, Yu C, Li L. Comprehensive identification and characterization of the HERV-K (HML-9) group in the human genome. Retrovirology 2022; 19:11. [PMID: 35676699 PMCID: PMC9178832 DOI: 10.1186/s12977-022-00596-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/09/2022] [Indexed: 12/14/2022] Open
Abstract
Background Human endogenous retroviruses (HERVs) result from ancestral infections caused by exogenous retroviruses that became incorporated into the germline DNA and evolutionarily fixed in the human genome. HERVs can be transmitted vertically in a Mendelian fashion and be stably maintained in the human genome, of which they are estimated to comprise approximately 8%. HERV-K (HML1-10) transcription has been confirmed to be associated with a variety of diseases, such as breast cancer, lung cancer, prostate cancer, melanoma, rheumatoid arthritis, and amyotrophic lateral sclerosis. However, the poor characterization of HML-9 prevents a detailed understanding of the regulation of the expression of this family in humans and its impact on the host genome. In light of this, a precise and updated HERV-K HML-9 genomic map is urgently needed to better evaluate the role of these elements in human health. Results We report a comprehensive analysis of the presence and distribution of HERV-K HML-9 elements within the human genome, with a detailed characterization of the structural and phylogenetic properties of the group. A total of 23 proviruses and 47 solo LTR elements were characterized, with a detailed description of the provirus structure, integration time, potential regulated genes, transcription factor binding sites (TFBS), and primer binding site (PBS) features. The integration time results showed that the HML-9 elements found in the human genome integrated into the primate lineage between 17.5 and 48.5 million years ago (mya). Conclusion The results provide a clear characterization of HML-9 and a comprehensive background for subsequent functional studies. Supplementary Information The online version contains supplementary material available at 10.1186/s12977-022-00596-2.
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Affiliation(s)
- Lei Jia
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Mengying Liu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Caiqin Yang
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Hanping Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Yongjian Liu
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Jingwan Han
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Xiuli Zhai
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Xiaolin Wang
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Tianyi Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Jingyun Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Bohan Zhang
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China
| | - Changyuan Yu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Lin Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China. .,State Key Laboratory of Pathogen and Biosecurity, Beijing, 100071, China.
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7
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van der Kuyl AC. Analysis of Simian Endogenous Retrovirus (SERV) Full-Length Proviruses in Old World Monkey Genomes. Genes (Basel) 2022; 13:119. [PMID: 35052460 PMCID: PMC8775094 DOI: 10.3390/genes13010119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/20/2021] [Accepted: 01/06/2022] [Indexed: 02/05/2023] Open
Abstract
Simian endogenous retrovirus, SERV, is a successful germ line invader restricted to Old World monkey (OWM) species. (1) Background: The availability of high-quality primate genomes warrants a study of the characteristics, evolution, and distribution of SERV proviruses. (2) Methods: Cercopithecinae OWM genomes from public databases were queried for the presence of full-length SERV proviruses. A dataset of 81 Cer-SERV genomes was generated and analyzed. (3) Results: Full-length Cer-SERV proviruses were mainly found in terrestrial OWM, and less so in arboreal, forest- dwelling monkeys. Phylogenetic analysis confirmed the existence of two genotypes, Cer-SERV-1 and Cer-SERV-2, with Cer-SERV-1 showing evidence of recent germ-line expansions. Long Terminal Repeat (LTR) variation indicated that most proviruses were of a similar age and were estimated to be between <0.3 and 10 million years old. Integrations shared between species were relatively rare. Sequence analysis further showed extensive CpG methylation-associated mutations, variable Primer Binding Site (PBS) use with Cer-SERV-1 using PBSlys3 and Cer-SERV-2 using PBSlys1,2, and the recent gain of LTR motifs for transcription factors active during embryogenesis in Cer-SERV-1. (4) Conclusions: sequence analysis of 81 SERV proviruses from Cercopithecinae OWM genomes provides evidence for the adaptation of this retrovirus to germ line reproduction.
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Affiliation(s)
- Antoinette C van der Kuyl
- Laboratory of Experimental Virology, Department of Medical Microbiology and Infection Prevention, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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8
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Grandi N, Pisano MP, Pessiu E, Scognamiglio S, Tramontano E. HERV-K(HML7) Integrations in the Human Genome: Comprehensive Characterization and Comparative Analysis in Non-Human Primates. BIOLOGY 2021; 10:biology10050439. [PMID: 34069102 PMCID: PMC8156875 DOI: 10.3390/biology10050439] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/18/2022]
Abstract
Simple Summary The human genome is not human at all, but it includes a multitude of sequences inherited from ancient viral infections that affected primates’ germ line. These elements can be seen as the fossils of now-extinct retroviruses, and are called Human Endogenous Retroviruses (HERVs). View as “junk DNA” for a long time, HERVs constitute 4 times the amount of DNA needed to produce all cellular proteins, and growing evidence indicates their crucial role in primate brain evolution, placenta development, and innate immunity shaping. HERVs are also intensively studied for a pathological role, even if the incomplete knowledge about their exact number and genomic position has thus far prevented any causal association. Among possible relevant HERVs, the HERV-K supergroup is of particular interest, including some of the oldest (HML5) as well as youngest (HML2) integrations. Among HERV-Ks, the HML7 group still lack a detailed description, and the present work thus aimed to identify and characterize all HML7 elements in the human genome. Results showed that the HML7 group includes 23 elements and an additional 160 “scars” of past infection that invaded in primates mostly between 20 and 30 million years ago, providing an exhaustive background to study their impact on human pathophysiology. Abstract Endogenous Retroviruses (ERVs) are ancient relics of infections that affected the primate germ line and constitute about 8% of our genome. Growing evidence indicates that ERVs had a major role in vertebrate evolution, being occasionally domesticated by the host physiology. In addition, human ERV (HERV) expression is highly investigated for a possible pathological role, even if no clear associations have been reported yet. In fact, on the one side, the study of HERV expression in high-throughput data is a powerful and promising tool to assess their actual dysregulation in diseased conditions; but, on the other side, the poor knowledge about the various HERV group genomic diversity and individual members somehow prevented the association between specific HERV loci and a given molecular mechanism of pathogenesis. The present study is focused on the HERV-K(HML7) group that—differently from the other HERV-K members—still remains poorly characterized. Starting from an initial identification performed with the software RetroTector, we collected 23 HML7 proviral insertions and about 160 HML7 solitary LTRs that were analyzed in terms of genomic distribution, revealing a significant enrichment in chromosome X and the frequent localization within human gene introns as well as in pericentromeric and centromeric regions. Phylogenetic analyses showed that HML7 members form a monophyletic group, which based on age estimation and comparative localization in non-human primates had its major diffusion between 20 and 30 million years ago. Structural characterization revealed that besides 3 complete HML7 proviruses, the other group members shared a highly defective structure that, however, still presents recognizable functional domains, making it worth further investigation in the human population to assess the presence of residual coding potential.
