1
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Talley MJ, Longworth MS. Retrotransposons in embryogenesis and neurodevelopment. Biochem Soc Trans 2024; 52:1159-1171. [PMID: 38716891 DOI: 10.1042/bst20230757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 06/27/2024]
Abstract
Retrotransposable elements (RTEs) are genetic elements that can replicate and insert new copies into different genomic locations. RTEs have long been identified as 'parasitic genes', as their mobilization can cause mutations, DNA damage, and inflammation. Interestingly, high levels of retrotransposon activation are observed in early embryogenesis and neurodevelopment, suggesting that RTEs may possess functional roles during these stages of development. Recent studies demonstrate that RTEs can function as transcriptional regulatory elements through mechanisms such as chromatin organization and noncoding RNAs. It is clear, however, that RTE expression and activity must be restrained at some level during development, since overactivation of RTEs during neurodevelopment is associated with several developmental disorders. Further investigation is needed to understand the importance of RTE expression and activity during neurodevelopment and the balance between RTE-regulated development and RTE-mediated pathogenesis.
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Affiliation(s)
- Mary Jo Talley
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, U.S.A
| | - Michelle S Longworth
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, U.S.A
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44195, U.S.A
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2
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Adler GL, Le K, Fu Y, Kim WS. Human Endogenous Retroviruses in Neurodegenerative Diseases. Genes (Basel) 2024; 15:745. [PMID: 38927681 PMCID: PMC11202925 DOI: 10.3390/genes15060745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 05/25/2024] [Accepted: 06/04/2024] [Indexed: 06/28/2024] Open
Abstract
Human endogenous retroviruses (HERVs) are DNA transposable elements that have integrated into the human genome via an ancestral germline infection. The potential importance of HERVs is underscored by the fact that they comprise approximately 8% of the human genome. HERVs have been implicated in the pathogenesis of neurodegenerative diseases, a group of CNS diseases characterized by a progressive loss of structure and function of neurons, resulting in cell death and multiple physiological dysfunctions. Much evidence indicates that HERVs are initiators or drivers of neurodegenerative processes in multiple sclerosis and amyotrophic lateral sclerosis, and clinical trials have been designed to target HERVs. In recent years, the role of HERVs has been explored in other major neurodegenerative diseases, including frontotemporal dementia, Alzheimer's disease and Parkinson's disease, with some interesting discoveries. This review summarizes and evaluates the past and current research on HERVs in neurodegenerative diseases. It discusses the potential role of HERVs in disease manifestation and neurodegeneration. It critically reviews antiretroviral strategies used in the therapeutic intervention of neurodegenerative diseases.
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Affiliation(s)
- Gabrielle L. Adler
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2050, Australia
| | - Kelvin Le
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2050, Australia
| | - YuHong Fu
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2050, Australia
| | - Woojin Scott Kim
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2050, Australia
- School of Biomedical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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3
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Liuzzi G, Artimagnella O, Frisari S, Mallamaci A. Foxg1 bimodally tunes L1-mRNA and -DNA dynamics in the developing murine neocortex. Development 2024; 151:dev202292. [PMID: 38655654 PMCID: PMC11190451 DOI: 10.1242/dev.202292] [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: 08/23/2023] [Accepted: 04/16/2024] [Indexed: 04/26/2024]
Abstract
Foxg1 masters telencephalic development via a pleiotropic control over its progression. Expressed within the central nervous system (CNS), L1 retrotransposons are implicated in progression of its histogenesis and tuning of its genomic plasticity. Foxg1 represses gene transcription, and L1 elements share putative Foxg1-binding motifs, suggesting the former might limit telencephalic expression (and activity) of the latter. We tested such a prediction, in vivo as well as in engineered primary neural cultures, using loss- and gain-of-function approaches. We found that Foxg1-dependent, transcriptional L1 repression specifically occurs in neopallial neuronogenic progenitors and post-mitotic neurons, where it is supported by specific changes in the L1 epigenetic landscape. Unexpectedly, we discovered that Foxg1 physically interacts with L1-mRNA and positively regulates neonatal neopallium L1-DNA content, antagonizing the retrotranscription-suppressing activity exerted by Mov10 and Ddx39a helicases. To the best of our knowledge, Foxg1 represents the first CNS patterning gene acting as a bimodal retrotransposon modulator, limiting transcription of L1 elements and promoting their amplification, within a specific domain of the developing mouse brain.
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Affiliation(s)
- Gabriele Liuzzi
- Laboratory of Cerebral Cortex Development, SISSA, Trieste 34136, Italy
| | | | - Simone Frisari
- Laboratory of Cerebral Cortex Development, SISSA, Trieste 34136, Italy
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4
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Workman S, Richardson SR. Every repeat is unique: Exploring the genomic impact of human L1 retrotransposons at locus-specific resolution. CELL GENOMICS 2024; 4:100504. [PMID: 38359785 PMCID: PMC10879126 DOI: 10.1016/j.xgen.2024.100504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/17/2024]
Abstract
Fully understanding the impact of the human retrotransposon L1 requires that each of ∼500,000 L1 copies be evaluated as a potentially unique genomic entity. In this issue of Cell Genomics, Lanciano et al.1 strive toward this goal, illuminating the reciprocal regulatory influence between individual L1s and their genomic integration sites.
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Affiliation(s)
- Stephanie Workman
- Mater Research Institute-University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Sandra R Richardson
- Mater Research Institute-University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia.
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5
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Lanciano S, Philippe C, Sarkar A, Pratella D, Domrane C, Doucet AJ, van Essen D, Saccani S, Ferry L, Defossez PA, Cristofari G. Locus-level L1 DNA methylation profiling reveals the epigenetic and transcriptional interplay between L1s and their integration sites. CELL GENOMICS 2024; 4:100498. [PMID: 38309261 PMCID: PMC10879037 DOI: 10.1016/j.xgen.2024.100498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/20/2023] [Accepted: 01/09/2024] [Indexed: 02/05/2024]
Abstract
Long interspersed element 1 (L1) retrotransposons are implicated in human disease and evolution. Their global activity is repressed by DNA methylation, but deciphering the regulation of individual copies has been challenging. Here, we combine short- and long-read sequencing to unveil L1 methylation heterogeneity across cell types, families, and individual loci and elucidate key principles involved. We find that the youngest primate L1 families are specifically hypomethylated in pluripotent stem cells and the placenta but not in most tumors. Locally, intronic L1 methylation is intimately associated with gene transcription. Conversely, the L1 methylation state can propagate to the proximal region up to 300 bp. This phenomenon is accompanied by the binding of specific transcription factors, which drive the expression of L1 and chimeric transcripts. Finally, L1 hypomethylation alone is typically insufficient to trigger L1 expression due to redundant silencing pathways. Our results illuminate the epigenetic and transcriptional interplay between retrotransposons and their host genome.
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Affiliation(s)
- Sophie Lanciano
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Claude Philippe
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Arpita Sarkar
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - David Pratella
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Cécilia Domrane
- University Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | - Aurélien J Doucet
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Dominic van Essen
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Simona Saccani
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Laure Ferry
- University Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | | | - Gael Cristofari
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France.
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6
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Doucet AJ, Cristofari G. Noninvasive and Multicancer Biomarkers: The Promise of LINE-1 Retrotransposons. Cancer Discov 2023; 13:2502-2504. [PMID: 38084092 DOI: 10.1158/2159-8290.cd-23-1063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
SUMMARY LINE-1 retrotransposons are frequently active in epithelial tumors. In a new study, Taylor, Wu and colleagues now describe that one of the proteins encoded by LINE-1 elements, ORF1p, is detected in the bloodstream of patients with cancer, and can be used as a noninvasive and multicancer biomarker for diagnosis or treatment monitoring. See related article by Taylor, Wu et al., p. 2532 (7).
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Affiliation(s)
- Aurelien J Doucet
- University Cote d'Azur, Inserm, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Gael Cristofari
- University Cote d'Azur, Inserm, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
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7
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Ahn HW, Worman ZF, Lechsinska A, Payer LM, Wang T, Malik N, Li W, Burns KH, Nath A, Levin HL. Retrotransposon insertions associated with risk of neurologic and psychiatric diseases. EMBO Rep 2023; 24:e55197. [PMID: 36367221 PMCID: PMC9827563 DOI: 10.15252/embr.202255197] [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: 04/08/2022] [Revised: 10/11/2022] [Accepted: 10/20/2022] [Indexed: 11/13/2022] Open
Abstract
Transposable elements (TEs) are active in neuronal cells raising the question whether TE insertions contribute to risk of neuropsychiatric disease. While genome-wide association studies (GWAS) serve as a tool to discover genetic loci associated with neuropsychiatric diseases, unfortunately GWAS do not directly detect structural variants such as TEs. To examine the role of TEs in psychiatric and neurologic disease, we evaluated 17,000 polymorphic TEs and find 76 are in linkage disequilibrium with disease haplotypes (P < 10-6 ) defined by GWAS. From these 76 polymorphic TEs, we identify potentially causal candidates based on having insertions in genomic regions of regulatory chromatin and on having associations with altered gene expression in brain tissues. We show that lead candidate insertions have regulatory effects on gene expression in human neural stem cells altering the activity of a minimal promoter. Taken together, we identify 10 polymorphic TE insertions that are potential candidates on par with other variants for having a causal role in neurologic and psychiatric disorders.
