101
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Mustafin RN. The Role of Transposable Elements in the Differentiation of Stem Cells. MOLECULAR GENETICS MICROBIOLOGY AND VIROLOGY 2019. [DOI: 10.3103/s0891416819020071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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102
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Yang WR, Ardeljan D, Pacyna CN, Payer LM, Burns KH. SQuIRE reveals locus-specific regulation of interspersed repeat expression. Nucleic Acids Res 2019; 47:e27. [PMID: 30624635 PMCID: PMC6411935 DOI: 10.1093/nar/gky1301] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 12/18/2018] [Accepted: 01/03/2019] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) are interspersed repeat sequences that make up much of the human genome. Their expression has been implicated in development and disease. However, TE-derived RNA-seq reads are difficult to quantify. Past approaches have excluded these reads or aggregated RNA expression to subfamilies shared by similar TE copies, sacrificing quantitative accuracy or the genomic context necessary to understand the basis of TE transcription. As a result, the effects of TEs on gene expression and associated phenotypes are not well understood. Here, we present Software for Quantifying Interspersed Repeat Expression (SQuIRE), the first RNA-seq analysis pipeline that provides a quantitative and locus-specific picture of TE expression (https://github.com/wyang17/SQuIRE). SQuIRE is an accurate and user-friendly tool that can be used for a variety of species. We applied SQuIRE to RNA-seq from normal mouse tissues and a Drosophila model of amyotrophic lateral sclerosis. In both model organisms, we recapitulated previously reported TE subfamily expression levels and revealed locus-specific TE expression. We also identified differences in TE transcription patterns relating to transcript type, gene expression and RNA splicing that would be lost with other approaches using subfamily-level analyses. Altogether, our findings illustrate the importance of studying TE transcription with locus-level resolution.
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Affiliation(s)
- Wan R Yang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daniel Ardeljan
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,McKusick-Nathans Institute of Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Clarissa N Pacyna
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Lindsay M Payer
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kathleen H Burns
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,McKusick-Nathans Institute of Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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103
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Saleh A, Macia A, Muotri AR. Transposable Elements, Inflammation, and Neurological Disease. Front Neurol 2019; 10:894. [PMID: 31481926 PMCID: PMC6710400 DOI: 10.3389/fneur.2019.00894] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 08/02/2019] [Indexed: 12/13/2022] Open
Abstract
Transposable Elements (TE) are mobile DNA elements that can replicate and insert themselves into different locations within the host genome. Their propensity to self-propagate has a myriad of consequences and yet their biological significance is not well-understood. Indeed, retrotransposons have evaded evolutionary attempts at repression and may contribute to somatic mosaicism. Retrotransposons are emerging as potent regulatory elements within the human genome. In the diseased state, there is mounting evidence that endogenous retroelements play a role in etiopathogenesis of inflammatory diseases, with a disposition for both autoimmune and neurological disorders. We postulate that active mobile genetic elements contribute more to human disease pathogenesis than previously thought.
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Affiliation(s)
- Aurian Saleh
- Department of Pediatrics, Rady Children's Hospital San Diego, University of California, San Diego, San Diego, CA, United States
| | - Angela Macia
- Department of Pediatrics, Rady Children's Hospital San Diego, University of California, San Diego, San Diego, CA, United States
| | - Alysson R Muotri
- Department of Pediatrics, Rady Children's Hospital San Diego, University of California, San Diego, San Diego, CA, United States
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104
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Navarro FCP, Hoops J, Bellfy L, Cerveira E, Zhu Q, Zhang C, Lee C, Gerstein MB. TeXP: Deconvolving the effects of pervasive and autonomous transcription of transposable elements. PLoS Comput Biol 2019; 15:e1007293. [PMID: 31425522 PMCID: PMC6715295 DOI: 10.1371/journal.pcbi.1007293] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 08/29/2019] [Accepted: 07/26/2019] [Indexed: 11/19/2022] Open
Abstract
The Long interspersed nuclear element 1 (LINE-1) is a primary source of genetic variation in humans and other mammals. Despite its importance, LINE-1 activity remains difficult to study because of its highly repetitive nature. Here, we developed and validated a method called TeXP to gauge LINE-1 activity accurately. TeXP builds mappability signatures from LINE-1 subfamilies to deconvolve the effect of pervasive transcription from autonomous LINE-1 activity. In particular, it apportions the multiple reads aligned to the many LINE-1 instances in the genome into these two categories. Using our method, we evaluated well-established cell lines, cell-line compartments and healthy tissues and found that the vast majority (91.7%) of transcriptome reads overlapping LINE-1 derive from pervasive transcription. We validated TeXP by independently estimating the levels of LINE-1 autonomous transcription using ddPCR, finding high concordance. Next, we applied our method to comprehensively measure LINE-1 activity across healthy somatic cells, while backing out the effect of pervasive transcription. Unexpectedly, we found that LINE-1 activity is present in many normal somatic cells. This finding contrasts with earlier studies showing that LINE-1 has limited activity in healthy somatic tissues, except for neuroprogenitor cells. Interestingly, we found that the amount of LINE-1 activity was associated with the with the amount of cell turnover, with tissues with low cell turnover rates (e.g. the adult central nervous system) showing lower LINE-1 activity. Altogether, our results show how accounting for pervasive transcription is critical to accurately quantify the activity of highly repetitive regions of the human genome. Repetitive sequences, such as LINEs, comprise more than half of the human genome. Due to their repetitive nature, LINEs are hard to grasp. In particular, we find that pervasive transcription is a major confounding factor in transcriptome data. We observe that, on average, more than 90% of LINE signal derives from pervasive transcription. To investigate this issue, we developed and validated a new method called TeXP. TeXP accounts and removes the effects of pervasive transcription when quantifying LINE activity. Our method uses the broad distribution of LINEs to estimate the effects of pervasive transcription. Using TeXP, we processed thousands of transcriptome datasets to uniformly, and unbiasedly measure LINE-1 activity across healthy somatic cells. By removing the pervasive transcription component, we find that (1) LINE-1 is broadly expressed in healthy somatic tissues; (2) Adult brain show small levels of LINE transcription and; (3) LINE-1 transcription level is correlated with tissue cell turnover. Our method thus offers insights into how repetitive sequences and influenced by pervasive transcription. Moreover, we uncover the activity of LINE-1 in somatic tissues at an unmatched scale.
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Affiliation(s)
- Fabio CP Navarro
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Jacob Hoops
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Lauren Bellfy
- The Jackson Laboratory for Genomic Medicine, Farmington, Michigan, United States of America
| | - Eliza Cerveira
- The Jackson Laboratory for Genomic Medicine, Farmington, Michigan, United States of America
| | - Qihui Zhu
- The Jackson Laboratory for Genomic Medicine, Farmington, Michigan, United States of America
| | - Chengsheng Zhang
- The Jackson Laboratory for Genomic Medicine, Farmington, Michigan, United States of America
| | - Charles Lee
- The Jackson Laboratory for Genomic Medicine, Farmington, Michigan, United States of America
- Department of Life Sciences, Ewha Womans University, Seoul, Korea
| | - Mark B. Gerstein
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Computer Science, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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105
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Banuelos-Sanchez G, Sanchez L, Benitez-Guijarro M, Sanchez-Carnerero V, Salvador-Palomeque C, Tristan-Ramos P, Benkaddour-Boumzaouad M, Morell S, Garcia-Puche JL, Heras SR, Franco-Montalban F, Tamayo JA, Garcia-Perez JL. Synthesis and Characterization of Specific Reverse Transcriptase Inhibitors for Mammalian LINE-1 Retrotransposons. Cell Chem Biol 2019; 26:1095-1109.e14. [DOI: 10.1016/j.chembiol.2019.04.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/29/2019] [Accepted: 04/19/2019] [Indexed: 12/24/2022]
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106
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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: 73] [Impact Index Per Article: 14.6] [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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107
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Abstract
Maintenance of genome stability requires control over the expression of transposable elements (TEs), whose activity can have substantial deleterious effects on the host. Chemical modification of DNA is a commonly used strategy to achieve this, and it has long been argued that the emergence of 5-methylcytosine (5mC) in many species was driven by the requirement to silence TEs. Potential roles in TE regulation have also been suggested for other DNA modifications, such as N6-methyladenine and oxidation derivatives of 5mC, although the underlying mechanistic relationships are poorly understood. Here, we discuss current evidence implicating DNA modifications and DNA-modifying enzymes in TE regulation across different species.
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Affiliation(s)
- Özgen Deniz
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, UK
| | - Jennifer M Frost
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, UK
| | - Miguel R Branco
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, UK.
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108
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Jönsson ME, Ludvik Brattås P, Gustafsson C, Petri R, Yudovich D, Pircs K, Verschuere S, Madsen S, Hansson J, Larsson J, Månsson R, Meissner A, Jakobsson J. Activation of neuronal genes via LINE-1 elements upon global DNA demethylation in human neural progenitors. Nat Commun 2019; 10:3182. [PMID: 31320637 PMCID: PMC6639357 DOI: 10.1038/s41467-019-11150-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 06/20/2019] [Indexed: 01/14/2023] Open
Abstract
DNA methylation contributes to the maintenance of genomic integrity in somatic cells, in part through the silencing of transposable elements. In this study, we use CRISPR-Cas9 technology to delete DNMT1, the DNA methyltransferase key for DNA methylation maintenance, in human neural progenitor cells (hNPCs). We observe that inactivation of DNMT1 in hNPCs results in viable, proliferating cells despite a global loss of DNA CpG-methylation. DNA demethylation leads to specific transcriptional activation and chromatin remodeling of evolutionarily young, hominoid-specific LINE-1 elements (L1s), while older L1s and other classes of transposable elements remain silent. The activated L1s act as alternative promoters for many protein-coding genes involved in neuronal functions, revealing a hominoid-specific L1-based transcriptional network controlled by DNA methylation that influences neuronal protein-coding genes. Our results provide mechanistic insight into the role of DNA methylation in silencing transposable elements in somatic human cells, as well as further implicating L1s in human brain development and disease. DNA methylation plays an important role in silencing transposable elements. Here the authors find that loss of DNMT1 and DNA methylation leads to transcriptional activation and chromatin remodelling of evolutionarily young—hominoid-specific —LINE-1 elements which then act as alternative promoters for neuronal genes.
