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Fukuda K. The role of transposable elements in human evolution and methods for their functional analysis: current status and future perspectives. Genes Genet Syst 2024; 98:289-304. [PMID: 37866889 DOI: 10.1266/ggs.23-00140] [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] [Indexed: 10/24/2023] Open
Abstract
Transposable elements (TEs) are mobile DNA sequences that can insert themselves into various locations within the genome, causing mutations that may provide advantages or disadvantages to individuals and species. The insertion of TEs can result in genetic variation that may affect a wide range of human traits including genetic disorders. Understanding the role of TEs in human biology is crucial for both evolutionary and medical research. This review discusses the involvement of TEs in human traits and disease susceptibility, as well as methods for functional analysis of TEs.
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Affiliation(s)
- Kei Fukuda
- Integrative Genomics Unit, The University of Melbourne
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2
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Suntsova MV, Buzdin AA. Differences between human and chimpanzee genomes and their implications in gene expression, protein functions and biochemical properties of the two species. BMC Genomics 2020; 21:535. [PMID: 32912141 PMCID: PMC7488140 DOI: 10.1186/s12864-020-06962-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 07/29/2020] [Indexed: 12/24/2022] Open
Abstract
Chimpanzees are the closest living relatives of humans. The divergence between human and chimpanzee ancestors dates to approximately 6,5-7,5 million years ago. Genetic features distinguishing us from chimpanzees and making us humans are still of a great interest. After divergence of their ancestor lineages, human and chimpanzee genomes underwent multiple changes including single nucleotide substitutions, deletions and duplications of DNA fragments of different size, insertion of transposable elements and chromosomal rearrangements. Human-specific single nucleotide alterations constituted 1.23% of human DNA, whereas more extended deletions and insertions cover ~ 3% of our genome. Moreover, much higher proportion is made by differential chromosomal inversions and translocations comprising several megabase-long regions or even whole chromosomes. However, despite of extensive knowledge of structural genomic changes accompanying human evolution we still cannot identify with certainty the causative genes of human identity. Most structural gene-influential changes happened at the level of expression regulation, which in turn provoked larger alterations of interactome gene regulation networks. In this review, we summarized the available information about genetic differences between humans and chimpanzees and their potential functional impacts on differential molecular, anatomical, physiological and cognitive peculiarities of these species.
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Affiliation(s)
- Maria V Suntsova
- Institute for personalized medicine, I.M. Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia
| | - Anton A Buzdin
- Institute for personalized medicine, I.M. Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia. .,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya, 16/10, Moscow, Russia. .,Omicsway Corp, Walnut, CA, USA. .,Moscow Institute of Physics and Technology (National Research University), 141700, Moscow, Russia.
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Thomas J, Perron H, Feschotte C. Variation in proviral content among human genomes mediated by LTR recombination. Mob DNA 2018; 9:36. [PMID: 30568734 PMCID: PMC6298018 DOI: 10.1186/s13100-018-0142-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/29/2018] [Indexed: 01/23/2023] Open
Abstract
Background Human endogenous retroviruses (HERVs) occupy a substantial fraction of the genome and impact cellular function with both beneficial and deleterious consequences. The vast majority of HERV sequences descend from ancient retroviral families no longer capable of infection or genomic propagation. In fact, most are no longer represented by full-length proviruses but by solitary long terminal repeats (solo LTRs) that arose via non-allelic recombination events between the two LTRs of a proviral insertion. Because LTR-LTR recombination events may occur long after proviral insertion but are challenging to detect in resequencing data, we hypothesize that this mechanism is a source of genomic variation in the human population that remains vastly underestimated. Results We developed a computational pipeline specifically designed to capture dimorphic proviral/solo HERV allelic variants from short-read genome sequencing data. When applied to 279 individuals sequenced as part of the Simons Genome Diversity Project, the pipeline retrieves most of the dimorphic loci previously reported for the HERV-K(HML2) subfamily as well as dozens of additional candidates, including members of the HERV-H and HERV-W families previously involved in human development and disease. We experimentally validate several of these newly discovered dimorphisms, including the first reported instance of an unfixed HERV-W provirus and an HERV-H locus driving a transcript (ESRG) implicated in the maintenance of embryonic stem cell pluripotency. Conclusions Our findings indicate that human proviral content exhibit more extensive interindividual variation than previously recognized, which has important bearings for deciphering the contribution of HERVs to human physiology and disease. Because LTR retroelements and LTR recombination are ubiquitous in eukaryotes, our computational pipeline should facilitate the mapping of this type of genomic variation for a wide range of organisms. Electronic supplementary material The online version of this article (10.1186/s13100-018-0142-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jainy Thomas