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Affiliation(s)
- Hyo Won Ahn
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
| | - Zelia F Worman
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
- Present address:
Seven BridgesCharlestownMAUSA
| | - Arianna Lechsinska
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
| | - Lindsay M Payer
- Department of PathologyJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Tongguang Wang
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Nasir Malik
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Wenxue Li
- Section of Infections of the Nervous SystemNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Kathleen H Burns
- Department of Oncologic PathologyDana‐Farber Cancer InstituteBostonMAUSA
| | - Avindra Nath
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
- Section of Infections of the Nervous SystemNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Henry L Levin
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
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8
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Garcia-Cañadas M, Sanchez-Luque FJ, Sanchez L, Rojas J, Garcia Perez JL. LINE-1 Retrotransposition Assays in Embryonic Stem Cells. Methods Mol Biol 2023; 2607:257-309. [PMID: 36449167 DOI: 10.1007/978-1-0716-2883-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The ongoing mobilization of active non-long terminal repeat (LTR) retrotransposons continues to impact the genomes of most mammals, including humans and rodents. Non-LTR retrotransposons mobilize using an intermediary RNA and a copy-and-paste mechanism termed retrotransposition. Non-LTR retrotransposons are subdivided into long and short interspersed elements (LINEs and SINEs, respectively), depending on their size and autonomy; while active class 1 LINEs (LINE-1s or L1s) encode the enzymatic machinery required to mobilize in cis, active SINEs use the enzymatic machinery of active LINE-1s to mobilize in trans. The mobilization mechanism used by LINE-1s/SINEs was exploited to develop ingenious plasmid-based retrotransposition assays in cultured cells, which typically exploit a reporter gene that can only be activated after a round of retrotransposition. Retrotransposition assays, in cis or in trans, are instrumental tools to study the biology of mammalian LINE-1s and SINEs. In fact, these and other biochemical/genetic assays were used to uncover that endogenous mammalian LINE-1s/SINEs naturally retrotranspose during early embryonic development. However, embryonic stem cells (ESCs) are typically used as a cellular model in these and other studies interrogating LINE-1/SINE expression/regulation during early embryogenesis. Thus, human and mouse ESCs represent an excellent model to understand how active retrotransposons are regulated and how their activity impacts the germline. Here, we describe robust and quantitative protocols to study human/mouse LINE-1 (in cis) and SINE (in trans) retrotransposition using (human and mice) ESCs. These protocols are designed to study the mobilization of active non-LTR retrotransposons in a cellular physiologically relevant context.
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Affiliation(s)
- Marta Garcia-Cañadas
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain.
| | - Francisco J Sanchez-Luque
- Institute of Parasitology and Biomedicine "Lopez-Neyra" (IPBLN), Spanish National Research Council (CSIC), PTS Granada, Granada, Spain
| | - Laura Sanchez
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Johana Rojas
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Jose L Garcia Perez
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain.
- MRC Human Genetics Unit, Institute of Genetics and Cancer (IGC)/University of Edinburgh, Western General Hospital Campus, Edinburgh, UK.
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9
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Smits N, Faulkner GJ. Nanopore Sequencing to Identify Transposable Element Insertions and Their Epigenetic Modifications. Methods Mol Biol 2023; 2607:151-171. [PMID: 36449163 DOI: 10.1007/978-1-0716-2883-6_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Over the past 20 years, high-throughput genomic assays have fundamentally changed how transposable elements (TEs) are studied. While short-read DNA sequencing has been at the heart of these efforts, novel technologies that generate longer reads are driving a shift in the field. Long-read sequencing now permits locus-specific approaches to locate individual TE insertions and understand their epigenetic and transcriptional regulation, while still profiling TE activity genome-wide. Here we provide detailed guidelines to implement Oxford Nanopore Technologies (ONT) sequencing to identify polymorphic TE insertions and profile TE epigenetic landscapes. Using human long interspersed element-1 (LINE-1, L1) as an example, we explain the procedures involved, including final visualization, and potential bottlenecks and pitfalls. ONT sequencing will be, in our view, a workhorse technology for the foreseeable future in the TE field.
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Affiliation(s)
- Nathan Smits
- Mater Research Institute, University of Queensland, Woolloongabba, QLD, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, Woolloongabba, QLD, Australia.
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia.
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10
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Wang L, Tracy L, Su W, Yang F, Feng Y, Silverman N, Zhang ZZZ. Retrotransposon activation during Drosophila metamorphosis conditions adult antiviral responses. Nat Genet 2022; 54:1933-1945. [PMID: 36396707 PMCID: PMC9795486 DOI: 10.1038/s41588-022-01214-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 09/29/2022] [Indexed: 11/18/2022]
Abstract
Retrotransposons are one type of mobile genetic element that abundantly reside in the genomes of nearly all animals. Their uncontrolled activation is linked to sterility, cancer and other pathologies, thereby being largely considered detrimental. Here we report that, within a specific time window of development, retrotransposon activation can license the host's immune system for future antiviral responses. We found that the mdg4 (also known as Gypsy) retrotransposon selectively becomes active during metamorphosis at the Drosophila pupal stage. At this stage, mdg4 activation educates the host's innate immune system by inducing the systemic antiviral function of the nuclear factor-κB protein Relish in a dSTING-dependent manner. Consequently, adult flies with mdg4, Relish or dSTING silenced at the pupal stage are unable to clear exogenous viruses and succumb to viral infection. Altogether, our data reveal that hosts can establish a protective antiviral response that endows a long-term benefit in pathogen warfare due to the developmental activation of mobile genetic elements.
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Affiliation(s)
- Lu Wang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA.
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.
| | - Lauren Tracy
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Weijia Su
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Fu Yang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Yu Feng
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Neal Silverman
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Z Z Zhao Zhang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA.
- Duke Regeneration Center, Duke University School of Medicine, Durham, NC, USA.
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11
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Savage AL, Iacoangeli A, Schumann GG, Rubio-Roldan A, Garcia-Perez JL, Al Khleifat A, Koks S, Bubb VJ, Al-Chalabi A, Quinn JP. Characterisation of retrotransposon insertion polymorphisms in whole genome sequencing data from individuals with amyotrophic lateral sclerosis. Gene 2022; 843:146799. [PMID: 35963498 DOI: 10.1016/j.gene.2022.146799] [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: 03/24/2022] [Revised: 07/15/2022] [Accepted: 08/05/2022] [Indexed: 11/15/2022]
Abstract
The genetics of an individual is a crucial factor in understanding the risk of developing the neurodegenerative disease amyotrophic lateral sclerosis (ALS). There is still a large proportion of the heritability of ALS, particularly in sporadic cases, to be understood. Among others, active transposable elements drive inter-individual variability, and in humans long interspersed element 1 (LINE1, L1), Alu and SINE-VNTR-Alu (SVA) retrotransposons are a source of polymorphic insertions in the population. We undertook a pilot study to characterise the landscape of non-reference retrotransposon insertion polymorphisms (non-ref RIPs) in 15 control and 15 ALS individuals' whole genomes from Project MinE, an international project to identify potential genetic causes of ALS. The combination of two bioinformatics tools (mobile element locator tool (MELT) and TEBreak) identified on average 1250 Alu, 232 L1 and 77 SVA non-ref RIPs per genome across the 30 analysed. Further PCR validation of individual polymorphic retrotransposon insertions showed a similar level of accuracy for MELT and TEBreak. Our preliminary study did not identify a specific RIP or a significant difference in the total number of non-ref RIPs in ALS compared to control genomes. The use of multiple bioinformatic tools improved the accuracy of non-ref RIP detection and our study highlights the potential importance of studying these elements further in ALS.
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Affiliation(s)
- Abigail L Savage
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 3BX, UK
| | - Alfredo Iacoangeli
- Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 9RT, UK; Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 8AF, UK
| | - Gerald G Schumann
- Division of Medical Biotechnology, Paul-Ehrlich-Institut, Langen 63225, Germany
| | - Alejandro Rubio-Roldan
- Department of Genomic Medicine and Department of Oncology, GENYO, Centre for Genomics & Oncology, PTS Granada, 18007, Spain
| | - Jose L Garcia-Perez
- Department of Genomic Medicine and Department of Oncology, GENYO, Centre for Genomics & Oncology, PTS Granada, 18007, Spain; MRC-HGU Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Ahmad Al Khleifat
- Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 9RT, UK
| | - Sulev Koks
- Perron Institute for Neurological and Translational Science, Perth, Western Australia 6009, Australia; Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, Western Australia 6150, Australia
| | - Vivien J Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 3BX, UK
| | - Ammar Al-Chalabi
- Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 9RT, UK; Department of Neurology, King's College Hospital, London SE5 9RS, UK
| | - John P Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 3BX, UK.
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12
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Bonaventure B, Rebendenne A, Chaves Valadão AL, Arnaud‐Arnould M, Gracias S, Garcia de Gracia F, McKellar J, Labaronne E, Tauziet M, Vivet‐Boudou V, Bernard E, Briant L, Gros N, Djilli W, Courgnaud V, Parrinello H, Rialle S, Blaise M, Lacroix L, Lavigne M, Paillart J, Ricci EP, Schulz R, Jouvenet N, Moncorgé O, Goujon C. The
DEAD
box
RNA
helicase
DDX42
is an intrinsic inhibitor of positive‐strand
RNA
viruses. EMBO Rep 2022; 23:e54061. [PMID: 36161446 PMCID: PMC9638865 DOI: 10.15252/embr.202154061] [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] [Received: 09/28/2021] [Revised: 08/30/2022] [Accepted: 09/07/2022] [Indexed: 11/29/2022] Open
Abstract
Genome‐wide screens are powerful approaches to unravel regulators of viral infections. Here, a CRISPR screen identifies the RNA helicase DDX42 as an intrinsic antiviral inhibitor of HIV‐1. Depletion of endogenous DDX42 increases HIV‐1 DNA accumulation and infection in cell lines and primary cells. DDX42 overexpression inhibits HIV‐1 infection, whereas expression of a dominant‐negative mutant increases infection. Importantly, DDX42 also restricts LINE‐1 retrotransposition and infection with other retroviruses and positive‐strand RNA viruses, including CHIKV and SARS‐CoV‐2. However, DDX42 does not impact the replication of several negative‐strand RNA viruses, arguing against an unspecific effect on target cells, which is confirmed by RNA‐seq analysis. Proximity ligation assays show DDX42 in the vicinity of viral elements, and cross‐linking RNA immunoprecipitation confirms a specific interaction of DDX42 with RNAs from sensitive viruses. Moreover, recombinant DDX42 inhibits HIV‐1 reverse transcription in vitro. Together, our data strongly suggest a direct mode of action of DDX42 on viral ribonucleoprotein complexes. Our results identify DDX42 as an intrinsic viral inhibitor, opening new perspectives to target the life cycle of numerous RNA viruses.
