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An Z, Jiang A, Chen J. Toward understanding the role of genomic repeat elements in neurodegenerative diseases. Neural Regen Res 2025; 20:646-659. [PMID: 38886931 PMCID: PMC11433896 DOI: 10.4103/nrr.nrr-d-23-01568] [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: 09/18/2023] [Revised: 12/21/2023] [Accepted: 03/02/2024] [Indexed: 06/20/2024] Open
Abstract
Neurodegenerative diseases cause great medical and economic burdens for both patients and society; however, the complex molecular mechanisms thereof are not yet well understood. With the development of high-coverage sequencing technology, researchers have started to notice that genomic repeat regions, previously neglected in search of disease culprits, are active contributors to multiple neurodegenerative diseases. In this review, we describe the association between repeat element variants and multiple degenerative diseases through genome-wide association studies and targeted sequencing. We discuss the identification of disease-relevant repeat element variants, further powered by the advancement of long-read sequencing technologies and their related tools, and summarize recent findings in the molecular mechanisms of repeat element variants in brain degeneration, such as those causing transcriptional silencing or RNA-mediated gain of toxic function. Furthermore, we describe how in silico predictions using innovative computational models, such as deep learning language models, could enhance and accelerate our understanding of the functional impact of repeat element variants. Finally, we discuss future directions to advance current findings for a better understanding of neurodegenerative diseases and the clinical applications of genomic repeat elements.
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Affiliation(s)
- Zhengyu An
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Aidi Jiang
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Jingqi Chen
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
- MOE Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Shanghai, China
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2
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Romerio F. Origin and functional role of antisense transcription in endogenous and exogenous retroviruses. Retrovirology 2023; 20:6. [PMID: 37194028 DOI: 10.1186/s12977-023-00622-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/30/2023] [Indexed: 05/18/2023] Open
Abstract
Most proteins expressed by endogenous and exogenous retroviruses are encoded in the sense (positive) strand of the genome and are under the control of regulatory elements within the 5' long terminal repeat (LTR). A number of retroviral genomes also encode genes in the antisense (negative) strand and their expression is under the control of negative sense promoters within the 3' LTR. In the case of the Human T-cell Lymphotropic Virus 1 (HTLV-1), the antisense protein HBZ has been shown to play a critical role in the virus lifecycle and in the pathogenic process, while the function of the Human Immunodeficiency Virus 1 (HIV-1) antisense protein ASP remains unknown. However, the expression of 3' LTR-driven antisense transcripts is not always demonstrably associated with the presence of an antisense open reading frame encoding a viral protein. Moreover, even in the case of retroviruses that do express an antisense protein, such as HTLV-1 and the pandemic strains of HIV-1, the 3' LTR-driven antisense transcript shows both protein-coding and noncoding activities. Indeed, the ability to express antisense transcripts appears to be phylogenetically more widespread among endogenous and exogenous retroviruses than the presence of a functional antisense open reading frame within these transcripts. This suggests that retroviral antisense transcripts may have originated as noncoding molecules with regulatory activity that in some cases later acquired protein-coding function. Here, we will review examples of endogenous and exogenous retroviral antisense transcripts, and the ways through which they benefit viral persistence in the host.
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Affiliation(s)
- Fabio Romerio
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Reviewing the Potential Links between Viral Infections and TDP-43 Proteinopathies. Int J Mol Sci 2023; 24:ijms24021581. [PMID: 36675095 PMCID: PMC9867397 DOI: 10.3390/ijms24021581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 01/15/2023] Open
Abstract
Transactive response DNA binding protein 43 kDa (TDP-43) was discovered in 2001 as a cellular factor capable to inhibit HIV-1 gene expression. Successively, it was brought to new life as the most prevalent RNA-binding protein involved in several neurological disorders, such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Despite the fact that these two research areas could be considered very distant from each other, in recent years an increasing number of publications pointed out the existence of a potentially important connection. Indeed, the ability of TDP-43 to act as an important regulator of all aspects of RNA metabolism makes this protein also a critical factor during expression of viral RNAs. Here, we summarize all recent observations regarding the involvement of TDP-43 in viral entry, replication and latency in several viruses that include enteroviruses (EVs), Theiler's murine encephalomyelitis virus (TMEV), human immunodeficiency virus (HIV), human endogenous retroviruses (HERVs), hepatitis B virus (HBV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), West Nile virus (WNV), and herpes simplex virus-2 (HSV). In particular, in this work, we aimed to highlight the presence of similarities with the most commonly studied TDP-43 related neuronal dysfunctions.
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Kessler SE, Tsangaras K, Rasoloharijaona S, Radespiel U, Greenwood AD. Long-term host-pathogen evolution of endogenous beta- and gammaretroviruses in mouse lemurs with little evidence of recent retroviral introgression. Virus Evol 2022; 9:veac117. [PMID: 36632481 PMCID: PMC9825726 DOI: 10.1093/ve/veac117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 11/03/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022] Open
Abstract
Madagascar's flora and fauna have evolved in relative isolation since the island split from the African and Indian continents. When the last common ancestors of lemurs left Africa between 40 and 70 million years ago, they carried a subset of the viral diversity of the mainland population within them, which continued to evolve throughout the lemur radiation. Relative to other primate radiations, we know very little about the past or present viral diversity of lemurs, particularly mouse lemurs. Using high-throughput sequencing, we identified two gammaretroviruses and three betaretroviruses in the genomes of four species of wild mouse lemurs. The two gammaretroviruses and two betaretroviruses have not previously been described. One betaretrovirus was previously identified. All identified viruses are present in both Lorisiformes and Lemuriformes but absent from haplorrhine primates. The estimated ages of these viruses are consistent with the estimated divergence dates of the host lineages, suggesting they colonized the lemur genome after the Haplorrhine-Strepsirrhine split, but before the Lorisiformes-Lemuriformes split and before the colonization of Madagascar. The viral phylogenies connect multiple lineages of retroviruses from non-lemur and non-Madagascar-native species, suggesting substantial cross-species transmission occurred deep in the primate clade prior to its geographic dispersal. These phylogenies provide novel insights into known retroviral clades. They suggest that the origin of gammaretroviruses in rodents or bats may be premature and that the Jaagsiekte sheep virus clade may be older and more broadly distributed among mammals than previously thought.
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Affiliation(s)
| | - Kyriakos Tsangaras
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Straße 17, Berlin 10315, Germany,Department of Life and Health Sciences, University of Nicosia, 46 Makedonitissas Avenue, CY-2417, P.O. Box 24005, Nicosia, CY-1700, Cyprus
| | - Solofonirina Rasoloharijaona
- Faculty of Science, Technology and Environment, University of Mahajanga, 5 Georges V Street - Building KAKAL Mahajanga Be - Po. Box 652 , Mahajanga 401, Madagascar
| | - Ute Radespiel
- Institute of Zoology, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, Hannover 30559, Germany
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Ilse V, Scholz R, Wermann M, Naumann M, Staege MS, Roßner S, Cynis H. Immunogenicity of the Envelope Surface Unit of Human Endogenous Retrovirus K18 in Mice. Int J Mol Sci 2022; 23:ijms23158330. [PMID: 35955468 PMCID: PMC9369184 DOI: 10.3390/ijms23158330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 02/06/2023] Open
Abstract
The triggers for the development of multiple sclerosis (MS) have not been fully understood to date. One hypothesis proposes a viral etiology. Interestingly, viral proteins from human endogenous retroviruses (HERVs) may play a role in the pathogenesis of MS. Allelic variants of the HERV-K18 env gene represent a genetic risk factor for MS, and the envelope protein is considered to be an Epstein–Barr virus-trans-activated superantigen. To further specify a possible role for HERV-K18 in MS, the present study examined the immunogenicity of the purified surface unit (SU). HERV-K18(SU) induced envelope-specific plasma IgG in immunized mice and triggered proliferation of T cells isolated from these mice. It did not trigger phenotypic changes in a mouse model of experimental autoimmune encephalomyelitis. Further studies are needed to investigate the underlying mechanisms of HERV-K18 interaction with immune system regulators in more detail.
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Affiliation(s)
- Victoria Ilse
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Rebekka Scholz
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Michael Wermann
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Marcel Naumann
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Martin S. Staege
- Department of Surgical and Conservative Pediatrics and Adolescent Medicine, Medical Faculty, Martin Luther University Halle-Wittenberg, Ernst-Grube-Str. 40, 06097 Halle, Germany;
| | - Steffen Roßner
- Paul Flechsig Institute for Brain Research, Leipzig University, Liebigstraße 19, 04103 Leipzig, Germany;
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
- Correspondence: ; Tel.: +49-345-13142835; Fax: +49-345-13142801
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Predicted Cellular Interactors of the Endogenous Retrovirus-K Integrase Enzyme. Microorganisms 2021; 9:microorganisms9071509. [PMID: 34361946 PMCID: PMC8303831 DOI: 10.3390/microorganisms9071509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/06/2021] [Accepted: 07/09/2021] [Indexed: 12/18/2022] Open
Abstract
Integrase (IN) enzymes are found in all retroviruses and are crucial in the retroviral integration process. Many studies have revealed how exogenous IN enzymes, such as the human immunodeficiency virus (HIV) IN, contribute to altered cellular function. However, the same consideration has not been given to viral IN originating from symbionts within our own DNA. Endogenous retrovirus-K (ERVK) is pathologically associated with neurological and inflammatory diseases along with several cancers. The ERVK IN interactome is unknown, and the question of how conserved the ERVK IN protein-protein interaction motifs are as compared to other retroviral integrases is addressed in this paper. The ERVK IN protein sequence was analyzed using the Eukaryotic Linear Motif (ELM) database, and the results are compared to ELMs of other betaretroviral INs and similar eukaryotic INs. A list of putative ERVK IN cellular protein interactors was curated from the ELM list and submitted for STRING analysis to generate an ERVK IN interactome. KEGG analysis was used to identify key pathways potentially influenced by ERVK IN. It was determined that the ERVK IN potentially interacts with cellular proteins involved in the DNA damage response (DDR), cell cycle, immunity, inflammation, cell signaling, selective autophagy, and intracellular trafficking. The most prominent pathway identified was viral carcinogenesis, in addition to select cancers, neurological diseases, and diabetic complications. This potentiates the role of ERVK IN in these pathologies via protein-protein interactions facilitating alterations in key disease pathways.
