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Yano N, Chong PF, Kojima KK, Miyoshi T, Luqmen-Fatah A, Kimura Y, Kora K, Kayaki T, Maizuru K, Hayashi T, Yokoyama A, Ajiro M, Hagiwara M, Kondo T, Kira R, Takita J, Yoshida T. Long-read sequencing identifies an SVA_D retrotransposon insertion deep within the intron of ATP7A as a novel cause of occipital horn syndrome. J Med Genet 2024:jmg-2024-110056. [PMID: 38960580 DOI: 10.1136/jmg-2024-110056] [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: 04/18/2024] [Accepted: 06/25/2024] [Indexed: 07/05/2024]
Abstract
BACKGROUND SINE-VNTR-Alu (SVA) retrotransposons move from one genomic location to another in a 'copy-and-paste' manner. They continue to move actively and cause monogenic diseases through various mechanisms. Currently, disease-causing SVA retrotransposons are classified into human-specific young SVA_E or SVA_F subfamilies. In this study, we identified an evolutionarily old SVA_D retrotransposon as a novel cause of occipital horn syndrome (OHS). OHS is an X-linked, copper metabolism disorder caused by dysfunction of the copper transporter, ATP7A. METHODS We investigated a 16-year-old boy with OHS whose pathogenic variant could not be detected via routine molecular genetic analyses. RESULTS A 2.8 kb insertion was detected deep within the intron of the patient's ATP7A gene. This insertion caused aberrant mRNA splicing activated by a new donor splice site located within it. Long-read circular consensus sequencing enabled us to accurately read the entire insertion sequence, which contained highly repetitive and GC-rich segments. Consequently, the insertion was identified as an SVA_D retrotransposon. Antisense oligonucleotides (AOs) targeting the new splice site restored the expression of normal transcripts and functional ATP7A proteins. AO treatment alleviated excessive accumulation of copper in patient fibroblasts in a dose-dependent manner. Pedigree analysis revealed that the retrotransposon had moved into the OHS-causing position two generations ago. CONCLUSION This is the first report of a human monogenic disease caused by the SVA_D retrotransposon. The fact that the evolutionarily old SVA_D is still actively transposed, leading to increased copy numbers may make a notable impact on rare genetic disease research.
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Affiliation(s)
- Naoko Yano
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Pin Fee Chong
- Department of Pediatric Neurology, Fukuoka Children's Hospital, Fukuoka, Japan
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kenji K Kojima
- Genetic Information Research Institute, Cupertino, CA, USA
| | - Tomoichiro Miyoshi
- Laboratory for Retrotransposon Dynamics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Department of Gene Mechanisms, Kyoto University Graduate School of Biostudies, Kyoto, Japan
| | - Ahmad Luqmen-Fatah
- Laboratory for Retrotransposon Dynamics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Yu Kimura
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Kengo Kora
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Taisei Kayaki
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kanako Maizuru
- Department of Pediatrics, Tenri Yorozu Hospital, Tenri, Japan
| | - Takahiro Hayashi
- Department of Pediatrics, Kurashiki Central Hospital, Kurashiki, Japan
| | - Atsushi Yokoyama
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masahiko Ajiro
- Division of Cancer RNA Research, National Cancer Center Research Institute, Tokyo, Japan
| | - Masatoshi Hagiwara
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Teruyuki Kondo
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Ryutaro Kira
- Department of Pediatric Neurology, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Junko Takita
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takeshi Yoshida
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
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2
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Moldovan JB, Kopera HC, Liu Y, Garcia-Canadas M, Catalina P, Leone PE, Sanchez L, Kitzman JO, Kidd JM, Garcia-Perez JL, Moran JV. Variable patterns of retrotransposition in different HeLa strains provide mechanistic insights into SINE RNA mobilization processes. Nucleic Acids Res 2024:gkae448. [PMID: 38850156 DOI: 10.1093/nar/gkae448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 05/08/2024] [Accepted: 05/14/2024] [Indexed: 06/10/2024] Open
Abstract
Alu elements are non-autonomous Short INterspersed Elements (SINEs) derived from the 7SL RNA gene that are present at over one million copies in human genomic DNA. Alu mobilizes by a mechanism known as retrotransposition, which requires the Long INterspersed Element-1 (LINE-1) ORF2-encoded protein (ORF2p). Here, we demonstrate that HeLa strains differ in their capacity to support Alu retrotransposition. Human Alu elements retrotranspose efficiently in HeLa-HA and HeLa-CCL2 (Alu-permissive) strains, but not in HeLa-JVM or HeLa-H1 (Alu-nonpermissive) strains. A similar pattern of retrotransposition was observed for other 7SL RNA-derived SINEs and tRNA-derived SINEs. In contrast, mammalian LINE-1s, a zebrafish LINE, a human SINE-VNTR-Alu (SVA) element, and an L1 ORF1-containing mRNA can retrotranspose in all four HeLa strains. Using an in vitro reverse transcriptase-based assay, we show that Alu RNAs associate with ORF2p and are converted into cDNAs in both Alu-permissive and Alu-nonpermissive HeLa strains, suggesting that 7SL- and tRNA-derived SINEs use strategies to 'hijack' L1 ORF2p that are distinct from those used by SVA elements and ORF1-containing mRNAs. These data further suggest ORF2p associates with the Alu RNA poly(A) tract in both Alu-permissive and Alu-nonpermissive HeLa strains, but that Alu retrotransposition is blocked after this critical step in Alu-nonpermissive HeLa strains.
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Affiliation(s)
- John B Moldovan
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Huira C Kopera
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ying Liu
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marta Garcia-Canadas
- Department of Genomic Medicine, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada 18016, Spain
| | | | - Paola E Leone
- Genetics and Genomics Laboratory, SOLCA Hospital, Quito, Ecuador
| | - Laura Sanchez
- Department of Genomic Medicine, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada 18016, Spain
| | - Jacob O Kitzman
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jeffrey M Kidd
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jose Luis Garcia-Perez
- Department of Genomic Medicine, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada 18016, Spain
| | - John V Moran
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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3
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Moldovan JB, Kopera HC, Liu Y, Garcia-Canadas M, Catalina P, Leone PE, Sanchez L, Kitzman JO, Kidd JM, Garcia-Perez JL, Moran JV. Variable patterns of retrotransposition in different HeLa strains provide mechanistic insights into SINE RNA mobilization processes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592410. [PMID: 38746229 PMCID: PMC11092746 DOI: 10.1101/2024.05.03.592410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Alu elements are non-autonomous Short INterspersed Elements (SINEs) derived from the 7SL RNA gene that are present at over one million copies in human genomic DNA. Alu mobilizes by a mechanism known as retrotransposition, which requires the Long INterspersed Element-1 (LINE-1 or L1) ORF2 -encoded protein (ORF2p). Here, we demonstrate that HeLa strains differ in their capacity to support Alu retrotransposition. Human Alu elements retrotranspose efficiently in HeLa-HA and HeLa-CCL2 ( Alu -permissive) strains, but not in HeLa-JVM or HeLa-H1 ( Alu -nonpermissive) strains. A similar pattern of retrotransposition was observed for other 7SL RNA -derived SINEs and tRNA -derived SINEs. In contrast, mammalian LINE-1s, a zebrafish LINE, a human SINE-VNTR - Alu ( SVA ) element, and an L1 ORF1 -containing messenger RNA can retrotranspose in all four HeLa strains. Using an in vitro reverse transcriptase-based assay, we show that Alu RNAs associate with ORF2p and are converted into cDNAs in both Alu -permissive and Alu -nonpermissive HeLa strains, suggesting that 7SL - and tRNA -derived SINE RNAs use strategies to 'hijack' L1 ORF2p that are distinct from those used by SVA elements and ORF1 -containing mRNAs. These data further suggest ORF2p associates with the Alu RNA poly(A) tract in both Alu -permissive and Alu -nonpermissive HeLa strains, but that Alu retrotransposition is blocked after this critical step in Alu -nonpermissive HeLa strains.
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4
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Hall A, Middlehurst B, Cadogan MAM, Reed X, Billingsley KJ, Bubb VJ, Quinn JP. A SINE-VNTR-Alu at the LRIG2 locus is associated with proximal and distal gene expression in CRISPR and population models. Sci Rep 2024; 14:792. [PMID: 38191889 PMCID: PMC10774264 DOI: 10.1038/s41598-023-50307-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 12/18/2023] [Indexed: 01/10/2024] Open
Abstract
SINE-VNTR-Alu (SVA) retrotransposons represent mobile regulatory elements that have the potential to influence the surrounding genome when they insert into a locus. Evolutionarily recent mobilisation has resulted in loci in the human genome where a given retrotransposon might be observed to be present or absent, termed a retrotransposon insertion polymorphism (RIP). We previously observed that an SVA RIP ~ 2 kb upstream of LRIG2 on chromosome 1, the 'LRIG2 SVA', was associated with differences in local gene expression and methylation, and that the two were correlated. Here, we have used CRISPR-mediated deletion of the LRIG2 SVA in a cell line model to validate that presence of the retrotransposon is directly affecting local expression and provide evidence that is suggestive of a modest role for the SVA in modulating nearby methylation. Additionally, in leveraging an available Hi-C dataset we observed that the LRIG2 SVA was also involved in long-range chromatin interactions with a cluster of genes ~ 300 kb away, and that expression of these genes was to varying degrees associated with dosage of the SVA in both CRISPR cell line and population models. Altogether, these data support a regulatory role for SVAs in the modulation of gene expression, with the latter potentially involving chromatin looping, consistent with the model that RIPs may contribute to interpersonal differences in transcriptional networks.
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Affiliation(s)
- Ashley Hall
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7BE, UK
| | - Ben Middlehurst
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7BE, UK
| | - Max A M Cadogan
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7BE, UK
| | - Xylena Reed
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
- Center for Alzheimer's and Related Dementias, National Institute on Aging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kimberley J Billingsley
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
- Center for Alzheimer's and Related Dementias, National Institute on Aging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Vivien J Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7BE, UK
| | - John P Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7BE, UK.
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5
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Mendez-Dorantes C, Burns KH. LINE-1 retrotransposition and its deregulation in cancers: implications for therapeutic opportunities. Genes Dev 2023; 37:948-967. [PMID: 38092519 PMCID: PMC10760644 DOI: 10.1101/gad.351051.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Long interspersed element 1 (LINE-1) is the only protein-coding transposon that is active in humans. LINE-1 propagates in the genome using RNA intermediates via retrotransposition. This activity has resulted in LINE-1 sequences occupying approximately one-fifth of our genome. Although most copies of LINE-1 are immobile, ∼100 copies are retrotransposition-competent. Retrotransposition is normally limited via epigenetic silencing, DNA repair, and other host defense mechanisms. In contrast, LINE-1 overexpression and retrotransposition are hallmarks of cancers. Here, we review mechanisms of LINE-1 regulation and how LINE-1 may promote genetic heterogeneity in tumors. Finally, we discuss therapeutic strategies to exploit LINE-1 biology in cancers.
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Affiliation(s)
- Carlos Mendez-Dorantes
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - Kathleen H Burns
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
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6
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Switzer CH. Non-canonical nitric oxide signalling and DNA methylation: Inflammation induced epigenetic alterations and potential drug targets. Br J Pharmacol 2023. [PMID: 38116806 DOI: 10.1111/bph.16302] [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: 05/31/2023] [Revised: 08/29/2023] [Accepted: 09/20/2023] [Indexed: 12/21/2023] Open
Abstract
DNA methylation controls DNA accessibility to transcription factors and other regulatory proteins, thereby affecting gene expression and hence cellular identity and function. As epigenetic modifications control the transcriptome, epigenetic dysfunction is strongly associated with pathological conditions and ageing. The development of pharmacological agents that modulate the activity of major epigenetic proteins are in pre-clinical development and clinical use. However, recent publications have identified novel redox-based signalling pathways, and therefore novel drug targets, that may exert epigenetic effects. This review will discuss the recent developments in nitric oxide (NO) signalling on DNA methylation as well as potential epigenetic drug targets that have emerged from the intersection of inflammation/redox biology and epigenetic regulation.