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Affiliation(s)
- Marie E Jönsson
- Wallenberg Neuroscience Center and Lund Stem Cell Center, Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, BMC A11, Lund University, 221 84, Lund, Sweden
| | - Per Ludvik Brattås
- Wallenberg Neuroscience Center and Lund Stem Cell Center, Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, BMC A11, Lund University, 221 84, Lund, Sweden
| | - Charlotte Gustafsson
- Center for Hematology and Regenerative Medicine Huddinge, Karolinska Institute, 141 52, Stockholm, Sweden
| | - Rebecca Petri
- Wallenberg Neuroscience Center and Lund Stem Cell Center, Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, BMC A11, Lund University, 221 84, Lund, Sweden
| | - David Yudovich
- Division of Molecular Medicine and Gene Therapy, Department of Laboratory Medicine and Lund Stem Cell Center, BMC A12, Lund University, 221 84, Lund, Sweden
| | - Karolina Pircs
- Wallenberg Neuroscience Center and Lund Stem Cell Center, Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, BMC A11, Lund University, 221 84, Lund, Sweden
| | - Shana Verschuere
- Wallenberg Neuroscience Center and Lund Stem Cell Center, Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, BMC A11, Lund University, 221 84, Lund, Sweden
| | - Sofia Madsen
- Wallenberg Neuroscience Center and Lund Stem Cell Center, Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, BMC A11, Lund University, 221 84, Lund, Sweden
| | - Jenny Hansson
- Laboratory of Proteomic Hematology, Department of Laboratory Medicine and Lund Stem Cell Center, BMC B12, Lund University, 221 84, Lund, Sweden
| | - Jonas Larsson
- Division of Molecular Medicine and Gene Therapy, Department of Laboratory Medicine and Lund Stem Cell Center, BMC A12, Lund University, 221 84, Lund, Sweden
| | - Robert Månsson
- Center for Hematology and Regenerative Medicine Huddinge, Karolinska Institute, 141 52, Stockholm, Sweden
| | - Alexander Meissner
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195, Berlin, Germany
| | - Johan Jakobsson
- Wallenberg Neuroscience Center and Lund Stem Cell Center, Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, BMC A11, Lund University, 221 84, Lund, Sweden.
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109
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Sexton CE, Han MV. Paired-end mappability of transposable elements in the human genome. Mob DNA 2019; 10:29. [PMID: 31320939 PMCID: PMC6617613 DOI: 10.1186/s13100-019-0172-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/02/2019] [Indexed: 01/02/2023] Open
Abstract
Though transposable elements make up around half of the human genome, the repetitive nature of their sequences makes it difficult to accurately align conventional sequencing reads. However, in light of new advances in sequencing technology, such as increased read length and paired-end libraries, these repetitive regions are now becoming easier to align to. This study investigates the mappability of transposable elements with 50 bp, 76 bp and 100 bp paired-end read libraries. With respect to those read lengths and allowing for 3 mismatches during alignment, over 68, 85, and 88% of all transposable elements in the RepeatMasker database are uniquely mappable, suggesting that accurate locus-specific mapping of older transposable elements is well within reach.
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Affiliation(s)
- Corinne E Sexton
- 1School of Life Sciences, University of Nevada, Las Vegas, NV 89154 USA.,Nevada Institute of Personalized Medicine, Las Vegas, NV 89154 USA
| | - Mira V Han
- 1School of Life Sciences, University of Nevada, Las Vegas, NV 89154 USA.,Nevada Institute of Personalized Medicine, Las Vegas, NV 89154 USA
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110
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Ye Z, McQuillan L, Poduri A, Green TE, Matsumoto N, Mefford HC, Scheffer IE, Berkovic SF, Hildebrand MS. Somatic mutation: The hidden genetics of brain malformations and focal epilepsies. Epilepsy Res 2019; 155:106161. [PMID: 31295639 DOI: 10.1016/j.eplepsyres.2019.106161] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 01/12/2023]
Abstract
Over the past decade there has been a substantial increase in genetic studies of brain malformations, fueled by the availability of improved technologies to study surgical tissue to address the hypothesis that focal lesions arise from focal, post-zygotic genetic disruptions. Traditional genetic studies of patients with malformations utilized leukocyte-derived DNA to search for germline variants, which are inherited or arise de novo in parental gametes. Recent studies have demonstrated somatic variants that arise post-zygotically also underlie brain malformations, and that somatic mutation explains a larger proportion of focal malformations than previously thought. We now know from studies of non-diseased individuals that somatic variation occurs routinely during cell division, including during early brain development when the rapid proliferation of neuronal precursor cells provides the ideal environment for somatic mutation to occur and somatic variants to accumulate. When confined to brain, pathogenic variants contribute to the "hidden genetics" of neurological diseases. With burgeoning novel high-throughput genetic technologies, somatic genetic variations are increasingly being recognized. Here we discuss accumulating evidence for the presence of somatic variants in normal brain tissue, review our current understanding of somatic variants in brain malformations associated with lesional epilepsy, and provide strategies to identify the potential contribution of somatic mutation to non-lesional epilepsies. We also discuss technologies that may improve detection of somatic variants in the future in these and other neurological conditions.
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Affiliation(s)
- Zimeng Ye
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia
| | - Lara McQuillan
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, and Department of Neurology, Harvard Medical School, Boston, MA, United States
| | - Timothy E Green
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington and Seattle Children's Hospital, Seattle, WA, United States
| | - Ingrid E Scheffer
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia; Department of Pediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Parkville, Victoria, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Samuel F Berkovic
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia
| | - Michael S Hildebrand
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.
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111
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Sanchez-Luque FJ, Kempen MJHC, Gerdes P, Vargas-Landin DB, Richardson SR, Troskie RL, Jesuadian JS, Cheetham SW, Carreira PE, Salvador-Palomeque C, García-Cañadas M, Muñoz-Lopez M, Sanchez L, Lundberg M, Macia A, Heras SR, Brennan PM, Lister R, Garcia-Perez JL, Ewing AD, Faulkner GJ. LINE-1 Evasion of Epigenetic Repression in Humans. Mol Cell 2019; 75:590-604.e12. [PMID: 31230816 DOI: 10.1016/j.molcel.2019.05.024] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/08/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023]
Abstract
Epigenetic silencing defends against LINE-1 (L1) retrotransposition in mammalian cells. However, the mechanisms that repress young L1 families and how L1 escapes to cause somatic genome mosaicism in the brain remain unclear. Here we report that a conserved Yin Yang 1 (YY1) transcription factor binding site mediates L1 promoter DNA methylation in pluripotent and differentiated cells. By analyzing 24 hippocampal neurons with three distinct single-cell genomic approaches, we characterized and validated a somatic L1 insertion bearing a 3' transduction. The source (donor) L1 for this insertion was slightly 5' truncated, lacked the YY1 binding site, and was highly mobile when tested in vitro. Locus-specific bisulfite sequencing revealed that the donor L1 and other young L1s with mutated YY1 binding sites were hypomethylated in embryonic stem cells, during neurodifferentiation, and in liver and brain tissue. These results explain how L1 can evade repression and retrotranspose in the human body.
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Affiliation(s)
- Francisco J Sanchez-Luque
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain.
| | - Marie-Jeanne H C Kempen
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Patricia Gerdes
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Dulce B Vargas-Landin
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, the University of Western Australia, Perth, WA 6009, Australia; Harry Perkins Institute of Medical Research, Perth, WA 6009, Australia
| | - Sandra R Richardson
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Robin-Lee Troskie
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - J Samuel Jesuadian
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Seth W Cheetham
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Patricia E Carreira
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Carmen Salvador-Palomeque
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Marta García-Cañadas
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain
| | - Martin Muñoz-Lopez
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain
| | - Laura Sanchez
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain
| | - Mischa Lundberg
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Angela Macia
- Department of Pediatrics/Rady Children's Hospital San Diego, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Sara R Heras
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain; Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
| | - Paul M Brennan
- Edinburgh Cancer Research Centre, Western General Hospital, Edinburgh, EH4 2XR, UK
| | - Ryan Lister
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, the University of Western Australia, Perth, WA 6009, Australia; Harry Perkins Institute of Medical Research, Perth, WA 6009, Australia
| | - Jose L Garcia-Perez
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, 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
| | - 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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112
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Raghuram GV, Chaudhary S, Johari S, Mittra I. Illegitimate and Repeated Genomic Integration of Cell-Free Chromatin in the Aetiology of Somatic Mosaicism, Ageing, Chronic Diseases and Cancer. Genes (Basel) 2019; 10:genes10060407. [PMID: 31142004 PMCID: PMC6628102 DOI: 10.3390/genes10060407] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/15/2019] [Accepted: 05/22/2019] [Indexed: 12/19/2022] Open
Abstract
Emerging evidence suggests that an individual is a complex mosaic of genetically divergent cells. Post-zygotic genomes of the same individual can differ from one another in the form of single nucleotide variations, copy number variations, insertions, deletions, inversions, translocations, other structural and chromosomal variations and footprints of transposable elements. High-throughput sequencing has led to increasing detection of mosaicism in healthy individuals which is related to ageing, neuro-degenerative disorders, diabetes mellitus, cardiovascular diseases and cancer. These age-related disorders are also known to be associated with significant increase in DNA damage and inflammation. Herein, we discuss a newly described phenomenon wherein the genome is under constant assault by illegitimate integration of cell-free chromatin (cfCh) particles that are released from the billions of cells that die in the body every day. We propose that such repeated genomic integration of cfCh followed by dsDNA breaks and repair by non-homologous-end-joining as well as physical damage to chromosomes occurring throughout life may lead to somatic/chromosomal mosaicism which would increase with age. We also discuss the recent finding that genomic integration of cfCh and the accompanying DNA damage is associated with marked activation of inflammatory cytokines. Thus, the triple pathologies of somatic mosaicism, DNA/chromosomal damage and inflammation brought about by a common mechanism of genomic integration of cfCh may help to provide an unifying model for the understanding of aetiologies of the inter-related conditions of ageing, degenerative disorders and cancer.
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Affiliation(s)
- Gorantla V Raghuram
- Translational Research Laboratory, Advanced Centre for Treatment, Research and Education in Cancer, Tata Memorial Centre, Navi-Mumbai 410210, India.
| | - Shahid Chaudhary
- Translational Research Laboratory, Advanced Centre for Treatment, Research and Education in Cancer, Tata Memorial Centre, Navi-Mumbai 410210, India.
| | - Shweta Johari
- Translational Research Laboratory, Advanced Centre for Treatment, Research and Education in Cancer, Tata Memorial Centre, Navi-Mumbai 410210, India.
| | - Indraneel Mittra
- Translational Research Laboratory, Advanced Centre for Treatment, Research and Education in Cancer, Tata Memorial Centre, Navi-Mumbai 410210, India.
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113
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Chang YH, Keegan RM, Prazak L, Dubnau J. Cellular labeling of endogenous retrovirus replication (CLEVR) reveals de novo insertions of the gypsy retrotransposable element in cell culture and in both neurons and glial cells of aging fruit flies. PLoS Biol 2019; 17:e3000278. [PMID: 31095565 PMCID: PMC6541305 DOI: 10.1371/journal.pbio.3000278] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 05/29/2019] [Accepted: 05/03/2019] [Indexed: 12/11/2022] Open
Abstract
Evidence is rapidly mounting that transposable element (TE) expression and replication may impact biology more widely than previously thought. This includes potential effects on normal physiology of somatic tissues and dysfunctional impacts in diseases associated with aging, such as cancer and neurodegeneration. Investigation of the biological impact of mobile elements in somatic cells will be greatly facilitated by the use of donor elements that are engineered to report de novo events in vivo. In multicellular organisms, reporter constructs demonstrating engineered long interspersed nuclear element (LINE-1; L1) mobilization have been in use for quite some time, and strategies similar to L1 retrotransposition reporter assays have been developed to report replication of Ty1 elements in yeast and mouse intracisternal A particle (IAP) long terminal repeat (LTR) retrotransposons in cultivated cells. We describe a novel approach termed cellular labeling of endogenous retrovirus replication (CLEVR), which reports replication of the gypsy element within specific cells in vivo in Drosophila. The gypsy-CLEVR reporter reveals gypsy replication both in cell culture and in individual neurons and glial cells of the aging adult fly. We also demonstrate that the gypsy-CLEVR replication rate is increased when the short interfering RNA (siRNA) silencing system is genetically disrupted. This CLEVR strategy makes use of universally conserved features of retroviruses and should be widely applicable to other LTR retrotransposons, endogenous retroviruses (ERVs), and exogenous retroviruses.