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Weber M, Padmanabhan Nair V, Bauer T, Sprinzl MF, Protzer U, Vincendeau M. Increased HERV-K(HML-2) Transcript Levels Correlate with Clinical Parameters of Liver Damage in Hepatitis C Patients. Cells 2021; 10:cells10040774. [PMID: 33807462 PMCID: PMC8065411 DOI: 10.3390/cells10040774] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/27/2021] [Accepted: 03/29/2021] [Indexed: 12/23/2022] Open
Abstract
Chronic hepatitis C virus (HCV) infection is closely associated with a plethora of diseases, including cancers and autoimmune disorders. However, the distinct triggers and cellular networks leading to such HCV-derived diseases are poorly understood. Around 8% of the human genome consists of human endogenous retroviruses. They are usually silenced but can be reactivated by environmental conditions, including viral infections. Our current understanding indicates that the activation of one specific family-namely, HERV-K(HML-2)-is linked to distinct pathologies, including cancer and autoimmunity. In this study, we analyzed the transcription levels of HERV-K(HML-2) in 42 HCV-infected patients receiving direct-acting antiviral therapies. Samples from the start of treatment until 12 weeks post-treatment were investigated. Our results show increased HERV-K(HML-2) transcript levels in patients with HCV-derived liver cirrhosis throughout the observation period. Several clinical parameters specifying poor liver function are positively correlated with HERV-K(HML-2) expression. Of note, patients without a sustained viral clearance showed a drastic increase in HERV-K(HML-2) transcript levels. Together, our data suggest that increased HERV-K(HML-2) expression is correlated with reduced liver function as well as therapy success in HCV-infected patients.
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Affiliation(s)
- Melanie Weber
- Institute of Virology, HelmholtzZentrum München, Neuherberg 85764, Germany; (M.W.); (V.P.N.); (T.B.)
| | - Vidya Padmanabhan Nair
- Institute of Virology, HelmholtzZentrum München, Neuherberg 85764, Germany; (M.W.); (V.P.N.); (T.B.)
| | - Tanja Bauer
- Institute of Virology, HelmholtzZentrum München, Neuherberg 85764, Germany; (M.W.); (V.P.N.); (T.B.)
- Institute of Virology, Technische Universität München, Munich 81675, Germany
- German Center for Infection Research (DZIF), Partner Site, Munich 81675, Germany
| | - Martin F. Sprinzl
- Medical Department, University Hospital Mainz, Mainz 55131, Germany;
| | - Ulrike Protzer
- Institute of Virology, HelmholtzZentrum München, Neuherberg 85764, Germany; (M.W.); (V.P.N.); (T.B.)
- Institute of Virology, Technische Universität München, Munich 81675, Germany
- German Center for Infection Research (DZIF), Partner Site, Munich 81675, Germany
- Correspondence: (U.P.); (M.V.)
| | - Michelle Vincendeau
- Institute of Virology, HelmholtzZentrum München, Neuherberg 85764, Germany; (M.W.); (V.P.N.); (T.B.)
- Correspondence: (U.P.); (M.V.)
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Gröger V, Emmer A, Staege MS, Cynis H. Endogenous Retroviruses in Nervous System Disorders. Pharmaceuticals (Basel) 2021; 14:ph14010070. [PMID: 33467098 PMCID: PMC7829834 DOI: 10.3390/ph14010070] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
Human endogenous retroviruses (HERV) have been implicated in the pathogenesis of several nervous system disorders including multiple sclerosis and amyotrophic lateral sclerosis. The toxicity of HERV-derived RNAs and proteins for neuronal cells has been demonstrated. The involvement of HERV in the pathogenesis of currently incurable diseases might offer new treatment strategies based on the inhibition of HERV activities by small molecules or therapeutic antibodies.
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Affiliation(s)
- Victoria Gröger
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, 06120 Halle (Saale), Germany;
| | - Alexander Emmer
- Department of Neurology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany;
| | - Martin S. Staege
- Department of Surgical and Conservative Pediatrics and Adolescent Medicine, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
- Correspondence: (M.S.S.); (H.C.); Tel.: +49-345-557-7280 (M.S.S.); +49-345-13142835 (H.C.)
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, 06120 Halle (Saale), Germany;
- Correspondence: (M.S.S.); (H.C.); Tel.: +49-345-557-7280 (M.S.S.); +49-345-13142835 (H.C.)
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Yee JL, Grant RF, Van Rompay KKA, Roberts JA, Kuller L, Cunningham JL, Simmons JH, Papin JF. In vitro and In vivo Susceptibility of Baboons ( Papio sp.) to Infection with and Apparent Antibody Reactivity to Simian Betaretrovirus (SRV). Comp Med 2020; 70:75-82. [PMID: 31747991 PMCID: PMC7024778 DOI: 10.30802/aalas-cm-19-000014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/04/2019] [Accepted: 04/19/2019] [Indexed: 11/05/2022]
Abstract
Despite the lack of confirmed reports of an exogenous Simian betaretrovirus (SRV) isolated from baboons (Papio sp.), reports of simian endogenous gammaretrovirus (SERV) in baboons with complete genomes suggest that such viruses may be potentially infectious. In addition, serologic tests have repeatedly demonstrated antibody reactivity to SRV in baboons from multiple colonies. These findings complicate the management and use of such animals for research. To provide further insight into this situation, we performed in vitro and in vivo studies to determine if baboons are or can be infected with SRV. In our initial experiment, we were not able to isolate SRV from 6 seropositive or sero-indeterminate baboons by coculturing their peripheral blood mononuclear cells (PBMC) with macaque PBMC or permissive cell lines. In a subsequent experiment, we found that baboon PBMC infected in vitro with high dose SRV were permissive to virus replication. To test in vivo infectibil- ity, groups of naive baboons were infused intravenously with either (i) the same SRV tissue culture virus stocks used for the in vitro studies, (ii) SRV antibody positive and PCR positive macaque blood, (iii) SRV antibody positive or indeterminate, but PCR negative baboon blood, or (iv) SRV antibody and PCR negative baboon blood. Sustained SRV infection, as defined by reproducible PCR detection and/or antibody seroconversion, was confirmed in 2 of 3 baboons receiving tissue culture virus but not in any recipients of transfused blood from seropositive macaques or baboons. In conclusion, the data indicate that even though baboon cells can be infected experimentally with high doses of tissue culture grown SRV, baboons that are repeatedly SRV antibody positive and PCR negative are unlikely to be infected with exogenous SRV and thus are unlikely to transmit a virus that would threaten the SPF status of captive baboon colonies.
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Affiliation(s)
- JoAnn L Yee
- California National Primate Research Center, University of California, Davis, California
| | - Richard F Grant
- Washington National Primate Research Center, University of Washington, Seattle, Washington
| | - Koen K A Van Rompay
- California National Primate Research Center, University of California, Davis, California
| | - Jeffrey A Roberts
- California National Primate Research Center, University of California, Davis, California
| | - LaRene Kuller
- Washington National Primate Research Center, University of Washington, Seattle, Washington
| | - Jesse L Cunningham
- California National Primate Research Center, University of California, Davis, California
| | - Joe H Simmons
- Michale E. Keeling Center for Comparative Medicine and Research, University of Texas MD Anderson Cancer Center, Bastrop, Texas; and
| | - James F Papin
- Department of Pathology, Division of Comparative Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma
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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: 58] [Impact Index Per Article: 9.7] [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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Grandi N, Tramontano E. Human Endogenous Retroviruses Are Ancient Acquired Elements Still Shaping Innate Immune Responses. Front Immunol 2018; 9:2039. [PMID: 30250470 PMCID: PMC6139349 DOI: 10.3389/fimmu.2018.02039] [Citation(s) in RCA: 180] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/20/2018] [Indexed: 12/25/2022] Open
Abstract
About 8% of our genome is composed of sequences with viral origin, namely human Endogenous Retroviruses (HERVs). HERVs are relics of ancient infections that affected the primates' germ line along the last 100 million of years, and became stable elements at the interface between self and foreign DNA. Intriguingly, HERV co-evolution with the host led to the domestication of activities previously devoted to the retrovirus life cycle, providing novel cellular functions. For example, selected HERV envelope proteins have been coopted for pregnancy-related purposes, and proviral Long Terminal Repeats participate in the transcriptional regulation of various cellular genes. Given the HERV persistence in the host genome and its basal expression in most healthy tissues, it is reasonable that human defenses should prevent HERV-mediated immune activation. Despite this, HERVs and their products (including RNA, cytosolic DNA, and proteins) are still able to modulate and be influenced by the host immune system, fascinatingly suggesting a central role in the evolution and functioning of the human innate immunity. Indeed, HERV sequences had been major contributors in shaping and expanding the interferon network, dispersing inducible genes that have been occasionally domesticated in various mammalian lineages. Also the HERV integration within or near to genes encoding for critical immune factors has been shown to influence their activity, or to be responsible for their polymorphic variation in the human population, such as in the case of an HERV-K(HML10) provirus in the major histocompatibility complex region. In addition, HERV expressed products have been shown to modulate innate immunity effectors, being therefore often related on the one side to inflammatory and autoimmune disorders, while on the other side to the control of excessive immune activation through their immunosuppressive properties. Finally, HERVs have been proposed to establish a protective effect against exogenous infections. The present review summarizes the involvement of HERVs and their products in innate immune responses, describing how their intricate interplay with the first line of human defenses can actively contribute either to the host protection or to his damage, implying a subtle balance between the persistence of HERV expression and the maintenance of a basal immune alert.