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Affiliation(s)
- Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Monserrato, Cagliari, Italy; (M.P.P.); (E.P.); (S.S.); (E.T.)
- Correspondence:
| | - Maria Paola Pisano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Monserrato, Cagliari, Italy; (M.P.P.); (E.P.); (S.S.); (E.T.)
| | - Eleonora Pessiu
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Monserrato, Cagliari, Italy; (M.P.P.); (E.P.); (S.S.); (E.T.)
| | - Sante Scognamiglio
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Monserrato, Cagliari, Italy; (M.P.P.); (E.P.); (S.S.); (E.T.)
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Monserrato, Cagliari, Italy; (M.P.P.); (E.P.); (S.S.); (E.T.)
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche (CNR), 09042 Monserrato, Cagliari, Italy
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Mayer J, Harz C, Sanchez L, Pereira GC, Maldener E, Heras SR, Ostrow LW, Ravits J, Batra R, Meese E, García-Pérez JL, Goodier JL. Transcriptional profiling of HERV-K(HML-2) in amyotrophic lateral sclerosis and potential implications for expression of HML-2 proteins. Mol Neurodegener 2018; 13:39. [PMID: 30068350 PMCID: PMC6091006 DOI: 10.1186/s13024-018-0275-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 07/23/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder. About 90% of ALS cases are without a known genetic cause. The human endogenous retrovirus multi-copy HERV-K(HML-2) group was recently reported to potentially contribute to neurodegeneration and disease pathogenesis in ALS because of transcriptional upregulation and toxic effects of HML-2 Envelope (Env) protein. Env and other proteins are encoded by some transcriptionally active HML-2 loci. However, more detailed information is required regarding which HML-2 loci are transcribed in ALS, which of their proteins are expressed, and differences between the disease and non-disease states. METHODS For brain and spinal cord tissue samples from ALS patients and controls, we identified transcribed HML-2 loci by generating and mapping HML-2-specific cDNA sequences. We predicted expression of HML-2 env gene-derived proteins based on the observed cDNA sequences. Furthermore, we determined overall HML-2 transcript levels by RT-qPCR and investigated presence of HML-2 Env protein in ALS and control tissue samples by Western blotting. RESULTS We identified 24 different transcribed HML-2 loci. Some of those loci are transcribed at relatively high levels. However, significant differences in HML-2 loci transcriptional activities were not seen when comparing ALS and controls. Likewise, overall HML-2 transcript levels, as determined by RT-qPCR, were not significantly different between ALS and controls. Indeed, we were unable to detect full-length HML-2 Env protein in ALS and control tissue samples despite reasonable sensitivity. Rather our analyses suggest that a number of HML-2 protein variants other than full-length Env may potentially be expressed in ALS patients. CONCLUSIONS Our results expand and refine recent publications on HERV-K(HML-2) and ALS. Some of our results are in conflict with recent findings and call for further specific analyses. Our profiling of HML-2 transcription in ALS opens up the possibility that HML-2 proteins other than canonical full-length Env may have to be considered when studying the role of HML-2 in ALS disease.
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Affiliation(s)
- Jens Mayer
- Department of Human Genetics, University of Saarland, Homburg, Germany
| | - Christian Harz
- Department of Human Genetics, University of Saarland, Homburg, Germany
| | - Laura Sanchez
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - Gavin C. Pereira
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Esther Maldener
- Department of Human Genetics, University of Saarland, Homburg, Germany
| | - Sara R. Heras
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
| | - Lyle W. Ostrow
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 28217 USA
| | - John Ravits
- Department of Neurosciences, School of Medicine, UCSD, San Diego, CA USA
| | - Ranjan Batra
- Department of Neurosciences, School of Medicine, UCSD, San Diego, CA USA
| | - Eckart Meese
- Department of Human Genetics, University of Saarland, Homburg, Germany
| | - Jose Luis García-Pérez
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - John L. Goodier
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
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Turnbull MG, Douville RN. Related Endogenous Retrovirus-K Elements Harbor Distinct Protease Active Site Motifs. Front Microbiol 2018; 9:1577. [PMID: 30072963 PMCID: PMC6058741 DOI: 10.3389/fmicb.2018.01577] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/25/2018] [Indexed: 02/06/2023] Open
Abstract
Background: Endogenous retrovirus-K is a group of related genomic elements descending from retroviral infections in human ancestors. HML2 is the clade of these viruses which contains the most intact provirus copies. These elements can be transcribed and translated in healthy and diseased tissues, and some of them produce active retroviral enzymes, such as protease. Retroviral gene products, including protease, contribute to illness in exogenous retroviral infections. There are ongoing efforts to test anti-retroviral regimens against endogenous retroviruses. Herein, we examine the potential activity and diversity of human endogenous retrovirus-K proteases, and their potential for impact on immunity and human disease. Results: Sequences similar to the endogenous retrovirus-K HML2 protease and reverse transcriptase were identified in the human genome, classified by phylogenetic inference and compared to Repbase reference sequences. The topologies of trees inferred from protease and reverse transcriptase sequences were similar and agreed with the classification using reference sequences. Surprisingly, only 62/480 protease sequences identified by BLAST were classified as HML2; the remainder were classified as other HML groups, with the majority (216) classified as HML3. Variation in functionally significant protease motifs was explored, and two major active site variants were identified – the DTGAD variant is common in all groups, but the DTGVD motif appears limited to HML3, HML5, and HML6. Furthermore, distinct RNA expression patterns of protease variants are seen in disease states, such as amyotrophic lateral sclerosis, breast cancer, and prostate cancer. Conclusion: Transcribed ERVK proteases exhibit a diversity which could impact immunity and inhibitor-based treatments, and these facets should be considered when designing therapeutic regimens.