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Affiliation(s)
- Yung-Heng Chang
- Department of Anesthesiology, Stony Brook School of Medicine, Stony Brook, New York, United States of America
| | - Richard M. Keegan
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America
| | - Lisa Prazak
- Biology, Farmingdale State College, Farmingdale, New York, United States of America
| | - Josh Dubnau
- Department of Anesthesiology, Stony Brook School of Medicine, Stony Brook, New York, United States of America
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America
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114
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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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115
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Flasch DA, Macia Á, Sánchez L, Ljungman M, Heras SR, García-Pérez JL, Wilson TE, Moran JV. Genome-wide de novo L1 Retrotransposition Connects Endonuclease Activity with Replication. Cell 2019; 177:837-851.e28. [PMID: 30955886 DOI: 10.1016/j.cell.2019.02.050] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 01/10/2019] [Accepted: 02/25/2019] [Indexed: 12/18/2022]
Abstract
L1 retrotransposon-derived sequences comprise approximately 17% of the human genome. Darwinian selective pressures alter L1 genomic distributions during evolution, confounding the ability to determine initial L1 integration preferences. Here, we generated high-confidence datasets of greater than 88,000 engineered L1 insertions in human cell lines that act as proxies for cells that accommodate retrotransposition in vivo. Comparing these insertions to a null model, in which L1 endonuclease activity is the sole determinant dictating L1 integration preferences, demonstrated that L1 insertions are not significantly enriched in genes, transcribed regions, or open chromatin. By comparison, we provide compelling evidence that the L1 endonuclease disproportionately cleaves predominant lagging strand DNA replication templates, while lagging strand 3'-hydroxyl groups may prime endonuclease-independent L1 retrotransposition in a Fanconi anemia cell line. Thus, acquisition of an endonuclease domain, in conjunction with the ability to integrate into replicating DNA, allowed L1 to become an autonomous, interspersed retrotransposon.
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Affiliation(s)
- Diane A Flasch
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, 48109, USA.
| | - Ángela Macia
- Department of Genomic Medicine, GENYO: Centre for Genomics and Oncology (Pfizer-University of Granada and Andalusian Regional Government), PTS Granada, 18016, Spain
| | - Laura Sánchez
- Department of Genomic Medicine, GENYO: Centre for Genomics and Oncology (Pfizer-University of Granada and Andalusian Regional Government), PTS Granada, 18016, Spain
| | - Mats Ljungman
- Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, Translational Oncology Program and Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, 48109, USA; Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Sara R Heras
- Department of Genomic Medicine, GENYO: Centre for Genomics and Oncology (Pfizer-University of Granada and Andalusian Regional Government), PTS Granada, 18016, Spain
| | - José L García-Pérez
- Department of Genomic Medicine, GENYO: Centre for Genomics and Oncology (Pfizer-University of Granada and Andalusian Regional Government), PTS Granada, 18016, Spain; Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Thomas E Wilson
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, 48109, USA; Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, 48109, USA.
| | - John V Moran
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, 48109, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, 48109, USA.
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116
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Sultana T, van Essen D, Siol O, Bailly-Bechet M, Philippe C, Zine El Aabidine A, Pioger L, Nigumann P, Saccani S, Andrau JC, Gilbert N, Cristofari G. The Landscape of L1 Retrotransposons in the Human Genome Is Shaped by Pre-insertion Sequence Biases and Post-insertion Selection. Mol Cell 2019; 74:555-570.e7. [PMID: 30956044 DOI: 10.1016/j.molcel.2019.02.036] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 01/28/2019] [Accepted: 02/25/2019] [Indexed: 01/10/2023]
Abstract
L1 retrotransposons are transposable elements and major contributors of genetic variation in humans. Where L1 integrates into the genome can directly impact human evolution and disease. Here, we experimentally induced L1 retrotransposition in cells and mapped integration sites at nucleotide resolution. At local scales, L1 integration is mostly restricted by genome sequence biases and the specificity of the L1 machinery. At regional scales, L1 shows a broad capacity for integration into all chromatin states, in contrast to other known mobile genetic elements. However, integration is influenced by the replication timing of target regions, suggesting a link to host DNA replication. The distribution of new L1 integrations differs from those of preexisting L1 copies, which are significantly reshaped by natural selection. Our findings reveal that the L1 machinery has evolved to efficiently target all genomic regions and underline a predominant role for post-integrative processes on the distribution of endogenous L1 elements.
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Affiliation(s)
- Tania Sultana
- Université Côte d'Azur, Inserm, CNRS, IRCAN, Nice, France
| | | | - Oliver Siol
- Institut de Génétique Humaine, University of Montpellier, CNRS, Montpellier, France
| | | | | | - Amal Zine El Aabidine
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Léo Pioger
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Pilvi Nigumann
- Université Côte d'Azur, Inserm, CNRS, IRCAN, Nice, France
| | - Simona Saccani
- Université Côte d'Azur, Inserm, CNRS, IRCAN, Nice, France
| | - Jean-Christophe Andrau
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Nicolas Gilbert
- Institut de Génétique Humaine, University of Montpellier, CNRS, Montpellier, France; Institut de Médecine Régénératrice et de Biothérapie, Inserm U1183, CHU Montpellier, Montpellier, France
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117
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Bodea GO, McKelvey EGZ, Faulkner GJ. Retrotransposon-induced mosaicism in the neural genome. Open Biol 2019; 8:rsob.180074. [PMID: 30021882 PMCID: PMC6070720 DOI: 10.1098/rsob.180074] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/21/2018] [Indexed: 12/18/2022] Open
Abstract
Over the past decade, major discoveries in retrotransposon biology have depicted the neural genome as a dynamic structure during life. In particular, the retrotransposon LINE-1 (L1) has been shown to be transcribed and mobilized in the brain. Retrotransposition in the developing brain, as well as during adult neurogenesis, provides a milieu in which neural diversity can arise. Dysregulation of retrotransposon activity may also contribute to neurological disease. Here, we review recent reports of retrotransposon activity in the brain, and discuss the temporal nature of retrotransposition and its regulation in neural cells in response to stimuli. We also put forward hypotheses regarding the significance of retrotransposons for brain development and neurological function, and consider the potential implications of this phenomenon for neuropsychiatric and neurodegenerative conditions.
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Affiliation(s)
- Gabriela O Bodea
- Mater Research Institute-University of Queensland, TRI Building, Brisbane, Queensland 4102, Australia .,Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Eleanor G Z McKelvey
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute-University of Queensland, TRI Building, Brisbane, Queensland 4102, Australia .,Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
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118
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Dynamic Methylation of an L1 Transduction Family during Reprogramming and Neurodifferentiation. Mol Cell Biol 2019; 39:MCB.00499-18. [PMID: 30692270 PMCID: PMC6425141 DOI: 10.1128/mcb.00499-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/11/2019] [Indexed: 01/28/2023] Open
Abstract
The retrotransposon LINE-1 (L1) is a significant source of endogenous mutagenesis in humans. In each individual genome, a few retrotransposition-competent L1s (RC-L1s) can generate new heritable L1 insertions in the early embryo, primordial germ line, and germ cells. L1 retrotransposition can also occur in the neuronal lineage and cause somatic mosaicism. Although DNA methylation mediates L1 promoter repression, the temporal pattern of methylation applied to individual RC-L1s during neurogenesis is unclear. Here, we identified a de novo L1 insertion in a human induced pluripotent stem cell (hiPSC) line via retrotransposon capture sequencing (RC-seq). The L1 insertion was full-length and carried 5' and 3' transductions. The corresponding donor RC-L1 was part of a large and recently active L1 transduction family and was highly mobile in a cultured-cell L1 retrotransposition reporter assay. Notably, we observed distinct and dynamic DNA methylation profiles for the de novo L1 and members of its extended transduction family during neuronal differentiation. These experiments reveal how a de novo L1 insertion in a pluripotent stem cell is rapidly recognized and repressed, albeit incompletely, by the host genome during neurodifferentiation, while retaining potential for further retrotransposition.
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119
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Schumann GG, Fuchs NV, Tristán-Ramos P, Sebe A, Ivics Z, Heras SR. The impact of transposable element activity on therapeutically relevant human stem cells. Mob DNA 2019; 10:9. [PMID: 30899334 PMCID: PMC6408843 DOI: 10.1186/s13100-019-0151-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/27/2019] [Indexed: 12/11/2022] Open
Abstract
Human stem cells harbor significant potential for basic and clinical translational research as well as regenerative medicine. Currently ~ 3000 adult and ~ 30 pluripotent stem cell-based, interventional clinical trials are ongoing worldwide, and numbers are increasing continuously. Although stem cells are promising cell sources to treat a wide range of human diseases, there are also concerns regarding potential risks associated with their clinical use, including genomic instability and tumorigenesis concerns. Thus, a deeper understanding of the factors and molecular mechanisms contributing to stem cell genome stability are a prerequisite to harnessing their therapeutic potential for degenerative diseases. Chemical and physical factors are known to influence the stability of stem cell genomes, together with random mutations and Copy Number Variants (CNVs) that accumulated in cultured human stem cells. Here we review the activity of endogenous transposable elements (TEs) in human multipotent and pluripotent stem cells, and the consequences of their mobility for genomic integrity and host gene expression. We describe transcriptional and post-transcriptional mechanisms antagonizing the spread of TEs in the human genome, and highlight those that are more prevalent in multipotent and pluripotent stem cells. Notably, TEs do not only represent a source of mutations/CNVs in genomes, but are also often harnessed as tools to engineer the stem cell genome; thus, we also describe and discuss the most widely applied transposon-based tools and highlight the most relevant areas of their biomedical applications in stem cells. Taken together, this review will contribute to the assessment of the risk that endogenous TE activity and the application of genetically engineered TEs constitute for the biosafety of stem cells to be used for substitutive and regenerative cell therapies.
