1
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Betancourt AJ, Wei KHC, Huang Y, Lee YCG. Causes and Consequences of Varying Transposable Element Activity: An Evolutionary Perspective. Annu Rev Genomics Hum Genet 2024; 25:1-25. [PMID: 38603565 DOI: 10.1146/annurev-genom-120822-105708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Transposable elements (TEs) are genomic parasites found in nearly all eukaryotes, including humans. This evolutionary success of TEs is due to their replicative activity, involving insertion into new genomic locations. TE activity varies at multiple levels, from between taxa to within individuals. The rapidly accumulating evidence of the influence of TE activity on human health, as well as the rapid growth of new tools to study it, motivated an evaluation of what we know about TE activity thus far. Here, we discuss why TE activity varies, and the consequences of this variation, from an evolutionary perspective. By studying TE activity in nonhuman organisms in the context of evolutionary theories, we can shed light on the factors that affect TE activity. While the consequences of TE activity are usually deleterious, some have lasting evolutionary impacts by conferring benefits on the host or affecting other evolutionary processes.
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Affiliation(s)
- Andrea J Betancourt
- Institute of Infection, Veterinary, and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Kevin H-C Wei
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yuheng Huang
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
| | - Yuh Chwen G Lee
- Center for Complex Biological Systems, University of California, Irvine, California, USA;
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
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2
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Cinar M, Martinez-Medina L, Puvvula P, Arakelyan A, Vardarajan B, Anthony N, Nagaraju G, Park D, Feng L, Sheff F, Mosunjac M, Saxe D, Flygare S, Alese O, Kaufman J, Lonial S, Sarmiento J, Lossos I, Vertino P, Lopez J, El-Rayes B, Bernal-Mizrachi L. Transposon DNA sequences facilitate the tissue-specific gene transfer of circulating tumor DNA between human cells. Nucleic Acids Res 2024; 52:7539-7555. [PMID: 38783375 PMCID: PMC11260451 DOI: 10.1093/nar/gkae427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 05/01/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
The exchange of genes between cells is known to play an important physiological and pathological role in many organisms. We show that circulating tumor DNA (ctDNA) facilitates cell-specific gene transfer between human cancer cells and explain part of the mechanisms behind this phenomenon. As ctDNA migrates into the nucleus, genetic information is transferred. Cell targeting and ctDNA integration require ERVL, SINE or LINE DNA sequences. Chemically manufactured AluSp and MER11C sequences replicated multiple myeloma (MM) ctDNA cell targeting and integration. Additionally, we found that ctDNA may alter the treatment response of MM and pancreatic cancer models. This study shows that retrotransposon DNA sequences promote cancer gene transfer. However, because cell-free DNA has been detected in physiological and other pathological conditions, our findings have a broader impact than just cancer. Furthermore, the discovery that transposon DNA sequences mediate tissue-specific targeting will open up a new avenue for the delivery of genes and therapies.
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Affiliation(s)
- Munevver Cinar
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | | | | | - Arsen Arakelyan
- Bioinformatics group, Institute of Molecular Biology NAS RA, Yerevan, Armenia
| | | | - Neil Anthony
- Integrated Cellular Imaging Core, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Ganji P Nagaraju
- Division of hematology and oncology, O’Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dongkyoo Park
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Lei Feng
- Kodikaz Therapeutic Solutions, Inc, New York, NY, USA
| | - Faith Sheff
- Pathology and Laboratory Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Marina Mosunjac
- Pathology and Laboratory Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Debra Saxe
- Pathology and Laboratory Medicine, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Steven Flygare
- Department of Computational Biology/ Genetics, The University of Utah, Salt Lake City, UT, USA
| | - Olatunji B Alese
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Jonathan L Kaufman
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Sagar Lonial
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Juan M Sarmiento
- Department of Surgery, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Izidore S Lossos
- Department of Medicine, Division of Hematology-Oncology and Molecular and Cellular Pharmacology, Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL, USA
| | - Paula M Vertino
- Department of Biomedical Genetics and the Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Jose A Lopez
- Bloodworks Northwest Research Institute, Division of Hematology, University of Washington School of Medicine, Seattle, WA, USA
| | - Bassel El-Rayes
- Division of hematology and oncology, O’Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Leon Bernal-Mizrachi
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
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3
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Talley MJ, Longworth MS. Retrotransposons in embryogenesis and neurodevelopment. Biochem Soc Trans 2024; 52:1159-1171. [PMID: 38716891 PMCID: PMC11346457 DOI: 10.1042/bst20230757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 06/27/2024]
Abstract
Retrotransposable elements (RTEs) are genetic elements that can replicate and insert new copies into different genomic locations. RTEs have long been identified as 'parasitic genes', as their mobilization can cause mutations, DNA damage, and inflammation. Interestingly, high levels of retrotransposon activation are observed in early embryogenesis and neurodevelopment, suggesting that RTEs may possess functional roles during these stages of development. Recent studies demonstrate that RTEs can function as transcriptional regulatory elements through mechanisms such as chromatin organization and noncoding RNAs. It is clear, however, that RTE expression and activity must be restrained at some level during development, since overactivation of RTEs during neurodevelopment is associated with several developmental disorders. Further investigation is needed to understand the importance of RTE expression and activity during neurodevelopment and the balance between RTE-regulated development and RTE-mediated pathogenesis.
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Affiliation(s)
- Mary Jo Talley
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, U.S.A
| | - Michelle S. Longworth
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, U.S.A
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44195, U.S.A
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4
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Oliveira DS, Fablet M, Larue A, Vallier A, Carareto CA, Rebollo R, Vieira C. ChimeraTE: a pipeline to detect chimeric transcripts derived from genes and transposable elements. Nucleic Acids Res 2023; 51:9764-9784. [PMID: 37615575 PMCID: PMC10570057 DOI: 10.1093/nar/gkad671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 07/25/2023] [Accepted: 08/09/2023] [Indexed: 08/25/2023] Open
Abstract
Transposable elements (TEs) produce structural variants and are considered an important source of genetic diversity. Notably, TE-gene fusion transcripts, i.e. chimeric transcripts, have been associated with adaptation in several species. However, the identification of these chimeras remains hindered due to the lack of detection tools at a transcriptome-wide scale, and to the reliance on a reference genome, even though different individuals/cells/strains have different TE insertions. Therefore, we developed ChimeraTE, a pipeline that uses paired-end RNA-seq reads to identify chimeric transcripts through two different modes. Mode 1 is the reference-guided approach that employs canonical genome alignment, and Mode 2 identifies chimeras derived from fixed or insertionally polymorphic TEs without any reference genome. We have validated both modes using RNA-seq data from four Drosophila melanogaster wild-type strains. We found ∼1.12% of all genes generating chimeric transcripts, most of them from TE-exonized sequences. Approximately ∼23% of all detected chimeras were absent from the reference genome, indicating that TEs belonging to chimeric transcripts may be recent, polymorphic insertions. ChimeraTE is the first pipeline able to automatically uncover chimeric transcripts without a reference genome, consisting of two running Modes that can be used as a tool to investigate the contribution of TEs to transcriptome plasticity.