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Affiliation(s)
| | - Renée N Douville
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada.,Department of Immunology, University of Manitoba, Winnipeg, MB, Canada
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11
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Broecker F, Horton R, Heinrich J, Franz A, Schweiger MR, Lehrach H, Moelling K. The intron-enriched HERV-K(HML-10) family suppresses apoptosis, an indicator of malignant transformation. Mob DNA 2016; 7:25. [PMID: 27980690 PMCID: PMC5142424 DOI: 10.1186/s13100-016-0081-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 11/19/2016] [Indexed: 02/06/2023] Open
Abstract
Background Human endogenous retroviruses (HERVs) constitute 8% of the human genome and contribute substantially to the transcriptome. HERVs have been shown to generate RNAs that modulate host gene expression. However, experimental evidence for an impact of these regulatory transcripts on the cellular phenotype has been lacking. Results We characterized the previously little described HERV-K(HML-10) endogenous retrovirus family on a genome-wide scale. HML-10 invaded the ancestral genome of Old World monkeys about 35 Million years ago and is enriched within introns of human genes when compared to other HERV families. We show that long terminal repeats (LTRs) of HML-10 exhibit variable promoter activity in human cancer cell lines. One identified HML-10 LTR-primed RNA was in opposite orientation to the pro-apoptotic Death-associated protein 3 (DAP3). In HeLa cells, experimental inactivation of HML-10 LTR-primed transcripts induced DAP3 expression levels, which led to apoptosis. Conclusions Its enrichment within introns suggests that HML-10 may have been evolutionary co-opted for gene regulation more than other HERV families. We demonstrated such a regulatory activity for an HML-10 RNA that suppressed DAP3-mediated apoptosis in HeLa cells. Since HML-10 RNA appears to be upregulated in various tumor cell lines and primary tumor samples, it may contribute to evasion of apoptosis in malignant cells. However, the overall weak expression of HML-10 transcripts described here raises the question whether our result described for HeLa represent a rare event in cancer. A possible function in other cells or tissues requires further investigation. Electronic supplementary material The online version of this article (doi:10.1186/s13100-016-0081-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Felix Broecker
- Max Planck Institute for molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany ; Institute of Medical Microbiology, University of Zurich, Gloriastr. 32, 8006 Zurich, Switzerland ; Current affiliation: Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany
| | - Roger Horton
- Max Planck Institute for molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany
| | - Jochen Heinrich
- Institute of Medical Microbiology, University of Zurich, Gloriastr. 32, 8006 Zurich, Switzerland
| | - Alexandra Franz
- Max Planck Institute for molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany ; Current affiliation: University of Zurich, Institute of Molecular Life Sciences, Winterthurerstr. 190, 8057 Zurich, Switzerland
| | - Michal-Ruth Schweiger
- Max Planck Institute for molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany ; Current affiliation: Functional Epigenomics, CCG, Cologne University Hospital, University of Cologne, Weyertal 115b, 50931 Cologne, Germany
| | - Hans Lehrach
- Max Planck Institute for molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany ; Dahlem Centre for Genome Research and Medical Systems Biology, Fabeckstr. 60-62, 14195 Berlin, Germany
| | - Karin Moelling
- Max Planck Institute for molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany ; Institute of Medical Microbiology, University of Zurich, Gloriastr. 32, 8006 Zurich, Switzerland
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Hanke K, Hohn O, Bannert N. HERV-K(HML-2), a seemingly silent subtenant - but still waters run deep. APMIS 2016; 124:67-87. [PMID: 26818263 DOI: 10.1111/apm.12475] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/12/2015] [Indexed: 01/26/2023]
Abstract
A large proportion of the human genome consists of endogenous retroviruses, some of which are well preserved, showing transcriptional activity, and expressing retroviral proteins. The HERV-K(HML-2) family represents the most intact members of these elements, with some having open and intact reading frames for viral proteins and the ability to form virus-like particles. Although generally suppressed in most healthy tissues by a variety of epigenetic processes and antiviral mechanisms, there is evidence that some members of this family are (at least partly) still active - particularly in certain stem cells and various tumors. This raises the possibility of their involvement in tumor induction or in developmental processes. In recent years, many new insights into this fascinating field have been attained, and this review focuses on new discoveries about coevolutionary events and intracellular defense mechanisms against HERV-K(HML-2) activity. We also describe what might occur when these mechanisms fail or become modulated by viral proteins or other viruses and discuss the new vistas opened up by the reconstitution of ancestral viral proteins and even complete HML-2 viruses.
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Affiliation(s)
- Kirsten Hanke
- Department HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
| | - Oliver Hohn
- Department HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
| | - Norbert Bannert
- Department HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
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13
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Hohn O, Hanke K, Bannert N. HERV-K(HML-2), the Best Preserved Family of HERVs: Endogenization, Expression, and Implications in Health and Disease. Front Oncol 2013; 3:246. [PMID: 24066280 PMCID: PMC3778440 DOI: 10.3389/fonc.2013.00246] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 09/05/2013] [Indexed: 12/14/2022] Open
Abstract
Retroviruses that have the ability to infect germ line cells can become an integral and inherited part of the host genome. About 8% of the human chromosomal DNA consists of sequences derived from infections by retroviruses that presumably circulated 2-40 millions of years ago, and some elements are actually much older. Post-insertional recombinations, deletions, and mutations have rendered all known human endogenous retroviruses (HERVs) non-infectious. However some, particularly the most recently acquired proviruses of the HERV-K(HML-2) family, can expresses viral proteins and produce viral particles. In this review we will first discuss the major aspects of the endogenization process and peculiarities of the different HERV-K families. We will then focus on the genes and proteins encoded by HERV-K(HML-2) as well as inactivation of these proviruses by postinsertional mutations and their inhibition by antiretroviral factors. After describing the evolutionary interplay between host and endogenous retrovirus we will delve deeper into the currently limited understanding of HERV-K and its possible association with disease, particularly tumorigenesis.