- 1Department of Human Genetics, University of Utah School of Medicine, 15 North 2030 East, Rm 5100, Salt Lake City, UT 84112 USA
| | - Hervé Perron
- GeNeuro, Plan-les-Ouates, Geneva, Switzerland.,3Université Claude Bernard, Lyon, France
| | - Cédric Feschotte
- 4Department of Molecular Biology and Genetics, Cornell University, 107 Biotechnology Building, Ithaca, NY 14853 USA
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Wallace AD, Wendt GA, Barcellos LF, de Smith AJ, Walsh KM, Metayer C, Costello JF, Wiemels JL, Francis SS. To ERV Is Human: A Phenotype-Wide Scan Linking Polymorphic Human Endogenous Retrovirus-K Insertions to Complex Phenotypes. Front Genet 2018; 9:298. [PMID: 30154825 PMCID: PMC6102640 DOI: 10.3389/fgene.2018.00298] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/16/2018] [Indexed: 12/13/2022] Open
Abstract
Approximately 8% of the human genome is comprised of endogenous retroviral insertions (ERVs) originating from historic retroviral integration into germ cells. The function of ERVs as regulators of gene expression is well established. Less well studied are insertional polymorphisms of ERVs and their contribution to the heritability of complex phenotypes. The most recent integration of ERV, HERV-K, is expressed in a range of complex human conditions from cancer to neurologic diseases. Using an in-house computational pipeline and whole-genome sequencing data from the diverse 1,000 Genomes Phase 3 population (n = 2,504), we identified 46 polymorphic HERV-K insertions that are tagged by adjacent single nucleotide polymorphisms (SNPs). To test the potential role of polymorphic HERV-K in the heritability of complex diseases, existing databases were queried for enrichment of established relationships between the HERV-K insertion-associated SNPs (hiSNPs), and tissue specific gene expression and disease phenotypes. Overall, hiSNPs for the 46 polymorphic HERV-K sites were statistically enriched (p < 1.0E-16) for eQTLs across 44 human tissues. Fifteen of the 46 HERV-K insertions had hiSNPs annotated in the EMBL-EBI GWAS Catalog and cumulatively associated with >100 phenotypes. Experimental factor ontology enrichment analysis suggests that polymorphic HERV-K specifically contribute to neurologic and immunologic disease phenotypes, including traits related to intra cranial volume (FDR 2.00E-09), Parkinson's disease (FDR 1.80E-09), and autoimmune diseases (FDR 1.80E-09). These results provide strong candidates for context-specific study of polymorphic HERV-K insertions in disease-related traits, serving as a roadmap for future studies of the heritability of complex disease.
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Affiliation(s)
- Amelia D Wallace
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - George A Wendt
- Division of Epidemiology, School of Community Health Sciences, University of Nevada, Reno, NV, United States
| | - Lisa F Barcellos
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Adam J de Smith
- Department of Epidemiology and Biostatistics, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
| | - Kyle M Walsh
- Department of Neurosurgery, Duke University, Durham, NC, United States
| | - Catherine Metayer
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Joseph F Costello
- Department of Neurosurgery, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
| | - Joseph L Wiemels
- Department of Epidemiology and Biostatistics, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States.,Department of Neurosurgery, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
| | - Stephen S Francis
- Division of Epidemiology, School of Community Health Sciences, University of Nevada, Reno, NV, United States.,Department of Epidemiology and Biostatistics, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
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Cakmak Guner B, Karlik E, Marakli S, Gozukirmizi N. Detection of HERV-K6 and HERV-K11 transpositions in the human genome. Biomed Rep 2018; 9:53-59. [PMID: 29930805 DOI: 10.3892/br.2018.1096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 04/24/2018] [Indexed: 01/24/2023] Open
Abstract
Mobile genetic elements classed as transposons comprise an estimated 45% of the human genome, and 8% of these elements are human endogenous retroviruses (HERVs). Endogenous retroviruses are retrotransposons, containing 5' and 3' long terminal repeat sequences and encoding envelope, group-specific antigen and DNA polymerase proteins. The aim of the present study was to analyse genome integration polymorphisms of HERV type K member 6 (HERV-K6) and HERV-K11 by using the retrotransposon based molecular marker technique, inter-retrotransposon amplified polymorphism (IRAP). For this purpose, blood samples of 18 healthy individuals within the age range of 10-79 years (10 females and 8 males) were collected, genomic DNAs were isolated and IRAP-polymerase chain reaction (PCR) was performed. IRAP-PCR analyses demonstrated that there were 0-70% polymorphism rates for HERV-K6, and 0-38% polymorphism rates for HERV-K11 among all the samples. Furthermore, the polymorphism rates were 0-70% among females and 11-60% among males for HERV-K6, and 0-38% among females and 0-25% among males for HERV-K11. Age-associated polymorphism was also investigated, but no age-associated polymorphism was observed among the samples. Therefore, HERV-K6 and HERV-K11 polymorphisms may arise on an individual-specific basis. Various previous studies have investigated the associations between the expression of HERVs and cancer or other major diseases. However, few reports have analysed HERV-K movements among individuals. This is the first report to investigate HERV-K6 and HERV-K11 retrotransposon polymorphisms between the genders and different age groups.