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Affiliation(s)
| | | | | | | | - Ségolène Gracias
- Virus Sensing and Signaling Unit, Department of Virology, Institut Pasteur Université de Paris Cité, CNRS UMR 3569 Paris France
| | | | | | | | | | - Valérie Vivet‐Boudou
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002 Strasbourg France
| | | | | | - Nathalie Gros
- CEMIPAI, CNRS Université de Montpellier Montpellier France
| | | | | | - Hugues Parrinello
- Montpellier GenomiX (MGX), Biocampus, CNRS, INSERM Université de Montpellier Montpellier France
| | - Stéphanie Rialle
- Montpellier GenomiX (MGX), Biocampus, CNRS, INSERM Université de Montpellier Montpellier France
| | | | - Laurent Lacroix
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM Université PSL Paris France
| | - Marc Lavigne
- Department of Virology Institut Pasteur Paris France
| | | | | | - Reiner Schulz
- Department of Medical & Molecular Genetics King's College London London UK
| | - Nolwenn Jouvenet
- Virus Sensing and Signaling Unit, Department of Virology, Institut Pasteur Université de Paris Cité, CNRS UMR 3569 Paris France
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13
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Jahangir M, Li L, Zhou JS, Lang B, Wang XP. L1 Retrotransposons: A Potential Endogenous Regulator for Schizophrenia. Front Genet 2022; 13:878508. [PMID: 35832186 PMCID: PMC9271560 DOI: 10.3389/fgene.2022.878508] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
The long interspersed nuclear elements 1 (LINE-1/L1s) are the only active autonomous retrotransposons found in humans which can integrate anywhere in the human genome. They can expand the genome and thus bring good or bad effects to the host cells which really depends on their integration site and associated polymorphism. LINE-1 retrotransposition has been found participating in various neurological disorders such as autism spectrum disorder, Alzheimer’s disease, major depression disorder, post-traumatic stress disorder and schizophrenia. Despite the recent progress, the roles and pathological mechanism of LINE-1 retrotransposition in schizophrenia and its heritable risks, particularly, contribution to “missing heritability” are yet to be determined. Therefore, this review focuses on the potentially etiological roles of L1s in the development of schizophrenia, possible therapeutic choices and unaddressed questions in order to shed lights on the future research.
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Affiliation(s)
| | | | | | - Bing Lang
- *Correspondence: Bing Lang, ; Xiao-Ping Wang,
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14
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Billon V, Sanchez-Luque FJ, Rasmussen J, Bodea GO, Gerhardt DJ, Gerdes P, Cheetham SW, Schauer SN, Ajjikuttira P, Meyer TJ, Layman CE, Nevonen KA, Jansz N, Garcia-Perez JL, Richardson SR, Ewing AD, Carbone L, Faulkner GJ. Somatic retrotransposition in the developing rhesus macaque brain. Genome Res 2022; 32:1298-1314. [PMID: 35728967 PMCID: PMC9341517 DOI: 10.1101/gr.276451.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/14/2022] [Indexed: 12/03/2022]
Abstract
The retrotransposon LINE-1 (L1) is central to the recent evolutionary history of the human genome and continues to drive genetic diversity and germline pathogenesis. However, the spatiotemporal extent and biological significance of somatic L1 activity are poorly defined and are virtually unexplored in other primates. From a single L1 lineage active at the divergence of apes and Old World monkeys, successive L1 subfamilies have emerged in each descendant primate germline. As revealed by case studies, the presently active human L1 subfamily can also mobilize during embryonic and brain development in vivo. It is unknown whether nonhuman primate L1s can similarly generate somatic insertions in the brain. Here we applied approximately 40× single-cell whole-genome sequencing (scWGS), as well as retrotransposon capture sequencing (RC-seq), to 20 hippocampal neurons from two rhesus macaques (Macaca mulatta). In one animal, we detected and PCR-validated a somatic L1 insertion that generated target site duplications, carried a short 5′ transduction, and was present in ∼7% of hippocampal neurons but absent from cerebellum and nonbrain tissues. The corresponding donor L1 allele was exceptionally mobile in vitro and was embedded in PRDM4, a gene expressed throughout development and in neural stem cells. Nanopore long-read methylome and RNA-seq transcriptome analyses indicated young retrotransposon subfamily activation in the early embryo, followed by repression in adult tissues. These data highlight endogenous macaque L1 retrotransposition potential, provide prototypical evidence of L1-mediated somatic mosaicism in a nonhuman primate, and allude to L1 mobility in the brain over the past 30 million years of human evolution.
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15
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The Role of Transposable Elements of the Human Genome in Neuronal Function and Pathology. Int J Mol Sci 2022; 23:ijms23105847. [PMID: 35628657 PMCID: PMC9148063 DOI: 10.3390/ijms23105847] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) have been extensively studied for decades. In recent years, the introduction of whole-genome and whole-transcriptome approaches, as well as single-cell resolution techniques, provided a breakthrough that uncovered TE involvement in host gene expression regulation underlying multiple normal and pathological processes. Of particular interest is increased TE activity in neuronal tissue, and specifically in the hippocampus, that was repeatedly demonstrated in multiple experiments. On the other hand, numerous neuropathologies are associated with TE dysregulation. Here, we provide a comprehensive review of literature about the role of TEs in neurons published over the last three decades. The first chapter of the present review describes known mechanisms of TE interaction with host genomes in general, with the focus on mammalian and human TEs; the second chapter provides examples of TE exaptation in normal neuronal tissue, including TE involvement in neuronal differentiation and plasticity; and the last chapter lists TE-related neuropathologies. We sought to provide specific molecular mechanisms of TE involvement in neuron-specific processes whenever possible; however, in many cases, only phenomenological reports were available. This underscores the importance of further studies in this area.
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16
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Valdebenito-Maturana B, Guatimosim C, Carrasco MA, Tapia JC. Spatially Resolved Expression of Transposable Elements in Disease and Somatic Tissue with SpatialTE. Int J Mol Sci 2021; 22:ijms222413623. [PMID: 34948421 PMCID: PMC8708317 DOI: 10.3390/ijms222413623] [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: 10/15/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 11/23/2022] Open
Abstract
Spatial transcriptomics (ST) is transforming the way we can study gene expression and its regulation through position-specific resolution within tissues. However, as in bulk RNA-Seq, transposable elements (TEs) are not being studied due to their highly repetitive nature. In recent years, TEs have been recognized as important regulators of gene expression, and thus, TE expression analysis in a spatially resolved manner could further help to understand their role in gene regulation within tissues. We present SpatialTE, a tool to analyze TE expression from ST datasets and show its application in somatic and diseased tissues. The results indicate that TEs have spatially regulated expression patterns and that their expression profiles are spatially altered in ALS disease, indicating that TEs might perform differential regulatory functions within tissue organs. We have made SpatialTE publicly available as open-source software under an MIT license.
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Affiliation(s)
- Braulio Valdebenito-Maturana
- Núcleo Científico Multidisciplinario, School of Medicine, Universidad de Talca, Campus Talca, Talca 3460000, Chile;
| | - Cristina Guatimosim
- Departamento de Morfologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil;
| | - Mónica Alejandra Carrasco
- School of Medicine, Universidad de Talca, Campus Talca, Talca 3460000, Chile
- Correspondence: (M.A.C.); (J.C.T.)
| | - Juan Carlos Tapia
- School of Medicine, Universidad de Talca, Campus Talca, Talca 3460000, Chile
- Correspondence: (M.A.C.); (J.C.T.)
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17
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Van der Mude A. A proposed Information-Based modality for the treatment of cancer. Biosystems 2021; 211:104587. [PMID: 34915101 DOI: 10.1016/j.biosystems.2021.104587] [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: 06/13/2021] [Revised: 11/20/2021] [Accepted: 12/01/2021] [Indexed: 11/02/2022]
Abstract
Treatment modalities for cancer involve physical manipulations such as surgery, immunology, radiation, chemotherapy or gene editing. This is a proposal for an information-based modality. This modality does not change the internal state of the cancer cell directly - instead, the cancer cell is manipulated by giving it information to instruct the cell to perform an action. This modality is based on a theory of Structure Encoding in DNA, where information about body part structure controls the epigenetic state of cells in the process of development from pluripotent cells to fully differentiated cells. It has been noted that cancer is often due to errors in morphogenetic differentiation accompanied by associated epigenetic processes. This implies a model of cancer called the Epigenetic Differentiation Model. A major feature of the Structure Encoding Theory is that the characteristics of the differentiated cell are affected by inter-cellular information passed in the tissue microenvironment, which specifies the exact location of a cell in a body part structure. This is done by exosomes that carry fragments of long non-coding RNA and transposons, which convey structure information. In the normal process of epigenetic differentiation, the information passed may lead to apoptosis due to the constraints of a particular body part structure. The proposed treatment involves determining what structure information is being passed in a particular tumor, then adding artificial exosomes that overwhelm the current information with commands for the cells to go into apoptosis.
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18
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Hu K, Liang P. Transcriptome Analysis Reveals Higher Levels of Mobile Element-Associated Abnormal Gene Transcripts in Temporal Lobe Epilepsy Patients. Front Genet 2021; 12:767341. [PMID: 34868252 PMCID: PMC8640520 DOI: 10.3389/fgene.2021.767341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) is the most common form of epilepsy, and temporal lobe epilepsy patients with hippocampal sclerosis (TLE-HS) show worse drug treatment effects and prognosis. TLE has been shown to have a genetic component, but its genetic research has been mostly limited to coding sequences of genes with known association to epilepsy. Representing a major component of the genome, mobile elements (MEs) are believed to contribute to the genetic etiology of epilepsy despite limited research. We analyzed publicly available human RNA-seq-based transcriptome data to determine the role of mobile elements in epilepsy by performing de novo transcriptome assembly, followed by identification of spliced gene transcripts containing mobile element (ME) sequences (ME-transcripts), to compare their frequency across different sample groups. Significantly higher levels of ME-transcripts in hippocampal tissues of epileptic patients, particularly in TLE-HS, were observed. Among ME classes, short interspersed nuclear elements (SINEs) were shown to be the most frequent contributor to ME-transcripts, followed by long interspersed nuclear elements (LINEs) and DNA transposons. These ME sequences almost in all cases represent older MEs normally located in the intron sequences. For protein coding genes, ME sequences were mostly found in the 3'-UTR regions, with a significant portion also in the coding sequences (CDSs), leading to reading frame disruption. Genes associated with ME-transcripts showed enrichment for the mRNA splicing process and an apparent bias in epileptic transcriptomes toward neural- and epilepsy-associated genes. The findings of this study suggest that abnormal splicing involving MEs, leading to loss of functions in critical genes, plays a role in epilepsy, particularly in TLE-HS, thus providing a novel insight into the molecular mechanisms underlying epileptogenesis.