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Affiliation(s)
- Oliver Hohn
- Division for HIV and Other Retroviruses, Robert Koch Institute , Berlin , Germany
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14
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Lee A, Nolan A, Watson J, Tristem M. Identification of an ancient endogenous retrovirus, predating the divergence of the placental mammals. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120503. [PMID: 23938752 PMCID: PMC3758187 DOI: 10.1098/rstb.2012.0503] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evolutionary arms race between mammals and retroviruses has long been recognized as one of the oldest host-parasite interactions. Rapid evolution rates in exogenous retroviruses have often made accurate viral age estimations highly problematic. Endogenous retroviruses (ERVs), however, integrate into the germline of their hosts, and are subjected to their evolutionary rates. This study describes, for the first time, a retroviral orthologue predating the divergence of placental mammals, giving it a minimum age of 104-110 Myr. Simultaneously, other orthologous selfish genetic elements (SGEs), inserted into the ERV sequence, provide evidence for the oldest individual mammalian-wide interspersed repeat and medium-reiteration frequency interspersed repeat mammalian repeats, with the same minimum age. The combined use of shared SGEs and reconstruction of viral orthologies defines new limits and increases maximum 'lookback' times, with subsequent implications for the field of paleovirology.
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Affiliation(s)
- Adam Lee
- Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Alison Nolan
- Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| | - Jason Watson
- Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| | - Michael Tristem
- Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
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15
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Betaretroviral envelope subunits are noncovalently associated and restricted to the mammalian class. J Virol 2012; 87:1937-46. [PMID: 23221553 DOI: 10.1128/jvi.01442-12] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The structure of the transmembrane subunit (TM) of the retroviral envelope glycoprotein (Env) is highly conserved among most retrovirus genera and includes a pair of cysteines that forms an intramolecular disulfide loop within the ectodomain. Alpha-, gamma-, and deltaretroviruses have a third cysteine, adjacent to the loop, which forms a disulfide bond between TM and the surface subunit (SU) of Env, while lentiviruses, which have noncovalently associated subunits, lack this third cysteine. The Betaretrovirus genus includes Jaagsiekte sheep retrovirus (JSRV) and mouse mammary tumor virus (MMTV), as well as many endogenous retroviruses. Envelope subunit association had not been characterized in the betaretroviruses, but lack of a third cysteine in the TM ectodomain suggested noncovalently associated subunits. We tested the Env proteins of JSRV and MMTV, as well as human endogenous retrovirus K (HERV-K)108--a betaretrovirus-like human endogenous retrovirus--for intersubunit bonding and found that, as in the lentiviruses, the Env subunits lack an intersubunit disulfide bond. Since these results suggest that the number of cysteines in the TM loop region readily distinguishes between covalent and noncovalent structure, we surveyed endogenous retroviral TM sequences in the genomes of vertebrates represented in public databases and found that (i) retroviruses with noncovalently associated subunits have been present during all of anthropoid evolution and (ii) the noncovalent env motif is limited to mammals, while the covalent type is found among five vertebrate classes. We discuss implications of these findings for retroviral evolution, cross-species transmissions, and recombination events involving the env gene.
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16
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Age- and disease-dependent HERV-W envelope allelic variation in brain: association with neuroimmune gene expression. PLoS One 2011; 6:e19176. [PMID: 21559469 PMCID: PMC3084769 DOI: 10.1371/journal.pone.0019176] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 03/22/2011] [Indexed: 12/27/2022] Open
Abstract
Background The glycoprotein, Syncytin-1, is encoded by a human endogenous retrovirus (HERV)-W env gene and is capable of inducing neuroinflammation. The specific allele(s) responsible for Syncytin-1 expression in the brain is uncertain. Herein, HERV-W env diversity together with Syncytin-1 abundance and host immune gene profiles were examined in the nervous system using a multiplatform approach. Results HERV-W env sequences were encoded by multiple chromosomal encoding loci in primary human neurons compared with less chromosomal diversity in astrocytes and microglia (p<0.05). HERV-W env RNA sequences cloned from brains of patients with systemic or neurologic diseases were principally derived from chromosomal locus 7q21.2. Within the same specimens, HERV-W env transcript levels were correlated with the expression of multiple proinflammatory genes (p<0.05). Deep sequencing of brain transcriptomes disclosed the env transcripts to be the most abundant HERV-W transcripts, showing greater expression in fetal compared with healthy adult brain specimens. Syncytin-1's expression in healthy brain specimens was derived from multiple encoding loci and linked to distinct immune and developmental gene profiles. Conclusions Syncytin-1 expression in the brain during disease was associated with neuroinflammation and was principally encoded by a full length provirus. The present studies also highlighted the diversity in HERV gene expression within the brain and reinforce the potential contributions of HERV expression to neuroinflammatory diseases.