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Affiliation(s)
- Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy.,Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Cagliari, Italy
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12
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Hua Y, Wang J, Yuan DL, Qi Y, Tang Z, Zhu X, Jiang SW. A tag SNP in syncytin-2 3-UTR significantly correlates with the risk of severe preeclampsia. Clin Chim Acta 2018; 483:265-270. [PMID: 29750965 DOI: 10.1016/j.cca.2018.05.013] [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: 04/23/2018] [Revised: 05/05/2018] [Accepted: 05/07/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND Preeclampsia is a disease that frequently complicates pregnancy and poses a serious threat to maternal and fetal health. The causes and pathogenic mechanisms of preeclampsia are poorly defined. Genetic predisposition could be an important etiological factor. Previous studies have demonstrated that syncytin-1 and syncytin-2, encoded by the genes ERVWE1 and ERVFRDE-1, are involved in the pathogenesis of preeclampsia. METHODS In this study, we applied multiplex PCR and MALDI-TOF MS techniques to analyze six selected tag SNPs of ERVWE1 and ERVFRDE-1 in 120 preeclampsia patients and 181 normal controls. RESULTS One SNP polymorphism (rs9393931) with the recessive TT genotype located in the 3-UTR of ERVFRDE-1 gene was found to be significantly associated with an increased risk of preeclampsia (OR (95% CI) = 2.05 (1.27-3.32); p = 2.8 × 10-3). No significant correlation of this polymorphism with the clinical severity of preeclampsia, e.g. the extent of hypertension, was detected between carrier and non-carrier patients. CONCLUSIONS These results suggested that genetic predisposition in ERVFRDE-1 may be associated with an increased risk of preeclampsia. This polymorphism is possibly involved in the regulation of syncytin-2 expression in preeclamptic placenta.
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Affiliation(s)
- Ying Hua
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital and Yuying Children of Wenzhou Medical University, Wenzhou 325027, China
| | - Jing Wang
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Dong-Lan Yuan
- Department of Gynecology, Beijing Obstetrics and Gynecology, Taizhou People's Hospital, Taizhou 225300, Jiangsu, China
| | - Yaozhi Qi
- Department of Clinical Laboratory, Lianyungang, Maternal and Child Health Hospital, Jiangsu 222005, China
| | - Zuoqing Tang
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Xueqiong Zhu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital and Yuying Children of Wenzhou Medical University, Wenzhou 325027, China.
| | - Shi-Wen Jiang
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital and Yuying Children of Wenzhou Medical University, Wenzhou 325027, China; Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA 31404, USA.
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Novel endogenous simian retroviral integrations in Vero cells: implications for quality control of a human vaccine cell substrate. Sci Rep 2018; 8:644. [PMID: 29330501 PMCID: PMC5766633 DOI: 10.1038/s41598-017-18934-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 12/14/2017] [Indexed: 12/28/2022] Open
Abstract
African green monkey (AGM)-derived Vero cells have been utilized to produce various human vaccines. The Vero cell genome harbors a variety of simian endogenous type D retrovirus (SERV) sequences. In this study, a transcriptome analysis showed that DNA hypomethylation released the epigenetic repression of SERVs in Vero cells. Moreover, comparative genomic analysis of three Vero cell sublines and an AGM reference revealed that the genomes of the sublines have ~80 SERV integrations. Among them, ~60 integrations are present within all three cell sublines and absent from the reference sequence. At least several of these integrations consist of complete SERV proviruses. These results strongly suggest that SERVs integrated in the genome of Vero cells did not retrotranspose after the establishment of the cell lineage as far as cells were maintained under standard culture and passage conditions, providing a scientific basis for controlling the quality of pharmaceutical cell substrates and their derived biologics.
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Koonin EV. Viruses and mobile elements as drivers of evolutionary transitions. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0442. [PMID: 27431520 PMCID: PMC4958936 DOI: 10.1098/rstb.2015.0442] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2016] [Indexed: 12/22/2022] Open
Abstract
The history of life is punctuated by evolutionary transitions which engender emergence of new levels of biological organization that involves selection acting at increasingly complex ensembles of biological entities. Major evolutionary transitions include the origin of prokaryotic and then eukaryotic cells, multicellular organisms and eusocial animals. All or nearly all cellular life forms are hosts to diverse selfish genetic elements with various levels of autonomy including plasmids, transposons and viruses. I present evidence that, at least up to and including the origin of multicellularity, evolutionary transitions are driven by the coevolution of hosts with these genetic parasites along with sharing of ‘public goods’. Selfish elements drive evolutionary transitions at two distinct levels. First, mathematical modelling of evolutionary processes, such as evolution of primitive replicator populations or unicellular organisms, indicates that only increasing organizational complexity, e.g. emergence of multicellular aggregates, can prevent the collapse of the host–parasite system under the pressure of parasites. Second, comparative genomic analysis reveals numerous cases of recruitment of genes with essential functions in cellular life forms, including those that enable evolutionary transitions. This article is part of the themed issue ‘The major synthetic evolutionary transitions’.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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15
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Retroviral envelope proteins: Involvement in neuropathogenesis. J Neurol Sci 2017; 380:151-163. [DOI: 10.1016/j.jns.2017.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/23/2017] [Accepted: 07/18/2017] [Indexed: 02/07/2023]
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Grandi N, Tramontano E. Type W Human Endogenous Retrovirus (HERV-W) Integrations and Their Mobilization by L1 Machinery: Contribution to the Human Transcriptome and Impact on the Host Physiopathology. Viruses 2017; 9:v9070162. [PMID: 28653997 PMCID: PMC5537654 DOI: 10.3390/v9070162] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/08/2017] [Accepted: 06/20/2017] [Indexed: 01/07/2023] Open
Abstract
Human Endogenous Retroviruses (HERVs) are ancient infection relics constituting ~8% of our DNA. While HERVs’ genomic characterization is still ongoing, impressive amounts of data have been obtained regarding their general expression across tissues. Among HERVs, one of the most studied is the W group, which is the sole HERV group specifically mobilized by the long interspersed element-1 (LINE-1) machinery, providing a source of novel insertions by retrotransposition of HERV-W processed pseudogenes, and comprising a member encoding a functional envelope protein coopted for human placentation. The HERV-W group has been intensively investigated for its putative role in several diseases, such as cancer, inflammation, and autoimmunity. Despite major interest in the link between HERV-W expression and human pathogenesis, no conclusive correlation has been demonstrated so far. In general, (i) the absence of a proper identification of the specific HERV-W sequences expressed in a given condition; and (ii) the lack of studies attempting to connect the various observations in the same experimental conditions are the major problems preventing the definitive assessment of the HERV-W impact on human physiopathology. In this review, we summarize the current knowledge on the HERV-W group presence within the human genome and its expression in physiological tissues as well as in the main pathological contexts.
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Affiliation(s)
- Nicole Grandi
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554, 09042 Monserrato, Cagliari, Italy.
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554, 09042 Monserrato, Cagliari, Italy.
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche (CNR), 09042 Monserrato, Cagliari, Italy.
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Hancks DC, Kazazian HH. Roles for retrotransposon insertions in human disease. Mob DNA 2016; 7:9. [PMID: 27158268 PMCID: PMC4859970 DOI: 10.1186/s13100-016-0065-9] [Citation(s) in RCA: 421] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/14/2016] [Indexed: 12/12/2022] Open
Abstract
Over evolutionary time, the dynamic nature of a genome is driven, in part, by the activity of transposable elements (TE) such as retrotransposons. On a shorter time scale it has been established that new TE insertions can result in single-gene disease in an individual. In humans, the non-LTR retrotransposon Long INterspersed Element-1 (LINE-1 or L1) is the only active autonomous TE. In addition to mobilizing its own RNA to new genomic locations via a "copy-and-paste" mechanism, LINE-1 is able to retrotranspose other RNAs including Alu, SVA, and occasionally cellular RNAs. To date in humans, 124 LINE-1-mediated insertions which result in genetic diseases have been reported. Disease causing LINE-1 insertions have provided a wealth of insight and the foundation for valuable tools to study these genomic parasites. In this review, we provide an overview of LINE-1 biology followed by highlights from new reports of LINE-1-mediated genetic disease in humans.
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Affiliation(s)
- Dustin C. Hancks
- />Eccles Institute of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT USA
| | - Haig H. Kazazian
- />McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins School of Medicine, Baltimore, MD USA
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18
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Biniossek ML, Niemer M, Maksimchuk K, Mayer B, Fuchs J, Huesgen PF, McCafferty DG, Turk B, Fritz G, Mayer J, Haecker G, Mach L, Schilling O. Identification of Protease Specificity by Combining Proteome-Derived Peptide Libraries and Quantitative Proteomics. Mol Cell Proteomics 2016; 15:2515-24. [PMID: 27122596 DOI: 10.1074/mcp.o115.056671] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Indexed: 01/17/2023] Open
Abstract
We present protease specificity profiling based on quantitative proteomics in combination with proteome-derived peptide libraries. Peptide libraries are generated by endoproteolytic digestion of proteomes without chemical modification of primary amines before exposure to a protease under investigation. After incubation with a test protease, treated and control libraries are differentially isotope-labeled using cost-effective reductive dimethylation. Upon analysis by liquid chromatography-tandem mass spectrometry, cleavage products of the test protease appear as semi-specific peptides that are enriched for the corresponding isotope label. We validate our workflow with two proteases with well-characterized specificity profiles: trypsin and caspase-3. We provide the first specificity profile of a protease encoded by a human endogenous retrovirus and for chlamydial protease-like activity factor (CPAF). For CPAF, we also highlight the structural basis of negative subsite cooperativity between subsites S1 and S2'. For A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) -4, -5, and -15, we show a canonical preference profile, including glutamate in P1 and glycine in P3'. In total, we report nearly 4000 cleavage sites for seven proteases. Our protocol is fast, avoids enrichment or synthesis steps, and enables probing for lysine selectivity as well as subsite cooperativity. Due to its simplicity, we anticipate usability by most proteomic laboratories.