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Affiliation(s)
- Christopher H Switzer
- William Harvey Research Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
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7
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Woronzow V, Möhner J, Remane D, Zischler H. Generation of somatic de novo structural variation as a hallmark of cellular senescence in human lung fibroblasts. Front Cell Dev Biol 2023; 11:1274807. [PMID: 38152346 PMCID: PMC10751365 DOI: 10.3389/fcell.2023.1274807] [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: 08/08/2023] [Accepted: 11/29/2023] [Indexed: 12/29/2023] Open
Abstract
Cellular senescence is characterized by replication arrest in response to stress stimuli. Senescent cells accumulate in aging tissues and can trigger organ-specific and possibly systemic dysfunction. Although senescent cell populations are heterogeneous, a key feature is that they exhibit epigenetic changes. Epigenetic changes such as loss of repressive constitutive heterochromatin could lead to subsequent LINE-1 derepression, a phenomenon often described in the context of senescence or somatic evolution. LINE-1 elements decode the retroposition machinery and reverse transcription generates cDNA from autonomous and non-autonomous TEs that can potentially reintegrate into genomes and cause structural variants. Another feature of cellular senescence is mitochondrial dysfunction caused by mitochondrial damage. In combination with impaired mitophagy, which is characteristic of senescent cells, this could lead to cytosolic mtDNA accumulation and, as a genomic consequence, integrations of mtDNA into nuclear DNA (nDNA), resulting in mitochondrial pseudogenes called numts. Thus, both phenomena could cause structural variants in aging genomes that go beyond epigenetic changes. We therefore compared proliferating and senescent IMR-90 cells in terms of somatic de novo numts and integrations of a non-autonomous composite retrotransposons - the so-called SVA elements-that hijack the retropositional machinery of LINE-1. We applied a subtractive and kinetic enrichment technique using proliferating cell DNA as a driver and senescent genomes as a tester for the detection of nuclear flanks of de novo SVA integrations. Coupled with deep sequencing we obtained a genomic readout for SVA retrotransposition possibly linked to cellular senescence in the IMR-90 model. Furthermore, we compared the genomes of proliferative and senescent IMR-90 cells by deep sequencing or after enrichment of nuclear DNA using AluScan technology. A total of 1,695 de novo SVA integrations were detected in senescent IMR-90 cells, of which 333 were unique. Moreover, we identified a total of 81 de novo numts with perfect identity to both mtDNA and nuclear hg38 flanks. In summary, we present evidence for possible age-dependent structural genomic changes by paralogization that go beyond epigenetic modifications. We hypothesize, that the structural variants we observe potentially impact processes associated with replicative aging of IMR-90 cells.
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Affiliation(s)
- Valentina Woronzow
- Division of Anthropology, Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Jonas Möhner
- Division of Anthropology, Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Daniel Remane
- Division of Anthropology, Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
- HOX Life Science GmbH, Frankfurt, Hessen, Germany
| | - Hans Zischler
- Division of Anthropology, Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
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Devine SE. Emerging Opportunities to Study Mobile Element Insertions and Their Source Elements in an Expanding Universe of Sequenced Human Genomes. Genes (Basel) 2023; 14:1923. [PMID: 37895272 PMCID: PMC10606232 DOI: 10.3390/genes14101923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 09/29/2023] [Accepted: 09/30/2023] [Indexed: 10/29/2023] Open
Abstract
Three mobile element classes, namely Alu, LINE-1 (L1), and SVA elements, remain actively mobile in human genomes and continue to produce new mobile element insertions (MEIs). Historically, MEIs have been discovered and studied using several methods, including: (1) Southern blots, (2) PCR (including PCR display), and (3) the detection of MEI copies from young subfamilies. We are now entering a new phase of MEI discovery where these methods are being replaced by whole genome sequencing and bioinformatics analysis to discover novel MEIs. We expect that the universe of sequenced human genomes will continue to expand rapidly over the next several years, both with short-read and long-read technologies. These resources will provide unprecedented opportunities to discover MEIs and study their impact on human traits and diseases. They also will allow the MEI community to discover and study the source elements that produce these new MEIs, which will facilitate our ability to study source element regulation in various tissue contexts and disease states. This, in turn, will allow us to better understand MEI mutagenesis in humans and the impact of this mutagenesis on human biology.
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Affiliation(s)
- Scott E Devine
- Institute for Genome Sciences, Department of Medicine, and Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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9
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Luqman-Fatah A, Miyoshi T. Human LINE-1 retrotransposons: impacts on the genome and regulation by host factors. Genes Genet Syst 2023; 98:121-154. [PMID: 36436935 DOI: 10.1266/ggs.22-00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Genome sequencing revealed that nearly half of the human genome is comprised of transposable elements. Although most of these elements have been rendered inactive due to mutations, full-length intact long interspersed element-1 (LINE-1 or L1) copies retain the ability to mobilize through RNA intermediates by a so-called "copy-and-paste" mechanism, termed retrotransposition. L1 is the only known autonomous mobile genetic element in the genome, and its retrotransposition contributes to inter- or intra-individual genetic variation within the human population. However, L1 retrotransposition also poses a threat to genome integrity due to gene disruption and chromosomal instability. Moreover, recent studies suggest that aberrant L1 expression can impact human health by causing diseases such as cancer and chronic inflammation that might lead to autoimmune disorders. To counteract these adverse effects, the host cells have evolved multiple layers of defense mechanisms at the epigenetic, RNA and protein levels. Intriguingly, several host factors have also been reported to facilitate L1 retrotransposition, suggesting that there is competition between negative and positive regulation of L1 by host factors. Here, we summarize the known host proteins that regulate L1 activity at different stages of the replication cycle and discuss how these factors modulate disease-associated phenotypes caused by L1.
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Affiliation(s)
- Ahmad Luqman-Fatah
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
| | - Tomoichiro Miyoshi
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
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10
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Tan K, Wilkinson MF. Developmental regulators moonlighting as transposons defense factors. Andrology 2023; 11:891-903. [PMID: 36895139 PMCID: PMC11162177 DOI: 10.1111/andr.13427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/17/2023] [Accepted: 03/04/2023] [Indexed: 03/11/2023]
Abstract
BACKGROUND The germline perpetuates genetic information across generations. To maintain the integrity of the germline, transposable elements in the genome must be silenced, as these mobile elements would otherwise engender widespread mutations passed on to subsequent generations. There are several well-established mechanisms that are dedicated to providing defense against transposable elements, including DNA methylation, RNA interference, and the PIWI-interacting RNA pathway. OBJECTIVES Recently, several studies have provided evidence that transposon defense is not only provided by factors dedicated to this purpose but also factors with other roles, including in germline development. Many of these are transcription factors. Our objective is to summarize what is known about these "bi-functional" transcriptional regulators. MATERIALS AND METHODS Literature search. RESULTS AND CONCLUSION We summarize the evidence that six transcriptional regulators-GLIS3, MYBL1, RB1, RHOX10, SETDB1, and ZBTB16-are both developmental regulators and transposable element-defense factors. These factors act at different stages of germ cell development, including in pro-spermatogonia, spermatogonial stem cells, and spermatocytes. Collectively, the data suggest a model in which specific key transcriptional regulators have acquired multiple functions over evolutionary time to influence developmental decisions and safeguard transgenerational genetic information. It remains to be determined whether their developmental roles were primordial and their transposon defense roles were co-opted, or vice versa.
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Affiliation(s)
- Kun Tan
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego, La Jolla, California, USA
| | - Miles F. Wilkinson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego, La Jolla, California, USA
- Institute of Genomic Medicine, University of California San Diego, La Jolla, California, USA
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11
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Warkocki Z. An update on post-transcriptional regulation of retrotransposons. FEBS Lett 2023; 597:380-406. [PMID: 36460901 DOI: 10.1002/1873-3468.14551] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022]
Abstract
Retrotransposons, including LINE-1, Alu, SVA, and endogenous retroviruses, are one of the major constituents of human genomic repetitive sequences. Through the process of retrotransposition, some of them occasionally insert into new genomic locations by a copy-paste mechanism involving RNA intermediates. Irrespective of de novo genomic insertions, retrotransposon expression can lead to DNA double-strand breaks and stimulate cellular innate immunity through endogenous patterns. As a result, retrotransposons are tightly regulated by multi-layered regulatory processes to prevent the dangerous effects of their expression. In recent years, significant progress was made in revealing how retrotransposon biology intertwines with general post-transcriptional RNA metabolism. Here, I summarize current knowledge on the involvement of post-transcriptional factors in the biology of retrotransposons, focusing on LINE-1. I emphasize general RNA metabolisms such as methylation of adenine (m6 A), RNA 3'-end polyadenylation and uridylation, RNA decay and translation regulation. I discuss the effects of retrotransposon RNP sequestration in cytoplasmic bodies and autophagy. Finally, I summarize how innate immunity restricts retrotransposons and how retrotransposons make use of cellular enzymes, including the DNA repair machinery, to complete their replication cycles.
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Affiliation(s)
- Zbigniew Warkocki
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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12
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Nef Suppresses LINE-1 Retrotransposition through Two Distinct Mechanisms. J Virol 2022; 96:e0114822. [PMID: 36197106 DOI: 10.1128/jvi.01148-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Long interspersed element type 1 (LINE-1) is the only known type of retroelement that can replicate autonomously, and its retrotransposition activity can trigger interferon (IFN) production. IFN production suppresses the infectivity of exogenous viruses, such as human immunodeficiency virus (HIV). As a counteraction, HIV has been reported to use multiple proteins and mechanisms to suppress LINE-1 replication. However, the mechanisms of HIV-mediated LINE-1 regulation are not fully understood. In this study, we discovered that Nef protein, which is expressed by HIV and is important for HIV pathogenesis, inhibits LINE-1 retrotransposition. Two distinct mechanisms have been uncovered for Nef-induced LINE-1 suppression. Without direct interaction with LINE-1 DNA, Nef potently inhibits the promoter activity of the LINE-1 5'-untranslated region (5'-UTR) and reduces the expression levels of LINE-1 RNA and proteins. Alternatively, although Nef does not bind to the LINE-1 open reading frame 1 protein (ORF1p) or LINE-1 RNA, it significantly compromises the ORF1p-LINE-1 RNA interaction, which is essential for LINE-1 retrotransposition. Both mechanisms can be suppressed by the G2A mutation, which abolishes myristoylation of Nef, suggesting that membrane attachment is essential for Nef to suppress LINE-1. Consequently, through LINE-1 inhibition, Nef downregulates IFN production in host cells. Therefore, our data revealed that Nef is a potent LINE-1 suppressor and an effective innate immune regulator, which not only provides new information on the intricate interaction between HIV, LINE-1, and IFN signaling systems but also strengthens the importance of Nef in HIV infection and highlights the potential of designing novel Nef-targeting anti-HIV drugs. IMPORTANCE Human immunodeficiency viruses are pathogens of AIDS that were first discovered almost 40 years ago and continue to threaten human lives to date. While currently used anti-HIV drugs are sufficient to suppress viral loads in HIV-infected patients, both drug-resistant HIV strains and adverse side effects triggered by the long-term use of these drugs highlight the need to develop novel anti-HIV drugs targeting different viral proteins and/or different steps in viral replication. To achieve this, more information is required regarding HIV pathogenesis and especially its impact on cellular activities in host cells. In this study, we discovered that the Nef protein expressed by HIV potently inhibits LINE-1 retrotransposition. During our attempt to determine the mechanism of Nef-mediated LINE-1 suppression, two additional functions of Nef were uncovered. Nef effectively repressed the promoter activity of LINE-1 5'-UTR and destabilized the interaction between ORF1p and LINE-1 RNA. Consequently, Nef not only compromises LINE-1 replication but also reduces LINE-1-triggered IFN production. The reduction in IFN production, in theory, promotes HIV infectivity. Together with its previously known functions, these findings indicate that Nef is a potential target for the development of novel anti-HIV drugs. Notably, the G2 residue, which has been reported to be essential for most Nef functions, was found to be critical in the regulation of innate immune activation by Nef, suggesting that compromising myristoylation or membrane attachment of Nef may be a good strategy for the inhibition of HIV infection.
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Lee Y, Ha U, Moon S. Ongoing endeavors to detect mobilization of transposable elements. BMB Rep 2022. [PMID: 35725016 PMCID: PMC9340088 DOI: 10.5483/bmbrep.2022.55.7.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transposable elements (TEs) are DNA sequences capable of mobilization from one location to another in the genome. Since the discovery of ‘Dissociation (Dc) locus’ by Barbara McClintock in maize (1), mounting evidence in the era of genomics indicates that a significant fraction of most eukaryotic genomes is composed of TE sequences, involving in various aspects of biological processes such as development, physiology, diseases and evolution. Although technical advances in genomics have discovered numerous functional impacts of TE across species, our understanding of TEs is still ongoing process due to challenges resulted from complexity and abundance of TEs in the genome. In this mini-review, we briefly summarize biology of TEs and their impacts on the host genome, emphasizing importance of understanding TE landscape in the genome. Then, we introduce recent endeavors especially in vivo retrotransposition assays and long read sequencing technology for identifying de novo insertions/TE polymorphism, which will broaden our knowledge of extraordinary relationship between genomic cohabitants and their host.