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Douville R, Liu J, Rothstein J, Nath A. Identification of active loci of a human endogenous retrovirus in neurons of patients with amyotrophic lateral sclerosis. Ann Neurol 2011; 69:141-51. [PMID: 21280084 DOI: 10.1002/ana.22149] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Amyotrophic lateral sclerosis (ALS) is characterized by the progressive loss of motor neurons, of unknown etiology. Previous studies showed reverse transcriptase in serum of ALS patients at levels comparable to human immunodeficiency virus-infected patients; however, the source and significance of the retroviral elements is uncertain. METHODS Expression of a human endogenous retrovirus (HERV-K) was determined in autopsy brain tissue of patients with ALS and compared to control populations by real-time polymerase chain reaction followed by sequencing of the amplified genes and confirmed by immunostaining. RESULTS HERV-K pol transcripts were increased in patients with ALS compared to those with chronic systemic illness, but could not be detected in Parkinson disease or in the accidental death controls. Sequencing revealed several actively transcribed loci in the HML-2 and 3 subfamilies of HERV-K, with a specific pattern of expression including intact open reading frames and the transcription of a unique locus in ALS. The frequency of intact pol transcripts was highest in the motor cortex, and the reverse transcriptase protein was localized to cortical neurons of ALS patients. HERV-K expression strongly correlated with TDP-43, a multifunctional protein known to be dysregulated in ALS. INTERPRETATION We have identified a specific pattern of HERV-K expression in ALS, which may potentially define the pathophysiology of ALS. Targeting of activated genome-encoded retroviral elements may open new prospects for the treatment of ALS.
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Affiliation(s)
- Renée Douville
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
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18
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Distinct retroelement classes define evolutionary breakpoints demarcating sites of evolutionary novelty. BMC Genomics 2009; 10:334. [PMID: 19630942 PMCID: PMC2736999 DOI: 10.1186/1471-2164-10-334] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Accepted: 07/24/2009] [Indexed: 11/30/2022] Open
Abstract
Background Large-scale genome rearrangements brought about by chromosome breaks underlie numerous inherited diseases, initiate or promote many cancers and are also associated with karyotype diversification during species evolution. Recent research has shown that these breakpoints are nonrandomly distributed throughout the mammalian genome and many, termed "evolutionary breakpoints" (EB), are specific genomic locations that are "reused" during karyotypic evolution. When the phylogenetic trajectory of orthologous chromosome segments is considered, many of these EB are coincident with ancient centromere activity as well as new centromere formation. While EB have been characterized as repeat-rich regions, it has not been determined whether specific sequences have been retained during evolution that would indicate previous centromere activity or a propensity for new centromere formation. Likewise, the conservation of specific sequence motifs or classes at EBs among divergent mammalian taxa has not been determined. Results To define conserved sequence features of EBs associated with centromere evolution, we performed comparative sequence analysis of more than 4.8 Mb within the tammar wallaby, Macropus eugenii, derived from centromeric regions (CEN), euchromatic regions (EU), and an evolutionary breakpoint (EB) that has undergone convergent breakpoint reuse and past centromere activity in marsupials. We found a dramatic enrichment for long interspersed nucleotide elements (LINE1s) and endogenous retroviruses (ERVs) and a depletion of short interspersed nucleotide elements (SINEs) shared between CEN and EBs. We analyzed the orthologous human EB (14q32.33), known to be associated with translocations in many cancers including multiple myelomas and plasma cell leukemias, and found a conserved distribution of similar repetitive elements. Conclusion Our data indicate that EBs tracked within the class Mammalia harbor sequence features retained since the divergence of marsupials and eutherians that may have predisposed these genomic regions to large-scale chromosomal instability.
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Blomberg J, Benachenhou F, Blikstad V, Sperber G, Mayer J. Classification and nomenclature of endogenous retroviral sequences (ERVs): problems and recommendations. Gene 2009; 448:115-23. [PMID: 19540319 DOI: 10.1016/j.gene.2009.06.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2009] [Revised: 06/09/2009] [Accepted: 06/12/2009] [Indexed: 01/27/2023]
Abstract
The genomes of many species are crowded with repetitive mobile sequences. In the case of endogenous retroviruses (ERVs) there is, for various reasons, considerable confusion regarding names assigned to families/groups of ERVs as well as individual ERV loci. Human ERVs have been studied in greater detail, and naming of HERVs in the scientific literature is somewhat confusing not just to the outsider. Without guidelines, confusion for ERVs in other species will also probably increase if those ERVs are studied in greater detail. Based on previous experience, this review highlights some of the problems when naming and classifying ERVs, and provides some guidance for detecting and characterizing ERV sequences. Because of the close relationship between ERVs and exogenous retroviruses (XRVs) it is reasonable to reconcile their classification with that of XRVs. We here argue that classification should be based on a combination of similarity, structural features, (inferred) function, and previous nomenclature. Because the RepBase system is widely employed in genome annotation, RepBase designations should be considered in further taxonomic efforts. To lay a foundation for a phylogenetically based taxonomy, further analyses of ERVs in many hosts are needed. A dedicated, permanent, international consortium would best be suited to integrate and communicate our current and future knowledge on repetitive, mobile elements in general to the scientific community.
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Affiliation(s)
- Jonas Blomberg
- Section of Virology, Department of Medical Sciences, Academic Hospital, 75185 Uppsala, Sweden.
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20
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Abstract
Infection of germline cells with retroviruses initiates permanent proviral colonization of the germline genome. The germline-integrated proviruses, called endogenous retroviruses (ERVs), are inherited to offspring in a Mendelian order and belong to the transposable element family. Endogenous retroviruses and other long terminal repeat retroelements constitute ~8% and ~10% of the human and mouse genomes, respectively. It is likely that each individual has a distinct genomic ERV profile. Recent studies have revealed that a substantial fraction of ERVs retains the coding potentials necessary for virion assembly and replication. There are several layers of potential mechanisms controlling ERV expression: intracellular transcription environment (e.g., transcription factor pool, splicing machinery, hormones), epigenetic status of the genome (e.g., proviral methylation, histone acetylation), profile of transcription regulatory elements on each ERV's promoter, and a range of stress signals (e.g., injury, infection, environment). Endogenous retroviruses may exert pathophysiologic effects by infection followed by random reintegration into the genome, by their gene products (e.g., envelope, superantigen), and by altering the expression of neighboring genes. Several studies have provided evidence that ERVs are associated with a range of pathogenic processes involving multiple sclerosis, systemic lupus erythematosus, breast cancer, and the response to burn injury. For instance, the proinflammatory properties of the human ERV-W envelope protein play a central role in demyelination of oligodendrocytes. As reviewed in this article, recent advances in ERV biology and mammalian genomics suggest that ERVs may have a profound influence on various pathogenic processes including the response to injury and infection. Understanding the roles of ERVs in the pathogenesis of injury and infection will broaden insights into the underlying mechanisms of systemic immune disorder and organ failure in these patients.