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Affiliation(s)
- Gerald G Schumann
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Nina V Fuchs
- 2Host-Pathogen Interactions, Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51-59, 63225 Langen, Germany
| | - Pablo Tristán-Ramos
- 3GENYO. Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada-Avenida de la Ilustración, 114, 18016 Granada, Spain.,4Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
| | - Attila Sebe
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Zoltán Ivics
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Sara R Heras
- 3GENYO. Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada-Avenida de la Ilustración, 114, 18016 Granada, Spain.,4Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
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120
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Steranka JP, Tang Z, Grivainis M, Huang CRL, Payer LM, Rego FOR, Miller TLA, Galante PAF, Ramaswami S, Heguy A, Fenyö D, Boeke JD, Burns KH. Transposon insertion profiling by sequencing (TIPseq) for mapping LINE-1 insertions in the human genome. Mob DNA 2019; 10:8. [PMID: 30899333 PMCID: PMC6407172 DOI: 10.1186/s13100-019-0148-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/14/2019] [Indexed: 12/14/2022] Open
Abstract
Background Transposable elements make up a significant portion of the human genome. Accurately locating these mobile DNAs is vital to understand their role as a source of structural variation and somatic mutation. To this end, laboratories have developed strategies to selectively amplify or otherwise enrich transposable element insertion sites in genomic DNA. Results Here we describe a technique, Transposon Insertion Profiling by sequencing (TIPseq), to map Long INterspersed Element 1 (LINE-1, L1) retrotransposon insertions in the human genome. This method uses vectorette PCR to amplify species-specific L1 (L1PA1) insertion sites followed by paired-end Illumina sequencing. In addition to providing a step-by-step molecular biology protocol, we offer users a guide to our pipeline for data analysis, TIPseqHunter. Our recent studies in pancreatic and ovarian cancer demonstrate the ability of TIPseq to identify invariant (fixed), polymorphic (inherited variants), as well as somatically-acquired L1 insertions that distinguish cancer genomes from a patient’s constitutional make-up. Conclusions TIPseq provides an approach for amplifying evolutionarily young, active transposable element insertion sites from genomic DNA. Our rationale and variations on this protocol may be useful to those mapping L1 and other mobile elements in complex genomes. Electronic supplementary material The online version of this article (10.1186/s13100-019-0148-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jared P Steranka
- 1Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA.,2McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Zuojian Tang
- 3Department for Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016 USA.,4Institute for Systems Genetics, NYU Langone Health, New York, NY 10016 USA
| | - Mark Grivainis
- 3Department for Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016 USA.,4Institute for Systems Genetics, NYU Langone Health, New York, NY 10016 USA
| | - Cheng Ran Lisa Huang
- 2McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Lindsay M Payer
- 1Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Fernanda O R Rego
- 5Centro de Oncologia Molecular, Hospital Sírio-Libanês, São Paulo, Brazil
| | - Thiago Luiz Araujo Miller
- 5Centro de Oncologia Molecular, Hospital Sírio-Libanês, São Paulo, Brazil.,Departamento de Bioquímica, Instituto de Química, Universidade de São Paul, São Paulo, Brazil
| | - Pedro A F Galante
- 5Centro de Oncologia Molecular, Hospital Sírio-Libanês, São Paulo, Brazil
| | - Sitharam Ramaswami
- 7Genome Technology Center, Division of Advanced Research Technologies, NYU Langone Health, New York, NY USA
| | - Adriana Heguy
- 7Genome Technology Center, Division of Advanced Research Technologies, NYU Langone Health, New York, NY USA
| | - David Fenyö
- 3Department for Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016 USA.,4Institute for Systems Genetics, NYU Langone Health, New York, NY 10016 USA
| | - Jef D Boeke
- 4Institute for Systems Genetics, NYU Langone Health, New York, NY 10016 USA
| | - Kathleen H Burns
- 1Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA.,2McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
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121
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Savage AL, Schumann GG, Breen G, Bubb VJ, Al-Chalabi A, Quinn JP. Retrotransposons in the development and progression of amyotrophic lateral sclerosis. J Neurol Neurosurg Psychiatry 2019; 90:284-293. [PMID: 30305322 PMCID: PMC6518469 DOI: 10.1136/jnnp-2018-319210] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/04/2018] [Accepted: 09/06/2018] [Indexed: 02/07/2023]
Abstract
Endogenous retrotransposon sequences constitute approximately 42% of the human genome, and mobilisation of retrotransposons has resulted in rearrangements, duplications, deletions, novel transcripts and the introduction of new regulatory domains throughout the human genome. Both germline and somatic de novo retrotransposition events have been involved in a range of human diseases, and there is emerging evidence for the modulation of retrotransposon activity during the development of specific diseases. Particularly, there is unequivocal consensus that endogenous retrotransposition can occur in neuronal lineages. This review addresses our current knowledge of the different mechanisms through which retrotransposons might influence the development of and predisposition to amyotrophic lateral sclerosis.
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Affiliation(s)
- Abigail L Savage
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Gerald G Schumann
- Division of Medical Biotechnology, Paul-Ehrlich-Institut, Langen, Germany
| | - Gerome Breen
- Social, Genetic, and Developmental Psychiatry Research Centre, King's College London, London, UK
| | - Vivien J Bubb
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Ammar Al-Chalabi
- Department of Basic and Clinical Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, UK.,King's College Hospital, London, UK
| | - John P Quinn
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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122
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Specchia V, Puricella A, D'Attis S, Massari S, Giangrande A, Bozzetti MP. Drosophila melanogaster as a Model to Study the Multiple Phenotypes, Related to Genome Stability of the Fragile-X Syndrome. Front Genet 2019; 10:10. [PMID: 30815010 PMCID: PMC6381874 DOI: 10.3389/fgene.2019.00010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/11/2019] [Indexed: 12/14/2022] Open
Abstract
Fragile-X syndrome is one of the most common forms of inherited mental retardation and autistic behaviors. The reduction/absence of the functional FMRP protein, coded by the X-linked Fmr1 gene in humans, is responsible for the syndrome. Patients exhibit a variety of symptoms predominantly linked to the function of FMRP protein in the nervous system like autistic behavior and mild-to-severe intellectual disability. Fragile-X (FraX) individuals also display cellular and morphological traits including branched dendritic spines, large ears, and macroorchidism. The dFmr1 gene is the Drosophila ortholog of the human Fmr1 gene. dFmr1 mutant flies exhibit synaptic abnormalities, behavioral defects as well as an altered germline development, resembling the phenotypes observed in FraX patients. Therefore, Drosophila melanogaster is considered a good model to study the physiopathological mechanisms underlying the Fragile-X syndrome. In this review, we explore how the multifaceted roles of the FMRP protein have been addressed in the Drosophila model and how the gained knowledge may open novel perspectives for understanding the molecular defects causing the disease and for identifying novel therapeutical targets.
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Affiliation(s)
- Valeria Specchia
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
| | - Antonietta Puricella
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
| | - Simona D'Attis
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
| | - Serafina Massari
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
| | - Angela Giangrande
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Maria Pia Bozzetti
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
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123
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Nicolas G, Veltman JA. The role of de novo mutations in adult-onset neurodegenerative disorders. Acta Neuropathol 2019; 137:183-207. [PMID: 30478624 PMCID: PMC6513904 DOI: 10.1007/s00401-018-1939-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 11/14/2018] [Accepted: 11/14/2018] [Indexed: 12/13/2022]
Abstract
The genetic underpinnings of the most common adult-onset neurodegenerative disorders (AOND) are complex in majority of the cases. In some families, however, the disease can be inherited in a Mendelian fashion as an autosomal-dominant trait. Next to that, patients carrying mutations in the same disease genes have been reported despite a negative family history. Although challenging to demonstrate due to the late onset of the disease in most cases, the occurrence of de novo mutations can explain this sporadic presentation, as demonstrated for severe neurodevelopmental disorders. Exome or genome sequencing of patient-parent trios allows a hypothesis-free study of the role of de novo mutations in AOND and the discovery of novel disease genes. Another hypothesis that may explain a proportion of sporadic AOND cases is the occurrence of a de novo mutation after the fertilization of the oocyte (post-zygotic mutation) or even as a late-somatic mutation, restricted to the brain. Such somatic mutation hypothesis, that can be tested with the use of novel sequencing technologies, is fully compatible with the seeding and spreading mechanisms of the pathological proteins identified in most of these disorders. We review here the current knowledge and future perspectives on de novo mutations in known and novel candidate genes identified in the most common AONDs such as Alzheimer's disease, Parkinson's disease, the frontotemporal lobar degeneration spectrum and Prion disorders. Also, we review the first lessons learned from recent genomic studies of control and diseased brains and the challenges which remain to be addressed.
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Affiliation(s)
- Gaël Nicolas
- Normandie Univ, UNIROUEN, Inserm U1245 and Rouen University Hospital, Department of Genetics and CNR-MAJ, Normandy Center for Genomic and Personalized Medicine, 22, Boulevard Gambetta, 76000, 76031, Rouen Cedex, France.
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Joris A Veltman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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125
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Nishioka M, Bundo M, Iwamoto K, Kato T. Somatic mutations in the human brain: implications for psychiatric research. Mol Psychiatry 2019; 24:839-856. [PMID: 30087451 PMCID: PMC6756205 DOI: 10.1038/s41380-018-0129-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/27/2018] [Accepted: 05/25/2018] [Indexed: 01/18/2023]
Abstract
Psychiatric disorders such as schizophrenia and bipolar disorder are caused by complex gene-environment interactions. While recent advances in genomic technologies have enabled the identification of several risk variants for psychiatric conditions, including single-nucleotide variants and copy-number variations, these factors can explain only a portion of the liability to these disorders. Although non-inherited factors had previously been attributed to environmental causes, recent genomic analyses have demonstrated that de novo mutations are among the main non-inherited risk factors for several psychiatric conditions. Somatic mutations in the brain may also explain how stochastic developmental events and environmental insults confer risk for a psychiatric disorder following fertilization. Here, we review evidence regarding somatic mutations in the brains of individuals with and without neuropsychiatric diseases. We further discuss the potential biological mechanisms underlying somatic mutations in the brain as well as the technical issues associated with the detection of somatic mutations in psychiatric research.
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Affiliation(s)
- Masaki Nishioka
- 0000 0001 2151 536Xgrid.26999.3dDivision for Counseling and Support, The University of Tokyo, Tokyo, Japan
| | - Miki Bundo
- 0000 0001 0660 6749grid.274841.cDepartment of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan ,0000 0004 1754 9200grid.419082.6PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Kazuya Iwamoto
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
| | - Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Saitama, Japan.
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126
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Mustafin RN, Enikeeva RF, Davydova YD, Khusnutdinova EK. The Role of Epigenetic Factors in the Development of Depressive Disorders. RUSS J GENET+ 2018. [DOI: 10.1134/s1022795418120104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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127
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Raviram R, Rocha PP, Luo VM, Swanzey E, Miraldi ER, Chuong EB, Feschotte C, Bonneau R, Skok JA. Analysis of 3D genomic interactions identifies candidate host genes that transposable elements potentially regulate. Genome Biol 2018; 19:216. [PMID: 30541598 PMCID: PMC6292174 DOI: 10.1186/s13059-018-1598-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 11/28/2018] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND The organization of chromatin in the nucleus plays an essential role in gene regulation. About half of the mammalian genome comprises transposable elements. Given their repetitive nature, reads associated with these elements are generally discarded or randomly distributed among elements of the same type in genome-wide analyses. Thus, it is challenging to identify the activities and properties of individual transposons. As a result, we only have a partial understanding of how transposons contribute to chromatin folding and how they impact gene regulation. RESULTS Using PCR and Capture-based chromosome conformation capture (3C) approaches, collectively called 4Tran, we take advantage of the repetitive nature of transposons to capture interactions from multiple copies of endogenous retrovirus (ERVs) in the human and mouse genomes. With 4Tran-PCR, reads are selectively mapped to unique regions in the genome. This enables the identification of transposable element interaction profiles for individual ERV families and integration events specific to particular genomes. With this approach, we demonstrate that transposons engage in long-range intra-chromosomal interactions guided by the separation of chromosomes into A and B compartments as well as topologically associated domains (TADs). In contrast to 4Tran-PCR, Capture-4Tran can uniquely identify both ends of an interaction that involve retroviral repeat sequences, providing a powerful tool for uncovering the individual transposable element insertions that interact with and potentially regulate target genes. CONCLUSIONS 4Tran provides new insight into the manner in which transposons contribute to chromosome architecture and identifies target genes that transposable elements can potentially control.