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Affiliation(s)
| | - Melanie Niemer
- §Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | - Bettina Mayer
- From the ‡Institute of Molecular Medicine and Cell Research
| | | | - Pitter F Huesgen
- **Central Institute for Engineering, Electronics and Analytics, ZEA-3 Analytics, Forschungszentrum Jülich, 52425 Jülich, Germany
| | | | - Boris Turk
- ‡‡Department of Chemistry, Duke University, Medical Center, Durham, NC 27708, USA; Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Guenther Fritz
- §§Department of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Ljubljana, Slovenia; Department of Human Genetics and Center of Human and Molecular Biology, Medical Faculty, University of Saarland Homburg, Germany
| | | | | | - Lukas Mach
- §Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Oliver Schilling
- From the ‡Institute of Molecular Medicine and Cell Research, ‡‡‡BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany; §§§German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
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Tsangaras K, Mayer J, Alquezar-Planas DE, Greenwood AD. An Evolutionarily Young Polar Bear (Ursus maritimus) Endogenous Retrovirus Identified from Next Generation Sequence Data. Viruses 2015; 7:6089-107. [PMID: 26610552 PMCID: PMC4664997 DOI: 10.3390/v7112927] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/11/2015] [Accepted: 11/17/2015] [Indexed: 01/13/2023] Open
Abstract
Transcriptome analysis of polar bear (Ursus maritimus) tissues identified sequences with similarity to Porcine Endogenous Retroviruses (PERV). Based on these sequences, four proviral copies and 15 solo long terminal repeats (LTRs) of a newly described endogenous retrovirus were characterized from the polar bear draft genome sequence. Closely related sequences were identified by PCR analysis of brown bear (Ursus arctos) and black bear (Ursus americanus) but were absent in non-Ursinae bear species. The virus was therefore designated UrsusERV. Two distinct groups of LTRs were observed including a recombinant ERV that contained one LTR belonging to each group indicating that genomic invasions by at least two UrsusERV variants have recently occurred. Age estimates based on proviral LTR divergence and conservation of integration sites among ursids suggest the viral group is only a few million years old. The youngest provirus was polar bear specific, had intact open reading frames (ORFs) and could potentially encode functional proteins. Phylogenetic analyses of UrsusERV consensus protein sequences suggest that it is part of a pig, gibbon and koala retrovirus clade. The young age estimates and lineage specificity of the virus suggests UrsusERV is a recent cross species transmission from an unknown reservoir and places the viral group among the youngest of ERVs identified in mammals.
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Affiliation(s)
- Kyriakos Tsangaras
- Department of Translational Genetics, The Cyprus Institute of Neurology and Genetics, 6 International Airport Ave., 2370 Nicosia, Cyprus.
| | - Jens Mayer
- Department of Human Genetics, Center of Human and Molecular Biology, Medical Faculty, University of Saarland, 66421 Homburg, Germany.
| | - David E Alquezar-Planas
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research Berlin, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany.
| | - Alex D Greenwood
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research Berlin, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany.
- Department of Veterinary Medicine, Freie Universität Berlin, Oertzenweg 19b, 14163 Berlin, Germany.
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Xu H, Wang X, Veazey RS. Simian Immunodeficiency Virus Infection and Mucosal Immunity. Mucosal Immunol 2015. [DOI: 10.1016/b978-0-12-415847-4.00076-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Bae JH, Eo J, Kim TO, Yi JM. Biological changes of transposable elements by radiation: recent progress. Genes Genomics 2014. [DOI: 10.1007/s13258-014-0256-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Lexa M, Steflova P, Martinek T, Vorlickova M, Vyskot B, Kejnovsky E. Guanine quadruplexes are formed by specific regions of human transposable elements. BMC Genomics 2014; 15:1032. [PMID: 25431265 PMCID: PMC4407331 DOI: 10.1186/1471-2164-15-1032] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 10/29/2014] [Indexed: 11/23/2022] Open
Abstract
Background Transposable elements form a significant proportion of eukaryotic genomes. Recently, Lexa et al. (Nucleic Acids Res 42:968-978, 2014) reported that plant long terminal repeat (LTR) retrotransposons often contain potential quadruplex sequences (PQSs) in their LTRs and experimentally confirmed their ability to adopt four-stranded DNA conformations. Results Here, we searched for PQSs in human retrotransposons and found that PQSs are specifically localized in the 3’-UTR of LINE-1 elements, in LTRs of HERV elements and are strongly accumulated in specific regions of SVA elements. Circular dichroism spectroscopy confirmed that most PQSs had adopted monomolecular or bimolecular guanine quadruplex structures. Evolutionarily young SVA elements contained more PQSs than older elements and their propensity to form quadruplex DNA was higher. Full-length L1 elements contained more PQSs than truncated elements; the highest proportion of PQSs was found inside transpositionally active L1 elements (PA2 and HS families). Conclusions Conservation of quadruplexes at specific positions of transposable elements implies their importance in their life cycle. The increasing quadruplex presence in evolutionarily young LINE-1 and SVA families makes these elements important contributors toward present genome-wide quadruplex distribution. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1032) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Eduard Kejnovsky
- Department of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 61265 Brno, Czech Republic.
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Comprehensive analysis of human endogenous retrovirus group HERV-W locus transcription in multiple sclerosis brain lesions by high-throughput amplicon sequencing. J Virol 2013; 87:13837-52. [PMID: 24109235 DOI: 10.1128/jvi.02388-13] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Human endogenous retroviruses (HERVs) of the HERV-W group comprise hundreds of loci in the human genome. Deregulated HERV-W expression and HERV-W locus ERVWE1-encoded Syncytin-1 protein have been implicated in the pathogenesis of multiple sclerosis (MS). However, the actual transcription of HERV-W loci in the MS context has not been comprehensively analyzed. We investigated transcription of HERV-W in MS brain lesions and white matter brain tissue from healthy controls by employing next-generation amplicon sequencing of HERV-W env-specific reverse transcriptase (RT) PCR products, thus revealing transcribed HERV-W loci and the relative transcript levels of those loci. We identified more than 100 HERV-W loci that were transcribed in the human brain, with a limited number of loci being predominantly transcribed. Importantly, relative transcript levels of HERV-W loci were very similar between MS and healthy brain tissue samples, refuting deregulated transcription of HERV-W env in MS brain lesions, including the high-level-transcribed ERVWE1 locus encoding Syncytin-1. Quantitative RT-PCR likewise did not reveal differences in MS regarding HERV-W env general transcript or ERVWE1- and ERVWE2-specific transcript levels. However, we obtained evidence for interindividual differences in HERV-W transcript levels. Reporter gene assays indicated promoter activity of many HERV-W long terminal repeats (LTRs), including structurally incomplete LTRs. Our comprehensive analysis of HERV-W transcription in the human brain thus provides important information on the biology of HERV-W in MS lesions and normal human brain, implications for study design, and mechanisms by which HERV-W may (or may not) be involved in MS.
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Reis BS, Jungbluth AA, Frosina D, Holz M, Ritter E, Nakayama E, Ishida T, Obata Y, Carver B, Scher H, Scardino PT, Slovin S, Subudhi SK, Reuter VE, Savage C, Allison JP, Melamed J, Jäger E, Ritter G, Old LJ, Gnjatic S. Prostate cancer progression correlates with increased humoral immune response to a human endogenous retrovirus GAG protein. Clin Cancer Res 2013; 19:6112-25. [PMID: 24081977 DOI: 10.1158/1078-0432.ccr-12-3580] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Human endogenous retroviruses (HERV) encode 8% of the human genome. While HERVs may play a role in autoimmune and neoplastic disease, no mechanistic association has yet been established. We studied the expression and immunogenicity of a HERV-K GAG protein encoded on chromosome 22q11.23 in relation to the clinical course of prostate cancer. EXPERIMENTAL DESIGN In vitro expression of GAG-HERV-K was analyzed in panels of normal and malignant tissues, microarrays, and cell lines, and effects of demethylation and androgen stimulation were evaluated. Patient sera were analyzed for seroreactivity to GAG-HERV-K and other self-antigens by ELISA and seromics (protein array profiling). RESULTS GAG-HERV-K expression was most frequent in prostate tissues and regulated both by demethylation of the promoter region and by androgen stimulation. Serum screening revealed that antibodies to GAG-HERV-K are found in a subset of patients with prostate cancer (33 of 483, 6.8%) but rarely in male healthy donors (1 of 55, 1.8%). Autoantibodies to GAG-HERV-K occurred more frequently in patients with advanced prostate cancer (29 of 191 in stage III-IV, 21.0%) than in early prostate cancer (4 of 292 in stages I-II, 1.4%). Presence of GAG-HERV-K serum antibody was correlated with worse survival of patients with prostate cancer, with a trend for faster biochemical recurrence in patients with antibodies to GAG-HERV-K. CONCLUSIONS Preferential expression of GAG-HERV-K ch22q11.23 in prostate cancer tissue and increased frequency of autoantibodies observed in patients with advanced prostate cancer make this protein one of the first bona fide retroviral cancer antigens in humans, with potential as a biomarker for progression and biochemical recurrence rate of prostate cancer. Clin Cancer Res; 19(22); 6112-25. ©2013 AACR.