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Abstract
The capacity to integrate into the chromosomal DNA of germ-line cells has endowed retroviruses with the potential to be vertically transmitted from generation to generation and eventually become fixed in the genomes of the entire population. This has been independently accomplished by several ancient retroviruses that invaded the genomes of our early and more recent primate and hominoid ancestors. Some of the inherited elements then proliferated in the genome, resulting in a number of lineages with complex phylogenetic patterns. Although the vast majority of chromosomally integrated retroelements have suffered inactivating mutations and deletions, a significant impact on various aspects of human biology has been recently revealed and evidence for the present activity of at least one human endogenous retrovirus family continues to accumulate.
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Romano CM, Ramalho RF, Zanotto PMDA. Tempo and mode of ERV-K evolution in human and chimpanzee genomes. Arch Virol 2006; 151:2215-28. [PMID: 16830071 DOI: 10.1007/s00705-006-0792-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Accepted: 04/24/2006] [Indexed: 11/25/2022]
Abstract
Several families of endogenous retrovirus (ERV) exist in copious numbers in the genomes of primate species. Therefore, we undertook a systematic search for endogenous retrovirus sequences from the ERV-K family, comparing across both human (Homo sapiens) and chimpanzee (Pan troglodytes) genomes. Using conserved motifs of the ERV-K as query we identified and characterized 76 complete ERV-K elements, 54 in human (HERV-K), 34 of which were described previously, and 21 in the chimpanzee (CERV-K). Phylogenetic analysis using coding regions and LTRs showed the existence of two main branches. Group I was the most heterogeneous and had an average integration time of 18.3 MYBP (million years before present), using rates ranging from 1.5 to 4.0 x 10(-9) s/s/y (substitution per site per year). Group O/N integrated around 19.4 MYBP and nested Group N integrated about 14 MYBP. We found evidence for strong positive selection on the gag, pol and env coding regions and for A/T hypermutation. Our data suggest that the endogenous elements were possibly involved in chromosomal rearrangements and retained a great deal of information from their active stage, most likely as a consequence of host interactions. This study also contributes to the annotation effort of both human and chimpanzee genomes.
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Affiliation(s)
- C M Romano
- Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Biomedical Sciences Institute - ICB II, University of São Paulo, São Paulo, Brazil
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23
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Mayer J, Meese E. Human endogenous retroviruses in the primate lineage and their influence on host genomes. Cytogenet Genome Res 2005; 110:448-56. [PMID: 16093697 DOI: 10.1159/000084977] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 01/30/2004] [Indexed: 10/25/2022] Open
Abstract
Primates emerged about 60 million years ago. Since that time various primate-targeting retroviruses have integrated in the germ line of primate species, and some drifted to fixation. After germ line fixation, continued activity of proviruses resulted in intragenomic spread of so-called endogenous retroviruses (ERVs). Variant ERVs emerged, amplified in the genome and profoundly altered genome structures and potentially functionality. Importantly, ERVs are genome modifiers of exogenous origin. The human genome contains about 8% of sequences of retroviral origin. The human ERVs (HERVs) comprise many distinct families that amplified to copy numbers of up to several thousand. We review here the evolution of several well-characterized HERV families in the human lineage since initial germ line fixation. It is apparent that endogenous retroviruses profoundly affected the genomes of species in the evolutionary lineage leading to Homo sapiens.
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Affiliation(s)
- J Mayer
- Department of Human Genetics, Medical Faculty, University of Saarland, Homburg/Saar, Germany.
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Medstrand P, van de Lagemaat LN, Dunn CA, Landry JR, Svenback D, Mager DL. Impact of transposable elements on the evolution of mammalian gene regulation. Cytogenet Genome Res 2005; 110:342-52. [PMID: 16093686 DOI: 10.1159/000084966] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Accepted: 01/07/2004] [Indexed: 12/21/2022] Open
Abstract
Transposable elements (TEs) are present in all organisms and nearly half of the human and mouse genome is derived from ancient transpositions. This fact alone suggests that TEs have played a major role in genome organization and evolution. Studies undertaken over the last two decades or so clearly show that TEs of various kinds have played an important role in organism evolution. Here we review the impact TEs have on the evolution of gene regulation and gene function with an emphasis on humans. Understanding the mechanisms resulting in genomic change is central to our understanding of gene regulation, genetic disease and genome evolution. Full comprehension of these biological processes is not possible without an in depth knowledge of how TEs impact upon the genome.
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Affiliation(s)
- P Medstrand
- Department of Cell and Molecular Biology, Biomedical Centre, Lund University, Lund, Sweden.
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Greenwood AD, Stengel A, Erfle V, Seifarth W, Leib-Mösch C. The distribution of pol containing human endogenous retroviruses in non-human primates. Virology 2005; 334:203-13. [PMID: 15780870 DOI: 10.1016/j.virol.2005.01.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2004] [Revised: 12/30/2004] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
Few human endogenous retroviruses (HERVs) have been extensively studied in non-human primates. Such investigations have demonstrated that several element classes are primate unique, contain members with important biological function, are conserved in specific primate lineages, and have in some cases expanded in copy number. We have examined multiple sub-families of all major groups of HERVs using a DNA microarray based on the reverse transcriptase (RT) domain of the viral polymerase gene (pol). The microarray was used to investigate the distribution of HERVs in non-human primates with particular focus on the differences between New World monkeys (NWMs) and other anthropoids. This is the first study examining most HERV families in multiple non-human primate DNAs using a uniform and sensitive method and suggests that major differences exist between primate groups. The results indicate that a major invasion and expansion of pol containing HERVs occurred after the platyrrhine (NWM) lineage separated from the catarrhines (Old World Monkeys and apes).