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Affiliation(s)
- Yujeong Lee
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
| | - Una Ha
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
| | - Sungjin Moon
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
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14
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Differential MC5R loss in whales and manatees reveals convergent evolution to the marine environment. Dev Genes Evol 2022; 232:81-87. [PMID: 35648215 DOI: 10.1007/s00427-022-00688-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/16/2022] [Indexed: 02/05/2023]
Abstract
Melanocortin 5 receptor (MC5R), which is expressed in the terminally differentiated sebaceous gland, is a G protein-coupled receptor (GPCR). MC5R exists mostly in mammals but is completely lost in whales; only the relic of MC5R can be detected in manatees, and phenotypically, they have lost sebaceous glands. Interestingly, whales and manatees are both aquatic mammals but have no immediate common ancestors. The loss of MC5R and sebaceous glands in whales and manatees is likely to be a result of convergent evolution. Here, we find that MC5R in whales and manatees are lost by two different mechanisms. Homologous recombination of MC5R in manatees and the insertion of reverse transcriptase in whales lead to the gene loss, respectively. On one hand, in manatees, there are two "TTATC" sequences flanking MC5R, and homologous recombination of the segments between the two "TTATC" sequences resulted in the partial loss of the sequence of MC5R. On the other hand, in whales, reverse transcriptase inserts between MC2R and RNMT on the chromosome led to the loss of MC5R. Based on these two different mechanisms for gene loss in whales and manatees, we finally concluded that MC5R loss might be the result of convergent evolution to the marine environment, and we explored the impact on biological function that is significant to environmental adaptation.
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15
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Pfaff AL, Singleton LM, Kõks S. Mechanisms of disease-associated SINE-VNTR-Alus. Exp Biol Med (Maywood) 2022; 247:756-764. [PMID: 35387528 DOI: 10.1177/15353702221082612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
SINE-VNTR-Alus (SVAs) are the youngest retrotransposon family in the human genome. Their ongoing mobilization has generated genetic variation within the human population. At least 24 insertions to date, detailed in this review, have been associated with disease. The predominant mechanisms through which this occurs are alterations to normal splicing patterns, exonic insertions causing loss-of-function mutations, and large genomic deletions. Dissecting the functional impact of these SVAs and the mechanism through which they cause disease provides insight into the consequences of their presence in the genome and how these elements could influence phenotypes. Many of these disease-associated SVAs have been difficult to characterize and would not have been identified through routine analyses. However, the number identified has increased in recent years as DNA and RNA sequencing data became more widely available. Therefore, as the search for complex structural variation in disease continues, it is likely to yield further disease-causing SVA insertions.
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Affiliation(s)
- Abigail L Pfaff
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
| | - Lewis M Singleton
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia
| | - Sulev Kõks
- Perron Institute for Neurological and Translational Science, Perth, WA 6009, Australia.,Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA 6150, Australia
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16
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Hoyt SJ, Storer JM, Hartley GA, Grady PGS, Gershman A, de Lima LG, Limouse C, Halabian R, Wojenski L, Rodriguez M, Altemose N, Rhie A, Core LJ, Gerton JL, Makalowski W, Olson D, Rosen J, Smit AFA, Straight AF, Vollger MR, Wheeler TJ, Schatz MC, Eichler EE, Phillippy AM, Timp W, Miga KH, O’Neill RJ. From telomere to telomere: The transcriptional and epigenetic state of human repeat elements. Science 2022; 376:eabk3112. [PMID: 35357925 PMCID: PMC9301658 DOI: 10.1126/science.abk3112] [Citation(s) in RCA: 118] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mobile elements and repetitive genomic regions are sources of lineage-specific genomic innovation and uniquely fingerprint individual genomes. Comprehensive analyses of such repeat elements, including those found in more complex regions of the genome, require a complete, linear genome assembly. We present a de novo repeat discovery and annotation of the T2T-CHM13 human reference genome. We identified previously unknown satellite arrays, expanded the catalog of variants and families for repeats and mobile elements, characterized classes of complex composite repeats, and located retroelement transduction events. We detected nascent transcription and delineated CpG methylation profiles to define the structure of transcriptionally active retroelements in humans, including those in centromeres. These data expand our insight into the diversity, distribution, and evolution of repetitive regions that have shaped the human genome.
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Affiliation(s)
- Savannah J. Hoyt
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | | | - Gabrielle A. Hartley
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Patrick G. S. Grady
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Ariel Gershman
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
| | | | - Charles Limouse
- Department of Biochemistry, Stanford University, Stanford, CA, USA
| | - Reza Halabian
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Luke Wojenski
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Matias Rodriguez
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Nicolas Altemose
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
| | - Arang Rhie
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Leighton J. Core
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | | | - Wojciech Makalowski
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Daniel Olson
- Department of Computer Science, University of Montana, Missoula, MT, USA
| | - Jeb Rosen
- Institute for Systems Biology, Seattle, WA, USA
| | | | | | - Mitchell R. Vollger
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Travis J. Wheeler
- Department of Computer Science, University of Montana, Missoula, MT, USA
| | - Michael C. Schatz
- Department of Computer Science and Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Adam M. Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Winston Timp
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Karen H. Miga
- UC Santa Cruz Genomics Institute, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Rachel J. O’Neill
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA
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17
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Fröhlich A, Pfaff AL, Bubb VJ, Koks S, Quinn JP. Characterisation of the Function of a SINE-VNTR-Alu Retrotransposon to Modulate Isoform Expression at the MAPT Locus. Front Mol Neurosci 2022; 15:815695. [PMID: 35370538 PMCID: PMC8965460 DOI: 10.3389/fnmol.2022.815695] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/10/2022] [Indexed: 11/30/2022] Open
Abstract
SINE-VNTR-Alu retrotransposons represent one class of transposable elements which contribute to the regulation and evolution of the primate genome and have the potential to be involved in genetic instability and disease progression. However, these polymorphic elements have not been extensively analysed when addressing the missing heritability of neurodegenerative diseases, including Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS). SVA_67, a retrotransposon insertion polymorphism, is located in a 1.8 Mb region of high linkage disequilibrium, called the MAPT locus, which is known to contribute to increased risk of developing PD, frontotemporal dementia and other tauopathies. To investigate the role of SVA_67 in directing differential gene expression at this locus, we characterised the impact of SVA_67 allele dosage on isoform expression of several genes in the MAPT locus using the datasets from both the Parkinson’s Progression Markers Initiative and New York Genome Center Consortium Target ALS cohort. The Parkinson’s data was from gene expression in the blood and the ALS data from a variety of CNS regions and allowed us to demonstrate that SVA_67 presence or absence correlated with both isoform- and tissue-specific expression of multiple genes at this locus. This study highlights the importance of addressing SVA polymorphism in disease genetics to gain insight into a better understanding of the role of these regulatory domains to a variety of neurodegenerative diseases.
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Affiliation(s)
- Alexander Fröhlich
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- *Correspondence: Alexander Fröhlich,
| | - Abigail L. Pfaff
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Vivien J. Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Sulev Koks
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - John P. Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
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18
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Kaur D, Agrahari M, Bhattacharya A, Bhattacharya S. The non-LTR retrotransposons of Entamoeba histolytica: genomic organization and biology. Mol Genet Genomics 2022; 297:1-18. [PMID: 34999963 DOI: 10.1007/s00438-021-01843-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 11/26/2021] [Indexed: 11/24/2022]
Abstract
Genome sequence analysis of Entamoeba species revealed various classes of transposable elements. While E. histolytica and E. dispar are rich in non-long terminal repeat (LTR) retrotransposons, E. invadens contains predominantly DNA transposons. Non-LTR retrotransposons of E. histolytica constitute three families of long interspersed nuclear elements (LINEs), and their short, nonautonomous partners, SINEs. They occupy ~ 11% of the genome. The EhLINE1/EhSINE1 family is the most abundant and best studied. EhLINE1 is 4.8 kb, with two ORFs that encode functions needed for retrotransposition. ORF1 codes for the nucleic acid-binding protein, and ORF2 has domains for reverse transcriptase (RT) and endonuclease (EN). Most copies of EhLINEs lack complete ORFs. ORF1p is expressed constitutively, but ORF2p is not detected. Retrotransposition could be demonstrated upon ectopic over expression of ORF2p, showing that retrotransposition machinery is functional. The newly retrotransposed sequences showed a high degree of recombination. In transcriptomic analysis, RNA-Seq reads were mapped to individual EhLINE1 copies. Although full-length copies were transcribed, no full-length 4.8 kb transcripts were seen. Rather, sense transcripts mapped to ORF1, RT and EN domains. Intriguingly, there was strong antisense transcription almost exclusively from the RT domain. These unique features of EhLINE1 could serve to attenuate retrotransposition in E. histolytica.
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19
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Chuang NT, Gardner EJ, Terry DM, Crabtree J, Mahurkar AA, Rivell GL, Hong CC, Perry JA, Devine SE. Mutagenesis of human genomes by endogenous mobile elements on a population scale. Genome Res 2021; 31:2225-2235. [PMID: 34772701 PMCID: PMC8647825 DOI: 10.1101/gr.275323.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 09/16/2021] [Indexed: 01/22/2023]
Abstract
Several large-scale Illumina whole-genome sequencing (WGS) and whole-exome sequencing (WES) projects have emerged recently that have provided exceptional opportunities to discover mobile element insertions (MEIs) and study the impact of these MEIs on human genomes. However, these projects also have presented major challenges with respect to the scalability and computational costs associated with performing MEI discovery on tens or even hundreds of thousands of samples. To meet these challenges, we have developed a more efficient and scalable version of our mobile element locator tool (MELT) called CloudMELT. We then used MELT and CloudMELT to perform MEI discovery in 57,919 human genomes and exomes, leading to the discovery of 104,350 nonredundant MEIs. We leveraged this collection (1) to examine potentially active L1 source elements that drive the mobilization of new Alu, L1, and SVA MEIs in humans; (2) to examine the population distributions and subfamilies of these MEIs; and (3) to examine the mutagenesis of GENCODE genes, ENCODE-annotated features, and disease genes by these MEIs. Our study provides new insights on the L1 source elements that drive MEI mutagenesis and brings forth a better understanding of how this mutagenesis impacts human genomes.
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Affiliation(s)
- Nelson T Chuang
- Graduate Program in Molecular Medicine, University of Maryland, Baltimore, Baltimore, Maryland 21201, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
- Division of Gastroenterology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Eugene J Gardner
- Graduate Program in Molecular Medicine, University of Maryland, Baltimore, Baltimore, Maryland 21201, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Diane M Terry
- Graduate Program in Molecular Medicine, University of Maryland, Baltimore, Baltimore, Maryland 21201, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Jonathan Crabtree
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Anup A Mahurkar
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Guillermo L Rivell
- Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Charles C Hong
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - James A Perry
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Scott E Devine
- Graduate Program in Molecular Medicine, University of Maryland, Baltimore, Baltimore, Maryland 21201, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
- Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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20
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Ravel-Godreuil C, Znaidi R, Bonnifet T, Joshi RL, Fuchs J. Transposable elements as new players in neurodegenerative diseases. FEBS Lett 2021; 595:2733-2755. [PMID: 34626428 DOI: 10.1002/1873-3468.14205] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/23/2021] [Accepted: 10/03/2021] [Indexed: 01/02/2023]
Abstract
Neurodegenerative diseases (NDs), including the most prevalent Alzheimer's disease and Parkinson disease, share common pathological features. Despite decades of gene-centric approaches, the molecular mechanisms underlying these diseases remain widely elusive. In recent years, transposable elements (TEs), long considered 'junk' DNA, have gained growing interest as pathogenic players in NDs. Age is the major risk factor for most NDs, and several repressive mechanisms of TEs, such as heterochromatinization, fail with age. Indeed, heterochromatin relaxation leading to TE derepression has been reported in various models of neurodegeneration and NDs. There is also evidence that certain pathogenic proteins involved in NDs (e.g., tau, TDP-43) may control the expression of TEs. The deleterious consequences of TE activation are not well known but they could include DNA damage and genomic instability, altered host gene expression, and/or neuroinflammation, which are common hallmarks of neurodegeneration and aging. TEs might thus represent an overlooked pathogenic culprit for both brain aging and neurodegeneration. Certain pathological effects of TEs might be prevented by inhibiting their activity, pointing to TEs as novel targets for neuroprotection.