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Affiliation(s)
- Kai Hu
- Department of Biological Sciences, Brock University, St. Catharines, ON, Canada.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, ON, Canada
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19
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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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20
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Ketola K, Kaljunen H, Taavitsainen S, Kaarijärvi R, Järvelä E, Rodríguez-Martín B, Haase K, Woodcock DJ, Tubio J, Wedge DC, Nykter M, Bova GS. Subclone Eradication Analysis Identifies Targets for Enhanced Cancer Therapy and Reveals L1 Retrotransposition as a Dynamic Source of Cancer Heterogeneity. Cancer Res 2021; 81:4901-4909. [PMID: 34348967 PMCID: PMC9397610 DOI: 10.1158/0008-5472.can-21-0371] [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: 02/02/2021] [Revised: 06/03/2021] [Accepted: 08/02/2021] [Indexed: 01/07/2023]
Abstract
Treatment-eradicated cancer subclones have been reported in leukemia and have recently been detected in solid tumors. Here we introduce Differential Subclone Eradication and Resistance (DSER) analysis, a method developed to identify molecular targets for improved therapy by direct comparison of genomic features of eradicated and resistant subclones in pre- and posttreatment samples from a patient with BRCA2-deficient metastatic prostate cancer. FANCI and EYA4 were identified as candidate DNA repair-related targets for converting subclones from resistant to eradicable, and RNAi-mediated depletion of FANCI confirmed it as a potential target. The EYA4 alteration was associated with adjacent L1 transposon insertion during cancer evolution upon treatment, raising questions surrounding the role of therapy in L1 activation. Both carboplatin and enzalutamide turned on L1 transposon machinery in LNCaP and VCaP but not in PC3 and 22Rv1 prostate cancer cell lines. L1 activation in LNCaP and VCaP was inhibited by the antiretroviral drug azidothymidine. L1 activation was also detected postcastration in LuCaP 77 and LuCaP 105 xenograft models and postchemotherapy in previously published time-series transcriptomic data from SCC25 head and neck cancer cells. In conclusion, DSER provides an informative intermediate step toward effective precision cancer medicine and should be tested in future studies, especially those including dramatic but temporary metastatic tumor regression. L1 transposon activation may be a modifiable source of cancer genomic heterogeneity, suggesting the potential of leveraging newly discovered triggers and blockers of L1 activity to overcome therapy resistance. SIGNIFICANCE: Differential analysis of eradicated and resistant subclones following cancer treatment identifies that L1 activity associated with resistance is induced by current therapies and blocked by the antiretroviral drug azidothymidine.
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Affiliation(s)
- Kirsi Ketola
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.,Corresponding Authors: Kirsi Ketola, Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211, Finland. Phone: 358-503299984; E-mail: ; and G. S. Bova, Faculty of Medicine and Health Technology, Tampere University and Tays Cancer Center, PO Box 100, Tampere FI-33014, Finland. Phone: 358-502945211; E-mail:
| | - Heidi Kaljunen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Sinja Taavitsainen
- Faculty of Medicine and Health Technology, Tampere University and Tays Cancer Center, Tampere, Finland
| | - Roosa Kaarijärvi
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Emmi Järvelä
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Bernardo Rodríguez-Martín
- Genomes and Disease, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Department of Zoology, Genetics and Physical Anthropology, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Kerstin Haase
- Experimental and Clinical Research Center, Charité and the Max Delbrück Center for Molecular Medicine, Universitätsmedizin Berlin, Berlin, Germany
| | - Dan J. Woodcock
- Big Data Institute, University of Oxford, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
| | - Jose Tubio
- Genomes and Disease, Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Department of Zoology, Genetics and Physical Anthropology, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - David C. Wedge
- Manchester Cancer Research Centre, University of Manchester, Manchester, United Kingdom
| | - Matti Nykter
- Faculty of Medicine and Health Technology, Tampere University and Tays Cancer Center, Tampere, Finland
| | - G. Steven Bova
- Faculty of Medicine and Health Technology, Tampere University and Tays Cancer Center, Tampere, Finland.,Corresponding Authors: Kirsi Ketola, Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, Kuopio FI-70211, Finland. Phone: 358-503299984; E-mail: ; and G. S. Bova, Faculty of Medicine and Health Technology, Tampere University and Tays Cancer Center, PO Box 100, Tampere FI-33014, Finland. Phone: 358-502945211; E-mail:
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21
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Li M, Larsen PA. Primate-specific retrotransposons and the evolution of circadian networks in the human brain. Neurosci Biobehav Rev 2021; 131:988-1004. [PMID: 34592258 DOI: 10.1016/j.neubiorev.2021.09.049] [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: 04/05/2021] [Revised: 08/03/2021] [Accepted: 09/26/2021] [Indexed: 11/26/2022]
Abstract
The circadian rhythm of the human brain is attuned to sleep-wake cycles that entail global alterations in neuronal excitability. This periodicity involves a highly coordinated regulation of gene expression. A growing number of studies are documenting a fascinating connection between primate-specific retrotransposons (Alu elements) and key epigenetic regulatory processes in the primate brain. Collectively, these studies indicate that Alu elements embedded in the human neuronal genome mediate post-transcriptional processes that unite human-specific neuroepigenetic landscapes and circadian rhythm. Here, we review evidence linking Alu retrotransposon-mediated posttranscriptional pathways to circadian gene expression. We hypothesize that Alu retrotransposons participate in the organization of circadian brain function through multidimensional neuroepigenetic pathways. We anticipate that these pathways are closely tied to the evolution of human cognition and their perturbation contributes to the manifestation of human-specific neurological diseases. Finally, we address current challenges and accompanying opportunities in studying primate- and human-specific transposable elements.
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Affiliation(s)
- Manci Li
- University of Minnesota, St. Paul, MN, 55108, United States
| | - Peter A Larsen
- University of Minnesota, St. Paul, MN, 55108, United States.
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22
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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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23
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Genomic Mosaicism Formed by Somatic Variation in the Aging and Diseased Brain. Genes (Basel) 2021; 12:genes12071071. [PMID: 34356087 PMCID: PMC8305509 DOI: 10.3390/genes12071071] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/22/2022] Open
Abstract
Over the past 20 years, analyses of single brain cell genomes have revealed that the brain is composed of cells with myriad distinct genomes: the brain is a genomic mosaic, generated by a host of DNA sequence-altering processes that occur somatically and do not affect the germline. As such, these sequence changes are not heritable. Some processes appear to occur during neurogenesis, when cells are mitotic, whereas others may also function in post-mitotic cells. Here, we review multiple forms of DNA sequence alterations that have now been documented: aneuploidies and aneusomies, smaller copy number variations (CNVs), somatic repeat expansions, retrotransposons, genomic cDNAs (gencDNAs) associated with somatic gene recombination (SGR), and single nucleotide variations (SNVs). A catch-all term of DNA content variation (DCV) has also been used to describe the overall phenomenon, which can include multiple forms within a single cell’s genome. A requisite step in the analyses of genomic mosaicism is ongoing technology development, which is also discussed. Genomic mosaicism alters one of the most stable biological molecules, DNA, which may have many repercussions, ranging from normal functions including effects of aging, to creating dysfunction that occurs in neurodegenerative and other brain diseases, most of which show sporadic presentation, unlinked to causal, heritable genes.
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24
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Pasquesi GIM, Perry BW, Vandewege MW, Ruggiero RP, Schield DR, Castoe TA. Vertebrate Lineages Exhibit Diverse Patterns of Transposable Element Regulation and Expression across Tissues. Genome Biol Evol 2021; 12:506-521. [PMID: 32271917 PMCID: PMC7211425 DOI: 10.1093/gbe/evaa068] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2020] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) comprise a major fraction of vertebrate genomes, yet little is known about their expression and regulation across tissues, and how this varies across major vertebrate lineages. We present the first comparative analysis integrating TE expression and TE regulatory pathway activity in somatic and gametic tissues for a diverse set of 12 vertebrates. We conduct simultaneous gene and TE expression analyses to characterize patterns of TE expression and TE regulation across vertebrates and examine relationships between these features. We find remarkable variation in the expression of genes involved in TE negative regulation across tissues and species, yet consistently high expression in germline tissues, particularly in testes. Most vertebrates show comparably high levels of TE regulatory pathway activity across gonadal tissues except for mammals, where reduced activity of TE regulatory pathways in ovarian tissues may be the result of lower relative germ cell densities. We also find that all vertebrate lineages examined exhibit remarkably high levels of TE-derived transcripts in somatic and gametic tissues, with recently active TE families showing higher expression in gametic tissues. Although most TE-derived transcripts originate from inactive ancient TE families (and are likely incapable of transposition), such high levels of TE-derived RNA in the cytoplasm may have secondary, unappreciated biological relevance.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington
| | | | | | - Drew R Schield
- Department of Biology, University of Texas at Arlington.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington
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25
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Hutchins AP. Single cells and transposable element heterogeneity in stem cells and development. CELL REGENERATION (LONDON, ENGLAND) 2021; 10:23. [PMID: 34226968 PMCID: PMC8257793 DOI: 10.1186/s13619-021-00085-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 04/30/2021] [Indexed: 01/03/2023]
Abstract
Recent innovations in single cell sequencing-based technologies are shining a light on the heterogeneity of cellular populations in unprecedented detail. However, several cellular aspects are currently underutilized in single cell studies. One aspect is the expression and activity of transposable elements (TEs). TEs are selfish sequences of DNA that can replicate, and have been wildly successful in colonizing genomes. However, most TEs are mutated, fragmentary and incapable of transposition, yet they are actively bound by multiple transcription factors, host complex patterns of chromatin modifications, and are expressed in mRNAs as part of the transcriptome in both normal and diseased states. The contribution of TEs to development and cellular function remains unclear, and the routine inclusion of TEs in single cell sequencing analyses will potentially lead to insight into stem cells, development and human disease.