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Affiliation(s)
- Alex D Greenwood
- GSF-National Research Center for Environment and Health, Institute of Molecular Virology, D-85764 Neuherberg, Germany.
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Flockerzi A, Burkhardt S, Schempp W, Meese E, Mayer J. Human endogenous retrovirus HERV-K14 families: status, variants, evolution, and mobilization of other cellular sequences. J Virol 2005; 79:2941-9. [PMID: 15709013 PMCID: PMC548434 DOI: 10.1128/jvi.79.5.2941-2949.2005] [Citation(s) in RCA: 26] [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 human genome harbors many distinct families of human endogenous retroviruses (HERVs) that stem from exogenous retroviruses that infected the germ line millions of years ago. Many HERV families remain to be investigated. We report in the present study the detailed characterization of the HERV-K14I and HERV-K14CI families as they are represented in the human genome. Most of the 68 HERV-K14I and 23 HERV-K14CI proviruses are severely mutated, frequently displaying uniform deletions of retroviral genes and long terminal repeats (LTRs). Both HERV families entered the germ line approximately 39 million years ago, as evidenced by homologous sequences in hominoids and Old World primates and calculation of evolutionary ages based on a molecular clock. Proviruses of both families were formed during a brief period. A majority of HERV-K14CI proviruses on the Y chromosome mimic a higher evolutionary age, showing that LTR-LTR divergence data can indicate false ages. Fully translatable consensus sequences encoding major retroviral proteins were generated. Most HERV-K14I loci lack an env gene and are structurally reminiscent of LTR retrotransposons. A minority of HERV-K14I variants display an env gene. HERV-K14I proviruses are associated with three distinct LTR families, while HERV-K14CI is associated with a single LTR family. Hybrid proviruses consisting of HERV-K14I and HERV-W sequences that appear to have produced provirus progeny in the genome were detected. Several HERV-K14I proviruses harbor TRPC6 mRNA portions, exemplifying mobilization of cellular transcripts by HERVs. Our analysis contributes essential information on two more HERV families and on the biology of HERV sequences in general.
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Affiliation(s)
- Aline Flockerzi
- Department of Human Genetics, Building 60, University of Saarland, 66421 Homburg, Germany
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Yohn CT, Jiang Z, McGrath SD, Hayden KE, Khaitovich P, Johnson ME, Eichler MY, McPherson JD, Zhao S, Pääbo S, Eichler EE. Lineage-specific expansions of retroviral insertions within the genomes of African great apes but not humans and orangutans. PLoS Biol 2005; 3:e110. [PMID: 15737067 PMCID: PMC1054887 DOI: 10.1371/journal.pbio.0030110] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Accepted: 01/27/2005] [Indexed: 12/18/2022] Open
Abstract
Retroviral infections of the germline have the potential to episodically alter gene function and genome structure during the course of evolution. Horizontal transmissions between species have been proposed, but little evidence exists for such events in the human/great ape lineage of evolution. Based on analysis of finished BAC chimpanzee genome sequence, we characterize a retroviral element (Pan troglodytes endogenous retrovirus 1 [PTERV1]) that has become integrated in the germline of African great ape and Old World monkey species but is absent from humans and Asian ape genomes. We unambiguously map 287 retroviral integration sites and determine that approximately 95.8% of the insertions occur at non-orthologous regions between closely related species. Phylogenetic analysis of the endogenous retrovirus reveals that the gorilla and chimpanzee elements share a monophyletic origin with a subset of the Old World monkey retroviral elements, but that the average sequence divergence exceeds neutral expectation for a strictly nuclear inherited DNA molecule. Within the chimpanzee, there is a significant integration bias against genes, with only 14 of these insertions mapping within intronic regions. Six out of ten of these genes, for which there are expression data, show significant differences in transcript expression between human and chimpanzee. Our data are consistent with a retroviral infection that bombarded the genomes of chimpanzees and gorillas independently and concurrently, 3–4 million years ago. We speculate on the potential impact of such recent events on the evolution of humans and great apes. Comparison of human and other primate genomes provides evidence for a retroviral infection that bombarded the genomes of chimpanzees and gorillas 3-4 million years ago
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Affiliation(s)
- Chris T Yohn
- 1Department of Genetics, Case Western Reserve UniversityCleveland, OhioUnited States of America
| | - Zhaoshi Jiang
- 2Department of Genome Sciences, University of Washington School of MedicineSeattle, WashingtonUnited States of America
| | - Sean D McGrath
- 2Department of Genome Sciences, University of Washington School of MedicineSeattle, WashingtonUnited States of America
| | - Karen E Hayden
- 1Department of Genetics, Case Western Reserve UniversityCleveland, OhioUnited States of America
| | | | - Matthew E Johnson
- 1Department of Genetics, Case Western Reserve UniversityCleveland, OhioUnited States of America
- 2Department of Genome Sciences, University of Washington School of MedicineSeattle, WashingtonUnited States of America
| | - Marla Y Eichler
- 2Department of Genome Sciences, University of Washington School of MedicineSeattle, WashingtonUnited States of America
| | - John D McPherson
- 4Department of Molecular and Human Genetics, Baylor College of MedicineHouston, TexasUnited States of America
| | - Shaying Zhao
- 5The Institute for Genome Research, BethesdaMarylandUnited States of America
| | - Svante Pääbo
- 3Max-Planck Institute for Evolutionary AnthropologyLeipzigGermany
| | - Evan E Eichler
- 2Department of Genome Sciences, University of Washington School of MedicineSeattle, WashingtonUnited States of America
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Belshaw R, Katzourakis A, Paces J, Burt A, Tristem M. High copy number in human endogenous retrovirus families is associated with copying mechanisms in addition to reinfection. Mol Biol Evol 2005; 22:814-7. [PMID: 15659556 DOI: 10.1093/molbev/msi088] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There are at least 31 families of human endogenous retroviruses (HERVs), each derived from an independent infection by an exogenous virus. Using evidence of purifying selection on HERV genes, we have shown previously that reinfection by replication-competent elements was the predominant mechanism of copying in some families. Here we analyze the evolution of 17 HERV families using d(N)/d(S) ratios and find a positive relationship between copy number and the use of additional copying mechanisms. All families with more than 200 elements have also used one or more of the following mechanisms: (1) complementation in trans (elements copied by other elements of the same family; HERV-H and ERV-9), (2) retrotransposition in cis (elements copying themselves) within germ-line cells (HERV-K(HML3)), and (3) being copied by non-HERV machinery (HERV-W). We discuss why these other mechanisms are rare in most families and suggest why complementation in trans is significant only in the larger families.