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Affiliation(s)
- Camille Ravel-Godreuil
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rania Znaidi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Tom Bonnifet
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rajiv L Joshi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Julia Fuchs
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
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21
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Smits N, Rasmussen J, Bodea GO, Amarilla AA, Gerdes P, Sanchez-Luque FJ, Ajjikuttira P, Modhiran N, Liang B, Faivre J, Deveson IW, Khromykh AA, Watterson D, Ewing AD, Faulkner GJ. No evidence of human genome integration of SARS-CoV-2 found by long-read DNA sequencing. Cell Rep 2021; 36:109530. [PMID: 34380018 PMCID: PMC8316065 DOI: 10.1016/j.celrep.2021.109530] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 01/28/2023] Open
Abstract
A recent study proposed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hijacks the LINE-1 (L1) retrotransposition machinery to integrate into the DNA of infected cells. If confirmed, this finding could have significant clinical implications. Here, we apply deep (>50×) long-read Oxford Nanopore Technologies (ONT) sequencing to HEK293T cells infected with SARS-CoV-2 and do not find the virus integrated into the genome. By examining ONT data from separate HEK293T cultivars, we completely resolve 78 L1 insertions arising in vitro in the absence of L1 overexpression systems. ONT sequencing applied to hepatitis B virus (HBV)-positive liver cancer tissues located a single HBV insertion. These experiments demonstrate reliable resolution of retrotransposon and exogenous virus insertions by ONT sequencing. That we find no evidence of SARS-CoV-2 integration suggests that such events are, at most, extremely rare in vivo and therefore are unlikely to drive oncogenesis or explain post-recovery detection of the virus.
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Affiliation(s)
- Nathan Smits
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Jay Rasmussen
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia
| | - Gabriela O Bodea
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia
| | - Alberto A Amarilla
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Patricia Gerdes
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Francisco J Sanchez-Luque
- GENYO, Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research, PTS Granada 18016, Spain; MRC Human Genetics Unit, Institute of Genetics and Cancer (IGC), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Prabha Ajjikuttira
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia
| | - Naphak Modhiran
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Benjamin Liang
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Jamila Faivre
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif 94800, France
| | - Ira W Deveson
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Alexander A Khromykh
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, QLD 4072, Australia
| | - Daniel Watterson
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, QLD 4072, Australia
| | - Adam D Ewing
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia.
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22
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Sabatella M, Mantere T, Waanders E, Neveling K, Mensenkamp AR, van Dijk F, Hehir‐Kwa JY, Derks R, Kwint M, O'Gorman L, Tropa Martins M, Gidding CEM, Lequin MH, Küsters B, Wesseling P, Nelen M, Biegel JA, Hoischen A, Jongmans MC, Kuiper RP. Optical genome mapping identifies a germline retrotransposon insertion in SMARCB1 in two siblings with atypical teratoid rhabdoid tumors. J Pathol 2021; 255:202-211. [PMID: 34231212 PMCID: PMC8519051 DOI: 10.1002/path.5755] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/28/2021] [Accepted: 07/04/2021] [Indexed: 11/29/2022]
Abstract
In a subset of pediatric cancers, a germline cancer predisposition is highly suspected based on clinical and pathological findings, but genetic evidence is lacking, which hampers genetic counseling and predictive testing in the families involved. We describe a family with two siblings born from healthy parents who were both neonatally diagnosed with atypical teratoid rhabdoid tumor (ATRT). This rare and aggressive pediatric tumor is associated with biallelic inactivation of SMARCB1, and in 30% of the cases, a predisposing germline mutation is involved. Whereas the tumors of both siblings showed loss of expression of SMARCB1 and acquired homozygosity of the locus, whole exome and whole genome sequencing failed to identify germline or somatic SMARCB1 pathogenic mutations. We therefore hypothesized that the insertion of a pathogenic repeat‐rich structure might hamper its detection, and we performed optical genome mapping (OGM) as an alternative strategy to identify structural variation in this locus. Using this approach, an insertion of ~2.8 kb within intron 2 of SMARCB1 was detected. Long‐range PCR covering this region remained unsuccessful, but PacBio HiFi genome sequencing identified this insertion to be a SINE‐VNTR‐Alu, subfamily E (SVA‐E) retrotransposon element, which was present in a mosaic state in the mother. This SVA‐E insertion disrupts correct splicing of the gene, resulting in loss of a functional allele. This case demonstrates the power of OGM and long‐read sequencing to identify genomic variations in high‐risk cancer‐predisposing genes that are refractory to detection with standard techniques, thereby completing the clinical and molecular diagnosis of such complex cases and greatly improving counseling and surveillance of the families involved. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
| | - Tuomo Mantere
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Institute of Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Laboratory of Cancer Genetics and Tumor Biology, Cancer and Translational Medicine Research Unit and Biocenter OuluUniversity of OuluOuluFinland
| | - Esmé Waanders
- Department of GeneticsUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Kornelia Neveling
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
| | - Arjen R Mensenkamp
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Institute of Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Freerk van Dijk
- Princess Máxima Centre for Pediatric OncologyUtrechtThe Netherlands
| | | | - Ronnie Derks
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Institute of Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Michael Kwint
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Institute of Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Luke O'Gorman
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Institute of Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | | | | | - Maarten H Lequin
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Benno Küsters
- Department of PathologyRadboud University Medical CenterNijmegenThe Netherlands
| | - Pieter Wesseling
- Princess Máxima Centre for Pediatric OncologyUtrechtThe Netherlands
- Department of PathologyAmsterdam University Medical Centers, Location VUmc and Brain Tumor Center AmsterdamAmsterdamThe Netherlands
| | - Marcel Nelen
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Institute of Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Jacklyn A Biegel
- Department of Pathology and Laboratory MedicineChildren's Hospital, Los AngelesLos AngelesCAUSA
- Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Alexander Hoischen
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Institute of Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Department of Internal Medicine and Radboud Center for Infectious Diseases (RCI)Radboud University Medical CenterNijmegenThe Netherlands
| | - Marjolijn C Jongmans
- Princess Máxima Centre for Pediatric OncologyUtrechtThe Netherlands
- Department of GeneticsUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Roland P Kuiper
- Princess Máxima Centre for Pediatric OncologyUtrechtThe Netherlands
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
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23
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Frassinelli L, Orecchini E, Al-Wardat S, Tripodi M, Mancone C, Doria M, Galardi S, Ciafrè SA, Michienzi A. The RNA editing enzyme ADAR2 restricts L1 mobility. RNA Biol 2021; 18:75-87. [PMID: 34224323 PMCID: PMC8677026 DOI: 10.1080/15476286.2021.1940020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) are enzymes that convert adenosines to inosines in double-stranded RNAs (RNA editing A-to-I). ADAR1 and ADAR2 were previously reported as HIV-1 proviral factors. The aim of this study was to investigate the composition of the ADAR2 ribonucleoprotein complex during HIV-1 expression. By using a dual-tag affinity purification procedure in cells expressing HIV-1 followed by mass spectrometry analysis, we identified 10 non-ribosomal ADAR2-interacting factors. A significant fraction of these proteins was previously found associated to the Long INterspersed Element 1 (LINE1 or L1) ribonucleoparticles and to regulate the life cycle of L1 retrotransposons. Considering that we previously demonstrated that ADAR1 is an inhibitor of LINE-1 retrotransposon activity, we investigated whether also ADAR2 played a similar function. To reach this goal, we performed specific cell culture retrotransposition assays in cells overexpressing or ablated for ADAR2. These experiments unveil a novel function of ADAR2 as suppressor of L1 retrotransposition. Furthermore, we showed that ADAR2 binds the basal L1 RNP complex. Overall, these data support the role of ADAR2 as regulator of L1 life cycle.
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Affiliation(s)
- Loredana Frassinelli
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Elisa Orecchini
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Sofian Al-Wardat
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Marco Tripodi
- National Institute for Infectious Diseases L. Spallanzani, IRCCS, Rome, Italy.,Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Carmine Mancone
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Margherita Doria
- Unit of Primary Immunodeficiency, Bambino Gesu` Children's Hospital, IRCCS, Rome, Italy
| | - Silvia Galardi
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Silvia Anna Ciafrè
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Alessandro Michienzi
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
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Mastora E, Christodoulaki A, Papageorgiou K, Zikopoulos A, Georgiou I. Expression of Retroelements in Mammalian Gametes and Embryos. In Vivo 2021; 35:1921-1927. [PMID: 34182464 DOI: 10.21873/invivo.12458] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/18/2021] [Accepted: 05/24/2021] [Indexed: 11/10/2022]
Abstract
Retroelements are genetic mobile elements, expressed during male and female gamete differentiation. Retrotransposons are normally regulated by the methylation machinery, chromatin modifications, non-coding RNAs, and transcription factors, while retrotransposition control is of vital importance in cellular proliferation and differentiation process. Retrotransposition requires a transcription step, by a cellular RNA polymerase, followed by reverse transcription of an RNA intermediate to cDNA and its integration into a new genomic locus. Long interspersed elements (LINEs), human endogenous retroviruses (HERVs), short interspersed elements (SINEs) and SINE-VNTR-Alu elements (SVAs) constitute about half of the human genome, play a crucial role in genome organization, structure and function and interfere with several biological procedures. In this mini review, we discuss recent data regarding retroelement expression (LINE-1, HERVK-10, SVA and VL30) and retrotransposition events in mammalian oocytes and spermatozoa, as well as the importance of their impact on human and mouse preimplantation embryo development.
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Affiliation(s)
- Eirini Mastora
- Laboratory of Medical Genetics, School of Medicine, University of Ioannina and Medical Genetics and Assisted Reproduction Unit, Department of Obstetrics and Gynecology, University Hospital of Ioannina, Ioannina, Greece
| | - Antonia Christodoulaki
- Laboratory of Medical Genetics, School of Medicine, University of Ioannina and Medical Genetics and Assisted Reproduction Unit, Department of Obstetrics and Gynecology, University Hospital of Ioannina, Ioannina, Greece
| | - Kyriaki Papageorgiou
- Department of Biological Applications & Technologies, University of Ioannina and Institute of Molecular Biology and Biotechnology, Division of Biomedical Research, Foundation for Research and Technology, Ioannina, Greece
| | - Athanasios Zikopoulos
- Laboratory of Medical Genetics, School of Medicine, University of Ioannina and Medical Genetics and Assisted Reproduction Unit, Department of Obstetrics and Gynecology, University Hospital of Ioannina, Ioannina, Greece
| | - Ioannis Georgiou
- Laboratory of Medical Genetics, School of Medicine, University of Ioannina and Medical Genetics and Assisted Reproduction Unit, Department of Obstetrics and Gynecology, University Hospital of Ioannina, Ioannina, Greece;
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25
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Mukherjee K, Sur D, Singh A, Rai S, Das N, Sekar R, Narindi S, Dhingra VK, Jat B, Balraam KVV, Agarwal SP, Mandal PK. Robust expression of LINE-1 retrotransposon encoded proteins in oral squamous cell carcinoma. BMC Cancer 2021; 21:628. [PMID: 34044801 PMCID: PMC8161598 DOI: 10.1186/s12885-021-08174-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/07/2021] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Oral Squamous Cell Carcinoma (OSCC) results from a series of genetic alteration in squamous cells. This particular type of cancer considers one of the most aggressive malignancies to control because of its frequent local invasions to the regional lymph node. Although several biomarkers have been reported, the key marker used to predict the behavior of the disease is largely unknown. Here we report Long INterpersed Element-1 (LINE1 or L1) retrotransposon activity in post-operative oral cancer samples. L1 is the only active retrotransposon occupying around 17% of the human genome with an estimated 500,000 copies. An active L1 encodes two proteins (L1ORF1p and L1ORF2p); both of which are critical in the process of retrotransposition. Several studies report that the L1 retrotransposon is highly active in many cancers. L1 activity is generally determined by assaying L1ORF1p because of its high expression and availability of the antibody. However, due to its lower expression and unavailability of a robust antibody, detection of L1ORF2p has been limited. L1ORF2p is the crucial protein in the process of retrotransposition as it provides endonuclease and reverse transcriptase (RT) activity. METHODS Immunohistochemistry and Western blotting were performed on the post-operative oral cancer samples and murine tissues. RESULTS Using in house novel antibodies against both the L1 proteins (L1ORF1p and L1ORF2p), we found L1 retrotransposon is extremely active in post-operative oral cancer tissues. Here, we report a novel human L1ORF2p antibody generated using an 80-amino-acid stretch from the RT domain, which is highly conserved among different species. The antibody detects significant L1ORF2p expression in human oral squamous cell carcinoma (OSCC) samples and murine germ tissues. CONCLUSIONS We report exceptionally high L1ORF1p and L1ORF2p expression in post-operative oral cancer samples. The novel L1ORF2p antibody reported in this study will serve as a useful tool to understand why L1 activity is deregulated in OSCC and how it contributes to the progression of this particular cancer. Cross-species reactivity of L1ORF2p antibody due to the conserved epitope will be useful to study the retrotransposon biology in mice and rat germ tissues.