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Affiliation(s)
- Buket Cakmak Guner
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, 34134 Istanbul, Turkey
| | - Elif Karlik
- Department of Biotechnology, Institution of Science, Istanbul University, 34134 Istanbul, Turkey
| | - Sevgi Marakli
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, 34134 Istanbul, Turkey
| | - Nermin Gozukirmizi
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul University, 34134 Istanbul, Turkey
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Gerdes P, Richardson SR, Mager DL, Faulkner GJ. Transposable elements in the mammalian embryo: pioneers surviving through stealth and service. Genome Biol 2016; 17:100. [PMID: 27161170 PMCID: PMC4862087 DOI: 10.1186/s13059-016-0965-5] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Transposable elements (TEs) are notable drivers of genetic innovation. Over evolutionary time, TE insertions can supply new promoter, enhancer, and insulator elements to protein-coding genes and establish novel, species-specific gene regulatory networks. Conversely, ongoing TE-driven insertional mutagenesis, nonhomologous recombination, and other potentially deleterious processes can cause sporadic disease by disrupting genome integrity or inducing abrupt gene expression changes. Here, we discuss recent evidence suggesting that TEs may contribute regulatory innovation to mammalian embryonic and pluripotent states as a means to ward off complete repression by their host genome.
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Affiliation(s)
- Patricia Gerdes
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Sandra R Richardson
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Dixie L Mager
- Department of Medical Genetics, Terry Fox Laboratory, British Columbia Cancer Agency, University of British Columbia, Vancouver, BC, V5Z 1L3, Canada.
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia. .,School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
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Garazha A, Ivanova A, Suntsova M, Malakhova G, Roumiantsev S, Zhavoronkov A, Buzdin A. New bioinformatic tool for quick identification of functionally relevant endogenous retroviral inserts in human genome. Cell Cycle 2016; 14:1476-84. [PMID: 25853282 PMCID: PMC4612461 DOI: 10.1080/15384101.2015.1022696] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Endogenous retroviruses (ERVs) and LTR retrotransposons (LRs) occupy ∼8% of human genome. Deep sequencing technologies provide clues to understanding of functional relevance of individual ERVs/LRs by enabling direct identification of transcription factor binding sites (TFBS) and other landmarks of functional genomic elements. Here, we performed the genome-wide identification of human ERVs/LRs containing TFBS according to the ENCODE project. We created the first interactive ERV/LRs database that groups the individual inserts according to their familial nomenclature, number of mapped TFBS and divergence from their consensus sequence. Information on any particular element can be easily extracted by the user. We also created a genome browser tool, which enables quick mapping of any ERV/LR insert according to genomic coordinates, known human genes and TFBS. These tools can be used to easily explore functionally relevant individual ERV/LRs, and for studying their impact on the regulation of human genes. Overall, we identified ∼110,000 ERV/LR genomic elements having TFBS. We propose a hypothesis of “domestication” of ERV/LR TFBS by the genome milieu including subsequent stages of initial epigenetic repression, partial functional release, and further mutation-driven reshaping of TFBS in tight coevolution with the enclosing genomic loci.
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Affiliation(s)
- Andrew Garazha
- a Group for Genomic Regulation of Cell Signaling Systems ; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry ; Moscow , Russia
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8
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Suntsova M, Garazha A, Ivanova A, Kaminsky D, Zhavoronkov A, Buzdin A. Molecular functions of human endogenous retroviruses in health and disease. Cell Mol Life Sci 2015; 72:3653-75. [PMID: 26082181 PMCID: PMC11113533 DOI: 10.1007/s00018-015-1947-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 05/29/2015] [Accepted: 06/03/2015] [Indexed: 12/13/2022]
Abstract
Human endogenous retroviruses (HERVs) and related genetic elements form 504 distinct families and occupy ~8% of human genome. Recent success of high-throughput experimental technologies facilitated understanding functional impact of HERVs for molecular machinery of human cells. HERVs encode active retroviral proteins, which may exert important physiological functions in the body, but also may be involved in the progression of cancer and numerous human autoimmune, neurological and infectious diseases. The spectrum of related malignancies includes, but not limits to, multiple sclerosis, psoriasis, lupus, schizophrenia, multiple cancer types and HIV. In addition, HERVs regulate expression of the neighboring host genes and modify genomic regulatory landscape, e.g., by providing regulatory modules like transcription factor binding sites (TFBS). Indeed, recent bioinformatic profiling identified ~110,000 regulatory active HERV elements, which formed at least ~320,000 human TFBS. These and other peculiarities of HERVs might have played an important role in human evolution and speciation. In this paper, we focus on the current progress in understanding of normal and pathological molecular niches of HERVs, on their implications in human evolution, normal physiology and disease. We also review the available databases dealing with various aspects of HERV genetics.