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Affiliation(s)
- Bernardo Sgarbi Reis
- Authors' Affiliations: Ludwig Institute for Cancer Research, New York Branch at Memorial Sloan-Kettering Cancer Center; Departments of Surgery, Medicine, Pathology, Biostatistics, and Immunology, Memorial Sloan-Kettering Cancer Center; NYU Langone Medical Center, New York; Department of Immunology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama; RIKEN Bioresource Center, Tsukuba, Ibaraki, Japan; and Klinik für Onkologie und Hämatologie, Krankenhaus Nordwest, Frankfurt, Germany
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25
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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: 132] [Impact Index Per Article: 12.0] [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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26
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Koito A, Ikeda T. Intrinsic immunity against retrotransposons by APOBEC cytidine deaminases. Front Microbiol 2013; 4:28. [PMID: 23431045 PMCID: PMC3576619 DOI: 10.3389/fmicb.2013.00028] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 02/03/2013] [Indexed: 01/06/2023] Open
Abstract
Over 40% of the human genome is recognizable as having been derived from ancient retroelements, transported by an intracellular copy-and-paste process involving an RNA intermediate, with an additional few percent classified as DNA transposable elements. Endogenous retroviruses are long terminal repeat (LTR)-type retroelements that account for ~8% of human genomic DNA. Non-LTR members are present at extremely high copy numbers, with ~17% of the human genome consisting of long interspersed nuclear elements (LINEs). These LINEs modify vertebrate genomes not only through insertions, but also by the indirect replication of non-autonomous retrotransposons, such as short interspersed nuclear elements. As expected, vertebrate intrinsic immunity has evolved to support a balance between retroelement insertions that confer beneficial genetic diversity and those that cause deleterious gene disruptions. The mammalian cytidine deaminases encoded by the APOBEC3 genes can restrict a broad number of exogenous pathogens, such as exogenous retroviruses, and the mobility of endogenous retroelements. Furthermore, APOBEC1 from a variety of mammalian species, which mediates the cytidine (C) to uridine (U) deamination of apolipoprotein B (apoB) mRNA, a protein involved in lipid transport, also plays a role in controlling mobile elements. These mammalian apoB mRNA-editing, catalytic polypeptide (APOBEC) cytidine deaminases, which can bind to single-stranded DNA (ssDNA) as well as RNA, are able to insert mutations into ssDNA and/or RNA as a result of their ability to deaminate C to U. While these APOBEC cytidine deaminases with DNA mutagenic activity can be deleterious to cells, their biological modifications, such as protein-protein interactions and subcellular localization, in addition to their ability to bind to RNA, appear to have conferred a role for APOBECs as a cellular defense system against retroviruses and retroelements. In support of this notion, the expansion of the single APOBEC3 gene in mice to the seven APOBEC3 genes found in primates apparently correlates with the significant enhancement of the restriction of endogenous retroelements seen in primates, including humans. This review discusses the current understanding of the mechanism of action of APOBEC cytidine deaminases and attempts to summarize their roles in controlling retrotransposons.
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Affiliation(s)
- Atsushi Koito
- Department of Retrovirology and Self-Defense, Faculty of Life Sciences, Kumamoto University Kumamoto, Japan
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28
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Oliver KR, Greene WK. Transposable elements and viruses as factors in adaptation and evolution: an expansion and strengthening of the TE-Thrust hypothesis. Ecol Evol 2012; 2:2912-33. [PMID: 23170223 PMCID: PMC3501640 DOI: 10.1002/ece3.400] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 09/11/2012] [Accepted: 09/17/2012] [Indexed: 12/17/2022] Open
Abstract
In addition to the strong divergent evolution and significant and episodic evolutionary transitions and speciation we previously attributed to TE-Thrust, we have expanded the hypothesis to more fully account for the contribution of viruses to TE-Thrust and evolution. The concept of symbiosis and holobiontic genomes is acknowledged, with particular emphasis placed on the creativity potential of the union of retroviral genomes with vertebrate genomes. Further expansions of the TE-Thrust hypothesis are proposed regarding a fuller account of horizontal transfer of TEs, the life cycle of TEs, and also, in the case of a mammalian innovation, the contributions of retroviruses to the functions of the placenta. The possibility of drift by TE families within isolated demes or disjunct populations, is acknowledged, and in addition, we suggest the possibility of horizontal transposon transfer into such subpopulations. “Adaptive potential” and “evolutionary potential” are proposed as the extremes of a continuum of “intra-genomic potential” due to TE-Thrust. Specific data is given, indicating “adaptive potential” being realized with regard to insecticide resistance, and other insect adaptations. In this regard, there is agreement between TE-Thrust and the concept of adaptation by a change in allele frequencies. Evidence on the realization of “evolutionary potential” is also presented, which is compatible with the known differential survivals, and radiations of lineages. Collectively, these data further suggest the possibility, or likelihood, of punctuated episodes of speciation events and evolutionary transitions, coinciding with, and heavily underpinned by, intermittent bursts of TE activity.
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Affiliation(s)
- Keith R Oliver
- School of Biological Science and Biotechnology, Faculty of Science and Engineering, Murdoch University Perth, W.A., 6150, Australia
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Testori A, Caizzi L, Cutrupi S, Friard O, De Bortoli M, Cora' D, Caselle M. The role of Transposable Elements in shaping the combinatorial interaction of Transcription Factors. BMC Genomics 2012; 13:400. [PMID: 22897927 PMCID: PMC3478180 DOI: 10.1186/1471-2164-13-400] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 06/28/2012] [Indexed: 12/22/2022] Open
Abstract
Background In the last few years several studies have shown that Transposable Elements (TEs) in the human genome are significantly associated with Transcription Factor Binding Sites (TFBSs) and that in several cases their expansion within the genome led to a substantial rewiring of the regulatory network. Another important feature of the regulatory network which has been thoroughly studied is the combinatorial organization of transcriptional regulation. In this paper we combine these two observations and suggest that TEs, besides rewiring the network, also played a central role in the evolution of particular patterns of combinatorial gene regulation. Results To address this issue we searched for TEs overlapping Estrogen Receptor α (ERα) binding peaks in two publicly available ChIP-seq datasets from the MCF7 cell line corresponding to different modalities of exposure to estrogen. We found a remarkable enrichment of a few specific classes of Transposons. Among these a prominent role was played by MIR (Mammalian Interspersed Repeats) transposons. These TEs underwent a dramatic expansion at the beginning of the mammalian radiation and then stabilized. We conjecture that the special affinity of ERα for the MIR class of TEs could be at the origin of the important role assumed by ERα in Mammalians. We then searched for TFBSs within the TEs overlapping ChIP-seq peaks. We found a strong enrichment of a few precise combinations of TFBS. In several cases the corresponding Transcription Factors (TFs) were known cofactors of ERα, thus supporting the idea of a co-regulatory role of TFBS within the same TE. Moreover, most of these correlations turned out to be strictly associated to specific classes of TEs thus suggesting the presence of a well-defined "transposon code" within the regulatory network. Conclusions In this work we tried to shed light into the role of Transposable Elements (TEs) in shaping the regulatory network of higher eukaryotes. To test this idea we focused on a particular transcription factor: the Estrogen Receptor α (ERα) and we found that ERα preferentially targets a well defined set of TEs and that these TEs host combinations of transcriptional regulators involving several of known co-regulators of ERα. Moreover, a significant number of these TEs turned out to be conserved between human and mouse and located in the vicinity (and thus candidate to be regulators) of important estrogen-related genes.
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Affiliation(s)
- Alessandro Testori
- Center for Molecular Systems Biology, University of Turin, Turin, Candiolo I-10060, Italy.
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Camacho-Vanegas O, Camacho S, Till J, Miranda-Lorenzo I, Terzo E, Ramirez M, Schramm V, Cordovano G, Watts G, Mehta S, Kimonis V, Hoch B, Philibert K, Raabe C, Bishop D, Glucksman M, Martignetti J. Primate genome gain and loss: a bone dysplasia, muscular dystrophy, and bone cancer syndrome resulting from mutated retroviral-derived MTAP transcripts. Am J Hum Genet 2012; 90:614-27. [PMID: 22464254 DOI: 10.1016/j.ajhg.2012.02.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 01/19/2012] [Accepted: 02/16/2012] [Indexed: 10/28/2022] Open
Abstract
Diaphyseal medullary stenosis with malignant fibrous histiocytoma (DMS-MFH) is an autosomal-dominant syndrome characterized by bone dysplasia, myopathy, and bone cancer. We previously mapped the DMS-MFH tumor-suppressing-gene locus to chromosomal region 9p21-22 but failed to identify mutations in known genes in this region. We now demonstrate that DMS-MFH results from mutations in the most proximal of three previously uncharacterized terminal exons of the gene encoding methylthioadenosine phosphorylase, MTAP. Intriguingly, two of these MTAP exons arose from early and independent retroviral-integration events in primate genomes at least 40 million years ago, and since then, their genomic integration has gained a functional role. MTAP is a ubiquitously expressed homotrimeric-subunit enzyme critical to polyamine metabolism and adenine and methionine salvage pathways and was believed to be encoded as a single transcript from the eight previously described exons. Six distinct retroviral-sequence-containing MTAP isoforms, each of which can physically interact with archetype MTAP, have been identified. The disease-causing mutations occur within one of these retroviral-derived exons and result in exon skipping and dysregulated alternative splicing of all MTAP isoforms. Our results identify a gene involved in the development of bone sarcoma, provide evidence of the primate-specific evolution of certain parts of an existing gene, and demonstrate that mutations in parts of this gene can result in human disease despite its relatively recent origin.
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Hancks DC, Kazazian HH. Active human retrotransposons: variation and disease. Curr Opin Genet Dev 2012; 22:191-203. [PMID: 22406018 DOI: 10.1016/j.gde.2012.02.006] [Citation(s) in RCA: 440] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 01/18/2012] [Accepted: 02/06/2012] [Indexed: 12/12/2022]
Abstract
Mobile DNAs, also known as transposons or 'jumping genes', are widespread in nature and comprise an estimated 45% of the human genome. Transposons are divided into two general classes based on their transposition intermediate (DNA or RNA). Only one subclass, the non-LTR retrotransposons, which includes the Long INterspersed Element-1 (LINE-1 or L1), is currently active in humans as indicated by 96 disease-causing insertions. The autonomous LINE-1 is capable of retrotransposing not only a copy of its own RNA in cis but also other RNAs (Alu, SINE-VNTR-Alu (SVA), U6) in trans to new genomic locations through an element encoded reverse transcriptase. L1 can also retrotranspose cellular mRNAs, resulting in processed pseudogene formation. Here, we highlight recent reports that update our understanding of human L1 retrotransposition and their role in disease. Finally we discuss studies that provide insights into the past and current activity of these retrotransposons, and shed light on not just when, but where, retrotransposition occurs and its part in genetic variation.