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Affiliation(s)
- Koel Mukherjee
- Department of Biotechnology, IIT Roorkee, Roorkee, Uttarakhand India
| | - Debpali Sur
- Department of Biotechnology, IIT Roorkee, Roorkee, Uttarakhand India
| | - Abhijeet Singh
- Department of Head-Neck Surgery and Oncology, AIIMS Rishikesh, Rishikesh, Uttarakhand India
| | - Sandhya Rai
- Department of Biotechnology, IIT Roorkee, Roorkee, Uttarakhand India
| | | | - Rakshanya Sekar
- School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu India
| | | | - Vandana Kumar Dhingra
- Department of Head-Neck Surgery and Oncology, AIIMS Rishikesh, Rishikesh, Uttarakhand India
| | - Bhinyaram Jat
- Department of Head-Neck Surgery and Oncology, AIIMS Rishikesh, Rishikesh, Uttarakhand India
| | | | - Satya Prakash Agarwal
- Department of Head-Neck Surgery and Oncology, AIIMS Rishikesh, Rishikesh, Uttarakhand India
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26
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Reference SVA insertion polymorphisms are associated with Parkinson's Disease progression and differential gene expression. NPJ Parkinsons Dis 2021; 7:44. [PMID: 34035310 PMCID: PMC8149882 DOI: 10.1038/s41531-021-00189-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 04/23/2021] [Indexed: 12/20/2022] Open
Abstract
The development of Parkinson's disease (PD) involves a complex interaction of genetic and environmental factors. Genome-wide association studies using extensive single nucleotide polymorphism datasets have identified many loci involved in disease. However much of the heritability of Parkinson's disease is still to be identified and the functional elements associated with the risk to be determined and understood. To investigate the component of PD that may involve complex genetic variants we characterised the hominid specific retrotransposon SINE-VNTR-Alus (SVAs) in the Parkinson's Progression Markers Initiative cohort utilising whole genome sequencing. We identified 81 reference SVAs polymorphic for their presence/absence, seven of which were associated with the progression of the disease and with differential gene expression in whole blood RNA sequencing data. This study highlights the importance of addressing SVA variants and potentially other types of retrotransposons in PD genetics, furthermore, these SVA elements should be considered as regulatory domains that could play a role in disease progression.
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27
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Mangiavacchi A, Liu P, Della Valle F, Orlando V. New insights into the functional role of retrotransposon dynamics in mammalian somatic cells. Cell Mol Life Sci 2021; 78:5245-5256. [PMID: 33990851 PMCID: PMC8257530 DOI: 10.1007/s00018-021-03851-5] [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: 10/29/2020] [Revised: 03/31/2021] [Accepted: 05/04/2021] [Indexed: 12/18/2022]
Abstract
Retrotransposons are genetic elements present across all eukaryotic genomes. While their role in evolution is considered as a potentially beneficial natural source of genetic variation, their activity is classically considered detrimental due to their potentially harmful effects on genome stability. However, studies are increasingly shedding light on the regulatory function and beneficial role of somatic retroelement reactivation in non-pathological contexts. Here, we review recent findings unveiling the regulatory potential of retrotransposons, including their role in noncoding RNA transcription, as modulators of mammalian transcriptional and epigenome landscapes. We also discuss technical challenges in deciphering the multifaceted activity of retrotransposable elements, highlighting an unforeseen central role of this neglected portion of the genome both in early development and in adult life.
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Affiliation(s)
- Arianna Mangiavacchi
- Biological Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Peng Liu
- Biological Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Francesco Della Valle
- Biological Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Valerio Orlando
- Biological Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
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28
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Abstract
I have been fortunate and privileged to have participated in amazing breakthroughs in human genetics since the 1960s. I was lucky to have trained in medical school at Dartmouth and Johns Hopkins, in pediatrics at the University of Minnesota and Johns Hopkins, and in genetics and molecular biology with Dr. Barton Childs at Johns Hopkins and Dr. Harvey Itano at the National Institutes of Health. Later, the collaborative spirit at Johns Hopkins and the University of Pennsylvania were important to my career. Here, I describe the thrill of scientific discovery in two diverse areas of human genetics: DNA haplotypes and their role in solving the molecular basis of beta thalassemia and the role of retrotransposons (jumping genes) in human biology. I hope that this article may inspire others who love human genetics as much as I do.
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Affiliation(s)
- Haig H Kazazian
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA;
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29
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Gazquez-Gutierrez A, Witteveldt J, R Heras S, Macias S. Sensing of transposable elements by the antiviral innate immune system. RNA (NEW YORK, N.Y.) 2021; 27:rna.078721.121. [PMID: 33888553 PMCID: PMC8208052 DOI: 10.1261/rna.078721.121] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/17/2021] [Indexed: 05/15/2023]
Abstract
Around half of the genome in mammals is composed of transposable elements (TEs) such as DNA transposons and retrotransposons. Several mechanisms have evolved to prevent their activity and the detrimental impact of their insertional mutagenesis. Despite these potentially negative effects, TEs are essential drivers of evolution, and in certain settings, beneficial to their hosts. For instance, TEs have rewired the antiviral gene regulatory network and are required for early embryonic development. However, due to structural similarities between TE-derived and viral nucleic acids, cells can misidentify TEs as invading viruses and trigger the major antiviral innate immune pathway, the type I interferon (IFN) response. This review will focus on the different settings in which the role of TE-mediated IFN activation has been documented, including cancer and senescence. Importantly, TEs may also play a causative role in the development of complex autoimmune diseases characterised by constitutive type I IFN activation. All these observations suggest the presence of strong but opposing forces driving the coevolution of TEs and antiviral defence. A better biological understanding of the TE replicative cycle as well as of the antiviral nucleic acid sensing mechanisms will provide insights into how these two biological processes interact and will help to design better strategies to treat human diseases characterised by aberrant TE expression and/or type I IFN activation.
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Affiliation(s)
| | - Jeroen Witteveldt
- University of Edinburgh - Institute of Immunology and Infection Research
| | - Sara R Heras
- GENYO. Centre for Genomics and Oncological Research, Pfizer University of Granada
| | - Sara Macias
- Institute of Immunology and Infection Research
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30
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Hepatitis C virus infection restricts human LINE-1 retrotransposition in hepatoma cells. PLoS Pathog 2021; 17:e1009496. [PMID: 33872335 PMCID: PMC8084336 DOI: 10.1371/journal.ppat.1009496] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/29/2021] [Accepted: 03/23/2021] [Indexed: 12/17/2022] Open
Abstract
LINE-1 (L1) retrotransposons are autonomous transposable elements that can affect gene expression and genome integrity. Potential consequences of exogenous viral infections for L1 activity have not been studied to date. Here, we report that hepatitis C virus (HCV) infection causes a significant increase of endogenous L1-encoded ORF1 protein (L1ORF1p) levels and translocation of L1ORF1p to HCV assembly sites at lipid droplets. HCV replication interferes with retrotransposition of engineered L1 reporter elements, which correlates with HCV RNA-induced formation of stress granules and can be partially rescued by knockdown of the stress granule protein G3BP1. Upon HCV infection, L1ORF1p localizes to stress granules, associates with HCV core in an RNA-dependent manner and translocates to lipid droplets. While HCV infection has a negative effect on L1 mobilization, L1ORF1p neither restricts nor promotes HCV infection. In summary, our data demonstrate that HCV infection causes an increase of endogenous L1 protein levels and that the observed restriction of retrotransposition of engineered L1 reporter elements is caused by sequestration of L1ORF1p in HCV-induced stress granules. Members of the Long Interspersed Nuclear Element 1 (LINE-1, L1) class of retrotransposons account for ~17% of the human genome and include ~100–150 intact L1 loci that are still functional. L1 mobilization is known to affect genomic integrity, thereby leading to disease-causing mutations, but little is known about the impact of exogenous viral infections on L1 and vice versa. While L1 retrotransposition is controlled by various mechanisms including CpG methylation, hypomethylation of L1 has been observed in hepatocellular carcinoma tissues of hepatitis C virus (HCV)-infected patients. Here, we demonstrate molecular interactions between HCV and L1 elements. HCV infection stably increases cellular levels of the L1-encoded ORF1 protein (L1ORF1p). HCV core and L1ORF1p interact in ribonucleoprotein complexes that traffic to lipid droplets. Despite its redistribution to HCV assembly sites, L1ORF1p is dispensable for HCV infection. In contrast, retrotransposition of engineered L1 reporter elements is restricted by HCV, correlating with an increased formation of L1ORF1p-containing cytoplasmic stress granules. Thus, our data provide first insights into the molecular interplay of endogenous transposable elements and exogenous viruses that might contribute to disease progression in vivo.
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31
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Abstract
Exogenous retroviruses are RNA viruses that require reverse transcription for their replication. Among these viruses, human immunodeficiency virus (HIV) is infectious to humans and causes the development of acquired immune deficiency syndrome (AIDS). There are also endogenous retroelements that require reverse transcription for their retrotransposition, among which the type 1 long interspersed element (LINE-1) is the only type of retroelement that can replicate autonomously. It was once believed that retroviruses like HIV and retroelements like LINE-1 share similarities in processes such as reverse transcription and integration. Accordingly, many HIV suppressors are also potent LINE-1 inhibitors. However, in many cases, one suppressor uses two or more distinct mechanisms to repress HIV and LINE-1. In this review, we discuss some of these suppressors, focusing on their alternative mechanisms opposing the replication of HIV and LINE-1. Based on the differences in HIV and LINE-1 activity, the subcellular localization of these suppressors, and the impact of LINE-1 retrotransposition on human cells, we propose possible reasons for the inhibition of HIV and LINE-1 through different pathways by these suppressors, with the hope of accelerating future studies in associated research fields.
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Affiliation(s)
- Juan Du
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, China.,Key Laboratory of Organ Regeneration & Transplantation of the Ministry of Education, First Hospital of Jilin University, Changchun, China
| | - Ke Zhao
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, China.,Key Laboratory of Organ Regeneration & Transplantation of the Ministry of Education, First Hospital of Jilin University, Changchun, China
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32
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Striking heterogeneity of somatic L1 retrotransposition in single normal and cancerous gastrointestinal cells. Proc Natl Acad Sci U S A 2020; 117:32215-32222. [PMID: 33277430 DOI: 10.1073/pnas.2019450117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Somatic LINE-1 (L1) retrotransposition has been detected in early embryos, adult brains, and the gastrointestinal (GI) tract, and many cancers, including epithelial GI tumors. We previously found numerous somatic L1 insertions in paired normal and GI cancerous tissues. Here, using a modified method of single-cell analysis for somatic L1 insertions, we studied adenocarcinomas of colon, pancreas, and stomach, and found a variable number of somatic L1 insertions in tumors of the same type from patient to patient. We detected no somatic L1 insertions in single cells of 5 of 10 tumors studied. In three tumors, aneuploid cells were detected by FACS. In one pancreatic tumor, there were many more L1 insertions in aneuploid than in euploid tumor cells. In one gastric cancer, both aneuploid and euploid cells contained large numbers of likely clonal insertions. However, in a second gastric cancer with aneuploid cells, no somatic L1 insertions were found. We suggest that when the cellular environment is favorable to retrotransposition, aneuploidy predisposes tumor cells to L1 insertions, and retrotransposition may occur at the transition from euploidy to aneuploidy. Seventeen percent of insertions were also present in normal cells, similar to findings in genomic DNA from normal tissues of GI tumor patients. We provide evidence that: 1) The number of L1 insertions in tumors of the same type is highly variable, 2) most somatic L1 insertions in GI cancer tissues are absent from normal tissues, and 3) under certain conditions, somatic L1 retrotransposition exhibits a propensity for occurring in aneuploid cells.