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Affiliation(s)
- Daniel S Oliveira
- São Paulo State University (Unesp), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, SP, Brazil
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR5558, Villeurbanne, Rhone-Alpes, 69100, France
| | - Marie Fablet
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR5558, Villeurbanne, Rhone-Alpes, 69100, France
- Institut Universitaire de France (IUF), Paris, Île-de-FranceF-75231, France
| | - Anaïs Larue
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR5558, Villeurbanne, Rhone-Alpes, 69100, France
- Univ Lyon, INRAE, INSA-Lyon, BF2I, UMR 203, 69621 Villeurbanne, France
| | - Agnès Vallier
- Univ Lyon, INRAE, INSA-Lyon, BF2I, UMR 203, 69621 Villeurbanne, France
| | - Claudia M A Carareto
- São Paulo State University (Unesp), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, SP, Brazil
| | - Rita Rebollo
- Univ Lyon, INRAE, INSA-Lyon, BF2I, UMR 203, 69621 Villeurbanne, France
| | - Cristina Vieira
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR5558, Villeurbanne, Rhone-Alpes, 69100, France
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Wodrich APK, Scott AW, Giniger E. What do we mean by "aging"? Questions and perspectives revealed by studies in Drosophila. Mech Ageing Dev 2023; 213:111839. [PMID: 37354919 PMCID: PMC10330756 DOI: 10.1016/j.mad.2023.111839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 06/26/2023]
Abstract
What is the nature of aging, and how best can we study it? Here, using a series of questions that highlight differing perspectives about the nature of aging, we ask how data from Drosophila melanogaster at the organismal, tissue, cellular, and molecular levels shed light on the complex interactions among the phenotypes associated with aging. Should aging be viewed as an individual's increasing probability of mortality over time or as a progression of physiological states? Are all age-correlated changes in physiology detrimental to vigor or are some compensatory changes that maintain vigor? Why do different age-correlated functions seem to change at different rates in a single individual as it ages? Should aging be considered as a single, integrated process across the scales of biological resolution, from organismal to molecular, or must we consider each level of biological scale as a separate, distinct entity? Viewing aging from these differing perspectives yields distinct but complementary interpretations about the properties and mechanisms of aging and may offer a path through the complexities related to understanding the nature of aging.
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Affiliation(s)
- Andrew P K Wodrich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, United States; Interdisciplinary Program in Neuroscience, Georgetown University, Washington DC, United States; College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Andrew W Scott
- National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, United States.
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6
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De Donno MD, Puricella A, D'Attis S, Specchia V, Bozzetti MP. Expression of Transposable Elements in the Brain of the Drosophila melanogaster Model for Fragile X Syndrome. Genes (Basel) 2023; 14:genes14051060. [PMID: 37239420 DOI: 10.3390/genes14051060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/03/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
Fragile X syndrome is a neuro-developmental disease affecting intellectual abilities and social interactions. Drosophila melanogaster represents a consolidated model to study neuronal pathways underlying this syndrome, especially because the model recapitulates complex behavioural phenotypes. Drosophila Fragile X protein, or FMRP, is required for a normal neuronal structure and for correct synaptic differentiation in both the peripheral and central nervous systems, as well as for synaptic connectivity during development of the neuronal circuits. At the molecular level, FMRP has a crucial role in RNA homeostasis, including a role in transposon RNA regulation in the gonads of D. m. Transposons are repetitive sequences regulated at both the transcriptional and post-transcriptional levels to avoid genomic instability. De-regulation of transposons in the brain in response to chromatin relaxation has previously been related to neurodegenerative events in Drosophila models. Here, we demonstrate for the first time that FMRP is required for transposon silencing in larval and adult brains of Drosophila "loss of function" dFmr1 mutants. This study highlights that flies kept in isolation, defined as asocial conditions, experience activation of transposable elements. In all, these results suggest a role for transposons in the pathogenesis of certain neurological alterations in Fragile X as well as in abnormal social behaviors.
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Affiliation(s)
- Maria Dolores De Donno
- Department of Biological and Environmental Sciences and Technologies, DiSTeBA, University of Salento, Via Monteroni 165, 73100 Lecce, Italy
| | - Antonietta Puricella
- Department of Biological and Environmental Sciences and Technologies, DiSTeBA, University of Salento, Via Monteroni 165, 73100 Lecce, Italy
| | - Simona D'Attis
- Department of Biological and Environmental Sciences and Technologies, DiSTeBA, University of Salento, Via Monteroni 165, 73100 Lecce, Italy
| | - Valeria Specchia
- Department of Biological and Environmental Sciences and Technologies, DiSTeBA, University of Salento, Via Monteroni 165, 73100 Lecce, Italy
| | - Maria Pia Bozzetti
- Department of Biological and Environmental Sciences and Technologies, DiSTeBA, University of Salento, Via Monteroni 165, 73100 Lecce, Italy
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7
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Cao J, Yu T, Xu B, Hu Z, Zhang XO, Theurkauf W, Weng Z. Epigenetic and chromosomal features drive transposon insertion in Drosophila melanogaster. Nucleic Acids Res 2023; 51:2066-2086. [PMID: 36762470 PMCID: PMC10018349 DOI: 10.1093/nar/gkad054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/12/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
Abstract
Transposons are mobile genetic elements prevalent in the genomes of most species. The distribution of transposons within a genome reflects the actions of two opposing processes: initial insertion site selection, and selective pressure from the host. By analyzing whole-genome sequencing data from transposon-activated Drosophila melanogaster, we identified 43 316 de novo and 237 germline insertions from four long-terminal-repeat (LTR) transposons, one LINE transposon (I-element), and one DNA transposon (P-element). We found that all transposon types favored insertion into promoters de novo, but otherwise displayed distinct insertion patterns. De novo and germline P-element insertions preferred replication origins, often landing in a narrow region around transcription start sites and in regions of high chromatin accessibility. De novo LTR transposon insertions preferred regions with high H3K36me3, promoters and exons of active genes; within genes, LTR insertion frequency correlated with gene expression. De novo I-element insertion density increased with distance from the centromere. Germline I-element and LTR transposon insertions were depleted in promoters and exons, suggesting strong selective pressure to remove transposons from functional elements. Transposon movement is associated with genome evolution and disease; therefore, our results can improve our understanding of genome and disease biology.
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Affiliation(s)
| | - Tianxiong Yu
- Correspondence may also be addressed to Tianxiong Yu. Tel: +1 774 641 0409; Fax: +1 508 856 0017;
| | - Bo Xu
- The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Zhongren Hu
- The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Xiao-ou Zhang
- The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - William E Theurkauf
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Zhiping Weng
- To whom correspondence should be addressed. Tel: +1 508 856 8866; Fax: +1 508 856 0017;
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8
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van den Beek M, Rubanova N, Siudeja K. Experimental Approaches to Study Somatic Transposition in Drosophila Using Whole-Genome DNA Sequencing. Methods Mol Biol 2023; 2607:311-327. [PMID: 36449168 DOI: 10.1007/978-1-0716-2883-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The extent of transposable element (TE) mobilization in different somatic tissues and throughout diverse species is not well understood. Somatic transposition is often challenging to study as it generates de novo TE insertions that represent rare genetic variants present in heterogenous tissues. Here, we describe experimental approaches that can be applied to address TE mobility in somatic tissues with the use of short- and long-read whole-genome DNA sequencing. Focusing on the analysis of the Drosophila melanogaster intestinal and head tissues, we provide instructions on how to design, perform, and validate experiments that aim at detecting somatic transposition. In addition to providing examples of protocols, this chapter intends to deliver general experimental guidelines that may be adapted to other fly tissues or to other species.
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Affiliation(s)
- Marius van den Beek
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France
- The Pennsylvania State University, University Park, PA, USA
| | - Natalia Rubanova
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France
| | - Katarzyna Siudeja
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France.