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Affiliation(s)
- Ramya Raviram
- Department of Pathology, New York University School of Medicine, New York, NY 10016 USA
- Department of Biology, New York University, New York, NY 10003 USA
- Ludwig Institute for Cancer Research, La Jolla, CA USA
| | - Pedro P. Rocha
- Department of Pathology, New York University School of Medicine, New York, NY 10016 USA
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892 USA
| | - Vincent M. Luo
- Department of Pathology, New York University School of Medicine, New York, NY 10016 USA
- Department of Biology, New York University, New York, NY 10003 USA
| | - Emily Swanzey
- Department of Developmental Genetics, New York University School of Medicine, New York, NY 10016 USA
| | - Emily R. Miraldi
- Department of Biology, New York University, New York, NY 10003 USA
- Department of Computer Science, Courant Institute of Mathematical Sciences, New York, NY 10003 USA
- Simons Center for Data Analysis, New York, NY 10010 USA
- Divisions of Immunobiology and Biomedical Informatics, Cincinnati Children’s Hospital, Cincinnati, OH 45229 USA
| | - Edward B. Chuong
- BioFrontiers Institute, Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309 USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850 USA
| | - Richard Bonneau
- Department of Biology, New York University, New York, NY 10003 USA
- Department of Computer Science, Courant Institute of Mathematical Sciences, New York, NY 10003 USA
- Simons Center for Data Analysis, New York, NY 10010 USA
| | - Jane A. Skok
- Department of Pathology, New York University School of Medicine, New York, NY 10016 USA
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128
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Lee MH, Siddoway B, Kaeser GE, Segota I, Rivera R, Romanow WJ, Liu CS, Park C, Kennedy G, Long T, Chun J. Somatic APP gene recombination in Alzheimer's disease and normal neurons. Nature 2018; 563:639-645. [PMID: 30464338 DOI: 10.1038/s41586-018-0718-6] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 10/09/2018] [Indexed: 11/09/2022]
Abstract
The diversity and complexity of the human brain are widely assumed to be encoded within a constant genome. Somatic gene recombination, which changes germline DNA sequences to increase molecular diversity, could theoretically alter this code but has not been documented in the brain, to our knowledge. Here we describe recombination of the Alzheimer's disease-related gene APP, which encodes amyloid precursor protein, in human neurons, occurring mosaically as thousands of variant 'genomic cDNAs' (gencDNAs). gencDNAs lacked introns and ranged from full-length cDNA copies of expressed, brain-specific RNA splice variants to myriad smaller forms that contained intra-exonic junctions, insertions, deletions, and/or single nucleotide variations. DNA in situ hybridization identified gencDNAs within single neurons that were distinct from wild-type loci and absent from non-neuronal cells. Mechanistic studies supported neuronal 'retro-insertion' of RNA to produce gencDNAs; this process involved transcription, DNA breaks, reverse transcriptase activity, and age. Neurons from individuals with sporadic Alzheimer's disease showed increased gencDNA diversity, including eleven mutations known to be associated with familial Alzheimer's disease that were absent from healthy neurons. Neuronal gene recombination may allow 'recording' of neural activity for selective 'playback' of preferred gene variants whose expression bypasses splicing; this has implications for cellular diversity, learning and memory, plasticity, and diseases of the human brain.
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Affiliation(s)
- Ming-Hsiang Lee
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Benjamin Siddoway
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Gwendolyn E Kaeser
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.,Biomedical Sciences Program, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Igor Segota
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Richard Rivera
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - William J Romanow
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Christine S Liu
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.,Biomedical Sciences Program, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Chris Park
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.,Biomedical Sciences Program, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Grace Kennedy
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Tao Long
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Jerold Chun
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
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129
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Bourque G, Burns KH, Gehring M, Gorbunova V, Seluanov A, Hammell M, Imbeault M, Izsvák Z, Levin HL, Macfarlan TS, Mager DL, Feschotte C. Ten things you should know about transposable elements. Genome Biol 2018; 19:199. [PMID: 30454069 PMCID: PMC6240941 DOI: 10.1186/s13059-018-1577-z] [Citation(s) in RCA: 639] [Impact Index Per Article: 106.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Transposable elements (TEs) are major components of eukaryotic genomes. However, the extent of their impact on genome evolution, function, and disease remain a matter of intense interrogation. The rise of genomics and large-scale functional assays has shed new light on the multi-faceted activities of TEs and implies that they should no longer be marginalized. Here, we introduce the fundamental properties of TEs and their complex interactions with their cellular environment, which are crucial to understanding their impact and manifold consequences for organismal biology. While we draw examples primarily from mammalian systems, the core concepts outlined here are relevant to a broad range of organisms.
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Affiliation(s)
- Guillaume Bourque
- Department of Human Genetics, McGill University, Montréal, Québec, H3A 0G1, Canada.
- Canadian Center for Computational Genomics, McGill University, Montréal, Québec, H3A 0G1, Canada.
| | - Kathleen H Burns
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Mary Gehring
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA
| | - Vera Gorbunova
- Department of Biology, University of Rochester, Rochester, NY, 14627, USA
| | - Andrei Seluanov
- Department of Biology, University of Rochester, Rochester, NY, 14627, USA
| | - Molly Hammell
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Michaël Imbeault
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK
| | - Zsuzsanna Izsvák
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany
| | - Henry L Levin
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland, USA
| | - Todd S Macfarlan
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, Maryland, USA
| | - Dixie L Mager
- Terry Fox Laboratory, British Columbia Cancer Agency and Department of Medical Genetics, University of BC, Vancouver, BC, V5Z1L3, Canada
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA.
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130
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Rohrback S, Siddoway B, Liu CS, Chun J. Genomic mosaicism in the developing and adult brain. Dev Neurobiol 2018; 78:1026-1048. [PMID: 30027562 PMCID: PMC6214721 DOI: 10.1002/dneu.22626] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 12/18/2022]
Abstract
Since the discovery of DNA, the normal developing and functioning brain has been assumed to be composed of cells with identical genomes, which remains the dominant view even today. However, this pervasive assumption is incorrect, as proven by increasing numbers of reports within the last 20 years that have identified multiple forms of somatically produced genomic mosaicism (GM), wherein brain cells-especially neurons-from a single individual show diverse alterations in DNA, distinct from the germline. Critically, these changes alter the actual DNA nucleotide sequences-in contrast to epigenetic mechanisms-and almost certainly contribute to the remarkably diverse phenotypes of single brain cells, including single-cell transcriptomic profiles. Here, we review the history of GM within the normal brain, including its major forms, initiating mechanisms, and possible functions. GM forms include aneuploidies and aneusomies, smaller copy number variations (CNVs), long interspersed nuclear element type 1 (LINE1) repeat elements, and single nucleotide variations (SNVs), as well as DNA content variation (DCV) that reflects all forms of GM with greatest coverage of large, brain cell populations. In addition, technical considerations are examined, along with relationships among GM forms and multiple brain diseases. GM affecting genes and loci within the brain contrast with current neural discovery approaches that rely on sequencing nonbrain DNA (e.g., genome-wide association studies (GWAS)). Increasing knowledge of neural GM has implications for mechanisms of development, diversity, and function, as well as understanding diseases, particularly considering the overwhelming prevalence of sporadic brain diseases that are unlinked to germline mutations. © 2018 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc. Develop Neurobiol, 2018.
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Affiliation(s)
- Suzanne Rohrback
- Biomedical Sciences Graduate Program, School of MedicineUniversity of California San DiegoLa JollaCalifornia92093
- Sanford Burnham Prebys Medical Discovery InstituteLa JollaCalifornia
- Present address:
Illumina, Inc.San DiegoCA 92122USA
| | - Benjamin Siddoway
- Sanford Burnham Prebys Medical Discovery InstituteLa JollaCalifornia
| | - Christine S. Liu
- Biomedical Sciences Graduate Program, School of MedicineUniversity of California San DiegoLa JollaCalifornia92093
- Sanford Burnham Prebys Medical Discovery InstituteLa JollaCalifornia
| | - Jerold Chun
- Sanford Burnham Prebys Medical Discovery InstituteLa JollaCalifornia
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131
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Komkov AY, Minervina AA, Nugmanov GA, Saliutina MV, Khodosevich KV, Lebedev YB, Mamedov IZ. An advanced enrichment method for rare somatic retroelement insertions sequencing. Mob DNA 2018; 9:31. [PMID: 30450130 PMCID: PMC6208084 DOI: 10.1186/s13100-018-0136-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 10/15/2018] [Indexed: 12/18/2022] Open
Abstract
Background There is increasing evidence that the transpositional activity of retroelements (REs) is not limited to germ line cells, but often occurs in tumor and normal somatic cells. Somatic transpositions were found in several human tissues and are especially typical for the brain. Several computational and experimental approaches for detection of somatic retroelement insertions was developed in the past few years. These approaches were successfully applied to detect somatic insertions in clonally expanded tumor cells. At the same time, identification of somatic insertions presented in small proportion of cells, such as neurons, remains a considerable challenge. Results In this study, we developed a normalization procedure for library enrichment by DNA sequences corresponding to rare somatic RE insertions. Two rounds of normalization increased the number of fragments adjacent to somatic REs in the sequenced sample by more than 26-fold, and the number of identified somatic REs was increased by 8-fold. Conclusions The developed technique can be used in combination with vast majority of modern RE identification approaches and can dramatically increase their capacity to detect rare somatic RE insertions in different types of cells. Electronic supplementary material The online version of this article (10.1186/s13100-018-0136-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexander Y Komkov
- 1Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Miklukho-Maklaya str. 16/10, Moscow, 117997 Russia.,Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Samory Mashela str. 1, Moscow, 117997 Russia
| | - Anastasia A Minervina
- 1Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Miklukho-Maklaya str. 16/10, Moscow, 117997 Russia
| | - Gaiaz A Nugmanov
- 1Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Miklukho-Maklaya str. 16/10, Moscow, 117997 Russia
| | - Mariia V Saliutina
- 1Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Miklukho-Maklaya str. 16/10, Moscow, 117997 Russia
| | - Konstantin V Khodosevich
- 3Biotech Research and Innovation Centre, Copenhagen University, Ole Maaløes Vej 5, Copenhagen, 2200 Denmark
| | - Yuri B Lebedev
- 1Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Miklukho-Maklaya str. 16/10, Moscow, 117997 Russia
| | - Ilgar Z Mamedov
- 1Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Miklukho-Maklaya str. 16/10, Moscow, 117997 Russia.,4Pirogov Russian National Research Medical University, Ostrovitianov str. 1, Moscow, 117997 Russia
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132
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Orqueda AJ, Gatti CR, Ogara MF, Falzone TL. SOX-11 regulates LINE-1 retrotransposon activity during neuronal differentiation. FEBS Lett 2018; 592:3708-3719. [PMID: 30276805 DOI: 10.1002/1873-3468.13260] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 09/20/2018] [Accepted: 09/22/2018] [Indexed: 01/25/2023]
Abstract
Activity of the human long interspersed nuclear elements-1 (LINE-1) retrotransposon occurs mainly in early embryonic development and during hippocampal neurogenesis. SOX-11, a transcription factor relevant to neuronal development, has unknown functions in the control of LINE-1 retrotransposon activity during neuronal differentiation. To study the dependence of LINE-1 activity on SOX-11 during neuronal differentiation, we induced differentiation of human SH-SY5Y neuroblastoma cells and adult adipose mesenchymal stem cells (hASCs) to a neuronal fate and found increased LINE-1 activity. We also show that SOX-11 protein binding to the LINE-1 promoter is higher in differentiating neuroblastoma cells, while knock-down of SOX-11 inhibits the induction of LINE-1 transcription in differentiating conditions. These results suggest that activation of LINE-1 retrotransposition during neuronal differentiation is mediated by SOX-11.