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33
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Abstract
Transposable elements (TEs) are mobile DNA sequences that propagate within genomes. Through diverse invasion strategies, TEs have come to occupy a substantial fraction of nearly all eukaryotic genomes, and they represent a major source of genetic variation and novelty. Here we review the defining features of each major group of eukaryotic TEs and explore their evolutionary origins and relationships. We discuss how the unique biology of different TEs influences their propagation and distribution within and across genomes. Environmental and genetic factors acting at the level of the host species further modulate the activity, diversification, and fate of TEs, producing the dramatic variation in TE content observed across eukaryotes. We argue that cataloging TE diversity and dissecting the idiosyncratic behavior of individual elements are crucial to expanding our comprehension of their impact on the biology of genomes and the evolution of species.
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Affiliation(s)
- Jonathan N Wells
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850; ,
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850; ,
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34
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Ewing AD, Smits N, Sanchez-Luque FJ, Faivre J, Brennan PM, Richardson SR, Cheetham SW, Faulkner GJ. Nanopore Sequencing Enables Comprehensive Transposable Element Epigenomic Profiling. Mol Cell 2020; 80:915-928.e5. [PMID: 33186547 DOI: 10.1016/j.molcel.2020.10.024] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/12/2022]
Abstract
Transposable elements (TEs) drive genome evolution and are a notable source of pathogenesis, including cancer. While CpG methylation regulates TE activity, the locus-specific methylation landscape of mobile human TEs has to date proven largely inaccessible. Here, we apply new computational tools and long-read nanopore sequencing to directly infer CpG methylation of novel and extant TE insertions in hippocampus, heart, and liver, as well as paired tumor and non-tumor liver. As opposed to an indiscriminate stochastic process, we find pronounced demethylation of young long interspersed element 1 (LINE-1) retrotransposons in cancer, often distinct to the adjacent genome and other TEs. SINE-VNTR-Alu (SVA) retrotransposons, including their internal tandem repeat-associated CpG island, are near-universally methylated. We encounter allele-specific TE methylation and demethylation of aberrantly expressed young LINE-1s in normal tissues. Finally, we recover the complete sequences of tumor-specific LINE-1 insertions and their retrotransposition hallmarks, demonstrating how long-read sequencing can simultaneously survey the epigenome and detect somatic TE mobilization.
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Affiliation(s)
- Adam D Ewing
- Mater Research Institute, University of Queensland, Woolloongabba, QLD 4102, Australia.
| | - Nathan Smits
- Mater Research Institute, University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Francisco J Sanchez-Luque
- GENYO, Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research, PTS Granada 18016, Spain; MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Jamila Faivre
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif 94800, France
| | - Paul M Brennan
- Translational Neurosurgery, Centre for Clinical Brain Sciences, Edinburgh EH16 4SB, UK
| | - Sandra R Richardson
- Mater Research Institute, University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Seth W Cheetham
- Mater Research Institute, University of Queensland, Woolloongabba, QLD 4102, Australia.
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, Woolloongabba, QLD 4102, Australia; Queensland Brain Institute, University of Queensland, St. Lucia, QLD 4067, Australia.
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The tumor suppressor microRNA let-7 inhibits human LINE-1 retrotransposition. Nat Commun 2020; 11:5712. [PMID: 33177501 PMCID: PMC7658363 DOI: 10.1038/s41467-020-19430-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 10/03/2020] [Indexed: 12/13/2022] Open
Abstract
Nearly half of the human genome is made of transposable elements (TEs) whose activity continues to impact its structure and function. Among them, Long INterspersed Element class 1 (LINE-1 or L1) elements are the only autonomously active TEs in humans. L1s are expressed and mobilized in different cancers, generating mutagenic insertions that could affect tumor malignancy. Tumor suppressor microRNAs are ∼22nt RNAs that post-transcriptionally regulate oncogene expression and are frequently downregulated in cancer. Here we explore whether they also influence L1 mobilization. We show that downregulation of let-7 correlates with accumulation of L1 insertions in human lung cancer. Furthermore, we demonstrate that let-7 binds to the L1 mRNA and impairs the translation of the second L1-encoded protein, ORF2p, reducing its mobilization. Overall, our data reveals that let-7, one of the most relevant microRNAs, maintains somatic genome integrity by restricting L1 retrotransposition. Human Long INterspersed Element class 1 (LINE-1) elements are expressed and mobilized in many types of cancer, contributing to malignancy. Here the authors show that the tumor suppressor microRNA let-7 targets the LINE-1 mRNA and reduces LINE-1 mobilization.
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A SINE-VNTR- Alu in the LRIG2 Promoter Is Associated with Gene Expression at the Locus. Int J Mol Sci 2020; 21:ijms21228486. [PMID: 33187279 PMCID: PMC7697779 DOI: 10.3390/ijms21228486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 12/12/2022] Open
Abstract
The hominid SINE-VNTR-Alu (SVA) retrotransposons represent a repertoire of genomic variation which could have significant effects on genome function. A human-specific SVA in the promoter region of the gene leucine-rich repeats and immunoglobulin-like domains 2 (LRIG2), which we termed SVA_LRIG2, is a common retrotransposon insertion polymorphism (RIP), defined as an element which is polymorphic for its presence or absence in the genome. We hypothesised that this RIP might be associated with differential levels of expression of LRIG2. The RIP genotype of SVA_LRIG2 was determined in a subset of frontal cortex DNA samples from the North American Brain Expression Consortium (NABEC) cohort and was imputed for a larger set of that cohort. Utilising available frontal cortex total RNA-seq and CpG methylation data for this cohort, we observed that increased allele dosage of SVA_LRIG2 was non-significantly associated with a decrease in transcription from the region and significantly associated with increased methylation of the CpG probe nearest to SVA_LRIG2, i.e., SVA_LRIG2 is a significant methylation quantitative trait loci (mQTL) at the LRIG2 locus. These data are consistent with SVA_LRIG2 being a transcriptional regulator, which in part may involve epigenetic modulation.
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37
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Shademan M, Zare K, Zahedi M, Mosannen Mozaffari H, Bagheri Hosseini H, Ghaffarzadegan K, Goshayeshi L, Dehghani H. Promoter methylation, transcription, and retrotransposition of LINE-1 in colorectal adenomas and adenocarcinomas. Cancer Cell Int 2020; 20:426. [PMID: 32905102 PMCID: PMC7466817 DOI: 10.1186/s12935-020-01511-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/21/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The methylation of the CpG islands of the LINE-1 promoter is a tight control mechanism on the function of mobile elements. However, simultaneous quantification of promoter methylation and transcription of LINE-1 has not been performed in progressive stages of colorectal cancer. In addition, the insertion of mobile elements in the genome of advanced adenoma stage, a precancerous stage before colorectal carcinoma has not been emphasized. In this study, we quantify promoter methylation and transcripts of LINE-1 in three stages of colorectal non-advanced adenoma, advanced adenoma, and adenocarcinoma. In addition, we analyze the insertion of LINE-1, Alu, and SVA elements in the genome of patient tumors with colorectal advanced adenomas. METHODS LINE-1 hypomethylation status was evaluated by absolute quantitative analysis of methylated alleles (AQAMA) assay. To quantify the level of transcripts for LINE-1, quantitative RT-PCR was performed. To find mobile element insertions, the advanced adenoma tissue samples were subjected to whole genome sequencing and MELT analysis. RESULTS We found that the LINE-1 promoter methylation in advanced adenoma and adenocarcinoma was significantly lower than that in non-advanced adenomas. Accordingly, the copy number of LINE-1 transcripts in advanced adenoma was significantly higher than that in non-advanced adenomas, and in adenocarcinomas was significantly higher than that in the advanced adenomas. Whole-genome sequencing analysis of colorectal advanced adenomas revealed that at this stage polymorphic insertions of LINE-1, Alu, and SVA comprise approximately 16%, 51%, and 74% of total insertions, respectively. CONCLUSIONS Our correlative analysis showing a decreased methylation of LINE-1 promoter accompanied by the higher level of LINE-1 transcription, and polymorphic genomic insertions in advanced adenoma, suggests that the early and advanced polyp stages may host very important pathogenic processes concluding to cancer.
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Affiliation(s)
- Milad Shademan
- Graduate Program in Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Khadijeh Zare
- Stem Cell Biology and Regenerative Medicine Research Group, Research Institute of Biotechnology, Ferdowsi University of Mashhad, Azadi Square, Mashhad, 91779-48974 Iran
| | - Morteza Zahedi
- Graduate Program in Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hooman Mosannen Mozaffari
- Department of Gastroenterology and Hepatology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Gastroenterology and Hepatology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hadi Bagheri Hosseini
- Department of Gastroenterology and Hepatology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Gastroenterology and Hepatology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Kamran Ghaffarzadegan
- Pathology Department, Education and Research Department, Razavi Hospital, Mashhad, Iran
| | - Ladan Goshayeshi
- Department of Gastroenterology and Hepatology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Surgical Oncology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hesam Dehghani
- Stem Cell Biology and Regenerative Medicine Research Group, Research Institute of Biotechnology, Ferdowsi University of Mashhad, Azadi Square, Mashhad, 91779-48974 Iran
- Division of Biotechnology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
- Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
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38
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Damert A. LINE-1 ORF1p does not determine substrate preference for human/orangutan SVA and gibbon LAVA. Mob DNA 2020; 11:27. [PMID: 32676128 PMCID: PMC7353768 DOI: 10.1186/s13100-020-00222-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 07/06/2020] [Indexed: 12/28/2022] Open
Abstract
Background Non-autonomous VNTR (Variable Number of Tandem Repeats) composite retrotransposons – SVA (SINE-R-VNTR-Alu) and LAVA (L1-Alu-VNTR-Alu) – are specific to hominoid primates. SVA expanded in great apes, LAVA in gibbon. Both SVA and LAVA have been shown to be mobilized by the autonomous LINE-1 (L1)-encoded protein machinery in a cell-based assay in trans. The efficiency of human SVA retrotransposition in vitro has, however, been considerably lower than would be expected based on recent pedigree-based in vivo estimates. The VNTR composite elements across hominoids – gibbon LAVA, orangutan SVA_A descendants and hominine SVA_D descendants – display characteristic structures of the 5′ Alu-like domain and the VNTR. Different partner L1 subfamilies are currently active in each of the lineages. The possibility that the lineage-specific types of VNTR composites evolved in response to evolutionary changes in their autonomous partners, particularly in the nucleic acid binding L1 ORF1-encoded protein, has not been addressed. Results Here I report the identification and functional characterization of a highly active human SVA element using an improved mneo retrotransposition reporter cassette. The modified cassette (mneoM) minimizes splicing between the VNTR of human SVAs and the neomycin phosphotransferase stop codon. SVA deletion analysis provides evidence that key elements determining its mobilization efficiency reside in the VNTR and 5′ hexameric repeats. Simultaneous removal of the 5′ hexameric repeats and part of the VNTR has an additive negative effect on mobilization rates. Taking advantage of the modified reporter cassette that facilitates robust cross-species comparison of SVA/LAVA retrotransposition, I show that the ORF1-encoded proteins of the L1 subfamilies currently active in gibbon, orangutan and human do not display substrate preference for gibbon LAVA versus orangutan SVA versus human SVA. Finally, I demonstrate that an orangutan-derived ORF1p supports only limited retrotransposition of SVA/LAVA in trans, despite being fully functional in L1 mobilization in cis. Conclusions Overall, the analysis confirms SVA as a highly active human retrotransposon and preferred substrate of the L1-encoded protein machinery. Based on the results obtained in human cells coevolution of L1 ORF1p and VNTR composites does not appear very likely. The changes in orangutan L1 ORF1p that markedly reduce its mobilization capacity in trans might explain the different SVA insertion rates in the orangutan and hominine lineages, respectively.