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9
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Rigal J, Martin Anduaga A, Bitman E, Rivellese E, Kadener S, Marr MT. Artificially stimulating retrotransposon activity increases mortality and accelerates a subset of aging phenotypes in Drosophila. eLife 2022; 11:80169. [PMID: 35980024 PMCID: PMC9427105 DOI: 10.7554/elife.80169] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/17/2022] [Indexed: 11/19/2022] Open
Abstract
Transposable elements (TEs) are mobile sequences of DNA that can become transcriptionally active as an animal ages. Whether TE activity is simply a by-product of heterochromatin breakdown or can contribute toward the aging process is not known. Here, we place the TE gypsy under the control of the UAS GAL4 system to model TE activation during aging. We find that increased TE activity shortens the life span of male Drosophila melanogaster. The effect is only apparent in middle-aged animals. The increase in mortality is not seen in young animals. An intact reverse transcriptase is necessary for the decrease in life span, implicating a DNA-mediated process in the effect. The decline in life span in the active gypsy flies is accompanied by the acceleration of a subset of aging phenotypes. TE activity increases sensitivity to oxidative stress and promotes a decline in circadian rhythmicity. The overexpression of the Forkhead-box O family (FOXO) stress response transcription factor can partially rescue the detrimental effects of increased TE activity on life span. Our results provide evidence that active TEs can behave as effectors in the aging process and suggest a potential novel role for dFOXO in its promotion of longevity in D. melanogaster.
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Affiliation(s)
- Joyce Rigal
- Department of Biology, Brandeis University, Waltham, United States
| | | | - Elena Bitman
- Department of Biology, Brandeis University, Waltham, United States
| | - Emma Rivellese
- Department of Biology, Brandeis University, Waltham, United States
| | | | - Michael T Marr
- Department of Biology, Brandeis University, Waltham, United States
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10
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Lee Y, Ha U, Moon S. Ongoing endeavors to detect mobilization of transposable elements. BMB Rep 2022. [PMID: 35725016 PMCID: PMC9340088 DOI: 10.5483/bmbrep.2022.55.7.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transposable elements (TEs) are DNA sequences capable of mobilization from one location to another in the genome. Since the discovery of ‘Dissociation (Dc) locus’ by Barbara McClintock in maize (1), mounting evidence in the era of genomics indicates that a significant fraction of most eukaryotic genomes is composed of TE sequences, involving in various aspects of biological processes such as development, physiology, diseases and evolution. Although technical advances in genomics have discovered numerous functional impacts of TE across species, our understanding of TEs is still ongoing process due to challenges resulted from complexity and abundance of TEs in the genome. In this mini-review, we briefly summarize biology of TEs and their impacts on the host genome, emphasizing importance of understanding TE landscape in the genome. Then, we introduce recent endeavors especially in vivo retrotransposition assays and long read sequencing technology for identifying de novo insertions/TE polymorphism, which will broaden our knowledge of extraordinary relationship between genomic cohabitants and their host.
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Affiliation(s)
- Yujeong Lee
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
| | - Una Ha
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
| | - Sungjin Moon
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
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11
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Billon V, Sanchez-Luque FJ, Rasmussen J, Bodea GO, Gerhardt DJ, Gerdes P, Cheetham SW, Schauer SN, Ajjikuttira P, Meyer TJ, Layman CE, Nevonen KA, Jansz N, Garcia-Perez JL, Richardson SR, Ewing AD, Carbone L, Faulkner GJ. Somatic retrotransposition in the developing rhesus macaque brain. Genome Res 2022; 32:1298-1314. [PMID: 35728967 PMCID: PMC9341517 DOI: 10.1101/gr.276451.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/14/2022] [Indexed: 12/03/2022]
Abstract
The retrotransposon LINE-1 (L1) is central to the recent evolutionary history of the human genome and continues to drive genetic diversity and germline pathogenesis. However, the spatiotemporal extent and biological significance of somatic L1 activity are poorly defined and are virtually unexplored in other primates. From a single L1 lineage active at the divergence of apes and Old World monkeys, successive L1 subfamilies have emerged in each descendant primate germline. As revealed by case studies, the presently active human L1 subfamily can also mobilize during embryonic and brain development in vivo. It is unknown whether nonhuman primate L1s can similarly generate somatic insertions in the brain. Here we applied approximately 40× single-cell whole-genome sequencing (scWGS), as well as retrotransposon capture sequencing (RC-seq), to 20 hippocampal neurons from two rhesus macaques (Macaca mulatta). In one animal, we detected and PCR-validated a somatic L1 insertion that generated target site duplications, carried a short 5' transduction, and was present in ∼7% of hippocampal neurons but absent from cerebellum and nonbrain tissues. The corresponding donor L1 allele was exceptionally mobile in vitro and was embedded in PRDM4, a gene expressed throughout development and in neural stem cells. Nanopore long-read methylome and RNA-seq transcriptome analyses indicated young retrotransposon subfamily activation in the early embryo, followed by repression in adult tissues. These data highlight endogenous macaque L1 retrotransposition potential, provide prototypical evidence of L1-mediated somatic mosaicism in a nonhuman primate, and allude to L1 mobility in the brain over the past 30 million years of human evolution.
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Affiliation(s)
- Victor Billon
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
- Biology Department, École Normale Supérieure Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Francisco J Sanchez-Luque
- GENYO. Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research, PTS Granada 18016, Spain
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
- Institute of Parasitology and Biomedicine "Lopez-Neyra"-Spanish National Research Council, PTS Granada 18016, Spain
| | - Jay Rasmussen
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
| | - Gabriela O Bodea
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Daniel J Gerhardt
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Patricia Gerdes
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Seth W Cheetham
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Stephanie N Schauer
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Prabha Ajjikuttira
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
| | - Thomas J Meyer
- Division of Genetics, Oregon National Primate Research Center, Beaverton, Oregon 97006, USA
| | - Cora E Layman
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Kimberly A Nevonen
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Natasha Jansz
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Jose L Garcia-Perez
- GENYO. Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research, PTS Granada 18016, Spain
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
| | - Sandra R Richardson
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Adam D Ewing
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Lucia Carbone
- Division of Genetics, Oregon National Primate Research Center, Beaverton, Oregon 97006, USA
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Geoffrey J Faulkner
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland 4067, Australia
- Mater Research Institute-University of Queensland, Woolloongabba, Queensland 4102, Australia
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12
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Hearn J, Little TJ. Daphnia magna egg piRNA cluster expression profiles change as mothers age. BMC Genomics 2022; 23:429. [PMID: 35672706 PMCID: PMC9175491 DOI: 10.1186/s12864-022-08660-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 05/30/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND PiRNAs prevent transposable elements wreaking havoc on the germline genome. Changes in piRNA expression over the lifetime of an individual may impact on ageing through continued suppression, or release, of transposable element expression. We identified piRNA producing clusters in the genome of Daphnia magna by a combination of bioinformatic methods, and then contrasted their expression between parthenogenetically produced eggs representing maternally-deposited germline piRNAs of young (having their 1st clutch) and old (having their 5th clutch) mothers. Results from eggs were compared to cluster expression in three generations of adults. RESULTS As for other arthropods, D. magna encodes long uni-directionally transcribed non-coding RNAs consisting of fragmented transposable elements which account for most piRNAs expressed. Egg tissues showed extensive differences between clutches from young mothers and those from old mothers, with 578 and 686 piRNA clusters upregulated, respectively. Most log fold-change differences for significant clusters were modest, however. When considering only highly expressed clusters, there was a bias towards 1st clutch eggs at 41 upregulated versus eight clusters in the eggs from older mothers. F0 generation differences between young and old mothers were fewer than eggs, as 179 clusters were up-regulated in young versus 170 old mothers. This dropped to 31 versus 22 piRNA clusters when comparing adults in the F1 generation, and no differences were detected in the F3 generation. Inter-generational losses of differential piRNA cluster were similar to that observed for D. magna micro-RNA expression. CONCLUSIONS Little overlap in differentially expressed clusters was found between adults containing mixed somatic and germline (ovary) tissues and germ-line representing eggs. A cluster encompassing a Tudor domain containing gene important in the piRNA pathway was upregulated in the eggs from old mothers. We hypothesise that regulation of this gene could form part of a feedback loop that reduces piRNA pathway activity explaining the reduced number of highly-expressed clusters in eggs from old mothers.