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Affiliation(s)
- Andrés J Orqueda
- Instituto de Medicina Traslacional e Ingeniería Biomédica (IMTIB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Hospital Italiano de Buenos Aires e Instituto Universitario del Hospital Italiano, Buenos Aires, Argentina
| | - Cintia R Gatti
- Instituto de Medicina Traslacional e Ingeniería Biomédica (IMTIB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Hospital Italiano de Buenos Aires e Instituto Universitario del Hospital Italiano, Buenos Aires, Argentina
| | - María F Ogara
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), FCEN, UBA, Buenos Aires, Argentina
| | - Tomás L Falzone
- Instituto de Biología Celular y Neurociencias (IBCN-CONICET-UBA), Facultad de Medicina, UBA, Buenos Aires, Argentina.,Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
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133
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Somatic mosaicism and neurodevelopmental disease. Nat Neurosci 2018; 21:1504-1514. [PMID: 30349109 DOI: 10.1038/s41593-018-0257-3] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 09/21/2018] [Indexed: 12/19/2022]
Abstract
Traditionally, we have considered genetic mutations that cause neurodevelopmental diseases to be inherited or de novo germline mutations. Recently, we have come to appreciate the importance of de novo somatic mutations, which occur postzygotically and are thus present in only a subset of the cells of an affected individual. The advent of next-generation sequencing and single-cell sequencing technologies has shown that somatic mutations contribute to normal and abnormal human brain development. Somatic mutations are one important cause of neuronal migration and brain overgrowth disorders, as suggested by visible focal lesions. In addition, somatic mutations contribute to neurodevelopmental diseases without visible lesions, including epileptic encephalopathies, intellectual disability, and autism spectrum disorder, and may contribute to a broad range of neuropsychiatric diseases. Studying somatic mutations provides insight into the mechanisms underlying human brain development and neurodevelopmental diseases and has important implications for diagnosis and treatment.
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134
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Abstract
DNA mutations as a consequence of errors during DNA damage repair, replication, or mitosis are the substrate for evolution. In multicellular organisms, mutations can occur in the germline and also in somatic tissues, where they are associated with cancer and other chronic diseases and possibly with aging. Recent advances in high-throughput sequencing have made it relatively easy to study germline de novo mutations, but in somatic cells, the vast majority of mutations are low-abundant and can be detected only in clonal lineages, such as tumors, or single cells. Here we review recent results on somatic mutations in normal human and animal tissues with a focus on their possible functional consequences.
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Affiliation(s)
- Lei Zhang
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA;
| | - Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA;
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135
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Benitez-Guijarro M, Lopez-Ruiz C, Tarnauskaitė Ž, Murina O, Mian Mohammad M, Williams TC, Fluteau A, Sanchez L, Vilar-Astasio R, Garcia-Canadas M, Cano D, Kempen MJH, Sanchez-Pozo A, Heras SR, Jackson AP, Reijns MA, Garcia-Perez JL. RNase H2, mutated in Aicardi-Goutières syndrome, promotes LINE-1 retrotransposition. EMBO J 2018; 37:e98506. [PMID: 29959219 PMCID: PMC6068448 DOI: 10.15252/embj.201798506] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 05/23/2018] [Accepted: 05/28/2018] [Indexed: 12/03/2022] Open
Abstract
Long INterspersed Element class 1 (LINE-1) elements are a type of abundant retrotransposons active in mammalian genomes. An average human genome contains ~100 retrotransposition-competent LINE-1s, whose activity is influenced by the combined action of cellular repressors and activators. TREX1, SAMHD1 and ADAR1 are known LINE-1 repressors and when mutated cause the autoinflammatory disorder Aicardi-Goutières syndrome (AGS). Mutations in RNase H2 are the most common cause of AGS, and its activity was proposed to similarly control LINE-1 retrotransposition. It has therefore been suggested that increased LINE-1 activity may be the cause of aberrant innate immune activation in AGS Here, we establish that, contrary to expectations, RNase H2 is required for efficient LINE-1 retrotransposition. As RNase H1 overexpression partially rescues the defect in RNase H2 null cells, we propose a model in which RNase H2 degrades the LINE-1 RNA after reverse transcription, allowing retrotransposition to be completed. This also explains how LINE-1 elements can retrotranspose efficiently without their own RNase H activity. Our findings appear to be at odds with LINE-1-derived nucleic acids driving autoinflammation in AGS.
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Affiliation(s)
- Maria Benitez-Guijarro
- GENYO, Centro de Genómica e Investigación Oncológica: Pfizer - Universidad de Granada - Junta de Andalucía, PTS, Granada, Spain
| | - Cesar Lopez-Ruiz
- GENYO, Centro de Genómica e Investigación Oncológica: Pfizer - Universidad de Granada - Junta de Andalucía, PTS, Granada, Spain
| | - Žygimantė Tarnauskaitė
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - Olga Murina
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - Mahwish Mian Mohammad
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - Thomas C Williams
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - Adeline Fluteau
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - Laura Sanchez
- GENYO, Centro de Genómica e Investigación Oncológica: Pfizer - Universidad de Granada - Junta de Andalucía, PTS, Granada, Spain
| | - Raquel Vilar-Astasio
- GENYO, Centro de Genómica e Investigación Oncológica: Pfizer - Universidad de Granada - Junta de Andalucía, PTS, Granada, Spain
| | - Marta Garcia-Canadas
- GENYO, Centro de Genómica e Investigación Oncológica: Pfizer - Universidad de Granada - Junta de Andalucía, PTS, Granada, Spain
| | - David Cano
- GENYO, Centro de Genómica e Investigación Oncológica: Pfizer - Universidad de Granada - Junta de Andalucía, PTS, Granada, Spain
| | - Marie-Jeanne Hc Kempen
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - Antonio Sanchez-Pozo
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Sara R Heras
- GENYO, Centro de Genómica e Investigación Oncológica: Pfizer - Universidad de Granada - Junta de Andalucía, PTS, Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Andrew P Jackson
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - Martin Am Reijns
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - Jose L Garcia-Perez
- GENYO, Centro de Genómica e Investigación Oncológica: Pfizer - Universidad de Granada - Junta de Andalucía, PTS, Granada, Spain
- MRC Human Genetics Unit, MRC, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
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136
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Enigma of Retrotransposon Biology in Mammalian Early Embryos and Embryonic Stem Cells. Stem Cells Int 2018; 2018:6239245. [PMID: 30123290 PMCID: PMC6079326 DOI: 10.1155/2018/6239245] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/05/2018] [Accepted: 07/03/2018] [Indexed: 12/22/2022] Open
Abstract
Retrotransposons comprise a significant fraction of mammalian genome with unclear functions. Increasing evidence shows that they are not just remnants of ancient retroviruses but play important roles in multiple biological processes. Retrotransposons are epigenetically silenced in most somatic tissues and become reactivated in early embryos. Notably, abundant retrotransposon expression in mouse embryonic stem cells (ESCs) marks transient totipotency status, while retrotransposon enrichment in human ESCs indicates naive-like status. Some retrotransposon elements retained the capacity to retrotranspose, such as LINE1, producing genetic diversity or disease. Some other retrotransposons reside in the vicinity of endogenous genes and are capable of regulating nearby genes and cell fate, possibly through providing alternative promoters, regulatory modules, or orchestrating high-order chromatin assembly. In addition, retrotransposons may mediate epigenetic memory, regulate gene expression posttranscriptionally, defend virus infection, and so on. In this review, we summarize expression patterns and regulatory functions of different retrotransposons in early embryos and ESCs, as well as document molecular mechanisms controlling retrotransposon expression and their potential functions. Further investigations on the regulatory network of retrotransposons in early embryogenesis and ESCs will provide valuable insights and a deeper understanding of retrotransposon biology. Additionally, endeavors made to unveil the roles of these mysterious elements may facilitate stem cell status conversion and manipulation of pluripotency.
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137
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Faulkner GJ, Billon V. L1 retrotransposition in the soma: a field jumping ahead. Mob DNA 2018; 9:22. [PMID: 30002735 PMCID: PMC6035798 DOI: 10.1186/s13100-018-0128-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/27/2018] [Indexed: 12/13/2022] Open
Abstract
Retrotransposons are transposable elements (TEs) capable of "jumping" in germ, embryonic and tumor cells and, as is now clearly established, in the neuronal lineage. Mosaic TE insertions form part of a broader landscape of somatic genome variation and hold significant potential to generate phenotypic diversity, in the brain and elsewhere. At present, the LINE-1 (L1) retrotransposon family appears to be the most active autonomous TE in most mammals, based on experimental data obtained from disease-causing L1 mutations, engineered L1 reporter systems tested in cultured cells and transgenic rodents, and single-cell genomic analyses. However, the biological consequences of almost all somatic L1 insertions identified thus far remain unknown. In this review, we briefly summarize the current state-of-the-art in the field, including estimates of L1 retrotransposition rate in neurons. We bring forward the hypothesis that an extensive subset of retrotransposition-competent L1s may be de-repressed and mobile in the soma but largely inactive in the germline. We discuss recent reports of non-canonical L1-associated sequence variants in the brain and propose that the elevated L1 DNA content reported in several neurological disorders may predominantly comprise accumulated, unintegrated L1 nucleic acids, rather than somatic L1 insertions. Finally, we consider the main objectives and obstacles going forward in elucidating the biological impact of somatic retrotransposition.