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Affiliation(s)
- Annette Damert
- Primate Genetics Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
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39
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Burns KH. Our Conflict with Transposable Elements and Its Implications for Human Disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2020; 15:51-70. [PMID: 31977294 DOI: 10.1146/annurev-pathmechdis-012419-032633] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Our genome is a historic record of successive invasions of mobile genetic elements. Like other eukaryotes, we have evolved mechanisms to limit their propagation and minimize the functional impact of new insertions. Although these mechanisms are vitally important, they are imperfect, and a handful of retroelement families remain active in modern humans. This review introduces the intrinsic functions of transposons, the tactics employed in their restraint, and the relevance of this conflict to human pathology. The most straightforward examples of disease-causing transposable elements are germline insertions that disrupt a gene and result in a monogenic disease allele. More enigmatic are the abnormal patterns of transposable element expression in disease states. Changes in transposon regulation and cellular responses to their expression have implicated these sequences in diseases as diverse as cancer, autoimmunity, and neurodegeneration. Distinguishing their epiphenomenal from their pathogenic effects may provide wholly new perspectives on our understanding of disease.
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Affiliation(s)
- Kathleen H Burns
- Department of Pathology, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA;
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40
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Jones KD, Radziwon A, Birch DG, MacDonald IM. A novel SVA retrotransposon insertion in the CHM gene results in loss of REP-1 causing choroideremia. Ophthalmic Genet 2020; 41:341-344. [PMID: 32441177 DOI: 10.1080/13816810.2020.1768557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND Choroideremia is an X-linked retinal disease characterized by progressive atrophy of the choroid and retinal pigment epithelium caused by mutations in the CHM gene. SVA (SINE-R/VNTR/Alu) elements are a type of non-autonomous retrotransposon that occasionally self-replicate, reinsert randomly into a gene, and cause disease. Intragenic SVA insertions have been reported as the mechanism underlying a number of diseases including a syndromic form of retinal dystrophy, but have never been found in CHM. MATERIALS AND METHODS Here we identified and characterized a novel hemizygous SVA insertion, c.97_98inSVA (p.Arg33insSVA), in exon 2 of CHM in a male choroideremia patient. The SVA insertion's impact was evaluated by establishing a patient-derived lymphoblastoid cell line as a source of RNA for mRNA analysis of the CHM transcript, and protein for immunoblot analysis of Rab Escort Protein 1 (REP-1). RESULTS Immunoblot analysis revealed the absence of REP-1 protein, while a smaller than expected PCR product was amplified from cDNA. Sequencing of this PCR product showed skipping of exon 2, denoted r.50_116del. Ophthalmic examination including psychophysical tests, visual electrophysiology, and fundus imaging showed the patient's phenotype was consistent with severe early manifestations of choroideremia. CONCLUSIONS This case is the first report of a SVA insertion in the CHM gene causing choroideremia.
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Affiliation(s)
| | - Alina Radziwon
- Department of Ophthalmology and Visual Sciences, University of Alberta , Edmonton, Alberta, Canada
| | - David G Birch
- Retina Foundation of the S.W ., Dallas, TX, USA.,Ophthalmology, UTSW Medical Center , Dallas, TX, USA
| | - Ian M MacDonald
- Department of Ophthalmology and Visual Sciences, University of Alberta , Edmonton, Alberta, Canada
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41
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Zhou W, Emery SB, Flasch DA, Wang Y, Kwan KY, Kidd JM, Moran JV, Mills RE. Identification and characterization of occult human-specific LINE-1 insertions using long-read sequencing technology. Nucleic Acids Res 2020; 48:1146-1163. [PMID: 31853540 PMCID: PMC7026601 DOI: 10.1093/nar/gkz1173] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/14/2019] [Accepted: 12/05/2019] [Indexed: 11/13/2022] Open
Abstract
Long Interspersed Element-1 (LINE-1) retrotransposition contributes to inter- and intra-individual genetic variation and occasionally can lead to human genetic disorders. Various strategies have been developed to identify human-specific LINE-1 (L1Hs) insertions from short-read whole genome sequencing (WGS) data; however, they have limitations in detecting insertions in complex repetitive genomic regions. Here, we developed a computational tool (PALMER) and used it to identify 203 non-reference L1Hs insertions in the NA12878 benchmark genome. Using PacBio long-read sequencing data, we identified L1Hs insertions that were absent in previous short-read studies (90/203). Approximately 81% (73/90) of the L1Hs insertions reside within endogenous LINE-1 sequences in the reference assembly and the analysis of unique breakpoint junction sequences revealed 63% (57/90) of these L1Hs insertions could be genotyped in 1000 Genomes Project sequences. Moreover, we observed that amplification biases encountered in single-cell WGS experiments led to a wide variation in L1Hs insertion detection rates between four individual NA12878 cells; under-amplification limited detection to 32% (65/203) of insertions, whereas over-amplification increased false positive calls. In sum, these data indicate that L1Hs insertions are often missed using standard short-read sequencing approaches and long-read sequencing approaches can significantly improve the detection of L1Hs insertions present in individual genomes.
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Affiliation(s)
- Weichen Zhou
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, 100 Washtenaw Avenue, Ann Arbor, MI 48109, USA
| | - Sarah B Emery
- Department of Human Genetics, University of Michigan Medical School, 1241 East Catherine Street, Ann Arbor, MI 48109, USA
| | - Diane A Flasch
- Department of Human Genetics, University of Michigan Medical School, 1241 East Catherine Street, Ann Arbor, MI 48109, USA
| | - Yifan Wang
- Department of Human Genetics, University of Michigan Medical School, 1241 East Catherine Street, Ann Arbor, MI 48109, USA
| | - Kenneth Y Kwan
- Department of Human Genetics, University of Michigan Medical School, 1241 East Catherine Street, Ann Arbor, MI 48109, USA.,Molecular and Behavioral Neuroscience Institute, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Jeffrey M Kidd
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, 100 Washtenaw Avenue, Ann Arbor, MI 48109, USA.,Department of Human Genetics, University of Michigan Medical School, 1241 East Catherine Street, Ann Arbor, MI 48109, USA
| | - John V Moran
- Department of Human Genetics, University of Michigan Medical School, 1241 East Catherine Street, Ann Arbor, MI 48109, USA.,Department of Internal Medicine, University of Michigan, 1500 East Medical Center Drive, Ann Arbor, MI 48109, USA
| | - Ryan E Mills
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, 100 Washtenaw Avenue, Ann Arbor, MI 48109, USA.,Department of Human Genetics, University of Michigan Medical School, 1241 East Catherine Street, Ann Arbor, MI 48109, USA
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42
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Tristan-Ramos P, Morell S, Sanchez L, Toledo B, Garcia-Perez JL, Heras SR. sRNA/L1 retrotransposition: using siRNAs and miRNAs to expand the applications of the cell culture-based LINE-1 retrotransposition assay. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190346. [PMID: 32075559 DOI: 10.1098/rstb.2019.0346] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The cell culture-based retrotransposition reporter assay has been (and is) an essential tool for the study of vertebrate Long INterspersed Elements (LINEs). Developed more than 20 years ago, this assay has been instrumental in characterizing the role of LINE-encoded proteins in retrotransposition, understanding how ribonucleoprotein particles are formed, how host factors regulate LINE mobilization, etc. Moreover, variations of the conventional assay have been developed to investigate the biology of other currently active human retrotransposons, such as Alu and SVA. Here, we describe a protocol that allows combination of the conventional cell culture-based LINE-1 retrotransposition reporter assay with short interfering RNAs (siRNAs) and microRNA (miRNAs) mimics or inhibitors, which has allowed us to uncover specific miRNAs and host factors that regulate retrotransposition. The protocol described here is highly reproducible, quantitative, robust and flexible, and allows the study of several small RNA classes and various retrotransposons. To illustrate its utility, here we show that siRNAs to Fanconi anaemia proteins (FANC-A and FANC-C) and an inhibitor of miRNA-20 upregulate and downregulate human L1 retrotransposition, respectively. This article is part of a discussion meeting issue 'Crossroads between transposons and gene regulation'.
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Affiliation(s)
- Pablo Tristan-Ramos
- Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, GENYO, Granada, Spain.,Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Santiago Morell
- Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, GENYO, Granada, Spain
| | - Laura Sanchez
- Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, GENYO, Granada, Spain
| | - Belen Toledo
- Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, GENYO, Granada, Spain.,Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Jose L Garcia-Perez
- Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, GENYO, Granada, Spain.,MRC-Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Sara R Heras
- Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, GENYO, Granada, Spain.,Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
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43
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McKerrow W, Tang Z, Steranka JP, Payer LM, Boeke JD, Keefe D, Fenyö D, Burns KH, Liu C. Human transposon insertion profiling by sequencing (TIPseq) to map LINE-1 insertions in single cells. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190335. [PMID: 32075555 PMCID: PMC7061987 DOI: 10.1098/rstb.2019.0335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Long interspersed element-1 (LINE-1, L1) sequences, which comprise about 17% of human genome, are the product of one of the most active types of mobile DNAs in modern humans. LINE-1 insertion alleles can cause inherited and de novo genetic diseases, and LINE-1-encoded proteins are highly expressed in some cancers. Genome-wide LINE-1 mapping in single cells could be useful for defining somatic and germline retrotransposition rates, and for enabling studies to characterize tumour heterogeneity, relate insertions to transcriptional and epigenetic effects at the cellular level, or describe cellular phylogenies in development. Our laboratories have reported a genome-wide LINE-1 insertion site mapping method for bulk DNA, named transposon insertion profiling by sequencing (TIPseq). There have been significant barriers applying LINE-1 mapping to single cells, owing to the chimeric artefacts and features of repetitive sequences. Here, we optimize a modified TIPseq protocol and show its utility for LINE-1 mapping in single lymphoblastoid cells. Results from single-cell TIPseq experiments compare well to known LINE-1 insertions found by whole-genome sequencing and TIPseq on bulk DNA. Among the several approaches we tested, whole-genome amplification by multiple displacement amplification followed by restriction enzyme digestion, vectorette ligation and LINE-1-targeted PCR had the best assay performance. This article is part of a discussion meeting issue 'Crossroads between transposons and gene regulation'.
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Affiliation(s)
- Wilson McKerrow
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, USA
| | - Zuojian Tang
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, USA
| | - Jared P Steranka
- Department of Pathology, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA
| | - Lindsay M Payer
- Department of Pathology, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA
| | - Jef D Boeke
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, USA
| | - David Keefe
- Department of Obstetrics and Gynecology, New York University Langone School of Medicine, 462 First Avenue, New York, NY 10016, USA.,Department of Cell Biology, New York University Langone School of Medicine, 462 First Avenue, New York, NY 10016, USA
| | - David Fenyö
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, USA
| | - Kathleen H Burns
- Department of Pathology, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA.,High Throughput (HiT) Biology Center, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA.,Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, 401N Broadway, Baltimore, MD 21231, USA
| | - Chunhong Liu
- Department of Pathology, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA
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44
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Terry DM, Devine SE. Aberrantly High Levels of Somatic LINE-1 Expression and Retrotransposition in Human Neurological Disorders. Front Genet 2020; 10:1244. [PMID: 31969897 PMCID: PMC6960195 DOI: 10.3389/fgene.2019.01244] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/11/2019] [Indexed: 12/31/2022] Open
Abstract
Retrotransposable elements (RTEs) have actively multiplied over the past 80 million years of primate evolution, and as a consequence, such elements collectively occupy ∼ 40% of the human genome. As RTE activity can have detrimental effects on the human genome and transcriptome, silencing mechanisms have evolved to restrict retrotransposition. The brain is the only known somatic tissue where RTEs are de-repressed throughout the life of a healthy human and each neuron in specific brain regions accumulates up to ∼13.7 new somatic L1 insertions (and perhaps more). However, even higher levels of somatic RTE expression and retrotransposition have been found in a number of human neurological disorders. This review is focused on how RTE expression and retrotransposition in neuronal tissues might contribute to the initiation and progression of these disorders. These disorders are discussed in three broad and sometimes overlapping categories: 1) disorders such as Rett syndrome, Aicardi-Goutières syndrome, and ataxia–telangiectasia, where expression/retrotransposition is increased due to mutations in genes that play a role in regulating RTEs in healthy cells, 2) disorders such as autism spectrum disorder, schizophrenia, and substance abuse disorders, which are thought to be caused by a combination of genetic and environmental stress factors, and 3) disorders associated with age, such as frontotemporal lobar degeneration (FTLD), amyotrophic lateral sclerosis (ALS), and normal aging, where there is a time-dependent accumulation of neurological degeneration, RTE copy number, and phenotypes. Research has revealed increased levels of RTE activity in many neurological disorders, but in most cases, a clear causal link between RTE activity and these disorders has not been well established. At the same time, even if increased RTE activity is a passenger and not a driver of disease, a detrimental effect is more likely than a beneficial one. Thus, a better understanding of the role of RTEs in neuronal tissues likely is an important part of understanding, preventing, and treating these disorders.