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Affiliation(s)
- Jack Hearn
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Tom J. Little
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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13
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Chesnokova E, Beletskiy A, Kolosov P. The Role of Transposable Elements of the Human Genome in Neuronal Function and Pathology. Int J Mol Sci 2022; 23:5847. [PMID: 35628657 PMCID: PMC9148063 DOI: 10.3390/ijms23105847] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) have been extensively studied for decades. In recent years, the introduction of whole-genome and whole-transcriptome approaches, as well as single-cell resolution techniques, provided a breakthrough that uncovered TE involvement in host gene expression regulation underlying multiple normal and pathological processes. Of particular interest is increased TE activity in neuronal tissue, and specifically in the hippocampus, that was repeatedly demonstrated in multiple experiments. On the other hand, numerous neuropathologies are associated with TE dysregulation. Here, we provide a comprehensive review of literature about the role of TEs in neurons published over the last three decades. The first chapter of the present review describes known mechanisms of TE interaction with host genomes in general, with the focus on mammalian and human TEs; the second chapter provides examples of TE exaptation in normal neuronal tissue, including TE involvement in neuronal differentiation and plasticity; and the last chapter lists TE-related neuropathologies. We sought to provide specific molecular mechanisms of TE involvement in neuron-specific processes whenever possible; however, in many cases, only phenomenological reports were available. This underscores the importance of further studies in this area.
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Affiliation(s)
- Ekaterina Chesnokova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, 117485 Moscow, Russia; (A.B.); (P.K.)
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14
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Somatic Mobilization: High Somatic Insertion Rate of mariner Transposable Element in Drosophila simulans. INSECTS 2022; 13:insects13050454. [PMID: 35621789 PMCID: PMC9144738 DOI: 10.3390/insects13050454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 11/17/2022]
Abstract
Although transposable elements (TEs) are usually silent in somatic tissues, they are sometimes mobilized in the soma and can potentially have biological consequences. The mariner element is one of the TEs involved in somatic mobilization (SM) in Drosophila and has a high rate of somatic excision. It is also known that temperature is an important factor in the increase of the mariner element SM in the fly. However, it is important to emphasize that excision is only one step of TE transposition, and the final step in this process is insertion. In the present study, we used an assay based on sequencing of the mariner flanking region and developed a pipeline to identify novel mariner insertions in Drosophila simulans at 20 and 28 °C. We found that flies carrying two mariner copies (one autonomous and one non-autonomous) had an average of 236.4 (±99.3) to 279 (±107.7) new somatic insertions at 20 °C and an average of 172.7 (±95.3) to 252.6 (±67.3) at 28 °C. In addition, we detected fragments containing mariner and others without mariner in the same regions with low-coverage long-read sequencing, indicating the process of excision and insertion. In conclusion, a low number of autonomous copies of the mariner transposon can promote a high rate of new somatic insertions during the developmental stages of Drosophila. Additionally, the developed method seems to be sensitive and adequate for the verification and estimation of somatic insertion.
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15
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Yang N, Srivastav SP, Rahman R, Ma Q, Dayama G, Li S, Chinen M, Lei EP, Rosbash M, Lau NC. Transposable element landscapes in aging Drosophila. PLoS Genet 2022; 18:e1010024. [PMID: 35239675 PMCID: PMC8893327 DOI: 10.1371/journal.pgen.1010024] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 01/10/2022] [Indexed: 11/28/2022] Open
Abstract
Genetic mechanisms that repress transposable elements (TEs) in young animals decline during aging, as reflected by increased TE expression in aged animals. Does increased TE expression during aging lead to more genomic TE copies in older animals? To address this question, we quantified TE Landscapes (TLs) via whole genome sequencing of young and aged Drosophila strains of wild-type and mutant backgrounds. We quantified TLs in whole flies and dissected brains and validated the feasibility of our approach in detecting new TE insertions in aging Drosophila genomes when small RNA and RNA interference (RNAi) pathways are compromised. We also describe improved sequencing methods to quantify extra-chromosomal DNA circles (eccDNAs) in Drosophila as an additional source of TE copies that accumulate during aging. Lastly, to combat the natural progression of aging-associated TE expression, we show that knocking down PAF1, a conserved transcription elongation factor that antagonizes RNAi pathways, may bolster suppression of TEs during aging and extend lifespan. Our study suggests that in addition to a possible influence by different genetic backgrounds, small RNA and RNAi mechanisms may mitigate genomic TL expansion despite the increase in TE transcripts during aging. Transposable elements, also called transposons, are genetic parasites found in all animal genomes. Normally, transposons are compacted away in silent chromatin in young animals. But, as animals age and transposon-silencing defense mechanisms break down, transposon RNAs accumulate to significant levels in old animals like fruit flies. An open question is whether the increased levels of transposon RNAs in older animals also correspond to increased genomic copies of transposons. This study approached this question by sequencing the whole genomes of young and old wild-type and mutant flies lacking a functional RNA interference (RNAi) pathway, which naturally silences transposon RNAs. Although the wild-type flies with intact RNAi activity had little new accumulation of transposon copies, the sequencing approach was able to detect several transposon accumulation occurrences in some RNAi mutants. In addition, we found that some fly transposon families can also accumulate as extra-chromosomal circular DNA copies. Lastly, we showed that genetically augmenting the expression of RNAi factors can counteract the rising transposon RNA levels in aging and promote longevity. This study improves our understanding of the animal host genome relationship with transposons during natural aging processes.
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Affiliation(s)
- Nachen Yang
- Boston University School of Medicine, Department of Biochemistry, Boston, Massachusetts, United States of America
| | - Satyam P. Srivastav
- Boston University School of Medicine, Department of Biochemistry, Boston, Massachusetts, United States of America
| | - Reazur Rahman
- Brandeis University, Department of Biology and Howard Hughes Medical Institute, Waltham, Massachusetts, United States of America
| | - Qicheng Ma
- Boston University School of Medicine, Department of Biochemistry, Boston, Massachusetts, United States of America
| | - Gargi Dayama
- Boston University School of Medicine, Department of Biochemistry, Boston, Massachusetts, United States of America
| | - Sizheng Li
- Boston University School of Medicine, Department of Biochemistry, Boston, Massachusetts, United States of America
| | - Madoka Chinen
- Nuclear Organization and Gene Expression Section, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Elissa P. Lei
- Nuclear Organization and Gene Expression Section, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Michael Rosbash
- Brandeis University, Department of Biology and Howard Hughes Medical Institute, Waltham, Massachusetts, United States of America
| | - Nelson C. Lau
- Boston University School of Medicine, Department of Biochemistry, Boston, Massachusetts, United States of America
- Boston University Genome Science Institute, Boston, Massachusetts, United States of America
- * E-mail:
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16
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Palazzo A, Caizzi R, Moschetti R, Marsano RM. What Have We Learned in 30 Years of Investigations on Bari Transposons? Cells 2022; 11:583. [PMID: 35159391 PMCID: PMC8834629 DOI: 10.3390/cells11030583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 12/17/2022] Open
Abstract
Transposable elements (TEs) have been historically depicted as detrimental genetic entities that selfishly aim at perpetuating themselves, invading genomes, and destroying genes. Scientists often co-opt "special" TEs to develop new and powerful genetic tools, that will hopefully aid in changing the future of the human being. However, many TEs are gentle, rarely unleash themselves to harm the genome, and bashfully contribute to generating diversity and novelty in the genomes they have colonized, yet they offer the opportunity to develop new molecular tools. In this review we summarize 30 years of research focused on the Bari transposons. Bari is a "normal" transposon family that has colonized the genomes of several Drosophila species and introduced genomic novelties in the melanogaster species. We discuss how these results have contributed to advance the field of TE research and what future studies can still add to the current knowledge.