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Affiliation(s)
- Geoffrey J. Faulkner
- Mater Research Institute – University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072 Australia
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072 Australia
| | - Victor Billon
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072 Australia
- Biology Department, École Normale Supérieure Paris-Saclay, 61 Avenue du Président Wilson, 94230 Cachan, France
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138
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Mustafin RN, Khusnutdinova EK. INTERRELATION OF PRIONS WITH NON-CODING RNAS. Vavilovskii Zhurnal Genet Selektsii 2018. [DOI: 10.18699/vj18.377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prions are alternative infectious conformations for some cellular proteins. For the protein PrPC(PrP – prion protein, С – common), a prion conformation, called PrPSc(S – scrapie), is pathological. For example, in mammals the PrPScprion causes transmissible spongiform encephalopathies accumulating in the brain tissues of PrPScaggregates that have amyloid properties. MicroRNAs and long non-coding RNAs can be translated into functional peptides. These peptides can have a regulatory effect on genes from which their non-coding RNAs are transcribed. It has been assumed that prions, like peptides, due to the presence of specific domains, can also activate certain non-coding RNAs. Some of the activated non-coding RNAs can catalyze the formation of new prions from normal protein, playing their role in the pathogenesis of prion diseases. Confirmation of this assumption is the presence of the association of alleles of microRNA with the development of the disease, which indicates the role of the specific sequences of noncoding RNAs in the catalysis of prion formation. In the brain tissues of patients with prion diseases, as well as in exosomes containing an abnormal PrPScisoform, changes in the levels of microRNA have been observed. A possible cause is the interaction of the spatial domains of PrPScwith the sequences of the non-coding RNA genes, which causes a change in their expression. MicroRNAs, in turn, affect the synthesis of long non-coding RNAs. We hypothesize that long noncoding RNAs and possibly microRNAs can interact with PrPCcatalyzing its transformation into PrPSc. As a result, the number of PrPScincreases exponentially. In the brain of animals and humans, transposon activity has been observed, which has a regulatory effect on the differentiation of neuronal stem cells. Transposons form the basis of domain structures of long non-coding RNAs. In addition, they are important sources of microRNA. Since prion diseases can arise as sporadic and hereditary cases, and hereditary predisposition is important for the development of pathology, we hypothesize the role of individual features of activation of transposons in the pathogenesis of prion diseases. The activation of transposons in the brain at certain stages of development, as well as under the influence of stress, is reflected in the peculiarities of expression of specific non-coding RNAs that are capable of catalyzing the transition of the PrPCprotein to PrPSc. Research in this direction can be the basis for targeted anti-microRNA therapy of prion diseases.
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139
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Mustafin RN, Khusnutdinova EK. Epigenetic Hypothesis of the Role of Peptides in Aging. ADVANCES IN GERONTOLOGY 2018. [DOI: 10.1134/s2079057018030128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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140
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Trizzino M, Kapusta A, Brown CD. Transposable elements generate regulatory novelty in a tissue-specific fashion. BMC Genomics 2018; 19:468. [PMID: 29914366 PMCID: PMC6006921 DOI: 10.1186/s12864-018-4850-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/01/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Transposable elements (TE) are an important source of evolutionary novelty in gene regulation. However, the mechanisms by which TEs contribute to gene expression are largely uncharacterized. RESULTS Here, we leverage Roadmap and GTEx data to investigate the association of TEs with active and repressed chromatin in 24 tissues. We find 112 human TE families enriched in active regions of the genome across tissues. Short Interspersed Nuclear Elements (SINEs) and DNA transposons are the most frequently enriched classes, while Long Terminal Repeat Retrotransposons (LTRs) are often enriched in a tissue-specific manner. We report across-tissue variability in TE enrichment in active regions. Genes with consistent expression across tissues are less likely to be associated with TE insertions. TE presence in repressed regions similarly follows tissue-specific patterns. Moreover, different TE classes correlate with different repressive marks: LTRs and Long Interspersed Nuclear Elements (LINEs) are overrepresented in regions marked by H3K9me3, while the other TEs are more likely to overlap regions with H3K27me3. Young TEs are typically enriched in repressed regions and depleted in active regions. We detect multiple instances of TEs that are enriched in tissue-specific active regulatory regions. Such TEs contain binding sites for transcription factors that are master regulators for the given tissue. These TEs are enriched in intronic enhancers, and their tissue-specific enrichment correlates with tissue-specific variations in the expression of the nearest genes. CONCLUSIONS We provide an integrated overview of the contribution of TEs to human gene regulation. Expanding previous analyses, we demonstrate that TEs can potentially contribute to the turnover of regulatory sequences in a tissue-specific fashion.
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Affiliation(s)
- Marco Trizzino
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA, USA. .,Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
| | - Aurélie Kapusta
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA.,USTAR, Center for Genetic Discovery, Salt Lake City, UT, USA
| | - Christopher D Brown
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA. .,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, PA, USA.
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141
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Guo C, Jeong HH, Hsieh YC, Klein HU, Bennett DA, De Jager PL, Liu Z, Shulman JM. Tau Activates Transposable Elements in Alzheimer's Disease. Cell Rep 2018; 23:2874-2880. [PMID: 29874575 PMCID: PMC6181645 DOI: 10.1016/j.celrep.2018.05.004] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 03/19/2018] [Accepted: 05/01/2018] [Indexed: 02/06/2023] Open
Abstract
Aging and neurodegenerative disease are characterized by genomic instability in neurons, including aberrant activation and mobilization of transposable elements (TEs). Integrating studies of human postmortem brain tissue and Drosophila melanogaster models, we investigate TE activation in association with Tau pathology in Alzheimer's disease (AD). Leveraging RNA sequencing from 636 human brains, we discover differential expression for several retrotransposons in association with neurofibrillary tangle burden and highlight evidence for global TE transcriptional activation among the long interspersed nuclear element 1 and endogenous retrovirus clades. In addition, we detect Tau-associated, active chromatin signatures at multiple HERV-Fc1 genomic loci. To determine whether Tau is sufficient to induce TE activation, we profile retrotransposons in Drosophila expressing human wild-type or mutant Tau throughout the brain. We discover heterogeneous response profiles, including both age- and genotype-dependent activation of TE expression by Tau. Our results implicate TE activation and associated genomic instability in Tau-mediated AD mechanisms.
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Affiliation(s)
- Caiwei Guo
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Hyun-Hwan Jeong
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yi-Chen Hsieh
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hans-Ulrich Klein
- Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA; Cell Circuits Program, Broad Institute, Cambridge, MA 02142, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Philip L De Jager
- Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA; Cell Circuits Program, Broad Institute, Cambridge, MA 02142, USA
| | - Zhandong Liu
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joshua M Shulman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA.
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142
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Ma J, Shen Z, Yu YC, Shi SH. Neural lineage tracing in the mammalian brain. Curr Opin Neurobiol 2018; 50:7-16. [PMID: 29125960 PMCID: PMC5938148 DOI: 10.1016/j.conb.2017.10.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 10/08/2017] [Accepted: 10/17/2017] [Indexed: 01/05/2023]
Abstract
Delineating the lineage of neural cells that captures the progressive steps in their specification is fundamental to understanding brain development, organization, and function. Since the earliest days of embryology, lineage questions have been addressed with methods of increasing specificity, capacity, and resolution. Yet, a full realization of individual cell lineages remains challenging for complex systems. A recent explosion of technical advances in genome-editing and single-cell sequencing has enabled lineage analysis in an unprecedented scale, speed, and depth across different species. In this review, we discuss the application of available as well as future genetic labeling techniques for tracking neural lineages in vivo in the mammalian nervous system.
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Affiliation(s)
- Jian Ma
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhongfu Shen
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yong-Chun Yu
- Institute of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Song-Hai Shi
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, U.S.A
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143
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Verheijen BM, Vermulst M, van Leeuwen FW. Somatic mutations in neurons during aging and neurodegeneration. Acta Neuropathol 2018; 135:811-826. [PMID: 29705908 PMCID: PMC5954077 DOI: 10.1007/s00401-018-1850-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 12/22/2022]
Abstract
The nervous system is composed of a large variety of neurons with a diverse array of morphological and functional properties. This heterogeneity is essential for the construction and maintenance of a distinct set of neural networks with unique characteristics. Accumulating evidence now indicates that neurons do not only differ at a functional level, but also at the genomic level. These genomic discrepancies seem to be the result of somatic mutations that emerge in nervous tissue during development and aging. Ultimately, these mutations bring about a genetically heterogeneous population of neurons, a phenomenon that is commonly referred to as "somatic brain mosaicism". Improved understanding of the development and consequences of somatic brain mosaicism is crucial to understand the impact of somatic mutations on neuronal function in human aging and disease. Here, we highlight a number of topics related to somatic brain mosaicism, including some early experimental evidence for somatic mutations in post-mitotic neurons of the hypothalamo-neurohypophyseal system. We propose that age-related somatic mutations are particularly interesting, because aging is a major risk factor for a variety of neuronal diseases, including Alzheimer's disease. We highlight potential links between somatic mutations and the development of these diseases and argue that recent advances in single-cell genomics and in vivo physiology have now finally made it possible to dissect the origins and consequences of neuronal mutations in unprecedented detail.
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Affiliation(s)
- Bert M Verheijen
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG, Utrecht, The Netherlands.
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3508 GA, Utrecht, The Netherlands.
| | - Marc Vermulst
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Fred W van Leeuwen
- Department of Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER, Maastricht, The Netherlands
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144
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Richardson SR, Faulkner GJ. Heritable L1 Retrotransposition Events During Development: Understanding Their Origins: Examination of heritable, endogenous L1 retrotransposition in mice opens up exciting new questions and research directions. Bioessays 2018; 40:e1700189. [PMID: 29709066 PMCID: PMC6681178 DOI: 10.1002/bies.201700189] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 03/04/2018] [Indexed: 01/08/2023]
Abstract
The retrotransposon Long Interspersed Element 1 (LINE-1 or L1) has played a major role in shaping the sequence composition of the mammalian genome. In our recent publication, "Heritable L1 retrotransposition in the mouse primordial germline and early embryo," we systematically assessed the rate and developmental timing of de novo, heritable endogenous L1 insertions in mice. Such heritable retrotransposition events allow L1 to exert an ongoing influence upon genome evolution. Here, we place our findings in the context of earlier studies, and highlight how our results corroborate, and depart from, previous research based on human patient samples and transgenic mouse models harboring engineered L1 reporter genes. In parallel, we outline outstanding questions regarding the stage-specificity, regulation, and functional impact of embryonic and germline L1 retrotransposition, and propose avenues for future research in this field.
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Affiliation(s)
- Sandra R. Richardson
- Mater Research Institute–University of QueenslandWoolloongabbaQueensland 4102Australia
| | - Geoffrey J. Faulkner
- Mater Research Institute–University of QueenslandWoolloongabbaQueensland 4102Australia
- Queensland Brain InstituteUniversity of QueenslandBrisbaneQueensland 4072Australia
- School of Biomedical SciencesUniversity of QueenslandBrisbaneQueensland 4072Australia
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145
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Krestel H, Meier JC. RNA Editing and Retrotransposons in Neurology. Front Mol Neurosci 2018; 11:163. [PMID: 29875629 PMCID: PMC5974252 DOI: 10.3389/fnmol.2018.00163] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/30/2018] [Indexed: 12/28/2022] Open
Abstract
Compared to sites in protein-coding sequences many more targets undergoing adenosine to inosine (A-to-I) RNA editing were discovered in non-coding regions of human cerebral transcripts, particularly in genetic transposable elements called retrotransposons. We review here the interaction mechanisms of RNA editing and retrotransposons and their impact on normal function and human neurological diseases. Exemplarily, A-to-I editing of retrotransposons embedded in protein-coding mRNAs can contribute to protein abundance and function via circular RNA formation, alternative splicing, and exonization or silencing of retrotransposons. Interactions leading to disease are not very well understood. We describe human diseases with involvement of the central nervous system including inborn errors of metabolism, neurodevelopmental disorders, neuroinflammatory and neurodegenerative and paroxysmal diseases, in which retrotransposons (Alu and/or L1 elements) appear to be causally involved in genetic rearrangements. Sole binding of single-stranded retrotransposon transcripts by RNA editing enzymes rather than enzymatic deamination may have a homeostatic effect on retrotransposon turnover. We also review evidence in support of the emerging pathophysiological function of A-to-I editing of retrotransposons in inflammation and its implication for different neurological diseases including amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's and Parkinson's disease, and epilepsy.