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Affiliation(s)
- Andrew P Hutchins
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, Southern University of Science and Technology, Shenzhen, 518055, China. .,Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, 518055, China.
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26
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Martin LJ, Benson DW. Focused Strategies for Defining the Genetic Architecture of Congenital Heart Defects. Genes (Basel) 2021; 12:827. [PMID: 34071175 PMCID: PMC8228798 DOI: 10.3390/genes12060827] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/14/2022] Open
Abstract
Congenital heart defects (CHD) are malformations present at birth that occur during heart development. Increasing evidence supports a genetic origin of CHD, but in the process important challenges have been identified. This review begins with information about CHD and the importance of detailed phenotyping of study subjects. To facilitate appropriate genetic study design, we review DNA structure, genetic variation in the human genome and tools to identify the genetic variation of interest. Analytic approaches powered for both common and rare variants are assessed. While the ideal outcome of genetic studies is to identify variants that have a causal role, a more realistic goal for genetic analytics is to identify variants in specific genes that influence the occurrence of a phenotype and which provide keys to open biologic doors that inform how the genetic variants modulate heart development. It has never been truer that good genetic studies start with good planning. Continued progress in unraveling the genetic underpinnings of CHD will require multidisciplinary collaboration between geneticists, quantitative scientists, clinicians, and developmental biologists.
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Affiliation(s)
- Lisa J. Martin
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, OH 45229, USA
| | - D. Woodrow Benson
- Department of Pediatrics, Medical College of Wisconsin, Wauwatosa, WI 53226, USA;
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27
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Chu C, Zhao B, Park PJ, Lee EA. Identification and Genotyping of Transposable Element Insertions From Genome Sequencing Data. ACTA ACUST UNITED AC 2021; 107:e102. [PMID: 32662945 DOI: 10.1002/cphg.102] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transposable element (TE) mobilization is a significant source of genomic variation and has been associated with various human diseases. The exponential growth of population-scale whole-genome sequencing and rapid innovations in long-read sequencing technologies provide unprecedented opportunities to study TE insertions and their functional impact in human health and disease. Identifying TE insertions, however, is challenging due to the repetitive nature of the TE sequences. Here, we review computational approaches to detecting and genotyping TE insertions using short- and long-read sequencing and discuss the strengths and weaknesses of different approaches. © 2020 Wiley Periodicals LLC.
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Affiliation(s)
- Chong Chu
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts
| | - Boxun Zhao
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Peter J Park
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts
| | - Eunjung Alice Lee
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts
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28
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Doyle GA, Reiner BC, Crist RC, Rao AM, Ojeah NS, Arauco-Shapiro G, Levinson RN, Shah LD, Sperling MR, Ferraro TN, Buono RJ, Berrettini WH. Investigation of long interspersed element-1 retrotransposons as potential risk factors for idiopathic temporal lobe epilepsy. Epilepsia 2021; 62:1329-1342. [PMID: 33826137 DOI: 10.1111/epi.16897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 03/19/2021] [Accepted: 03/19/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine if long interspersed element-1 (L1) retrotransposons convey risk for idiopathic temporal lobe epilepsy (TLE). METHODS Surgically resected temporal cortex from individuals with TLE (N = 33) and postmortem temporal cortex from individuals with no known neurological disease (N = 33) were analyzed for L1 content by Restriction Enzyme Based Enriched L1Hs sequencing (REBELseq). Expression of three KCNIP4 splice variants was assessed by droplet digital PCR (ddPCR). Protein ANalysis THrough Evolutionary Relationships (PANTHER) was used to determine ontologies and pathways for lists of genes harboring L1 insertions. RESULTS We identified novel L1 insertions specific to individuals with TLE, and others specific to controls. Although there were no statistically significant differences between cases and controls in the numbers of known and novel L1 insertions, PANTHER analyses of intragenic L1 insertions showed statistically significant enrichments for epilepsy-relevant gene ontologies in both cases and controls. Gene ontologies "neuron projection development" and "calcium ion transmembrane transport" were among those found only in individuals with TLE. We confirmed novel L1 insertions in several genes associated with seizures/epilepsy, including a de novo somatic L1 retrotransposition in KCNIP4 that occurred after neural crest formation in one patient. However, ddPCR results suggest this de novo L1 did not alter KCNIP4 mRNA expression. SIGNIFICANCE Given current data from this small cohort, we conclude that L1 elements, either rare heritable germline insertions or de novo somatic retrotranspositions, may contribute only minimally to overall genetic risk for idiopathic TLE. We suggest that further studies in additional patients and additional brain regions are warranted.
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Affiliation(s)
- Glenn A Doyle
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Benjamin C Reiner
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Richard C Crist
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Aditya M Rao
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Nkechi S Ojeah
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.,Lincoln University of School of Natural Sciences and Mathematics, Lincoln University, Lincoln, PA, USA
| | - Gabriella Arauco-Shapiro
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Rachel N Levinson
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Lokesh D Shah
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Michael R Sperling
- Department of Neurology, Comprehensive Epilepsy Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Thomas N Ferraro
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.,Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, USA
| | - Russell J Buono
- Department of Neurology, Comprehensive Epilepsy Center, Thomas Jefferson University, Philadelphia, PA, USA.,Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, USA
| | - Wade H Berrettini
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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29
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Keegan RM, Talbot LR, Chang YH, Metzger MJ, Dubnau J. Intercellular viral spread and intracellular transposition of Drosophila gypsy. PLoS Genet 2021; 17:e1009535. [PMID: 33886543 PMCID: PMC8096092 DOI: 10.1371/journal.pgen.1009535] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 05/04/2021] [Accepted: 04/06/2021] [Indexed: 01/12/2023] Open
Abstract
It has become increasingly clear that retrotransposons (RTEs) are more widely expressed in somatic tissues than previously appreciated. RTE expression has been implicated in a myriad of biological processes ranging from normal development and aging, to age related diseases such as cancer and neurodegeneration. Long Terminal Repeat (LTR)-RTEs are evolutionary ancestors to, and share many features with, exogenous retroviruses. In fact, many organisms contain endogenous retroviruses (ERVs) derived from exogenous retroviruses that integrated into the germ line. These ERVs are inherited in Mendelian fashion like RTEs, and some retain the ability to transmit between cells like viruses, while others develop the ability to act as RTEs. The process of evolutionary transition between LTR-RTE and retroviruses is thought to involve multiple steps by which the element loses or gains the ability to transmit copies between cells versus the ability to replicate intracellularly. But, typically, these two modes of transmission are incompatible because they require assembly in different sub-cellular compartments. Like murine IAP/IAP-E elements, the gypsy family of retroelements in arthropods appear to sit along this evolutionary transition. Indeed, there is some evidence that gypsy may exhibit retroviral properties. Given that gypsy elements have been found to actively mobilize in neurons and glial cells during normal aging and in models of neurodegeneration, this raises the question of whether gypsy replication in somatic cells occurs via intracellular retrotransposition, intercellular viral spread, or some combination of the two. These modes of replication in somatic tissues would have quite different biological implications. Here, we demonstrate that Drosophila gypsy is capable of both cell-associated and cell-free viral transmission between cultured S2 cells of somatic origin. Further, we demonstrate that the ability of gypsy to move between cells is dependent upon a functional copy of its viral envelope protein. This argues that the gypsy element has transitioned from an RTE into a functional endogenous retrovirus with the acquisition of its envelope gene. On the other hand, we also find that intracellular retrotransposition of the same genomic copy of gypsy can occur in the absence of the Env protein. Thus, gypsy exhibits both intracellular retrotransposition and intercellular viral transmission as modes of replicating its genome.
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Affiliation(s)
- Richard M. Keegan
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, New York City, New York, United States of America
| | - Lillian R. Talbot
- Medical Scientist Training Program, Department of Neurobiology and Behavior, Stony Brook University, New York City, New York, United States of America
| | - Yung-Heng Chang
- Department of Anesthesiology, Stony Brook School of Medicine, New York City, New York, United States of America
| | - Michael J. Metzger
- Pacific Northwest Research Institute, Seattle, Washington, United States of America
| | - Josh Dubnau
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, New York City, New York, United States of America
- Department of Anesthesiology, Stony Brook School of Medicine, New York City, New York, United States of America
- Pacific Northwest Research Institute, Seattle, Washington, United States of America
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30
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Sadeq S, Al-Hashimi S, Cusack CM, Werner A. Endogenous Double-Stranded RNA. Noncoding RNA 2021; 7:15. [PMID: 33669629 PMCID: PMC7930956 DOI: 10.3390/ncrna7010015] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 02/07/2023] Open
Abstract
The birth of long non-coding RNAs (lncRNAs) is closely associated with the presence and activation of repetitive elements in the genome. The transcription of endogenous retroviruses as well as long and short interspersed elements is not only essential for evolving lncRNAs but is also a significant source of double-stranded RNA (dsRNA). From an lncRNA-centric point of view, the latter is a minor source of bother in the context of the entire cell; however, dsRNA is an essential threat. A viral infection is associated with cytoplasmic dsRNA, and endogenous RNA hybrids only differ from viral dsRNA by the 5' cap structure. Hence, a multi-layered defense network is in place to protect cells from viral infections but tolerates endogenous dsRNA structures. A first line of defense is established with compartmentalization; whereas endogenous dsRNA is found predominantly confined to the nucleus and the mitochondria, exogenous dsRNA reaches the cytoplasm. Here, various sensor proteins recognize features of dsRNA including the 5' phosphate group of viral RNAs or hybrids with a particular length but not specific nucleotide sequences. The sensors trigger cellular stress pathways and innate immunity via interferon signaling but also induce apoptosis via caspase activation. Because of its central role in viral recognition and immune activation, dsRNA sensing is implicated in autoimmune diseases and used to treat cancer.
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Affiliation(s)
| | | | | | - Andreas Werner
- Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK; (S.S.); (S.A.-H.); (C.M.C.)