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Affiliation(s)
- Maria Suntsova
- Group for Genomic Regulation of Cell Signaling Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997, Russia.
- Laboratory of Bioinformatics, D. Rogachyov Federal Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, 117198, Russia.
| | - Andrew Garazha
- Group for Genomic Regulation of Cell Signaling Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997, Russia.
- Laboratory of Bioinformatics, D. Rogachyov Federal Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, 117198, Russia.
| | - Alena Ivanova
- Group for Genomic Regulation of Cell Signaling Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997, Russia.
- Pathway Pharmaceuticals, Wan Chai, Hong Kong, Hong Kong SAR.
| | - Dmitry Kaminsky
- Pathway Pharmaceuticals, Wan Chai, Hong Kong, Hong Kong SAR.
| | - Alex Zhavoronkov
- Pathway Pharmaceuticals, Wan Chai, Hong Kong, Hong Kong SAR.
- Department of Translational and Regenerative Medicine, Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow, 141700, Russia.
| | - Anton Buzdin
- Group for Genomic Regulation of Cell Signaling Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997, Russia.
- Pathway Pharmaceuticals, Wan Chai, Hong Kong, Hong Kong SAR.
- National Research Centre "Kurchatov Institute", Centre for Convergence of Nano-, Bio-, Information and Cognitive Sciences and Technologies, 1, Akademika Kurchatova sq., Moscow, 123182, Russia.
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Macfarlane CM, Badge RM. Genome-wide amplification of proviral sequences reveals new polymorphic HERV-K(HML-2) proviruses in humans and chimpanzees that are absent from genome assemblies. Retrovirology 2015; 12:35. [PMID: 25927962 PMCID: PMC4422153 DOI: 10.1186/s12977-015-0162-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To date, the human population census of proviruses of the Betaretrovirus-like human endogenous retroviral (HERV-K) (HML-2) family has been compiled from a limited number of complete genomes, making it certain that rare polymorphic loci are under-represented and are yet to be described. RESULTS Here we describe a suppression PCR-based method called genome-wide amplification of proviral sequences (GAPS) that selectively amplifies DNA fragments containing the termini of HERV-K(HML-2) proviral sequences and their flanking genomic sequences. We analysed the HERV-K(HML-2) proviral content of 101 unrelated humans, 4 common chimpanzees and three centre d'etude du polymorphisme humain (CEPH) pedigrees (44 individuals). The technique isolated HERV-K(HML-2) proviruses that had integrated in the genomes of the great apes throughout their divergence and included evolutionarily young elements still unfixed for presence/absence. CONCLUSIONS By examining the HERV-K(HML-2) proviral content of 145 humans we detected a new insertionally polymorphic Type I HERV-K(HML-2) provirus. We also observed provirus versus solo long terminal repeat (LTR) polymorphism within humans at a previously unreported, but ancient, locus. Finally, we report two novel chimpanzee specific proviruses, one of which is dimorphic for a provirus versus solo LTR. Thus GAPS enables the isolation of uncharacterised HERV-K(HML-2) proviral sequences and provides a direct means to assess inter-individual genetic variation associated with HERV-K(HML-2) proviruses.
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Affiliation(s)
- Catriona M Macfarlane
- Department of Genetics, University of Leicester, University Road, Leicester, LE1 7RH, UK.
| | - Richard M Badge
- Department of Genetics, University of Leicester, University Road, Leicester, LE1 7RH, UK.
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10
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Abstract
One lineage of human endogenous retroviruses (HERVs), HERV-K(HML2), is upregulated in many cancers, some autoimmune/inflammatory diseases, and HIV-infected cells. Despite 3 decades of research, it is not known if these viruses play a causal role in disease, and there has been recent interest in whether they can be used as immunotherapy targets. Resolution of both these questions will be helped by an ability to distinguish between the effects of different integrated copies of the virus (loci). Research so far has concentrated on the 20 or so recently integrated loci that, with one exception, are in the human reference genome sequence. However, this viral lineage has been copying in the human population within the last million years, so some loci will inevitably be present in the human population but absent from the reference sequence. We therefore performed the first detailed search for such loci by mining whole-genome sequences generated by next-generation sequencing. We found a total of 17 loci, and the frequency of their presence ranged from only 2 of the 358 individuals examined to over 95% of them. On average, each individual had six loci that are not in the human reference genome sequence. Comparing the number of loci that we found to an expectation derived from a neutral population genetic model suggests that the lineage was copying until at least ∼250,000 years ago. IMPORTANCE About 5% of the human genome sequence is composed of the remains of retroviruses that over millions of years have integrated into the chromosomes of egg and/or sperm precursor cells. There are indications that protein expression of these viruses is higher in some diseases, and we need to know (i) whether these viruses have a role in causing disease and (ii) whether they can be used as immunotherapy targets in some of them. Answering both questions requires a better understanding of how individuals differ in the viruses that they carry. We carried out the first careful search for new viruses in some of the many human genome sequences that are now available thanks to advances in sequencing technology. We also compared the number that we found to a theoretical expectation to see if it is likely that these viruses are still replicating in the human population today.