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Affiliation(s)
- Diane M Terry
- Molecular Medicine Graduate Program, University of Maryland School of Medicine, Baltimore, MD, United States.,Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Scott E Devine
- Molecular Medicine Graduate Program, University of Maryland School of Medicine, Baltimore, MD, United States.,Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States.,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States.,Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, United States
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45
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Gianfrancesco O, Geary B, Savage AL, Billingsley KJ, Bubb VJ, Quinn JP. The Role of SINE-VNTR-Alu (SVA) Retrotransposons in Shaping the Human Genome. Int J Mol Sci 2019; 20:ijms20235977. [PMID: 31783611 PMCID: PMC6928650 DOI: 10.3390/ijms20235977] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/16/2019] [Accepted: 11/17/2019] [Indexed: 12/29/2022] Open
Abstract
Retrotransposons can alter the regulation of genes both transcriptionally and post-transcriptionally, through mechanisms such as binding transcription factors and alternative splicing of transcripts. SINE-VNTR-Alu (SVA) retrotransposons are the most recently evolved class of retrotransposable elements, found solely in primates, including humans. SVAs are preferentially found at genic, high GC loci, and have been termed "mobile CpG islands". We hypothesise that the ability of SVAs to mobilise, and their non-random distribution across the genome, may result in differential regulation of certain pathways. We analysed SVA distribution patterns across the human reference genome and identified over-representation of SVAs at zinc finger gene clusters. Zinc finger proteins are able to bind to and repress SVA function through transcriptional and epigenetic mechanisms, and the interplay between SVAs and zinc fingers has been proposed as a major feature of genome evolution. We describe observations relating to the clustering patterns of both reference SVAs and polymorphic SVA insertions at zinc finger gene loci, suggesting that the evolution of this network may be ongoing in humans. Further, we propose a mechanism to direct future research and validation efforts, in which the interplay between zinc fingers and their epigenetic modulation of SVAs may regulate a network of zinc finger genes, with the potential for wider transcriptional consequences.
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Affiliation(s)
- Olympia Gianfrancesco
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3GE, UK; (O.G.); (A.L.S.); (K.J.B.); (V.J.B.)
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Bethany Geary
- Division of Molecular and Clinical Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK;
| | - Abigail L. Savage
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3GE, UK; (O.G.); (A.L.S.); (K.J.B.); (V.J.B.)
| | - Kimberley J. Billingsley
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3GE, UK; (O.G.); (A.L.S.); (K.J.B.); (V.J.B.)
| | - Vivien J. Bubb
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3GE, UK; (O.G.); (A.L.S.); (K.J.B.); (V.J.B.)
| | - John P. Quinn
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3GE, UK; (O.G.); (A.L.S.); (K.J.B.); (V.J.B.)
- Correspondence:
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Abstract
Long interspersed element-1s (L1s) encode 2 proteins (ORF1p and ORF2p) that preferentially mobilize (i.e., retrotranspose) their encoding messenger RNA (mRNA) transcript. ORF1p and/or ORF2p can also mobilize other cellular RNAs, including short interspersed elements (SINEs), U6 small nuclear RNA (snRNA), and mRNAs. Here, we demonstrate the RNA ligase RtcB can join U6 snRNA to L1 or other cellular RNAs to create chimeric RNAs; retrotransposition of the resultant chimeric RNAs leads to chimeric pseudogene formation; and chimeric U6/L1 RNAs are part of the transcriptome in multiple human cells. These data suggest RNA ligation contributes to the plasticity of the transcriptome and that the retrotransposition of chimeric RNAs can generate genetic variation in the human genome. Long interspersed element-1 (LINE-1 or L1) amplifies via retrotransposition. Active L1s encode 2 proteins (ORF1p and ORF2p) that bind their encoding transcript to promote retrotransposition in cis. The L1-encoded proteins also promote the retrotransposition of small-interspersed element RNAs, noncoding RNAs, and messenger RNAs in trans. Some L1-mediated retrotransposition events consist of a copy of U6 RNA conjoined to a variably 5′-truncated L1, but how U6/L1 chimeras are formed requires elucidation. Here, we report the following: The RNA ligase RtcB can join U6 RNAs ending in a 2′,3′-cyclic phosphate to L1 RNAs containing a 5′-OH in vitro; depletion of endogenous RtcB in HeLa cell extracts reduces U6/L1 RNA ligation efficiency; retrotransposition of U6/L1 RNAs leads to U6/L1 pseudogene formation; and a unique cohort of U6/L1 chimeric RNAs are present in multiple human cell lines. Thus, these data suggest that U6 small nuclear RNA (snRNA) and RtcB participate in the formation of chimeric RNAs and that retrotransposition of chimeric RNA contributes to interindividual genetic variation.
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48
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Cajuso T, Sulo P, Tanskanen T, Katainen R, Taira A, Hänninen UA, Kondelin J, Forsström L, Välimäki N, Aavikko M, Kaasinen E, Ristimäki A, Koskensalo S, Lepistö A, Renkonen-Sinisalo L, Seppälä T, Kuopio T, Böhm J, Mecklin JP, Kilpivaara O, Pitkänen E, Palin K, Aaltonen LA. Retrotransposon insertions can initiate colorectal cancer and are associated with poor survival. Nat Commun 2019; 10:4022. [PMID: 31492840 PMCID: PMC6731219 DOI: 10.1038/s41467-019-11770-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 07/31/2019] [Indexed: 12/20/2022] Open
Abstract
Genomic instability pathways in colorectal cancer (CRC) have been extensively studied, but the role of retrotransposition in colorectal carcinogenesis remains poorly understood. Although retrotransposons are usually repressed, they become active in several human cancers, in particular those of the gastrointestinal tract. Here we characterize retrotransposon insertions in 202 colorectal tumor whole genomes and investigate their associations with molecular and clinical characteristics. We find highly variable retrotransposon activity among tumors and identify recurrent insertions in 15 known cancer genes. In approximately 1% of the cases we identify insertions in APC, likely to be tumor-initiating events. Insertions are positively associated with the CpG island methylator phenotype and the genomic fraction of allelic imbalance. Clinically, high number of insertions is independently associated with poor disease-specific survival. Retrotransposons are usually dormant in healthy tissue, but become activated during malignancy. Here, in colorectal cancer, Cajuso et al. show that retrotransposon activity associates with clinical features of the disease.
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Affiliation(s)
- Tatiana Cajuso
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Päivi Sulo
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Tomas Tanskanen
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Riku Katainen
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Aurora Taira
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Ulrika A Hänninen
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Johanna Kondelin
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Linda Forsström
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Niko Välimäki
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Mervi Aavikko
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Eevi Kaasinen
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Ari Ristimäki
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Pathology, HUSLAB, University of Helsinki and Helsinki University Hospital, (Haartmaninkatu 3), FI-00290, Helsinki, Finland
| | - Selja Koskensalo
- Department of Gastrointestinal Surgery, Helsinki University Hospital, University of Helsinki, (Haartmaninkatu 4), FI-00290, Helsinki, Finland
| | - Anna Lepistö
- Department of Gastrointestinal Surgery, Helsinki University Hospital, University of Helsinki, (Haartmaninkatu 4), FI-00290, Helsinki, Finland
| | - Laura Renkonen-Sinisalo
- Department of Gastrointestinal Surgery, Helsinki University Hospital, University of Helsinki, (Haartmaninkatu 4), FI-00290, Helsinki, Finland
| | - Toni Seppälä
- Department of Gastrointestinal Surgery, Helsinki University Hospital, University of Helsinki, (Haartmaninkatu 4), FI-00290, Helsinki, Finland
| | - Teijo Kuopio
- Biological and Environmental Science, University of Jyväskylä, PO Box 35, (Seminaarinkatu 15), FI-40014, Jyväskylä, Finland.,Department of Pathology, Central Finland Health Care District, (Keskussairaalantie 19), FI-40620 Jyväskylä, Finland
| | - Jan Böhm
- Department of Pathology, Central Finland Health Care District, (Keskussairaalantie 19), FI-40620 Jyväskylä, Finland
| | - Jukka-Pekka Mecklin
- Department of Surgery, Jyväskylä Central Hospital, (Keskussairaalantie 19), FI-40620, Jyväskylä, Finland.,Department of Health Sciences, Faculty of Sport and Health Sciences, University of Jyväskylä, PO Box 35, (Seminaarinkatu 15), FI-40014, Jyväskylä, Finland
| | - Outi Kilpivaara
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Esa Pitkänen
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Kimmo Palin
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland
| | - Lauri A Aaltonen
- Applied Tumor Genomics Research Program, Faculty of Medicine University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland. .,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Biomedicum Helsinki, PO Box 63, (Haartmaninkatu 8), FI-00014, Helsinki, Finland.
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Wang Z, McSwiggin H, Newkirk SJ, Wang Y, Oliver D, Tang C, Lee S, Wang S, Yuan S, Zheng H, Ye P, An W, Yan W. Insertion of a chimeric retrotransposon sequence in mouse Axin1 locus causes metastable kinky tail phenotype. Mob DNA 2019; 10:17. [PMID: 31073336 PMCID: PMC6500023 DOI: 10.1186/s13100-019-0162-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 04/21/2019] [Indexed: 12/12/2022] Open
Abstract
Background Transposable elements (TEs) make up > 50% of the human genome, and the majority of retrotransposon insertions are truncated and many are located in introns. However, the effects of retrotransposition on the host genes remain incompletely known. Results We report here that insertion of a chimeric L1 (cL1), but not IAP solo LTR, into intron 6 of Axin1 using CRIPSR/Cas9 induced the kinky tail phenotype with ~ 80% penetrance in heterozygous Axin cL1 mice. Both penetrant (with kinky tails) and silent (without kinky tails) Axin cL1 mice, regardless of sex, could transmit the phenotype to subsequent generations with similar penetrance (~ 80%). Further analyses revealed that a longer Axin1 transcript isoform containing partial cL1-targeted intron was present in penetrant, but absent in silent and wild type mice, and the production of this unique Axin1 transcript appeared to correlate with altered levels of an activating histone modification, H3K9ac. Conclusions The mechanism for Axin cL1 mice is different from those previously identified in mice with spontaneous retrotransposition of IAP, e.g., Axin Fu and A vy , both of which have been associated with DNA methylation changes. Our data suggest that Axin1 locus is sensitive to genetic and epigenetic alteration by retrotransposons and thus, ideally suited for studying the effects of new retrotransposition events on target gene function in mice.
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Affiliation(s)
- Zhuqing Wang
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Hayden McSwiggin
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Simon J Newkirk
- 3Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007 USA
| | - Yue Wang
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Daniel Oliver
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Chong Tang
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Sandy Lee
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Shawn Wang
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Shuiqiao Yuan
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Huili Zheng
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Ping Ye
- 2Avera McKennan Hospital and University Health Center, Sioux Falls, SD 57108 USA.,3Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007 USA
| | - Wenfeng An
- 3Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007 USA
| | - Wei Yan
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA.,4Department of Obstetrics and Gynecology, University of Nevada, Reno School of Medicine, Reno, NV 89557 USA.,5Department of Biology, University of Nevada, Reno, Reno, NV 89557 USA
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50
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Bodea GO, McKelvey EGZ, Faulkner GJ. Retrotransposon-induced mosaicism in the neural genome. Open Biol 2019; 8:rsob.180074. [PMID: 30021882 PMCID: PMC6070720 DOI: 10.1098/rsob.180074] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/21/2018] [Indexed: 12/18/2022] Open
Abstract
Over the past decade, major discoveries in retrotransposon biology have depicted the neural genome as a dynamic structure during life. In particular, the retrotransposon LINE-1 (L1) has been shown to be transcribed and mobilized in the brain. Retrotransposition in the developing brain, as well as during adult neurogenesis, provides a milieu in which neural diversity can arise. Dysregulation of retrotransposon activity may also contribute to neurological disease. Here, we review recent reports of retrotransposon activity in the brain, and discuss the temporal nature of retrotransposition and its regulation in neural cells in response to stimuli. We also put forward hypotheses regarding the significance of retrotransposons for brain development and neurological function, and consider the potential implications of this phenomenon for neuropsychiatric and neurodegenerative conditions.
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Affiliation(s)
- Gabriela O Bodea
- Mater Research Institute-University of Queensland, TRI Building, Brisbane, Queensland 4102, Australia .,Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Eleanor G Z McKelvey
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute-University of Queensland, TRI Building, Brisbane, Queensland 4102, Australia .,Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
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