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31
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Kuroki R, Murata Y, Fuke S, Nakachi Y, Nakashima J, Kujoth GC, Prolla TA, Bundo M, Kato T, Iwamoto K. Establishment of Quantitative PCR Assays for Active Long Interspersed Nuclear Element-1 Subfamilies in Mice and Applications to the Analysis of Aging-Associated Retrotransposition. Front Genet 2020; 11:519206. [PMID: 33193604 PMCID: PMC7525186 DOI: 10.3389/fgene.2020.519206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 08/20/2020] [Indexed: 01/01/2023] Open
Abstract
The retrotransposon long interspersed nuclear element-1 (LINE-1) can autonomously increase its copy number within a host genome through the retrotransposition process. LINE-1 is active in the germline and in neural progenitor cells, and its somatic retrotransposition activity has a broad impact on neural development and susceptibility to neuropsychiatric disorders. The method to quantify the genomic copy number of LINE-1 would be important in unraveling the role of retrotransposition, especially in the brain. However, because of the species-specific evolution of LINE-1 sequences, methods for quantifying the copy number should be independently developed. Here, we developed a quantitative PCR (qPCR) assay to measure the copy number of active LINE-1 subfamilies in mice. Using the assay, we investigated aging-associated alterations of LINE-1 copy number in several brain regions in wild-type mice and Polg+/D257A mice as a model for accelerated aging. We found that aged Polg+/D257A mice showed higher levels of the type GfII LINE-1 in the basal ganglia than the wild-type mice did, highlighting the importance of assays that focus on an individual active LINE-1 subfamily.
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Affiliation(s)
- Ryota Kuroki
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yui Murata
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Satoshi Fuke
- Lab for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Japan
| | - Yutaka Nakachi
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Jun Nakashima
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Gregory C Kujoth
- Department of Genetics and Medical Genetics, University of Wisconsin, Madison, WI, United States
| | - Tomas A Prolla
- Department of Genetics and Medical Genetics, University of Wisconsin, Madison, WI, United States
| | - Miki Bundo
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.,PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Tadafumi Kato
- Lab for Molecular Dynamics of Mental Disorders, RIKEN Center for Brain Science, Wako, Japan
| | - Kazuya Iwamoto
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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32
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Savage AL, Lopez AI, Iacoangeli A, Bubb VJ, Smith B, Troakes C, Alahmady N, Koks S, Schumann GG, Al-Chalabi A, Quinn JP. Frequency and methylation status of selected retrotransposition competent L1 loci in amyotrophic lateral sclerosis. Mol Brain 2020; 13:154. [PMID: 33187550 PMCID: PMC7666467 DOI: 10.1186/s13041-020-00694-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/03/2020] [Indexed: 12/11/2022] Open
Abstract
Long interspersed element-1 (LINE-1/L1) is the only autonomous transposable element in the human genome that currently mobilises in both germline and somatic tissues. Recent studies have identified correlations between altered retrotransposon expression and the fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS) in a subset of patients. The risk of an individual developing ALS is dependent on an interaction of genetic variants and subsequent modifiers during life. These modifiers could include environmental factors, which can lead to epigenetic and genomic changes, such as somatic mutations, occurring in the neuronal cells that degenerate as the disease develops. There are more than 1 million L1 copies in the human genome today, but only 80-100 L1 loci in the reference genome are considered to be retrotransposition-competent (RC) and an even smaller number of these RC-L1s loci are highly active. We hypothesise that RC-L1s could affect normal cellular function through their mutagenic potential conferred by their ability to retrotranspose in neuronal cells and through DNA damage caused by the endonuclease activity of the L1-encoded ORF2 protein. To investigate whether either an increase in the genomic burden of RC-L1s or epigenetic changes to RC-L1s altering their expression, could play a role in disease development, we chose a set of seven well characterised genomic RC-L1 loci that were reported earlier to be highly active in a cellular L1 retrotransposition reporter assay or serve as major source elements for germline and/or somatic retrotransposition events. Analysis of the insertion allele frequency of five polymorphic RC-L1s, out of the set of seven, for their presence or absence, did not identify an increased number individually or when combined in individuals with the disease. However, we did identify reduced levels of methylation of RC-L1s in the motor cortex of those individuals with both familial and sporadic ALS compared to control brains. The changes to the regulation of the loci encompassing these RC-L1s demonstrated tissue specificity and could be related to the disease process.
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Affiliation(s)
- Abigail L Savage
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Ana Illera Lopez
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Alfredo Iacoangeli
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
- Department of Biostatistics and Health Informatics, King's College London, London, UK
| | - Vivien J Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Bradley Smith
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - Claire Troakes
- London Neurodegenerative Diseases Brain Bank, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Nada Alahmady
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
- Department of Biology, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Sulev Koks
- Perron Institute for Neurological and Translational Science, Perth, WA, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA, Australia
| | - Gerald G Schumann
- Division of Medical Biotechnology, Paul-Ehrlich-Institut, Langen, Germany
| | - Ammar Al-Chalabi
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - John P Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK.
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33
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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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34
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Pfaff AL, Bubb VJ, Quinn JP, Koks S. An Increased Burden of Highly Active Retrotransposition Competent L1s Is Associated with Parkinson's Disease Risk and Progression in the PPMI Cohort. Int J Mol Sci 2020; 21:E6562. [PMID: 32911699 PMCID: PMC7554759 DOI: 10.3390/ijms21186562] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 02/06/2023] Open
Abstract
Long interspersed element-1 (LINE-1/L1s) contributes 17% of the human genome with more than 1 million elements present; however, fewer than 100 of these have evidence for being retrotransposition competent (RC). In addition to those RC-L1s present in the reference genome, there are a small number of known non-reference L1 insertions that are also retrotransposition competent. L1 activity, whether through the potentially detrimental effects of their mRNA or protein expression or somatic retrotransposition events, has been linked to several neurological conditions. The polymorphic nature of both reference and non-reference RC-L1s in terms of their presence or absence will result in individuals harboring a different combination of these elements and it is currently unknown if this type of germline variation contributes to the risk of neurological disease. Here, we utilized whole-genome sequencing data from 178 healthy controls and 372 Parkinson's disease (PD) subjects from the Parkinson's Progression Markers Initiative (PPMI) to investigate the role of RC-L1s in PD. In the PPMI cohort, we identified 22 reference and 50 non-reference polymorphic RC-L1 loci. Focusing on 16 highly active RC-L1 loci, an increased burden of these elements (≥9) was associated with PD (OR 1.25, 95% CI 1.03-1.51, p = 0.02). In addition, we identified significant associations of progression markers of PD and the burden of highly active RC-L1s. This study has identified a novel type of genetic element associated with PD risk and disease progression.
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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
| | - Vivien J. Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 3BX, UK; (V.J.B.); (J.P.Q.)
| | - John P. Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 3BX, UK; (V.J.B.); (J.P.Q.)
| | - Sulev Koks
- 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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35
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Marthey S, Estellé J, Blin A, Wahlberg P, Créchet F, Lecardonnel J, Tessiot F, Rogel-Gaillard C, Bourneuf E. Transcription from a gene desert in a melanoma porcine model. Mol Genet Genomics 2020; 295:1239-1252. [PMID: 32529263 DOI: 10.1007/s00438-020-01694-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 06/03/2020] [Indexed: 01/11/2023]
Abstract
The genetic mechanisms underlying cutaneous melanoma onset and progression need to be further understood to improve patients' care. Several studies have focused on the genetic determinism of melanoma development in the MeLiM pig, a biomedical model of cutaneous melanoma. The objective of this study was to better describe the influence of a particular genomic region on melanoma progression in the MeliM model. Indeed, a large region of the Sus scrofa chromosome 1 has been identified by linkage and association analyses, but the causal mechanisms have remained elusive. To deepen the analysis of this candidate region, a dedicated SNP panel was used to fine map the locus, downsizing the interval to less than 2 Mb, in a genomic region located within a large gene desert. Transcription from this locus was addressed using a tiling array strategy and further validated by RT-PCR in a large panel of tissues. Overall, the gene desert showed an extensive transcriptional landscape, notably dominated by repeated element transcription in tumor and fetal tissues. The transcription of LINE-1 and PERVs has been confirmed in skin and tumor samples from MeLiM pigs. In conclusion, although this study still does not identify a candidate mutation for melanoma occurrence or progression, it highlights a potential role of repeated element transcriptional activity in the MeLiM model.
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Affiliation(s)
- S Marthey
- GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - J Estellé
- GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - A Blin
- GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
- Muséum national d'histoire naturelle, Centre national de la recherche scientifique, UMS 2700 2AD, CP51, 57 rue Cuvier, 75231, Paris Cedex 05, France
| | - P Wahlberg
- Department of Medical Biosciences, Umeå University, Umeå, Sweden
| | - F Créchet
- GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
- LREG, IRCM, DRF, CEA, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - J Lecardonnel
- GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - F Tessiot
- GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - C Rogel-Gaillard
- GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - E Bourneuf
- GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
- LREG, IRCM, DRF, CEA, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
- LCE, IRCM, DRF, CEA, Université Paris-Saclay, 92260, Fontenay-aux-Roses, France.