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Kurnosov AA, Ustiugova SV, Pogorelyĭ MV, Komkov AI, Bolotin DA, Khodosevich KV, Mamedov IZ, Lebedev IB. [A novel approach to identification of somatic retroelements' insertions in human genome]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2014; 39:466-76. [PMID: 24707728 DOI: 10.1134/s1068162013040110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The activity of retroelements is one of the factors leading to genetic variability of the modern humans. Insertions of retroelements may result in alteration of gene expression and functional diversity between cells. In recent years an increasing amount of data indicating an elevated level of retroelements' mobilisation in some human and animal tissues has been reported. Therefore, the development of a system for the detection of somatic retroposition events is required. Here we describe a novel approach to the whole-genome identification of somatic retroelemts' insertions in human genome. The developed approach was applied for the comparisons of somatic mosaicism levels in two tissues of the investigated individual. A total of 3410 insertions of retroelements belonging to AluYa5 subfamily were identified.
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13
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Human endogenous retrovirus-H insertion screening. Mol Med Rep 2013; 7:1305-9. [PMID: 23358623 DOI: 10.3892/mmr.2013.1295] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 01/22/2013] [Indexed: 11/05/2022] Open
Abstract
Endogenous retroviruses (ERVs) and ERV-like sequences comprise 8% of the human genome. We aimed to analyze genome integration polymorphisms of human endogenous retrovirus (HERV)-H by the inter-retrotransposon amplified polymorphism (IRAP) technique using the sequences of LTR7A (450 bp), LTR7B (445 bp) and LTR7C (471 bp). Blood samples from 20 individuals (10 females and 10 males) of diverse ethnic origins were used for the determination of integration variations at the genomic level. Isolated genomic DNA was screened using 3 pairs of primers corresponding to LTR regions of the HERV-H gene. We observed insertion polymorphism patterns between 0-87% in all subjects. The findings obtained contribute to our understanding of the effects of HERV-H on variations within the human genome.
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Amosova AL, Komkov AI, Ustiugova SV, Mamedov IZ, Lebedev IB. [Retroposons in modern human genome evolution]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2010; 35:779-88. [PMID: 20208577 DOI: 10.1134/s1068162009060053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The ascertainment of the rates and driving forces of human genome evolution along with the genetic diversity of populations or separate population groups remains a topical problem of fundamental and applied genomics. According to the results of comparative analysis, the most numerous human genome structure peculiarities are connected with the distribution of mobile genetic retroelements - LTR, LINE1, SVA, and Alu repeats. Due to the wide distribution in different genome loci, conversed retropositional activity, and the retroelements regulatory potential, let us regard them as one of the significant evolutionary driving forces and the source of human genome variability. In the current review, we summarize published data and recent results of our research aimed at the analysis of the evolutionary impact of the young retroelements group on the function and variability of the human genome. We examine modern approaches of the polygenomic identification of polymorphic retroelements inserts. Using an original Internet resource, we analyze special features of the genomic polymorphic inserts of Alu repeats. We thoroughly characterize the strategy of large-scale functional analysis of polymorphic retroelement inserts. The presented results confirm the hypothesis of the roles of retroelements as active cis regulatory elements that are able to modulate surrounding genes.
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Mamedov IZ, Shagina IA, Kurnikova MA, Novozhilov SN, Shagin DA, Lebedev YB. A new set of markers for human identification based on 32 polymorphic Alu insertions. Eur J Hum Genet 2010; 18:808-14. [PMID: 20179741 DOI: 10.1038/ejhg.2010.22] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
A number of genetic systems for human genetic identification based on short tandem repeats or single nucleotide polymorphisms are widely used for crime detection, kinship studies and in analysis of victims of mass disasters. Here, we have developed a new set of 32 molecular genetic markers for human genetic identification based on polymorphic retroelement insertions. Allele frequencies were determined in a group of 90 unrelated individuals from four genetically distant populations of the Russian Federation. The mean match probability and probability of paternal exclusion, calculated based on population data, were 5.53 x 10(-14) and 99.784%, respectively. The developed system is cheap and easy to use as compared to all previously published methods. The application of fluorescence-based methods for allele discrimination allows to use the human genetic identification set in automatic and high-throughput formats.