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Affiliation(s)
- Heinz Krestel
- Department of Neurology, Bern University Hospital and University of Bern, Bern, Switzerland.,Department for BioMedical Research, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Jochen C Meier
- Division Cell Physiology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
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146
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Giorgi G, Virgili M, Monti B, Del Re B. Long INterspersed nuclear Elements (LINEs) in brain and non-brain tissues of the rat. Cell Tissue Res 2018; 374:17-24. [PMID: 29725769 DOI: 10.1007/s00441-018-2843-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 04/11/2018] [Indexed: 10/17/2022]
Abstract
Long INterspersed Element-1 (L1) is a transposable element that can insert copies of itself in new genomic locations causing genomic instability. In somatic cells, L1 retrotransposition activity is usually repressed but somatic L1 retrotransposition has recently been observed during neuronal differentiation. In this study, we evaluate whether L1 elements are differentially active in rat tissues during postnatal development. To this purpose, we quantified L1 in genomic DNA extracted from the olfactory bulb (OB), cerebellum (CE), cortex (CO) and heart (H). Each analysis was repeated on rats aged 7, 21 and 60 days. We found that L1 content in OB and CE tissue was significantly higher than H tissue, in rats of all three ages studied, suggesting that L1 activity could be modulated in postnatal development and neurogenesis.
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Affiliation(s)
- Gianfranco Giorgi
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Marco Virgili
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Barbara Monti
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Brunella Del Re
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy.
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147
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Schauer SN, Carreira PE, Shukla R, Gerhardt DJ, Gerdes P, Sanchez-Luque FJ, Nicoli P, Kindlova M, Ghisletti S, Santos AD, Rapoud D, Samuel D, Faivre J, Ewing AD, Richardson SR, Faulkner GJ. L1 retrotransposition is a common feature of mammalian hepatocarcinogenesis. Genome Res 2018; 28:639-653. [PMID: 29643204 PMCID: PMC5932605 DOI: 10.1101/gr.226993.117] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 03/26/2018] [Indexed: 12/15/2022]
Abstract
The retrotransposon Long Interspersed Element 1 (LINE-1 or L1) is a continuing source of germline and somatic mutagenesis in mammals. Deregulated L1 activity is a hallmark of cancer, and L1 mutagenesis has been described in numerous human malignancies. We previously employed retrotransposon capture sequencing (RC-seq) to analyze hepatocellular carcinoma (HCC) samples from patients infected with hepatitis B or hepatitis C virus and identified L1 variants responsible for activating oncogenic pathways. Here, we have applied RC-seq and whole-genome sequencing (WGS) to an Abcb4 (Mdr2)-/- mouse model of hepatic carcinogenesis and demonstrated for the first time that L1 mobilization occurs in murine tumors. In 12 HCC nodules obtained from 10 animals, we validated four somatic L1 insertions by PCR and capillary sequencing, including TF subfamily elements, and one GF subfamily example. One of the TF insertions carried a 3' transduction, allowing us to identify its donor L1 and to demonstrate that this full-length TF element retained retrotransposition capacity in cultured cancer cells. Using RC-seq, we also identified eight tumor-specific L1 insertions from 25 HCC patients with a history of alcohol abuse. Finally, we used RC-seq and WGS to identify three tumor-specific L1 insertions among 10 intra-hepatic cholangiocarcinoma (ICC) patients, including one insertion traced to a donor L1 on Chromosome 22 known to be highly active in other cancers. This study reveals L1 mobilization as a common feature of hepatocarcinogenesis in mammals, demonstrating that the phenomenon is not restricted to human viral HCC etiologies and is encountered in murine liver tumors.
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Affiliation(s)
- Stephanie N Schauer
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Patricia E Carreira
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Ruchi Shukla
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Daniel J Gerhardt
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
- Invenra, Incorporated, Madison, Wisconsin 53719, USA
| | - Patricia Gerdes
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Francisco J Sanchez-Luque
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
- Department of Genomic Medicine, GENYO, Centre for Genomics and Oncological Research: Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Paola Nicoli
- Department of Experimental Oncology, European Institute of Oncology, 20146 Milan, Italy
| | - Michaela Kindlova
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
| | | | - Alexandre Dos Santos
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif 94800, France
- Université Paris-Sud, Faculté de Médecine, Villejuif 94800, France
| | - Delphine Rapoud
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif 94800, France
- Université Paris-Sud, Faculté de Médecine, Villejuif 94800, France
| | - Didier Samuel
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif 94800, France
- Université Paris-Sud, Faculté de Médecine, Villejuif 94800, France
| | - Jamila Faivre
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif 94800, France
- Université Paris-Sud, Faculté de Médecine, Villejuif 94800, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Pôle de Biologie Médicale, Paul-Brousse University Hospital, Villejuif 94800, France
| | - Adam D Ewing
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Sandra R Richardson
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute-University of Queensland, Woolloongabba, QLD 4102, Australia
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia
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148
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Mustafin RN, Khusnutdinova EK. The Role of Transposable Elements in Emergence of Metazoa. BIOCHEMISTRY (MOSCOW) 2018; 83:185-199. [PMID: 29625540 DOI: 10.1134/s000629791803001x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Systems initially emerged for protecting genomes against insertions of transposable elements and represented by mechanisms of splicing regulation, RNA-interference, and epigenetic factors have played a key role in the evolution of animals. Many studies have shown inherited transpositions of mobile elements in embryogenesis and preservation of their activities in certain tissues of adult organisms. It was supposed that on the emergence of Metazoa the self-regulation mechanisms of transposons related with the gene networks controlling their activity could be involved in intercellular cell coordination in the cascade of successive divisions with differentiated gene expression for generation of tissues and organs. It was supposed that during evolution species-specific features of transposons in the genomes of eukaryotes could form the basis for creation of dynamically related complexes of systems for epigenetic regulation of gene expression. These complexes could be produced due to the influence of noncoding transposon-derived RNAs on DNA methylation, histone modifications, and processing of alternative splicing variants, whereas the mobile elements themselves could be directly involved in the regulation of gene expression in cis and in trans. Transposons are widely distributed in the genomes of eukaryotes; therefore, their activation can change the expression of specific genes. In turn, this can play an important role in cell differentiation during ontogenesis. It is supposed that transposons can form a species-specific pattern for control of gene expression, and that some variants of this pattern can be favorable for adaptation. The presented data indicate the possible influence of transposons in karyotype formation. It is supposed that transposon localization relative to one another and to protein-coding genes can influence the species-specific epigenetic regulation of ontogenesis.
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Dubnau J. The Retrotransposon storm and the dangers of a Collyer's genome. Curr Opin Genet Dev 2018; 49:95-105. [PMID: 29705598 PMCID: PMC5975205 DOI: 10.1016/j.gde.2018.04.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 03/08/2018] [Accepted: 04/11/2018] [Indexed: 12/13/2022]
Abstract
Like the famous Collyer's mansion in NY, our genomes have accumulated vast quantities of sequences that have been referred to as 'junk DNA,' much of which consists of retrotransposons (RTEs). A recent literature establishes the phenomenology that many RTEs become expressed at progressively higher levels during the course of normal aging. This seems to reflect gradual loss of heterochromatin in old age. In addition, RTEs appear to be precociously expressed in brains of younger animals that are experiencing neurodegenerative decline. Although it is difficult to distinguish cause from consequence, several recent studies support the contention that RTE expression, and even perhaps transposition, causally contribute to both the normal deterioration seen with age and to the precipitous decline in some neurodegenerative disorders. This may reflect a two hit model in which normal age-dependent loss of heterochromatin synergizes with a disruption to posttranscriptional silencing of RTEs caused by genetic and environmental stress.
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Affiliation(s)
- Josh Dubnau
- Department of Anesthesiology, State University of New York at Stony Brook, Stony Brook, NY 11794-8480, United States; Department of Neurobiology & Behavior, Stony Brook University & Stony Brook School of Medicine, Stony Brook, NY 11794-8480, United States.
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150
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Nishioka M, Bundo M, Ueda J, Katsuoka F, Sato Y, Kuroki Y, Ishii T, Ukai W, Murayama S, Hashimoto E, Nagasaki M, Yasuda J, Kasai K, Kato T, Iwamoto K. Identification of somatic mutations in postmortem human brains by whole genome sequencing and their implications for psychiatric disorders. Psychiatry Clin Neurosci 2018; 72:280-294. [PMID: 29283202 DOI: 10.1111/pcn.12632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/07/2017] [Accepted: 12/21/2017] [Indexed: 12/20/2022]
Abstract
AIM Somatic mutations in the human brain are hypothesized to contribute to the functional diversity of brain cells as well as the pathophysiology of neuropsychiatric diseases. However, there are still few reports on somatic mutations in non-neoplastic human brain tissues. This study attempted to unveil the landscape of somatic mutations in the human brain. METHODS We explored the landscape of somatic mutations in human brain tissues derived from three individuals with no neuropsychiatric diseases by whole-genome deep sequencing at a depth of around 100. The candidate mutations underwent multi-layered filtering, and were validated by ultra-deep target amplicon sequencing at a depth of around 200 000. RESULTS Thirty-one somatic mutations were identified in the human brain, demonstrating the utility of whole-genome sequencing of bulk brain tissue. The mutations were enriched in neuron-expressed genes, and two-thirds of the identified somatic single nucleotide variants in the brain tissues were cytosine-to-thymine transitions, half of which were in CpG dinucleotides. CONCLUSION Our developed filtering and validation approaches will be useful to identify somatic mutations in the human brain. The vulnerability of neuron-expressed genes to mutational events suggests their potential relevance to neuropsychiatric diseases.
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Affiliation(s)
- Masaki Nishioka
- Department of Molecular Psychiatry, The University of Tokyo, Tokyo, Japan.,Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Division for Counseling and Support, The University of Tokyo, Tokyo, Japan
| | - Miki Bundo
- Department of Molecular Psychiatry, The University of Tokyo, Tokyo, Japan.,PRESTO, Japan Science and Technology Agency, Saitama, Japan.,Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Junko Ueda
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Saitama, Japan
| | - Fumiki Katsuoka
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Yukuto Sato
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Yoko Kuroki
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan.,Department of Genome Medicine, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Takao Ishii
- Department of Neuropsychiatry, School of Medicine, Sapporo Medical University, Sapporo, Japan
| | - Wataru Ukai
- Department of Neuropsychiatry, School of Medicine, Sapporo Medical University, Sapporo, Japan
| | - Shigeo Murayama
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Eri Hashimoto
- Department of Neuropsychiatry, School of Medicine, Sapporo Medical University, Sapporo, Japan
| | - Masao Nagasaki
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Jun Yasuda
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Kiyoto Kasai
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Saitama, Japan
| | - Kazuya Iwamoto
- Department of Molecular Psychiatry, The University of Tokyo, Tokyo, Japan.,Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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