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17
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Zakharenko LP. Phenotypically Unstable Mutations as Markers of Chromosomal Rearrangements Involving DNA Transposons. RUSS J GENET+ 2021. [DOI: 10.1134/s1022795421110156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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18
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Smits N, Rasmussen J, Bodea GO, Amarilla AA, Gerdes P, Sanchez-Luque FJ, Ajjikuttira P, Modhiran N, Liang B, Faivre J, Deveson IW, Khromykh AA, Watterson D, Ewing AD, Faulkner GJ. No evidence of human genome integration of SARS-CoV-2 found by long-read DNA sequencing. Cell Rep 2021; 36:109530. [PMID: 34380018 PMCID: PMC8316065 DOI: 10.1016/j.celrep.2021.109530] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 01/28/2023] Open
Abstract
A recent study proposed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hijacks the LINE-1 (L1) retrotransposition machinery to integrate into the DNA of infected cells. If confirmed, this finding could have significant clinical implications. Here, we apply deep (>50×) long-read Oxford Nanopore Technologies (ONT) sequencing to HEK293T cells infected with SARS-CoV-2 and do not find the virus integrated into the genome. By examining ONT data from separate HEK293T cultivars, we completely resolve 78 L1 insertions arising in vitro in the absence of L1 overexpression systems. ONT sequencing applied to hepatitis B virus (HBV)-positive liver cancer tissues located a single HBV insertion. These experiments demonstrate reliable resolution of retrotransposon and exogenous virus insertions by ONT sequencing. That we find no evidence of SARS-CoV-2 integration suggests that such events are, at most, extremely rare in vivo and therefore are unlikely to drive oncogenesis or explain post-recovery detection of the virus.
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Affiliation(s)
- Nathan Smits
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Jay Rasmussen
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia
| | - Gabriela O Bodea
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia
| | - Alberto A Amarilla
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Patricia Gerdes
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Francisco J Sanchez-Luque
- GENYO, Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research, PTS Granada 18016, Spain; MRC Human Genetics Unit, Institute of Genetics and Cancer (IGC), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Prabha Ajjikuttira
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia
| | - Naphak Modhiran
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Benjamin Liang
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Jamila Faivre
- INSERM, U1193, Paul-Brousse University Hospital, Hepatobiliary Centre, Villejuif 94800, France
| | - Ira W Deveson
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Alexander A Khromykh
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, QLD 4072, Australia
| | - Daniel Watterson
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, QLD 4072, Australia
| | - Adam D Ewing
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia.
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19
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Yu T, Huang X, Dou S, Tang X, Luo S, Theurkauf WE, Lu J, Weng Z. A benchmark and an algorithm for detecting germline transposon insertions and measuring de novo transposon insertion frequencies. Nucleic Acids Res 2021; 49:e44. [PMID: 33511407 PMCID: PMC8096211 DOI: 10.1093/nar/gkab010] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 12/28/2020] [Accepted: 01/06/2021] [Indexed: 02/01/2023] Open
Abstract
Transposons are genomic parasites, and their new insertions can cause instability and spur the evolution of their host genomes. Rapid accumulation of short-read whole-genome sequencing data provides a great opportunity for studying new transposon insertions and their impacts on the host genome. Although many algorithms are available for detecting transposon insertions, the task remains challenging and existing tools are not designed for identifying de novo insertions. Here, we present a new benchmark fly dataset based on PacBio long-read sequencing and a new method TEMP2 for detecting germline insertions and measuring de novo ‘singleton’ insertion frequencies in eukaryotic genomes. TEMP2 achieves high sensitivity and precision for detecting germline insertions when compared with existing tools using both simulated data in fly and experimental data in fly and human. Furthermore, TEMP2 can accurately assess the frequencies of de novo transposon insertions even with high levels of chimeric reads in simulated datasets; such chimeric reads often occur during the construction of short-read sequencing libraries. By applying TEMP2 to published data on hybrid dysgenic flies inflicted by de-repressed P-elements, we confirmed the continuous new insertions of P-elements in dysgenic offspring before they regain piRNAs for P-element repression. TEMP2 is freely available at Github: https://github.com/weng-lab/TEMP2.
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Affiliation(s)
- Tianxiong Yu
- Department of Thoracic Surgery, Clinical Translational Research Center, Shanghai Pulmonary Hospital, The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China.,Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Xiao Huang
- Department of Thoracic Surgery, Clinical Translational Research Center, Shanghai Pulmonary Hospital, The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Shengqian Dou
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Xiaolu Tang
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Shiqi Luo
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - William E Theurkauf
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jian Lu
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Zhiping Weng
- Department of Thoracic Surgery, Clinical Translational Research Center, Shanghai Pulmonary Hospital, The School of Life Sciences and Technology, Tongji University, Shanghai 200092, China.,Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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20
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Siudeja K, van den Beek M, Riddiford N, Boumard B, Wurmser A, Stefanutti M, Lameiras S, Bardin AJ. Unraveling the features of somatic transposition in the Drosophila intestine. EMBO J 2021; 40:e106388. [PMID: 33634906 PMCID: PMC8090852 DOI: 10.15252/embj.2020106388] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/20/2021] [Accepted: 01/27/2021] [Indexed: 12/22/2022] Open
Abstract
Transposable elements (TEs) play a significant role in evolution, contributing to genetic variation. However, TE mobilization in somatic cells is not well understood. Here, we address the prevalence of transposition in a somatic tissue, exploiting the Drosophila midgut as a model. Using whole-genome sequencing of in vivo clonally expanded gut tissue, we have mapped hundreds of high-confidence somatic TE integration sites genome-wide. We show that somatic retrotransposon insertions are associated with inactivation of the tumor suppressor Notch, likely contributing to neoplasia formation. Moreover, applying Oxford Nanopore long-read sequencing technology we provide evidence for tissue-specific differences in retrotransposition. Comparing somatic TE insertional activity with transcriptomic and small RNA sequencing data, we demonstrate that transposon mobility cannot be simply predicted by whole tissue TE expression levels or by small RNA pathway activity. Finally, we reveal that somatic TE insertions in the adult fly intestine are enriched in genic regions and in transcriptionally active chromatin. Together, our findings provide clear evidence of ongoing somatic transposition in Drosophila and delineate previously unknown features underlying somatic TE mobility in vivo.
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Affiliation(s)
- Katarzyna Siudeja
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Marius van den Beek
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Nick Riddiford
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Benjamin Boumard
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Annabelle Wurmser
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Marine Stefanutti
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Sonia Lameiras
- ICGex Next‐Generation Sequencing PlatformInstitut CuriePSL Research UniversityParisFrance
| | - Allison J Bardin
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
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21
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Striking heterogeneity of somatic L1 retrotransposition in single normal and cancerous gastrointestinal cells. Proc Natl Acad Sci U S A 2020; 117:32215-32222. [PMID: 33277430 DOI: 10.1073/pnas.2019450117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Somatic LINE-1 (L1) retrotransposition has been detected in early embryos, adult brains, and the gastrointestinal (GI) tract, and many cancers, including epithelial GI tumors. We previously found numerous somatic L1 insertions in paired normal and GI cancerous tissues. Here, using a modified method of single-cell analysis for somatic L1 insertions, we studied adenocarcinomas of colon, pancreas, and stomach, and found a variable number of somatic L1 insertions in tumors of the same type from patient to patient. We detected no somatic L1 insertions in single cells of 5 of 10 tumors studied. In three tumors, aneuploid cells were detected by FACS. In one pancreatic tumor, there were many more L1 insertions in aneuploid than in euploid tumor cells. In one gastric cancer, both aneuploid and euploid cells contained large numbers of likely clonal insertions. However, in a second gastric cancer with aneuploid cells, no somatic L1 insertions were found. We suggest that when the cellular environment is favorable to retrotransposition, aneuploidy predisposes tumor cells to L1 insertions, and retrotransposition may occur at the transition from euploidy to aneuploidy. Seventeen percent of insertions were also present in normal cells, similar to findings in genomic DNA from normal tissues of GI tumor patients. We provide evidence that: 1) The number of L1 insertions in tumors of the same type is highly variable, 2) most somatic L1 insertions in GI cancer tissues are absent from normal tissues, and 3) under certain conditions, somatic L1 retrotransposition exhibits a propensity for occurring in aneuploid cells.