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Affiliation(s)
- Dustin C Hancks
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, United States
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van der Kuyl AC. HIV infection and HERV expression: a review. Retrovirology 2012; 9:6. [PMID: 22248111 PMCID: PMC3311604 DOI: 10.1186/1742-4690-9-6] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 01/16/2012] [Indexed: 12/24/2022] Open
Abstract
The human genome contains multiple copies of retrovirus genomes known as endogenous retroviruses (ERVs) that have entered the germ-line at some point in evolution. Several of these proviruses have retained (partial) coding capacity, so that a number of viral proteins or even virus particles are expressed under various conditions. Human ERVs (HERVs) belong to the beta-, gamma-, or spuma- retrovirus groups. Endogenous delta- and lenti- viruses are notably absent in humans, although endogenous lentivirus genomes have been found in lower primates. Exogenous retroviruses that currently form a health threat to humans intriguingly belong to those absent groups. The best studied of the two infectious human retroviruses is the lentivirus human immunodeficiency virus (HIV) which has an overwhelming influence on its host by infecting cells of the immune system. One HIV-induced change is the induction of HERV transcription, often leading to induced HERV protein expression. This review will discuss the potential HIV-HERV interactions. Several studies have suggested that HERV proteins are unlikely to complement defective HIV virions, nor is HIV able to package HERV transcripts, probably due to low levels of sequence similarity. It is unclear whether the expression of HERVs has a negative, neutral, or positive influence on HIV-AIDS disease progression. A positive effect was recently reported by the specific expression of HERVs in chronically HIV-infected patients, which results in the presentation of HERV-derived peptides to CD8+ T-cells. These cytotoxic T-cells were not tolerant to HERV peptides, as would be expected for self-antigens, and consequently lysed the HIV-infected, HERV-presenting cells. This novel mechanism could control HIV replication and result in a low plasma viral load. The possibility of developing a vaccination strategy based on these HERV peptides will be discussed.
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Affiliation(s)
- Antoinette C van der Kuyl
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam, Academic Medical Center of the University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
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Diem O, Schäffner M, Seifarth W, Leib-Mösch C. Influence of antipsychotic drugs on human endogenous retrovirus (HERV) transcription in brain cells. PLoS One 2012; 7:e30054. [PMID: 22253875 PMCID: PMC3256206 DOI: 10.1371/journal.pone.0030054] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 12/08/2011] [Indexed: 01/26/2023] Open
Abstract
Human endogenous retroviruses (HERVs) have been associated with various neurological and neuropsychiatric disorders. Transcripts and proteins of at least three HERV groups, HERV-W, ERV9 and HERV-K(HML-2) have been detected repeatedly in brain samples or cerebrospinal fluid of patients with schizophrenia suggesting that alterations in HERV activity may play a role in etiopathogenesis. Current therapies otherwise include neuroleptics and/or antidepressants that may induce epigenetic alterations and thus influence HERV expression. To investigate the effects of these drugs on HERV transcriptional activity, HERV expression profiles of a broad range of human brain cell lines treated with valproic acid (VPA), haloperidol, risperidone, and clozapine were analyzed using a retrovirus-specific microarray and qRT-PCR. Investigation of 52 HERV subgroups revealed upregulation of several class I and class II HERV elements by VPA in a dose-dependent manner. The strongest effect was observed on HERV-W and ERV9 groups in the human glioblastoma cell lines SK-N-SH and SK-N-MC, respectively. The transcript level of HERV-K(HML-2) elements was not influenced. Transcription of HERV-W, ERV9 and HERV-K(HML-2) taxa was further quantified in postmortem brain samples of patients with schizophrenia, bipolar disorders and a healthy control group with regard to their medication. Patients with schizophrenia showed a significantly higher HERV-W transcription associated with VPA treatment. However in case of ERV9, enhanced transcript levels could not be explained solely by VPA treatment, since a slight increase was also found in untreated patients compared to healthy controls. HERV-K(HML-2) elements appeared to be upregulated in some patients with bipolar disorders independent from medication. In conclusion, these results suggest that antipsychotic medication may contribute to increased expression of distinct HERV taxa in patients with neuropsychiatric diseases.
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Affiliation(s)
- Olivia Diem
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- III. Medizinische Klinik, UMM-Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Marisa Schäffner
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Wolfgang Seifarth
- III. Medizinische Klinik, UMM-Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Christine Leib-Mösch
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- III. Medizinische Klinik, UMM-Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
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Sin HS, Koh E, Taya M, IIjima M, Sugimoto K, Maeda Y, Yoshida A, Iwamoto T, Namiki M. A Novel Y Chromosome Microdeletion With the Loss of an Endogenous Retrovirus Related, Testis Specific Transcript in AZFb Region. J Urol 2011; 186:1545-52. [DOI: 10.1016/j.juro.2011.05.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Indexed: 02/08/2023]
Affiliation(s)
- Ho-Su Sin
- Departments of Integrative Cancer Therapy and Urology, Andrology Unit, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Eitetsu Koh
- Departments of Integrative Cancer Therapy and Urology, Andrology Unit, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Masaki Taya
- Departments of Integrative Cancer Therapy and Urology, Andrology Unit, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Masashi IIjima
- Departments of Integrative Cancer Therapy and Urology, Andrology Unit, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Kazuhiro Sugimoto
- Departments of Integrative Cancer Therapy and Urology, Andrology Unit, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Yuji Maeda
- Departments of Integrative Cancer Therapy and Urology, Andrology Unit, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | | | - Teruaki Iwamoto
- Division of Male Infertility, Center for Infertility and IVF, International University of Health and Welfare, Nasushiobara, Japan
| | - Mikio Namiki
- Departments of Integrative Cancer Therapy and Urology, Andrology Unit, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
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Oliver KR, Greene WK. Mobile DNA and the TE-Thrust hypothesis: supporting evidence from the primates. Mob DNA 2011; 2:8. [PMID: 21627776 PMCID: PMC3123540 DOI: 10.1186/1759-8753-2-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 05/31/2011] [Indexed: 02/07/2023] Open
Abstract
Transposable elements (TEs) are increasingly being recognized as powerful facilitators of evolution. We propose the TE-Thrust hypothesis to encompass TE-facilitated processes by which genomes self-engineer coding, regulatory, karyotypic or other genetic changes. Although TEs are occasionally harmful to some individuals, genomic dynamism caused by TEs can be very beneficial to lineages. This can result in differential survival and differential fecundity of lineages. Lineages with an abundant and suitable repertoire of TEs have enhanced evolutionary potential and, if all else is equal, tend to be fecund, resulting in species-rich adaptive radiations, and/or they tend to undergo major evolutionary transitions. Many other mechanisms of genomic change are also important in evolution, and whether the evolutionary potential of TE-Thrust is realized is heavily dependent on environmental and ecological factors. The large contribution of TEs to evolutionary innovation is particularly well documented in the primate lineage. In this paper, we review numerous cases of beneficial TE-caused modifications to the genomes of higher primates, which strongly support our TE-Thrust hypothesis.
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Affiliation(s)
- Keith R Oliver
- School of Biological Sciences and Biotechnology, Faculty of Science and Engineering, Murdoch University, Perth W. A. 6150, Australia
| | - Wayne K Greene
- School of Veterinary and Biomedical Sciences, Faculty of Health Sciences, Murdoch University, Perth W. A. 6150, Australia
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Different transcription activity of HERV-K LTR-containing and LTR-lacking genes of the KIAA1245/NBPF gene subfamily. Genetica 2011; 139:733-41. [PMID: 21544646 DOI: 10.1007/s10709-011-9577-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 04/15/2011] [Indexed: 10/18/2022]
Abstract
Long terminal repeats (LTRs) of human endogenous retroviruses (HERVs) located near or within genes might affect their expression. We used the KIAA1245/NBPF human gene subfamily in an attempt to assess the regulatory potential of HERV LTRs. The subfamily includes five closely related paralogous genes: three of them contain an LTR in the second intron, and two genes lack it. Earlier we reported that the second and third exons of only LTR-containing genes of this subfamily could be detected in mature mRNAs of various cell lines and human tissues. The corresponding parts of mRNA of LTR-lacking genes analyzed in our study were absent from EST libraries, but other fragments of their mRNAs were available in EST databases. For a more unbiased view on the correlation between gene transcription and the intronic LTRs, in the present work we analyzed non-spliced pre-mRNA thus avoiding splicing effects. Based on RT-PCR analysis, we demonstrated that the KIAA1245/NBPF LTR-lacking gene AL592309/NBPF3 was transcriptionally active, but the LTR-containing genes showed significantly higher transcription levels. The data are in agreement with the suggestion that HERV-K LTRs within the second intron of the KIAA1245/NBPF subfamily genes might affect their transcriptional activity. However, it still remains to be investigated whether the revealed effect is due just to the LTR insertion or other factors are responsible for the difference.
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Mayer J, Blomberg J, Seal RL. A revised nomenclature for transcribed human endogenous retroviral loci. Mob DNA 2011; 2:7. [PMID: 21542922 PMCID: PMC3113919 DOI: 10.1186/1759-8753-2-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 05/04/2011] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Endogenous retroviruses (ERVs) and ERV-like sequences comprise 8% of the human genome. A hitherto unknown proportion of ERV loci are transcribed and thus contribute to the human transcriptome. A small proportion of these loci encode functional proteins. As the role of ERVs in normal and diseased biological processes is not yet established, transcribed ERV loci are of particular interest. As more transcribed ERV loci are likely to be identified in the near future, the development of a systematic nomenclature is important to ensure that all information on each locus can be easily retrieved. RESULTS Here we present a revised nomenclature of transcribed human endogenous retroviral loci that sorts loci into groups based on Repbase classifications. Each symbol is of the format ERV + group symbol + unique number. Group symbols are based on a mixture of Repbase designations and well-supported symbols used in the literature. The presented guidelines will allow newly identified loci to be easily incorporated into the scheme. CONCLUSIONS The naming system will be employed by the HUGO Gene Nomenclature Committee for naming transcribed human ERV loci. We hope that the system will contribute to clarifying a certain aspect of a sometimes confusing nomenclature for human endogenous retroviruses. The presented system may also be employed for naming transcribed loci of human non-ERV repeat loci.