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LeBien J, McCollam G, Atallah J. An in silico model of LINE-1-mediated neoplastic evolution. Bioinformatics 2020; 36:4144-4153. [PMID: 32365170 DOI: 10.1093/bioinformatics/btaa279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 04/19/2020] [Accepted: 04/24/2020] [Indexed: 11/13/2022] Open
Abstract
MOTIVATION Recent research has uncovered roles for transposable elements (TEs) in multiple evolutionary processes, ranging from somatic evolution in cancer to putatively adaptive germline evolution across species. Most models of TE population dynamics, however, have not incorporated actual genome sequence data. The effect of site integration preferences of specific TEs on evolutionary outcomes and the effects of different selection regimes on TE dynamics in a specific genome are unknown. We present a stochastic model of LINE-1 (L1) transposition in human cancer. This system was chosen because the transposition of L1 elements is well understood, the population dynamics of cancer tumors has been modeled extensively, and the role of L1 elements in cancer progression has garnered interest in recent years. RESULTS Our model predicts that L1 retrotransposition (RT) can play either advantageous or deleterious roles in tumor progression, depending on the initial lesion size, L1 insertion rate and tumor driver genes. Small changes in the RT rate or set of driver tumor-suppressor genes (TSGs) were observed to alter the dynamics of tumorigenesis. We found high variation in the density of L1 target sites across human protein-coding genes. We also present an analysis, across three cancer types, of the frequency of homozygous TSG disruption in wild-type hosts compared to those with an inherited driver allele. AVAILABILITY AND IMPLEMENTATION Source code is available at https://github.com/atallah-lab/neoplastic-evolution. CONTACT jlebien@uno.edu. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Jack LeBien
- Department of Biological Sciences, The University of New, Orleans, New Orleans, LA 70148, USA
| | - Gerald McCollam
- Advanced Academic Programs, John Hopkins University, Baltimore, MD 21218, USA
| | - Joel Atallah
- Department of Biological Sciences, The University of New, Orleans, New Orleans, LA 70148, USA
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Proukakis C. Somatic mutations in neurodegeneration: An update. Neurobiol Dis 2020; 144:105021. [PMID: 32712267 DOI: 10.1016/j.nbd.2020.105021] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/12/2020] [Accepted: 07/13/2020] [Indexed: 12/20/2022] Open
Abstract
Mosaicism, the presence of genomic differences between cells due to post-zygotic somatic mutations, is widespread in the human body, including within the brain. A role for this in neurodegenerative diseases has long been hypothesised, and technical developments are now allowing the question to be addressed in detail. The rapidly accumulating evidence is discussed in this review, with a focus on recent developments. Somatic mutations of numerous types may occur, including single nucleotide variants (SNVs), copy number variants (CNVs), and retrotransposon insertions. They could act as initiators or risk factors, especially if they arise in development, although they could also result from the disease process, potentially contributing to progression. In common sporadic neurodegenerative disorders, relevant mutations have been reported in synucleinopathies, comprising somatic gains of SNCA in Parkinson's disease and multiple system atrophy, and in Alzheimer's disease, where a novel recombination mechanism leading to somatic variants of APP, as well as an excess of somatic SNVs affecting tau phosphorylation, have been reported. In Mendelian repeat expansion disorders, mosaicism due to somatic instability, first detected 25 years ago, has come to the forefront. Brain somatic SNVs occur in DNA repair disorders, and there is evidence for a role of several ALS genes in DNA repair. While numerous challenges, and need for further validation, remain, this new, or perhaps rediscovered, area of research has the potential to transform our understanding of neurodegeneration.
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Affiliation(s)
- Christos Proukakis
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK.
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38
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Mucke HA. Drug Repurposing Patent Applications October–December 2019. Assay Drug Dev Technol 2020. [DOI: 10.1089/adt.2020.974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Van der Mude A. Structure encoding in DNA. J Theor Biol 2020; 492:110205. [PMID: 32070719 DOI: 10.1016/j.jtbi.2020.110205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 12/29/2019] [Accepted: 02/14/2020] [Indexed: 12/21/2022]
Abstract
It is proposed that transposons and related long non-coding RNA define the fine structure of body parts. Although morphogens have long been known to direct the formation of many gross structures in early embryonic development, they do not have the necessary precision to define a structure down to the individual cellular level. Using the distinction between procedural and declarative knowledge in information processing as an analogy, it is hypothesized that DNA encodes fine structure in a manner that is different from the genetic code for proteins. The hypothesis states that repeated or near-repeated sequences that are in transposons and non-coding RNA define body part structures. As the cells in a body part go through the epigenetic process of differentiation, the action of methylation serves to inactivate all but the relevant structure definitions and some associated cell type genes. The transposons left active will then physically modify the DNA sequence in the heterochromatin to establish the local context in the three-dimensional body part structure. This brings the encoded definition of the cell type to the histone. The histone code for that cell type starts the regulatory cascade that turns on the genes associated with that particular type of cell, transforming it from a multipotent cell to a fully differentiated cell. This mechanism creates structures in the musculoskeletal system, the organs of the body, the major parts of the brain, and other systems.
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40
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LINE-1 specific nuclear organization in mice olfactory sensory neurons. Mol Cell Neurosci 2020; 105:103494. [PMID: 32387751 DOI: 10.1016/j.mcn.2020.103494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/31/2020] [Accepted: 04/05/2020] [Indexed: 12/21/2022] Open
Abstract
Long interspersed nuclear elements-1 (LINE-1) are mobile DNA elements that comprise the majority of interspersed repeats in the mammalian genome. During the last decade, these transposable sequences have been described as controlling elements involved in transcriptional regulation and genome plasticity. Recently, LINE-1 have been implicated in neurogenesis, but to date little is known about their nuclear organization in neurons. The olfactory epithelium is a site of continuous neurogenesis, and loci of olfactory receptor genes are enriched in LINE-1 copies. Olfactory neurons have a unique inverted nuclear architecture and constitutive heterochromatin forms a block in the center of the nuclei. Our DNA FISH images show that, even though LINE-1 copies are dispersed throughout the mice genome, they are clustered forming a cap around the central heterochromatin block and frequently occupy the same position as facultative heterochromatin in olfactory neurons nuclei. This specific LINE-1 organization could not be observed in other olfactory epithelium cell types. Analyses of H3K27me3 and H3K9me3 ChIP-seq data from olfactory epithelium revealed that LINE-1 copies located at OR gene loci show different enrichment for these heterochromatin marks. We also found that LINE-1 are transcribed in mouse olfactory epithelium. These results suggest that LINE-1 play a role in the olfactory neurons' nuclear architecture. SIGNIFICANCE STATEMENT: LINE-1 are mobile DNA elements and comprise almost 20% of mice and human genomes. These retrotransposons have been implicated in neurogenesis. We show for the first time that LINE-1 retrotransposons have a specific nuclear organization in olfactory neurons, forming aggregates concentric to the heterochromatin block and frequently occupying the same region as facultative heterochromatin. We found that LINE-1 at olfactory receptor gene loci are differently enriched for H3K9me3 and H3K27me3, but LINE-1 transcripts could be detected in the olfactory epithelium. We speculate that these retrotransposons play an active role in olfactory neurons' nuclear architecture.
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Ochoa Thomas E, Zuniga G, Sun W, Frost B. Awakening the dark side: retrotransposon activation in neurodegenerative disorders. Curr Opin Neurobiol 2020; 61:65-72. [PMID: 32092528 PMCID: PMC7198348 DOI: 10.1016/j.conb.2020.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 01/07/2020] [Accepted: 01/23/2020] [Indexed: 12/30/2022]
Abstract
Nearly half (45%) of the human genome is composed of transposable elements, or 'jumping genes'. Since Barbara McClintock's original discovery of transposable elements in 1950, we have come to appreciate that transposable element mobilization is a major driver of evolution that transposons are active in the germline and the soma, and that transposable element dysregulation is causally associated with many human disorders. In the present review, we highlight recent studies investigating transposable element activation in the adult brain and in the context of neurodegeneration. Collectively, these studies contribute to a greater understanding of the frequency of complete retrotransposition in the adult brain as well as the presence of transposable element-derived RNA and protein in brain and fluids of patients with neurodegenerative disorders. We discuss therapeutic opportunities and speculate on the larger implications of transposable element activation in regard to current hot topics in the field of neurodegeneration.
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Affiliation(s)
- Elizabeth Ochoa Thomas
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Gabbe Zuniga
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Wenyan Sun
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Bess Frost
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, United States.
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42
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Grabuschnig S, Soh J, Heidinger P, Bachler T, Hirschböck E, Rosales Rodriguez I, Schwendenwein D, Sensen CW. Circulating cell-free DNA is predominantly composed of retrotransposable elements and non-telomeric satellite DNA. J Biotechnol 2020; 313:48-56. [DOI: 10.1016/j.jbiotec.2020.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/26/2020] [Accepted: 03/04/2020] [Indexed: 12/19/2022]
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Differential Responses of LINE-1 in the Dentate Gyrus, Striatum and Prefrontal Cortex to Chronic Neurotoxic Methamphetamine: A Study in Rat Brain. Genes (Basel) 2020; 11:genes11040364. [PMID: 32231019 PMCID: PMC7230251 DOI: 10.3390/genes11040364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/19/2020] [Accepted: 03/25/2020] [Indexed: 11/17/2022] Open
Abstract
Methamphetamine (METH) is a widely abused psychostimulant with the potential to cause a broad range of severe cognitive deficits as well as neurobehavioral abnormalities when abused chronically, particularly at high doses. Cognitive deficits are related to METH neurotoxicity in the striatum and hippocampus. The activation of transposable Long INterspersed Nuclear Element 1 (LINE-1) is associated with several neurological diseases and drug abuse, but there are very limited data regarding the effects of high-dose METH on the activity of LINE-1 in the adult brain. Using real-time quantitative PCR, the present study demonstrates that the chronic administration of neurotoxic METH doses results in the increased expression of LINE-1-encoded Open Reading Frame 1 (ORF-1) in rat striatum shortly after the last dose of the drug and decreased ORF-1 expression during METH withdrawal, with dentate gyrus potentially developing "tolerance" to these METH effects. LINE-1 activation may be a new factor mediating the neurotoxic effects of chronic METH in the striatum and, therefore, a new drug target against METH-induced psychomotor impairments in chronic METH users.
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Loh JW, Ha H, Lin T, Sun N, Burns KH, Xing J. Integrated Mobile Element Scanning (ME-Scan) method for identifying multiple types of polymorphic mobile element insertions. Mob DNA 2020; 11:12. [PMID: 32110248 PMCID: PMC7035633 DOI: 10.1186/s13100-020-00207-x] [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: 07/28/2019] [Accepted: 02/14/2020] [Indexed: 01/29/2023] Open
Abstract
Background Mobile elements are ubiquitous components of mammalian genomes and constitute more than half of the human genome. Polymorphic mobile element insertions (pMEIs) are a major source of human genomic variation and are gaining research interest because of their involvement in gene expression regulation, genome integrity, and disease. Results Building on our previous Mobile Element Scanning (ME-Scan) protocols, we developed an integrated ME-Scan protocol to identify three major active families of human mobile elements, AluYb, L1HS, and SVA. This approach selectively amplifies insertion sites of currently active retrotransposons for Illumina sequencing. By pooling the libraries together, we can identify pMEIs from all three mobile element families in one sequencing run. To demonstrate the utility of the new ME-Scan protocol, we sequenced 12 human parent-offspring trios. Our results showed high sensitivity (> 90%) and accuracy (> 95%) of the protocol for identifying pMEIs in the human genome. In addition, we also tested the feasibility of identifying somatic insertions using the protocol. Conclusions The integrated ME-Scan protocol is a cost-effective way to identify novel pMEIs in the human genome. In addition, by developing the protocol to detect three mobile element families, we demonstrate the flexibility of the ME-Scan protocol. We present instructions for the library design, a sequencing protocol, and a computational pipeline for downstream analyses as a complete framework that will allow researchers to easily adapt the ME-Scan protocol to their own projects in other genomes.