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22
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Wei KHC, Gibilisco L, Bachtrog D. Epigenetic conflict on a degenerating Y chromosome increases mutational burden in Drosophila males. Nat Commun 2020; 11:5537. [PMID: 33139741 PMCID: PMC7608633 DOI: 10.1038/s41467-020-19134-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 09/24/2020] [Indexed: 01/04/2023] Open
Abstract
Large portions of eukaryotic genomes consist of transposable elements (TEs), and the establishment of transcription-repressing heterochromatin during early development safeguards genome integrity in Drosophila. Repeat-rich Y chromosomes can act as reservoirs for TEs ('toxic' Y effect), and incomplete epigenomic defenses during early development can lead to deleterious TE mobilization. Here, we contrast the dynamics of early TE activation in two Drosophila species with vastly different Y chromosomes of different ages. Zygotic TE expression is elevated in male embryos relative to females in both species, mostly due to expression of Y-linked TEs. Interestingly, male-biased TE expression diminishes across development in D. pseudoobscura, but remains elevated in D. miranda, the species with the younger and larger Y chromosome. The repeat-rich Y of D. miranda still contains many actively transcribed genes, which compromise the formation of silencing heterochromatin. Elevated TE expression results in more de novo insertions of repeats in males compared to females. This lends support to the idea that the 'toxic' Y chromosome can create a mutational burden in males when genome-wide defense mechanisms are compromised, and suggests a previously unappreciated epigenetic conflict on evolving Y chromosomes between transcription of essential genes and silencing of selfish DNA.
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Affiliation(s)
- Kevin H-C Wei
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Lauren Gibilisco
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Doris Bachtrog
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA.
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23
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Transposon expression in the Drosophila brain is driven by neighboring genes and diversifies the neural transcriptome. Genome Res 2020; 30:1559-1569. [PMID: 32973040 PMCID: PMC7605248 DOI: 10.1101/gr.259200.119] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 09/22/2020] [Indexed: 12/15/2022]
Abstract
Somatic transposon expression in neural tissue is commonly considered as a measure of mobilization and has therefore been linked to neuropathology and organismal individuality. We combined genome sequencing data with single-cell mRNA sequencing of the same inbred fly strain to map transposon expression in the Drosophila midbrain and found that transposon expression patterns are highly stereotyped. Every detected transposon is resident in at least one cellular gene with a matching expression pattern. Bulk RNA sequencing from fly heads of the same strain revealed that coexpression is a physical link in the form of abundant chimeric transposon-gene mRNAs. We identified 264 genes where transposons introduce cryptic splice sites into the nascent transcript and thereby significantly expand the neural transcript repertoire. Some genes exclusively produce chimeric mRNAs with transposon sequence; on average, 11.6% of the mRNAs produced from a given gene are chimeric. Conversely, most transposon-containing transcripts are chimeric, which suggests that somatic expression of these transposons is largely driven by cellular genes. We propose that chimeric mRNAs produced by alternative splicing into polymorphic transposons, rather than transposon mobilization, may contribute to functional differences between individual cells and animals.
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24
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Mohamed M, Dang NTM, Ogyama Y, Burlet N, Mugat B, Boulesteix M, Mérel V, Veber P, Salces-Ortiz J, Severac D, Pélisson A, Vieira C, Sabot F, Fablet M, Chambeyron S. A Transposon Story: From TE Content to TE Dynamic Invasion of Drosophila Genomes Using the Single-Molecule Sequencing Technology from Oxford Nanopore. Cells 2020; 9:E1776. [PMID: 32722451 PMCID: PMC7465170 DOI: 10.3390/cells9081776] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/17/2020] [Accepted: 07/23/2020] [Indexed: 11/17/2022] Open
Abstract
Transposable elements (TEs) are the main components of genomes. However, due to their repetitive nature, they are very difficult to study using data obtained with short-read sequencing technologies. Here, we describe an efficient pipeline to accurately recover TE insertion (TEI) sites and sequences from long reads obtained by Oxford Nanopore Technology (ONT) sequencing. With this pipeline, we could precisely describe the landscapes of the most recent TEIs in wild-type strains of Drosophila melanogaster and Drosophila simulans. Their comparison suggests that this subset of TE sequences is more similar than previously thought in these two species. The chromosome assemblies obtained using this pipeline also allowed recovering piRNA cluster sequences, which was impossible using short-read sequencing. Finally, we used our pipeline to analyze ONT sequencing data from a D. melanogaster unstable line in which LTR transposition was derepressed for 73 successive generations. We could rely on single reads to identify new insertions with intact target site duplications. Moreover, the detailed analysis of TEIs in the wild-type strains and the unstable line did not support the trap model claiming that piRNA clusters are hotspots of TE insertions.
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Affiliation(s)
- Mourdas Mohamed
- Institute of Human Genetics, UMR9002, CNRS and Montpellier University, 34396 Montpellier, France; (M.M.); (Y.O.); (B.M.); (A.P.)
| | - Nguyet Thi-Minh Dang
- IRD/UM UMR DIADE, 911 avenue Agropolis BP64501, 34394 Montpellier, France; (N.T.-M.D.); (F.S.)
| | - Yuki Ogyama
- Institute of Human Genetics, UMR9002, CNRS and Montpellier University, 34396 Montpellier, France; (M.M.); (Y.O.); (B.M.); (A.P.)
| | - Nelly Burlet
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, 69622 Villeurbanne, France; (N.B.); (M.B.); (V.M.); (P.V.); (J.S.-O.); (C.V.)
| | - Bruno Mugat
- Institute of Human Genetics, UMR9002, CNRS and Montpellier University, 34396 Montpellier, France; (M.M.); (Y.O.); (B.M.); (A.P.)
| | - Matthieu Boulesteix
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, 69622 Villeurbanne, France; (N.B.); (M.B.); (V.M.); (P.V.); (J.S.-O.); (C.V.)
| | - Vincent Mérel
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, 69622 Villeurbanne, France; (N.B.); (M.B.); (V.M.); (P.V.); (J.S.-O.); (C.V.)
| | - Philippe Veber
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, 69622 Villeurbanne, France; (N.B.); (M.B.); (V.M.); (P.V.); (J.S.-O.); (C.V.)
| | - Judit Salces-Ortiz
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, 69622 Villeurbanne, France; (N.B.); (M.B.); (V.M.); (P.V.); (J.S.-O.); (C.V.)
- Institute of Evolutionary Biology (IBE), CSIC-Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Dany Severac
- MGX-Montpellier GenomiX, c/o Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 34094 Montpellier, France;
| | - Alain Pélisson
- Institute of Human Genetics, UMR9002, CNRS and Montpellier University, 34396 Montpellier, France; (M.M.); (Y.O.); (B.M.); (A.P.)
| | - Cristina Vieira
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, 69622 Villeurbanne, France; (N.B.); (M.B.); (V.M.); (P.V.); (J.S.-O.); (C.V.)
| | - François Sabot
- IRD/UM UMR DIADE, 911 avenue Agropolis BP64501, 34394 Montpellier, France; (N.T.-M.D.); (F.S.)
| | - Marie Fablet
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, 69622 Villeurbanne, France; (N.B.); (M.B.); (V.M.); (P.V.); (J.S.-O.); (C.V.)
| | - Séverine Chambeyron
- Institute of Human Genetics, UMR9002, CNRS and Montpellier University, 34396 Montpellier, France; (M.M.); (Y.O.); (B.M.); (A.P.)