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Affiliation(s)
- Jens Mayer
- HUGO Gene Nomenclature Committee, European Molecular Biology Laboratory-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK.
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Recent amplification of the kangaroo endogenous retrovirus, KERV, limited to the centromere. J Virol 2011; 85:4761-71. [PMID: 21389136 DOI: 10.1128/jvi.01604-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mammalian retrotransposons, transposable elements that are processed through an RNA intermediate, are categorized as short interspersed elements (SINEs), long interspersed elements (LINEs), and long terminal repeat (LTR) retroelements, which include endogenous retroviruses. The ability of transposable elements to autonomously amplify led to their initial characterization as selfish or junk DNA; however, it is now known that they may acquire specific cellular functions in a genome and are implicated in host defense mechanisms as well as in genome evolution. Interactions between classes of transposable elements may exert a markedly different and potentially more significant effect on a genome than interactions between members of a single class of transposable elements. We examined the genomic structure and evolution of the kangaroo endogenous retrovirus (KERV) in the marsupial genus Macropus. The complete proviral structure of the kangaroo endogenous retrovirus, phylogenetic relationship among relative retroviruses, and expression of this virus in both Macropus rufogriseus and M. eugenii are presented for the first time. In addition, we show the relative copy number and distribution of the kangaroo endogenous retrovirus in the Macropus genus. Our data indicate that amplification of the kangaroo endogenous retrovirus occurred in a lineage-specific fashion, is restricted to the centromeres, and is not correlated with LINE depletion. Finally, analysis of KERV long terminal repeat sequences using massively parallel sequencing indicates that the recent amplification in M. rufogriseus is likely due to duplications and concerted evolution rather than a high number of independent insertion events.
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Romanish MT, Cohen CJ, Mager DL. Potential mechanisms of endogenous retroviral-mediated genomic instability in human cancer. Semin Cancer Biol 2010; 20:246-53. [PMID: 20685251 DOI: 10.1016/j.semcancer.2010.05.005] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 05/12/2010] [Accepted: 05/19/2010] [Indexed: 01/13/2023]
Abstract
Malignancy results from a complex combination of genetic and epigenetic changes, the full effects of which are still largely unknown. Here we summarize current knowledge of the origin, retrotranspositional activity, epigenetic state, and transcription of human endogenous retroviruses (HERVs), and then discuss the potential effects of their deregulation in cancer. Evidence suggests that cancer-associated epigenetic changes most likely underlie potential HERV-mediated effects on genome and transcriptome instability and may play a role in malignancy. Despite our currently limited understanding of the importance of HERVs or other transposable elements in cancer development, we believe that the emerging era of high-throughput sequencing of cancer genomes, epigenomes, and transcriptomes will provide unprecedented opportunities to investigate these roles in the future.
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Affiliation(s)
- M T Romanish
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, BC, Canada.
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Villarreal LP, Witzany G. Viruses are essential agents within the roots and stem of the tree of life. J Theor Biol 2009; 262:698-710. [PMID: 19833132 DOI: 10.1016/j.jtbi.2009.10.014] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 09/28/2009] [Accepted: 10/08/2009] [Indexed: 02/06/2023]
Abstract
In contrast with former definitions of life limited to membrane-bound cellular life forms which feed, grow, metabolise and replicate (i) a role of viruses as genetic symbionts, (ii) along with peripheral phenomena such as cryptobiosis and (iii) the horizontal nature of genetic information acquisition and processing broaden our view of the tree of life. Some researchers insist on the traditional textbook conviction of what is part of the community of life. In a recent review [Moreira, D., Lopez-Garcia, P., 2009. Ten reasons to exclude viruses from the tree of life. Nat. Rev. Microbiol. 7, 306-311.] they assemble four main arguments which should exclude viruses from the tree of life because of their inability to self-sustain and self-replicate, their polyphyly, the cellular origin of their cell-like genes and the volatility of their genomes. In this article we will show that these features are not coherent with current knowledge about viruses but that viral agents play key roles within the roots and stem of the tree of life.
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Affiliation(s)
- Luis P Villarreal
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
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Lopes FR, Silva JC, Benchimol M, Costa GGL, Pereira GAG, Carareto CMA. The protist Trichomonas vaginalis harbors multiple lineages of transcriptionally active Mutator-like elements. BMC Genomics 2009; 10:330. [PMID: 19622157 PMCID: PMC2725143 DOI: 10.1186/1471-2164-10-330] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Accepted: 07/21/2009] [Indexed: 12/19/2022] Open
Abstract
Background For three decades the Mutator system was thought to be exclusive of plants, until the first homolog representatives were characterized in fungi and in early-diverging amoebas earlier in this decade. Results Here, we describe and characterize four families of Mutator-like elements in a new eukaryotic group, the Parabasalids. These Trichomonas vaginalis Mutator- like elements, or TvMULEs, are active in T. vaginalis and patchily distributed among 12 trichomonad species and isolates. Despite their relatively distinctive amino acid composition, the inclusion of the repeats TvMULE1, TvMULE2, TvMULE3 and TvMULE4 into the Mutator superfamily is justified by sequence, structural and phylogenetic analyses. In addition, we identified three new TvMULE-related sequences in the genome sequence of Candida albicans. While TvMULE1 is a member of the MuDR clade, predominantly from plants, the other three TvMULEs, together with the C. albicans elements, represent a new and quite distinct Mutator lineage, which we named TvCaMULEs. The finding of TvMULE1 sequence inserted into other putative repeat suggests the occurrence a novel TE family not yet described. Conclusion These findings expand the taxonomic distribution and the range of functional motif of MULEs among eukaryotes. The characterization of the dynamics of TvMULEs and other transposons in this organism is of particular interest because it is atypical for an asexual species to have such an extreme level of TE activity; this genetic landscape makes an interesting case study for causes and consequences of such activity. Finally, the extreme repetitiveness of the T. vaginalis genome and the remarkable degree of sequence identity within its repeat families highlights this species as an ideal system to characterize new transposable elements.
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Affiliation(s)
- Fabrício R Lopes
- UNESP, São Paulo State University, Department of Biology, São José do Rio Preto, São Paulo, Brazil.
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Kulski JK, Shigenari A, Shiina T, Hosomichi K, Yawata M, Inoko H. HLA-A allele associations with viral MER9-LTR nucleotide sequences at two distinct loci within the MHC alpha block. Immunogenetics 2009; 61:257-70. [PMID: 19294374 DOI: 10.1007/s00251-009-0364-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Accepted: 02/25/2009] [Indexed: 10/21/2022]
Abstract
The study of the association of the Human Leukocyte Antigen (HLA) alleles and polymorphic retrotransposons such as Alu, HERV, and LTR at various loci within the Major Histocompatibility Complex allows for a better identification and stratification of disease associations and the origins of HLA haplotypes in different populations. This paper provides sequence and association data on two structurally polymorphic MER9-LTR retrotransposons that are located 54 kb apart and in close proximity to the multiallelic HLA-A gene involved in the regulation of the human immune system. Direct DNA sequencing and analysis of the PCR products identified DNA nucleotide variations between the MER9-LTR sequences at the two loci and their associations with HLA-A alleles as potential haplotype and evolutionary markers. All MER9-LTR sequences were haplotypic when associated with common HLA-A alleles. The number of SNP loci was 2.5 times greater for the solo LTR at the AK locus, which is located closer to the HLA-A gene than the solo or 3' LTR at the HG locus. Our study shows that the nucleotide variations of the MER9-LTR DNA sequences are additional informative markers in fine mapping HLA-A genomic haplotypes for future population, evolutionary, and disease studies.
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Affiliation(s)
- Jerzy K Kulski
- Centre for Forensic Science, The University of Western Australia, Crawley, Western Australia, Australia.
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Preferential epigenetic suppression of the autonomous MusD over the nonautonomous ETn mouse retrotransposons. Mol Cell Biol 2009; 29:2456-68. [PMID: 19273603 DOI: 10.1128/mcb.01383-08] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nonautonomous retrotransposon subfamilies are often amplified in preference to their coding-competent relatives. However, the mechanisms responsible for such replicative success are poorly understood. Here, we demonstrate that the autonomous MusD long terminal repeat (LTR) retrotransposons are subject to greater epigenetic silencing than their nonautonomous cousins, the early transposons (ETns), which are expressed at a 170-fold-higher level than MusD in mouse embryonic stem (ES) cells. We show that, in ES cells, 5' LTRs and the downstream region of MusD elements are more heavily methylated and are associated with less-activating and more-repressive histone modifications than the highly similar ETnII sequences. The internal region of MusD likely contributes to their silencing, as transgenes with MusD, compared to those with ETnII sequences, show reduced reporter gene expression and a higher level of repressive histone marks. Genomic distribution patterns of MusD and ETn elements are consistent with stronger selection against MusD elements within introns, suggesting that MusD-associated silencing marks can negatively impact genes. We propose a model in which nonautonomous retrotransposons may gain transcriptional and retrotranspositional advantages over their coding-competent counterparts by elimination of the CpG-rich retroviral sequence targeting the autonomous subfamilies for silencing.