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Burmeister T, Ebert AD, Pritze W, Loddenkemper C, Schwartz S, Thiel E. Insertional polymorphisms of endogenous HERV-K113 and HERV-K115 retroviruses in breast cancer patients and age-matched controls. AIDS Res Hum Retroviruses 2004; 20:1223-9. [PMID: 15588344 DOI: 10.1089/aid.2004.20.1223] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Endogenous retroviral sequences resulting from ancient retrovirus infections of germline cells account for up to 8% of the human genome. Most of these sequences are highly truncated, have been altered by mutations, and do not encode functional genes. However, some members of the human endogenous retrovirus (HERV)-K family are remarkably intact and display high genetic homology to mouse mammary tumor virus (MMTV), a retrovirus causing breast cancer in mice. Two full-length HERVs (K113 and K115) have been reported to show insertional polymorphism. We used PCR to investigate the presence of these two HERVs in 102 female breast cancer patients and an equal number of age-matched controls with no history of malignancy (age range: 25-92 years). The two groups showed no significant difference in frequency (HERV-K113, 16.7% vs. 12.7%; HERV-K115, 4.9% vs. 9.8%) and no apparent association with histology, age at diagnosis, receptor status, HER-2/neu status, or TNM stage at diagnosis. This suggests that the two HERV-Ks do not play a pathogenetic role in the majority of breast cancer patients, though they may be involved in a minority of patients. The results are discussed.
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Affiliation(s)
- Thomas Burmeister
- Medizinische Klinik III, Charité-Campus Benjamin Franklin, 12200 Berlin, Germany
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Lavie L, Medstrand P, Schempp W, Meese E, Mayer J. Human endogenous retrovirus family HERV-K(HML-5): status, evolution, and reconstruction of an ancient betaretrovirus in the human genome. J Virol 2004; 78:8788-98. [PMID: 15280487 PMCID: PMC479102 DOI: 10.1128/jvi.78.16.8788-8798.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human genome harbors numerous distinct families of so-called human endogenous retroviruses (HERV) which are remnants of exogenous retroviruses that entered the germ line millions of years ago. We describe here the hitherto little-characterized betaretrovirus HERV-K(HML-5) family (named HERVK22 in Repbase) in greater detail. Out of 139 proviruses, only a few loci represent full-length proviruses, and many lack gag protease and/or env gene regions. We generated a consensus sequence from multiple alignment of 62 HML-5 loci that displays open reading frames for the four major retroviral proteins. Four HML-5 long terminal repeat (LTR) subfamilies were identified that are associated with monophyletic proviral bodies, implying different evolution of HML-5 LTRs and genes. Sequence analysis indicated that the proviruses formed approximately 55 million years ago. Accordingly, HML-5 proviral sequences were detected in Old World and New World primates but not in prosimians. No recent activity is associated with this HERV family. We also conclude that the HML-5 consensus sequence primer binding site is identical to methionine tRNA. Therefore, the family should be designated HERV-M. Our study provides important insights into the structure and evolution of the oldest betaretrovirus in the primate genome known to date.
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Affiliation(s)
- Laurence Lavie
- Department of Human Genetics, Building 60, University of Saarland, Medical Faculty, 66421 Homburg, Germany
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Mayer J, Meese EU. Presence of dUTPase in the various human endogenous retrovirus K (HERV-K) families. J Mol Evol 2004; 57:642-9. [PMID: 14745533 DOI: 10.1007/s00239-003-2514-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2003] [Accepted: 07/02/2003] [Indexed: 10/26/2022]
Abstract
Various retroviruses have been shown to encode dUTPase. The overall phylogeny of dUTPase is unclear, though. The human genome contains a significant amount of human endogenous retroviruses (HERV) representing fossilized sequences of ancient exogenous retroviruses. A few HERV families have been reported to harbor dUTPase domains. We surveyed the various HERV families for the presence of dUTPase and found that ancestors of all HERV-K families but one encoded dUTPase. With two exceptions phylogenetic analysis shows a monophyletic origin of dUTPase for the different HERV-K dUTPases. Sequences of consensus dUTPase domains suggest that the various exogenous ancestors of HERV-K once encoded active enzymes. Our analysis provides informations on dUTPase phylogeny and further shows that endogenous retroviruses provide important informations regarding retrovirus evolution.
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Affiliation(s)
- Jens Mayer
- Human Genetics, Building 60, University of Saar, Medical Faculty, 66421 Homburg, Germany.
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Abstract
The retroviral capacity for integration into the host genome can give rise to endogenous retroviruses (ERVs): retroviral sequences that are transmitted vertically as part of the host germ line, within which they may continue to replicate and evolve. ERVs represent both a unique archive of ancient viral sequence information and a dynamic component of host genomes. As such they hold great potential as informative markers for studies of both virus evolution and host genome evolution. Numerous novel ERVs have been described in recent years, particularly as genome sequencing projects have advanced. This review discusses the evolution of ERV lineages, considering the processes by which ERV distribution and diversity is generated. The diversity of ERVs isolated so far is summarised in terms of both their distribution across host taxa, and their relationships to recognised retroviral genera. Finally the relevance of ERVs to studies of genome evolution, host disease and viral ecology is considered, and recent findings discussed.
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Affiliation(s)
- Robert Gifford
- Department of Biological Sciences, Imperial College, Silwood Park, Buckhurst Road, Ascot Berkshire, SL5 7PY, UK
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