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Jönsson ME, Garza R, Johansson PA, Jakobsson J. Transposable Elements: A Common Feature of Neurodevelopmental and Neurodegenerative Disorders. Trends Genet 2020; 36:610-623. [PMID: 32499105 DOI: 10.1016/j.tig.2020.05.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/30/2022]
Abstract
The etiology of most neurological disorders is poorly understood and current treatments are largely ineffective. New ideas and concepts are therefore vitally important for future research in this area. This review explores the concept that dysregulation of transposable elements (TEs) contributes to the appearance and pathology of neurodevelopmental and neurodegenerative disorders. Despite TEs making up at least half of the human genome, they are vastly understudied in relation to brain disorders. However, recent advances in sequencing technologies and gene editing approaches are now starting to unravel the pathological role of TEs. Aberrant activation of TEs has been found in many neurological disorders; the resulting pathogenic effects, which include alterations of gene expression, neuroinflammation, and direct neurotoxicity, are starting to be resolved. An increased understanding of the relationship between TEs and pathological processes in the brain improves the potential for novel diagnostics and interventions for brain disorders.
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Affiliation(s)
- Marie E Jönsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, 221 84 Lund, Sweden
| | - Raquel Garza
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, 221 84 Lund, Sweden
| | - Pia A Johansson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, 221 84 Lund, Sweden
| | - Johan Jakobsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, 221 84 Lund, Sweden.
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26
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Kelleher ES, Barbash DA, Blumenstiel JP. Taming the Turmoil Within: New Insights on the Containment of Transposable Elements. Trends Genet 2020; 36:474-489. [PMID: 32473745 DOI: 10.1016/j.tig.2020.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/28/2022]
Abstract
Transposable elements (TEs) are mobile genetic parasites that can exponentially increase their genomic abundance through self-propagation. Classic theoretical papers highlighted the importance of two potentially escalating forces that oppose TE spread: regulated transposition and purifying selection. Here, we review new insights into mechanisms of TE regulation and purifying selection, which reveal the remarkable foresight of these theoretical models. We further highlight emergent connections between transcriptional control enacted by small RNAs and the contribution of TE insertions to structural mutation and host-gene regulation. Finally, we call for increased comparative analysis of TE dynamics and fitness effects, as well as host control mechanisms, to reveal how interconnected forces shape the differential prevalence and distribution of TEs across the tree of life.
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27
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Ochoa Thomas E, Zuniga G, Sun W, Frost B. Awakening the dark side: retrotransposon activation in neurodegenerative disorders. Curr Opin Neurobiol 2020; 61:65-72. [PMID: 32092528 PMCID: PMC7198348 DOI: 10.1016/j.conb.2020.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 01/07/2020] [Accepted: 01/23/2020] [Indexed: 12/30/2022]
Abstract
Nearly half (45%) of the human genome is composed of transposable elements, or 'jumping genes'. Since Barbara McClintock's original discovery of transposable elements in 1950, we have come to appreciate that transposable element mobilization is a major driver of evolution that transposons are active in the germline and the soma, and that transposable element dysregulation is causally associated with many human disorders. In the present review, we highlight recent studies investigating transposable element activation in the adult brain and in the context of neurodegeneration. Collectively, these studies contribute to a greater understanding of the frequency of complete retrotransposition in the adult brain as well as the presence of transposable element-derived RNA and protein in brain and fluids of patients with neurodegenerative disorders. We discuss therapeutic opportunities and speculate on the larger implications of transposable element activation in regard to current hot topics in the field of neurodegeneration.
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Affiliation(s)
- Elizabeth Ochoa Thomas
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Gabbe Zuniga
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Wenyan Sun
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Bess Frost
- Sam & Ann Barshop Institute for Longevity and Aging Studies, Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, United States.
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28
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Miller DE. Synaptonemal Complex-Deficient Drosophila melanogaster Females Exhibit Rare DSB Repair Events, Recurrent Copy-Number Variation, and an Increased Rate of de Novo Transposable Element Movement. G3 (BETHESDA, MD.) 2020; 10:525-537. [PMID: 31882405 PMCID: PMC7003089 DOI: 10.1534/g3.119.400853] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 12/23/2019] [Indexed: 01/11/2023]
Abstract
Genetic stability depends on the maintenance of a variety of chromosome structures and the precise repair of DNA breaks. During meiosis, programmed double-strand breaks (DSBs) made in prophase I are normally repaired as gene conversions or crossovers. DSBs can also be made by other mechanisms, such as the movement of transposable elements (TEs), which must also be resolved. Incorrect repair of these DNA lesions can lead to mutations, copy-number changes, translocations, and/or aneuploid gametes. In Drosophila melanogaster, as in most organisms, meiotic DSB repair occurs in the presence of a rapidly evolving multiprotein structure called the synaptonemal complex (SC). Here, whole-genome sequencing is used to investigate the fate of meiotic DSBs in D. melanogaster mutant females lacking functional SC, to assay for de novo CNV formation, and to examine the role of the SC in transposable element movement in flies. The data indicate that, in the absence of SC, copy-number variation still occurs and meiotic DSB repair by gene conversion occurs infrequently. Remarkably, an 856-kilobase de novo CNV was observed in two unrelated individuals of different genetic backgrounds and was identical to a CNV recovered in a previous wild-type study, suggesting that recurrent formation of large CNVs occurs in Drosophila. In addition, the rate of novel TE insertion was markedly higher than wild type in one of two SC mutants tested, suggesting that SC proteins may contribute to the regulation of TE movement and insertion in the genome. Overall, this study provides novel insight into the role that the SC plays in genome stability and provides clues as to why the sequence, but not structure, of SC proteins is rapidly evolving.
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Affiliation(s)
- Danny E Miller
- Division of Medical Genetics, Department of Medicine, and
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington 98105, and
- Seattle Children's Hospital, Seattle, Washington 98105
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29
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Moschetti R, Palazzo A, Lorusso P, Viggiano L, Massimiliano Marsano R. "What You Need, Baby, I Got It": Transposable Elements as Suppliers of Cis-Operating Sequences in Drosophila. BIOLOGY 2020; 9:E25. [PMID: 32028630 PMCID: PMC7168160 DOI: 10.3390/biology9020025] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/27/2020] [Accepted: 01/30/2020] [Indexed: 12/18/2022]
Abstract
Transposable elements (TEs) are constitutive components of both eukaryotic and prokaryotic genomes. The role of TEs in the evolution of genes and genomes has been widely assessed over the past years in a variety of model and non-model organisms. Drosophila is undoubtedly among the most powerful model organisms used for the purpose of studying the role of transposons and their effects on the stability and evolution of genes and genomes. Besides their most intuitive role as insertional mutagens, TEs can modify the transcriptional pattern of host genes by juxtaposing new cis-regulatory sequences. A key element of TE biology is that they carry transcriptional control elements that fine-tune the transcription of their own genes, but that can also perturb the transcriptional activity of neighboring host genes. From this perspective, the transposition-mediated modulation of gene expression is an important issue for the short-term adaptation of physiological functions to the environmental changes, and for long-term evolutionary changes. Here, we review the current literature concerning the regulatory and structural elements operating in cis provided by TEs in Drosophila. Furthermore, we highlight that, besides their influence on both TEs and host genes expression, they can affect the chromatin structure and epigenetic status as well as both the chromosome's structure and stability. It emerges that Drosophila is a good model organism to study the effect of TE-linked regulatory sequences, and it could help future studies on TE-host interactions in any complex eukaryotic genome.