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Affiliation(s)
- Jui Wan Loh
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA
| | - Hongseok Ha
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA.,2Human Genetic Institute of New Jersey, Rutgers, the State University of New Jersey, Piscataway, 08854 NJ USA
| | - Timothy Lin
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA
| | - Nawei Sun
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA.,2Human Genetic Institute of New Jersey, Rutgers, the State University of New Jersey, Piscataway, 08854 NJ USA
| | - Kathleen H Burns
- 3Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, 21205 MD USA
| | - Jinchuan Xing
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA.,2Human Genetic Institute of New Jersey, Rutgers, the State University of New Jersey, Piscataway, 08854 NJ USA
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45
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Percharde M, Sultana T, Ramalho-Santos M. What Doesn't Kill You Makes You Stronger: Transposons as Dual Players in Chromatin Regulation and Genomic Variation. Bioessays 2020; 42:e1900232. [PMID: 32053231 DOI: 10.1002/bies.201900232] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/10/2020] [Indexed: 12/22/2022]
Abstract
Transposable elements (TEs) are sequences currently or historically mobile, and are present across all eukaryotic genomes. A growing interest in understanding the regulation and function of TEs has revealed seemingly dichotomous roles for these elements in evolution, development, and disease. On the one hand, many gene regulatory networks owe their organization to the spread of cis-elements and DNA binding sites through TE mobilization during evolution. On the other hand, the uncontrolled activity of transposons can generate mutations and contribute to disease, including cancer, while their increased expression may also trigger immune pathways that result in inflammation or senescence. Interestingly, TEs have recently been found to have novel essential functions during mammalian development. Here, the function and regulation of TEs are discussed, with a focus on LINE1 in mammals. It is proposed that LINE1 is a beneficial endogenous dual regulator of gene expression and genomic diversity during mammalian development, and that both of these functions may be detrimental if deregulated in disease contexts.
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Affiliation(s)
- Michelle Percharde
- MRC London Institute of Medical Sciences (LMS), London, W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Tania Sultana
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, M5T 3L9, Ontario, Canada
| | - Miguel Ramalho-Santos
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, M5T 3L9, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, M5S 1A8, Ontario, Canada
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46
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The role of transposable elements activity in aging and their possible involvement in laminopathic diseases. Ageing Res Rev 2020; 57:100995. [PMID: 31786372 DOI: 10.1016/j.arr.2019.100995] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/17/2019] [Accepted: 11/25/2019] [Indexed: 01/17/2023]
Abstract
Eukaryotic genomes contain a large number of transposable elements, part of which are still active and able to transpose in the host genome. Mobile element activation is repressed to avoid deleterious effects, such as gene mutations or chromosome rearrangements. Control of transposable elements includes a variety of mechanisms comprising silencing pathways, which are based on the production of small non-coding RNAs. Silencing can occur either through transposable element RNA degradation or through the targeting of DNA sequences by heterochromatin formation and consequent transcriptional inhibition. Since the important role of the heterochromatin silencing, the gradual loss of heterochromatin marks in constitutive heterochromatin regions during the aging process promotes derepression of transposable elements, which is considered a cause of the progressive increase in genomic instability and of the activation of inflammatory responses. This review provides an overview of the effects of heterochromatin loss on the activity of transposable elements during the aging process and the possible impact on genome function. In this context, we discuss the possible role of the nuclear lamina, a major player in heterochromatin dynamics, in the regulation of transposable element activity and potential implications in laminopathic diseases.
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47
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Feusier J, Watkins WS, Thomas J, Farrell A, Witherspoon DJ, Baird L, Ha H, Xing J, Jorde LB. Pedigree-based estimation of human mobile element retrotransposition rates. Genome Res 2019; 29:1567-1577. [PMID: 31575651 PMCID: PMC6771411 DOI: 10.1101/gr.247965.118] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 08/14/2019] [Indexed: 12/26/2022]
Abstract
Germline mutation rates in humans have been estimated for a variety of mutation types, including single-nucleotide and large structural variants. Here, we directly measure the germline retrotransposition rate for the three active retrotransposon elements: L1, Alu, and SVA. We used three tools for calling mobile element insertions (MEIs) (MELT, RUFUS, and TranSurVeyor) on blood-derived whole-genome sequence (WGS) data from 599 CEPH individuals, comprising 33 three-generation pedigrees. We identified 26 de novo MEIs in 437 births. The retrotransposition rate estimates for Alu elements, one in 40 births, is roughly half the rate estimated using phylogenetic analyses, a difference in magnitude similar to that observed for single-nucleotide variants. The L1 retrotransposition rate is one in 63 births and is within range of previous estimates (1:20-1:200 births). The SVA retrotransposition rate, one in 63 births, is much higher than the previous estimate of one in 900 births. Our large, three-generation pedigrees allowed us to assess parent-of-origin effects and the timing of insertion events in either gametogenesis or early embryonic development. We find a statistically significant paternal bias in Alu retrotransposition. Our study represents the first in-depth analysis of the rate and dynamics of human retrotransposition from WGS data in three-generation human pedigrees.
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Affiliation(s)
- Julie Feusier
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - W Scott Watkins
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Jainy Thomas
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Andrew Farrell
- USTAR Center for Genetic Discovery, Salt Lake City, Utah 84112, USA
| | - David J Witherspoon
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Lisa Baird
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Hongseok Ha
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Jinchuan Xing
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Lynn B Jorde
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
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48
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Tam OH, Ostrow LW, Gale Hammell M. Diseases of the nERVous system: retrotransposon activity in neurodegenerative disease. Mob DNA 2019; 10:32. [PMID: 31372185 PMCID: PMC6659213 DOI: 10.1186/s13100-019-0176-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/18/2019] [Indexed: 12/13/2022] Open
Abstract
Transposable Elements (TEs) are mobile genetic elements whose sequences constitute nearly half of the human genome. Each TE copy can be present in hundreds to thousands of locations within the genome, complicating the genetic and genomic studies of these highly repetitive sequences. The recent development of better tools for evaluating TE derived sequences in genomic studies has enabled an increasing appreciation for the contribution of TEs to human development and disease. While some TEs have contributed novel and beneficial host functions, this review will summarize the evidence for detrimental TE activity in neurodegenerative disorders. Much of the evidence for pathogenicity implicates endogenous retroviruses (ERVs), a subset of TEs that entered the genome by retroviral infections of germline cells in our evolutionary ancestors and have since been passed down as a substantial fraction of the human genome. Human specific ERVs (HERVs) represent some of the youngest ERVs in the genome, and thus are presumed to retain greater function and resultant pathogenic potential.
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Affiliation(s)
- Oliver H Tam
- 1Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 USA
| | - Lyle W Ostrow
- 2Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Molly Gale Hammell
- 1Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 USA
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Gagnier L, Belancio VP, Mager DL. Mouse germ line mutations due to retrotransposon insertions. Mob DNA 2019; 10:15. [PMID: 31011371 PMCID: PMC6466679 DOI: 10.1186/s13100-019-0157-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/01/2019] [Indexed: 12/24/2022] Open
Abstract
Transposable element (TE) insertions are responsible for a significant fraction of spontaneous germ line mutations reported in inbred mouse strains. This major contribution of TEs to the mutational landscape in mouse contrasts with the situation in human, where their relative contribution as germ line insertional mutagens is much lower. In this focussed review, we provide comprehensive lists of TE-induced mouse mutations, discuss the different TE types involved in these insertional mutations and elaborate on particularly interesting cases. We also discuss differences and similarities between the mutational role of TEs in mice and humans.
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Affiliation(s)
- Liane Gagnier
- 1Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
| | - Victoria P Belancio
- 2Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| | - Dixie L Mager
- 1Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
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50
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Somatic LINE-1 retrotransposition in cortical neurons and non-brain tissues of Rett patients and healthy individuals. PLoS Genet 2019; 15:e1008043. [PMID: 30973874 PMCID: PMC6478352 DOI: 10.1371/journal.pgen.1008043] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 04/23/2019] [Accepted: 02/21/2019] [Indexed: 11/19/2022] Open
Abstract
Mounting evidence supports that LINE-1 (L1) retrotransposition can occur postzygotically in healthy and diseased human tissues, contributing to genomic mosaicism in the brain and other somatic tissues of an individual. However, the genomic distribution of somatic human-specific LINE-1 (L1Hs) insertions and their potential impact on carrier cells remain unclear. Here, using a PCR-based targeted bulk sequencing approach, we profiled 9,181 somatic insertions from 20 postmortem tissues from five Rett patients and their matched healthy controls. We identified and validated somatic L1Hs insertions in both cortical neurons and non-brain tissues. In Rett patients, somatic insertions were significantly depleted in exons—mainly contributed by long genes—than healthy controls, implying that cells carrying MECP2 mutations might be defenseless against a second exonic L1Hs insertion. We observed a significant increase of somatic L1Hs insertions in the brain compared with non-brain tissues from the same individual. Compared to germline insertions, somatic insertions were less sense-depleted to transcripts, indicating that they underwent weaker selective pressure on the orientation of insertion. Our observations demonstrate that somatic L1Hs insertions contribute to genomic diversity and MeCP2 dysfunction alters their genomic patterns in Rett patients. Human-specific LINE-1 (L1Hs) is the most active autonomous retrotransposon family in the human genome. Mounting evidence supports that L1Hs retrotransposition occurs postzygotically in the human brain cells, contributing to neuronal genomic diversity, but the extent of L1Hs-driven mosaicism in the brain is debated. In this study, we profiled genome-wide L1Hs insertions among 20 postmortem tissues from Rett patients and matched controls. We identified and validated somatic L1Hs insertions in both cortical neurons and non-brain tissues, with a higher jumping activity in the brain. We further found that MeCP2 dysfunction might alter the genomic pattern of somatic L1Hs in Rett patients.
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