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Affiliation(s)
- Ilgar Z Mamedov
- Laboratory of Comparative and Functional Genomics, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry RAS, Miklukho-Maklaya, Moscow, Russia.
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16
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Human-specific modulation of transcriptional activity provided by endogenous retroviral insertions. J Virol 2009; 83:6098-105. [PMID: 19339349 DOI: 10.1128/jvi.00123-09] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Many phenotypic differences exist between Homo sapiens and its closest relatives, chimpanzees, and these differences can arise as a result of variations in the regulation of certain genes common to these closely related species. Human-specific endogenous retroviruses (HERVs) and their solitary long terminal repeats (LTRs) are probable candidates for such a role due to the presence of regulatory elements, such as enhancers, promoters, splice sites, and polyadenylation signals. In this study we show for the first time that HERVs can participate in the specific antisense regulation of human gene expression owing to their LTR promoter activity. We found that two HERV LTRs situated in the introns of genes SLC4A8 (for sodium bicarbonate cotransporter) and IFT172 (for intraflagellar transport protein 172) in the antisense orientation serve in vivo as promoters for generating RNAs complementary to the exons of enclosing genes. The antisense transcripts formed from LTR promoter were shown to decrease the mRNA level of the corresponding genes. The human-specific regulation of these genes suggests their involvement in the evolutionary process.
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Abstract
For millions of years, retroviral infections have challenged vertebrates, occasionally leading to germline integration and inheritance as ERVs, genetic parasites whose remnants today constitute some 7% to 8% of the human genome. Although they have had significant evolutionary side effects, it is useful to view ERVs as fossil representatives of retroviruses extant at the time of their insertion into the germline and not as direct players in the evolutionary process itself. Expression of particular ERVs is associated with several positive physiological functions as well as certain diseases, although their roles in human disease as etiological agents, possible contributing factors, or disease markers-well demonstrated in animal models-remain to be established. Here we discuss ERV contributions to host genome structure and function, including their ability to mediate recombination, and physiological effects on the host transcriptome resulting from their integration, expression, and other events.
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Affiliation(s)
- Patric Jern
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
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18
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Mamedov IZ, Amosova AL, Fisunov GY, Lebedev YB. A new polymorphic retroelement database (PRED) for the human genome. Mol Biol 2008. [DOI: 10.1134/s0026893308040213] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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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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20
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Moyes D, Griffiths DJ, Venables PJ. Insertional polymorphisms: a new lease of life for endogenous retroviruses in human disease. Trends Genet 2007; 23:326-33. [PMID: 17524519 DOI: 10.1016/j.tig.2007.05.004] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 04/16/2007] [Accepted: 05/11/2007] [Indexed: 10/23/2022]
Abstract
Human endogenous retroviruses (HERVs) result from ancestral infection by infectious viruses over millions of years of primate evolution. Some are transcriptionally active, express proteins and therefore have the potential to cause disease. Here we review the controversial attempts to link them with cancer and autoimmunity. The main difficulty is that most HERVs investigated to date are present at the same locus in 100% of the population. However, a new class of insertionally polymorphic HERV-K family members, present in a minority of individuals, has recently been described. We propose that insertionally polymorphic HERVs could be novel genetic risk factors and hence provide a new lease of life for research into HERVs and disease.
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Affiliation(s)
- David Moyes
- The Kennedy Institute of Rheumatology, Imperial College London, London, UK
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21
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Buzdin A, Kovalskaya-Alexandrova E, Gogvadze E, Sverdlov E. At least 50% of human-specific HERV-K (HML-2) long terminal repeats serve in vivo as active promoters for host nonrepetitive DNA transcription. J Virol 2006; 80:10752-62. [PMID: 17041225 PMCID: PMC1641792 DOI: 10.1128/jvi.00871-06] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We report the first genome-wide comparison of in vivo promoter activities of a group of human-specific endogenous retroviruses in healthy and cancerous germ line tissues. To this end, we employed a recently developed technique termed genomic repeat expression monitoring. We found that at least 50% of human-specific long terminal repeats (LTRs) possessed promoter activity, and many of them were up- or downregulated in a seminoma. Individual LTRs were expressed at markedly different levels, ranging from approximately 0.001 to approximately 3% of the housekeeping beta-actin gene transcript level. We demonstrated that the main factors affecting the LTR promoter activity were the LTR type (5'-proviral, 3' proviral, or solitary) and position with regard to genes. The averaged promoter strengths of solitary and 3'-proviral LTRs were almost identical in both tissues, whereas 5'-proviral LTRs displayed two- to fivefold higher promoter activities. The relative content of promoter-active LTRs in gene-rich regions was significantly higher than that in gene-poor loci. This content was maximal in those regions where LTRs "overlapped" readthrough transcripts. Although many promoter-active LTRs were mapped near known genes, no clear-cut correlation was observed between transcriptional activities of genes and neighboring LTRs. Our data also suggest a selective suppression of transcription for LTRs located in gene introns.