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Beimforde N, Hanke K, Ammar I, Kurth R, Bannert N. Molecular cloning and functional characterization of the human endogenous retrovirus K113. Virology 2008; 371:216-25. [PMID: 18076964 DOI: 10.1016/j.virol.2007.09.036] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 06/11/2007] [Accepted: 09/24/2007] [Indexed: 11/27/2022]
Abstract
The human endogenous retrovirus-K113 (HERV-K113) is the most complete HERV known to date. It contains open reading frames for all viral proteins. Depending on ethnicity, up to 30% of the human population carries the provirus on chromosome 19. To facilitate molecular and functional studies, we have cloned the HERV-K113 sequence into a small plasmid vector and characterized its functional properties. Here we show that based on a substantial LTR-promoter activity, full length messenger RNA and spliced env-, rec- and 1.5 kb (hel)-transcripts are produced. The envelope protein of HERV-K113 is synthesized as an 85 kDa precursor that is found partially processed. The accessory Rec protein is highly expressed and accumulates in the nucleus. Expression analysis revealed synthesis of the Gag precursor and the protease. However, the cloned HERV-K113 provirus is not replication competent. It carries inactivating mutations in the reverse transcriptase gene. These mutations can be reversed to reconstitute the active enzyme, but the reversion is not sufficient to reconstitute replication capacity of the virus.
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Affiliation(s)
- Nadine Beimforde
- Robert Koch-Institut, ZBS 4, Nordufer 20, 13353 Berlin, Germany.
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Kulski JK, Shigenari A, Shiina T, Ota M, Hosomichi K, James I, Inoko H. Human endogenous retrovirus (HERVK9) structural polymorphism with haplotypic HLA-A allelic associations. Genetics 2008; 180:445-57. [PMID: 18757922 PMCID: PMC2535695 DOI: 10.1534/genetics.108.090340] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 07/09/2008] [Indexed: 11/18/2022] Open
Abstract
The frequency and HLA-A allelic associations of a HERVK9 DNA structural polymorphism located in close proximity to the highly polymorphic HLA-A gene within the major histocompatibility complex (MHC) genomic region were determined in Japanese, African Americans, and Australian Caucasians to better understand its human population evolutionary history. The HERVK9 insertion or deletion was detected as a 3' LTR or a solo LTR, respectively, by separate PCR assays. The average insertion frequency of the HERVK9.HG was significantly different (P < 1.083e(-6)) between the Japanese (0.59) and the African Americans (0.34) or Australian Caucasians (0.37). LD analysis predicted a highly significant (P < 1.0e(-5)) linkage between the HLA-A and HERVK9 alleles, probably as a result of hitchhiking (linkage). Evolutionary time estimates of the solo, 5' and 3' LTR nucleotide sequence divergences suggest that the HERVK9 was inserted 17.3 MYA with the first structural deletion occurring 15.1 MYA. The LTR/HLA-A haplotypes appear to have been formed mostly during the past 3.9 MY. The HERVK9 insertion and deletion, detected by a simple and economical PCR method, is an informative genetic and evolutionary marker for the study of HLA-A haplotype variations, human migration, the origins of contemporary populations, and the possibility of disease associations.
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Affiliation(s)
- Jerzy K Kulski
- Centre for Forensic Science, The University of Western Australia, Nedlands, Western Australia, Australia.
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Flockerzi A, Ruggieri A, Frank O, Sauter M, Maldener E, Kopper B, Wullich B, Seifarth W, Müller-Lantzsch N, Leib-Mösch C, Meese E, Mayer J. Expression patterns of transcribed human endogenous retrovirus HERV-K(HML-2) loci in human tissues and the need for a HERV Transcriptome Project. BMC Genomics 2008; 9:354. [PMID: 18664271 PMCID: PMC2525661 DOI: 10.1186/1471-2164-9-354] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 07/29/2008] [Indexed: 12/14/2022] Open
Abstract
Background A significant proportion of the human genome is comprised of human endogenous retroviruses (HERVs). HERV transcripts are found in every human tissue. Expression of proviruses of the HERV-K(HML-2) family has been associated with development of human tumors, in particular germ cell tumors (GCT). Very little is known about transcriptional activity of individual HML-2 loci in human tissues, though. Results By employing private nucleotide differences between loci, we assigned ~1500 HML-2 cDNAs to individual HML-2 loci, identifying, in total, 23 transcriptionally active HML-2 proviruses. Several loci are active in various human tissue types. Transcription levels of some HML-2 loci appear higher than those of other loci. Several HML-2 Rec-encoding loci are expressed in GCT and non-GCT tissues. A provirus on chromosome 22q11.21 appears strongly upregulated in pathologic GCT tissues and may explain high HML-2 Gag protein levels in GCTs. Presence of Gag and Env antibodies in GCT patients is not correlated with activation of individual loci. HML-2 proviruses previously reported capable of forming an infectious HML-2 variant are transcriptionally active in germ cell tissue. Our study furthermore shows that Expressed Sequence Tag (EST) data are insufficient to describe transcriptional activity of HML-2 and other HERV loci in tissues of interest. Conclusion Our, to date, largest-scale study reveals in greater detail expression patterns of individual HML-2 loci in human tissues of clinical interest. Moreover, large-scale, specialized studies are indicated to better comprehend transcriptional activity and regulation of HERVs. We thus emphasize the need for a specialized HERV Transcriptome Project.
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Affiliation(s)
- Aline Flockerzi
- Department of Human Genetics, Medical Faculty, University of Saarland, Homburg, Germany.
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Abstract
Immunoglobulins (Igs) in uninfected humans recognize residues 421-433 located in the B cell superantigenic site (SAg) of the HIV envelope protein gp120 and catalyze its hydrolysis by a serine protease-like mechanism. The catalytic activity is encoded by germline Ig variable (V) region genes, and is expressed at robust levels by IgMs and IgAs but poorly by IgGs. Mucosal IgAs are highly catalytic and neutralize HIV, suggesting that they constitute a first line of defense against HIV. Lupus patients produce the Igs at enhanced levels. Homology of the 421-433 region with an endogenous retroviral sequence and a bacterial protein may provide clues about the antigen driving anti-SAg synthesis in lupus patients and uninfected subjects. The potency and breadth of HIV neutralization revives hopes of clinical application of catalytic anti-421-433 Igs as immunotherapeutic and topical microbicide reagents. Adaptive improvement of anti-SAg catalytic Igs in HIV infected subjects is not customary. Further study of the properties of the naturally occurring anti-SAg catalytic Igs should provide valuable guidance in designing a prophylactic vaccine that amplifies protective catalytic immunity to HIV.
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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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Abstract
Lung cancer is a disease with enormous global medical and economic impact that remains refractory to conventional treatment modalities. Recent insights regarding mechanisms pertaining to epigenetic regulation of gene expression during malignant transformation, together with the identification of agents that modulate chromatin structure provide new opportunities for the treatment and prevention of this lethal disease.
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Affiliation(s)
- David S Schrump
- Thoracic Oncology Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-1201, USA.
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Flockerzi A, Maydt J, Frank O, Ruggieri A, Maldener E, Seifarth W, Medstrand P, Lengauer T, Meyerhans A, Leib-Mösch C, Meese E, Mayer J. Expression pattern analysis of transcribed HERV sequences is complicated by ex vivo recombination. Retrovirology 2007; 4:39. [PMID: 17550625 PMCID: PMC1904241 DOI: 10.1186/1742-4690-4-39] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 06/06/2007] [Indexed: 11/25/2022] Open
Abstract
Background The human genome comprises numerous human endogenous retroviruses (HERVs) that formed millions of years ago in ancestral species. A number of loci of the HERV-K(HML-2) family are evolutionarily much younger. A recent study suggested an infectious HERV-K(HML-2) variant in humans and other primates. Isolating such a variant from human individuals would be a significant finding for human biology. Results When investigating expression patterns of specific HML-2 proviruses we encountered HERV-K(HML-2) cDNA sequences without proviral homologues in the human genome, named HERV-KX, that could very well support recently suggested infectious HML-2 variants. However, detailed sequence analysis, using the software RECCO, suggested that HERV-KX sequences were produced by recombination, possibly arising ex vivo, between transcripts from different HML-2 proviral loci. Conclusion As RT-PCR probably will be instrumental for isolating an infectious HERV-K(HML-2) variant, generation of "new" HERV-K(HML-2) sequences by ex vivo recombination seems inevitable. Further complicated by an unknown amount of allelic sequence variation in HERV-K(HML-2) proviruses, newly identified HERV-K(HML-2) variants should be interpreted very cautiously.
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MESH Headings
- Base Sequence
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- DNA, Viral/chemistry
- DNA, Viral/genetics
- DNA, Viral/isolation & purification
- Endogenous Retroviruses/genetics
- Gene Expression
- Genome, Human
- Humans
- Molecular Sequence Data
- Phylogeny
- Proviruses/genetics
- RNA, Viral/biosynthesis
- RNA, Viral/genetics
- Recombination, Genetic
- Sequence Analysis, DNA
- Sequence Homology
- Software
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Affiliation(s)
- Aline Flockerzi
- Department of Human Genetics, Medical Faculty, University of Saarland, Homburg, Germany
| | - Jochen Maydt
- Max Planck-Institute for Informatics, Saarbruecken, Germany
| | - Oliver Frank
- Medical Faculty Mannheim of the Ruprecht-Karls, University of Heidelberg, Germany
| | - Alessia Ruggieri
- Department of Human Genetics, Medical Faculty, University of Saarland, Homburg, Germany
| | - Esther Maldener
- Department of Human Genetics, Medical Faculty, University of Saarland, Homburg, Germany
| | - Wolfgang Seifarth
- Medical Faculty Mannheim of the Ruprecht-Karls, University of Heidelberg, Germany
| | - Patrik Medstrand
- Department of Experimental Medical Sciences, Lund University, Lund, Sweden
| | | | - Andreas Meyerhans
- Institute of Virology, Medical Faculty, University of Saarland, Homburg, Germany
| | - Christine Leib-Mösch
- Medical Faculty Mannheim of the Ruprecht-Karls, University of Heidelberg, Germany
- GSF – National Research Center for Environment and Health, Institute of Molecular Virology, Neuherberg, Germany
| | - Eckart Meese
- Department of Human Genetics, Medical Faculty, University of Saarland, Homburg, Germany
| | - Jens Mayer
- Department of Human Genetics, Medical Faculty, University of Saarland, Homburg, Germany
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