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Affiliation(s)
- Anton Buzdin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 16/10 Miklukho-Maklaya, Moscow 117997, Russia.
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22
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Herrera RJ, Lowery RK, Alfonso A, McDonald JF, Luis JR. Ancient retroviral insertions among human populations. J Hum Genet 2006; 51:353-362. [PMID: 16518567 DOI: 10.1007/s10038-006-0370-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Accepted: 12/25/2005] [Indexed: 10/25/2022]
Abstract
Human endogenous retroviruses (HERVs) represent vestiges of ancient infections that resulted in stable integration of the viral genome. These insertional elements of viral origin are in fact molecular fossils and, as such, a source of evolutionary information. A family of HERV insertions designated HERV-K includes members that are still polymorphic for the original insertional event. The goal of this report is to describe a novel genetic marker system based on polymorphic retroviral insertions (PRVIs) and to assess its potential usefulness in human population genetic analyses. The allelic frequencies of four insertionally polymorphic HERV-K loci were analyzed in nine geographically targeted, worldwide populations. A polymerase chain reaction assay was employed to examine the frequencies of the provirus and/or solo long terminal repeat insertions at these four loci. Several statistical and phylogenetic analyses were performed based on the frequency data. The phylogenetic relationships observed among the nine populations based on the four retroviral HERV-K loci are consistent not only with prior genetic analyses with other traditional marker systems but also with reported historical and biogeographical data. These polymorphic endogenous retroviral sequences display features that make them excellent tools for forensic and population genetic studies.
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Affiliation(s)
- Rene J Herrera
- Department of Biological Sciences, Florida International University, University Park, OE 304, Miami, FL, 33199, USA.
| | - Robert K Lowery
- Department of Biological Sciences, Florida International University, University Park, OE 304, Miami, FL, 33199, USA
| | - Abraham Alfonso
- Department of Biological Sciences, Florida International University, University Park, OE 304, Miami, FL, 33199, USA
| | - John F McDonald
- School of Biology, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA, 30332-0230, USA
| | - Javier R Luis
- Department of Biological Sciences, Florida International University, University Park, OE 304, Miami, FL, 33199, USA
- Departamento de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, Vigo, Spain
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23
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Kovalskaya E, Buzdin A, Gogvadze E, Vinogradova T, Sverdlov E. Functional human endogenous retroviral LTR transcription start sites are located between the R and U5 regions. Virology 2006; 346:373-8. [PMID: 16337666 DOI: 10.1016/j.virol.2005.11.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 10/10/2005] [Accepted: 11/07/2005] [Indexed: 10/25/2022]
Abstract
Human endogenous retroviruses (HERVs) occupy about 5% of human DNA and are thought to be remnants of ancient retroviral infections of human ancestors' germ cells. HERVs can modify expression of host cell genes through their cis-regulatory elements concentrated in their long terminal repeats (LTRs). Although numerous HERV-related RNAs were identified in the human transcriptome, for most of them, it remains unclear whether they are LTR-promoted or read-through products initiated from neighboring genomic promoters. Here, we describe mapping of transcriptional start sites within solitary and proviral LTRs of the HERV-K (HML-2) human-specific subfamily of endogenous retroviruses. Surprisingly, the transcription was initiated predominantly from the very 3' termini of the LTR R regions. The data presented here may shed light on adaptive coevolution of human endogenous retroviruses with their host cells.
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Affiliation(s)
- Elena Kovalskaya
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 16/10 Miklukho-Maklaya, Moscow 117997, Russia
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24
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Katzourakis A, Rambaut A, Pybus OG. The evolutionary dynamics of endogenous retroviruses. Trends Microbiol 2005; 13:463-8. [PMID: 16109487 DOI: 10.1016/j.tim.2005.08.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 07/22/2005] [Accepted: 08/08/2005] [Indexed: 11/23/2022]
Abstract
Endogenous retroviruses (ERVs) are vertically transmitted intragenomic elements derived from integrated retroviruses. ERVs can proliferate within the genome of their host until they either acquire inactivating mutations or are lost by recombinational deletion. We present a model that unifies current knowledge of ERV biology into a single evolutionary framework. The model predicts the possible long-term outcomes of retroviral germline infection and can account for the variable patterns of observed ERV genetic diversity. We hope the model will provide a useful framework for understanding ERV evolution, enabling the testing of evolutionary hypotheses and the estimation of parameters governing ERV proliferation.
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Affiliation(s)
- Aris Katzourakis
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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25
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Buzdin A, Vinogradova T, Lebedev Y, Sverdlov E. Genome-wide experimental identification and functional analysis of human specific retroelements. Cytogenet Genome Res 2005; 110:468-74. [PMID: 16093700 DOI: 10.1159/000084980] [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: 10/16/2003] [Accepted: 12/18/2003] [Indexed: 12/24/2022] Open
Abstract
Retroelements (REs) actively reshape genomes through genomic rearrangements, creation of new genes and modulation of the regulatory machinery of existing genes, thus introducing genomic novelties which potentially may be subject to natural selection. Thousands of RE integrations, presumably distinguishing the human and chimpanzee genomes, might well be involved in modern human speciation. In this self-review we describe our recent results on genome-wide identification of human specific RE integrations and their transcriptional activity obtained with three new experimental techniques (TGDA, DiffIR and SDDIR) developed by us for such studies. A new mechanism of the formation of retroelements involving template switches during L1-mediated mRNA reverse transcription, revealed in this research, will also be described in the review.
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Affiliation(s)
- A Buzdin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
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26
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Belshaw R, Dawson ALA, Woolven-Allen J, Redding J, Burt A, Tristem M. Genomewide screening reveals high levels of insertional polymorphism in the human endogenous retrovirus family HERV-K(HML2): implications for present-day activity. J Virol 2005; 79:12507-14. [PMID: 16160178 PMCID: PMC1211540 DOI: 10.1128/jvi.79.19.12507-12514.2005] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Accepted: 07/01/2005] [Indexed: 11/20/2022] Open
Abstract
The published human genome sequence contains many thousands of endogenous retroviruses (HERVs) but all are defective, containing nonsense mutations or major deletions. Only the HERV-K(HML2) family has been active since the divergence of humans and chimpanzees; it contains many members that are human specific, as well as several that are insertionally polymorphic (an inserted element present only in some human individuals). Here we perform a genomewide survey of insertional polymorphism levels in this family by using the published human genome sequence and a diverse sample of 19 humans. We find that there are 113 human-specific HERV-K(HML2) elements in the human genome sequence, 8 of which are insertionally polymorphic (11 if we extrapolate to those within regions of the genome that were not suitable for amplification). The average rate of accumulation since the divergence with chimpanzees is thus approximately 3.8 x 10(-4) per haploid genome per generation. Furthermore, we find that the number of polymorphic elements is not significantly different from that predicted by a standard population genetic model that assumes constant activity of the family until the present. This suggests to us that the HERV-K(HML2) family may be active in present-day humans. Active (replication-competent) elements are likely to have inserted very recently and to be present at low allele frequencies, and they may be causing disease in the individuals carrying them. This view of the family from a population perspective rather than a genome perspective will inform the current debate about a possible role of HERV-K(HML2) in human disease.
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Affiliation(s)
- Robert Belshaw
- Department of Biological Sciences, Imperial College, Ascot, Berks, United Kingdom.
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27
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Mamedov IZ, Arzumanyan ES, Amosova AL, Lebedev YB, Sverdlov ED. Whole-genome experimental identification of insertion/deletion polymorphisms of interspersed repeats by a new general approach. Nucleic Acids Res 2005; 33:e16. [PMID: 15673711 PMCID: PMC548376 DOI: 10.1093/nar/gni018] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A new experimental technique for genome-wide detection of integration sites of polymorphic retroelements (REs) is described. The technique allows one to reveal the absence of a retroelement in an individual genome provided that this retroelement is present in at least one of several other genomes under comparison. Since quite a number of genomes are compared simultaneously, the search for polymorphic REs insertions is very efficient. The technique includes two whole-genome selective PCR amplifications of sequences flanking REs: one for a particular genome and another one for a mixture of ten different genomes. A subsequent subtractive hybridization of the obtained amplicons with DNA of a particular genome as driver results in isolation of polymorphic insertions. The technique was successfully applied for identification of 41 new polymorphic human AluYa5/Ya8 insertions. Among them, 18 individual Alu elements first sequenced in this work were not found in the available human genome databases. This result suggests that significant part of polymorphic REs were not identified during genome sequencing and remain to be detected and characterized. The proposed method does not depend on preliminary knowledge of evolutionary history of retroelements and can be applied for identification of insertion/deletion polymorphic markers in genomes of different species.
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Affiliation(s)
- Ilgar Z Mamedov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences 16/10 Miklukho-Maklaya Street, 117997 Moscow, Russia.
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