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Affiliation(s)
- Roberta Moschetti
- Dipartimento di Biologia, Università degli Studi di Bari “Aldo Moro”, Via Orabona 4, 70125 Bari, Italy; (R.M.); (P.L.); (L.V.)
| | - Antonio Palazzo
- Laboratory of Translational Nanotechnology, “Istituto Tumori Giovanni Paolo II” I.R.C.C.S, Viale Orazio Flacco 65, 70125 Bari, Italy;
| | - Patrizio Lorusso
- Dipartimento di Biologia, Università degli Studi di Bari “Aldo Moro”, Via Orabona 4, 70125 Bari, Italy; (R.M.); (P.L.); (L.V.)
| | - Luigi Viggiano
- Dipartimento di Biologia, Università degli Studi di Bari “Aldo Moro”, Via Orabona 4, 70125 Bari, Italy; (R.M.); (P.L.); (L.V.)
| | - René Massimiliano Marsano
- Dipartimento di Biologia, Università degli Studi di Bari “Aldo Moro”, Via Orabona 4, 70125 Bari, Italy; (R.M.); (P.L.); (L.V.)
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30
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Della Valle F, Thimma MP, Caiazzo M, Pulcrano S, Celii M, Adroub SA, Liu P, Alanis-Lobato G, Broccoli V, Orlando V. Transdifferentiation of Mouse Embryonic Fibroblasts into Dopaminergic Neurons Reactivates LINE-1 Repetitive Elements. Stem Cell Reports 2020; 14:60-74. [PMID: 31902705 PMCID: PMC6962658 DOI: 10.1016/j.stemcr.2019.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 12/01/2019] [Accepted: 12/02/2019] [Indexed: 12/15/2022] Open
Abstract
In mammals, LINE-1 (L1) retrotransposons constitute between 15% and 20% of the genome. Although only a few copies have retained the ability to retrotranspose, evidence in brain and differentiating pluripotent cells indicates that L1 retrotransposition occurs and creates mosaics in normal somatic tissues. The function of de novo insertions remains to be understood. The transdifferentiation of mouse embryonic fibroblasts to dopaminergic neuronal fate provides a suitable model for studying L1 dynamics in a defined genomic and unaltered epigenomic background. We found that L1 elements are specifically re-expressed and mobilized during the initial stages of reprogramming and that their insertions into specific acceptor loci coincides with higher chromatin accessibility and creation of new transcribed units. Those events accompany the maturation of neuronal committed cells. We conclude that L1 retrotransposition is a non-random process correlating with chromatin opening and lncRNA production that accompanies direct somatic cell reprogramming. L1 activation accompanies induced dopaminergic neuron maturation L1 inhibition impairs the transdifferentiation potential of MEFs L1 retrotransposition creates a lineage-specific genetic mosaicism L1 insertions correlates with open chromatin and lncRNA transcription
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Affiliation(s)
- Francesco Della Valle
- King Abdullah University of Science and Technology (KAUST), Biological Environmental Science and Engineering Division, KAUST Environmental Epigenetics Program, Bld 2, Level 3, Room 3234, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Manjula P Thimma
- King Abdullah University of Science and Technology (KAUST), Biological Environmental Science and Engineering Division, KAUST Environmental Epigenetics Program, Bld 2, Level 3, Room 3234, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Massimiliano Caiazzo
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), 3584 Utrecht, the Netherlands; Institute of Genetics and Biophysics, "A. Buzzati-Traverso", C.N.R., 80131 Naples, Italy; Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Salvatore Pulcrano
- Institute of Genetics and Biophysics, "A. Buzzati-Traverso", C.N.R., 80131 Naples, Italy
| | - Mirko Celii
- King Abdullah University of Science and Technology (KAUST), Biological Environmental Science and Engineering Division, KAUST Environmental Epigenetics Program, Bld 2, Level 3, Room 3234, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Sabir A Adroub
- King Abdullah University of Science and Technology (KAUST), Biological Environmental Science and Engineering Division, KAUST Environmental Epigenetics Program, Bld 2, Level 3, Room 3234, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Peng Liu
- King Abdullah University of Science and Technology (KAUST), Biological Environmental Science and Engineering Division, KAUST Environmental Epigenetics Program, Bld 2, Level 3, Room 3234, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Gregorio Alanis-Lobato
- King Abdullah University of Science and Technology (KAUST), Biological Environmental Science and Engineering Division, KAUST Environmental Epigenetics Program, Bld 2, Level 3, Room 3234, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Institute of Molecular Biology, Computational Biology and Data Mining Unit, 55128 Mainz, Germany
| | - Vania Broccoli
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Valerio Orlando
- King Abdullah University of Science and Technology (KAUST), Biological Environmental Science and Engineering Division, KAUST Environmental Epigenetics Program, Bld 2, Level 3, Room 3234, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
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31
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The role of transposable elements activity in aging and their possible involvement in laminopathic diseases. Ageing Res Rev 2020; 57:100995. [PMID: 31786372 DOI: 10.1016/j.arr.2019.100995] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/17/2019] [Accepted: 11/25/2019] [Indexed: 01/17/2023]
Abstract
Eukaryotic genomes contain a large number of transposable elements, part of which are still active and able to transpose in the host genome. Mobile element activation is repressed to avoid deleterious effects, such as gene mutations or chromosome rearrangements. Control of transposable elements includes a variety of mechanisms comprising silencing pathways, which are based on the production of small non-coding RNAs. Silencing can occur either through transposable element RNA degradation or through the targeting of DNA sequences by heterochromatin formation and consequent transcriptional inhibition. Since the important role of the heterochromatin silencing, the gradual loss of heterochromatin marks in constitutive heterochromatin regions during the aging process promotes derepression of transposable elements, which is considered a cause of the progressive increase in genomic instability and of the activation of inflammatory responses. This review provides an overview of the effects of heterochromatin loss on the activity of transposable elements during the aging process and the possible impact on genome function. In this context, we discuss the possible role of the nuclear lamina, a major player in heterochromatin dynamics, in the regulation of transposable element activity and potential implications in laminopathic diseases.
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32
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The piRNA Response to Retroviral Invasion of the Koala Genome. Cell 2019; 179:632-643.e12. [PMID: 31607510 DOI: 10.1016/j.cell.2019.09.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/19/2019] [Accepted: 08/30/2019] [Indexed: 12/20/2022]
Abstract
Antisense Piwi-interacting RNAs (piRNAs) guide silencing of established transposons during germline development, and sense piRNAs drive ping-pong amplification of the antisense pool, but how the germline responds to genome invasion is not understood. The KoRV-A gammaretrovirus infects the soma and germline and is sweeping through wild koalas by a combination of horizontal and vertical transfer, allowing direct analysis of retroviral invasion of the germline genome. Gammaretroviruses produce spliced Env mRNAs and unspliced transcripts encoding Gag, Pol, and the viral genome, but KoRV-A piRNAs are almost exclusively derived from unspliced genomic transcripts and are strongly sense-strand biased. Significantly, selective piRNA processing of unspliced proviral transcripts is conserved from insects to placental mammals. We speculate that bypassed splicing generates a conserved molecular pattern that directs proviral genomic transcripts to the piRNA biogenesis machinery and that this "innate" piRNA response suppresses transposition until antisense piRNAs are produced, establishing sequence-specific adaptive immunity.
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33
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Barckmann B, El-Barouk M, Pélisson A, Mugat B, Li B, Franckhauser C, Fiston Lavier AS, Mirouze M, Fablet M, Chambeyron S. The somatic piRNA pathway controls germline transposition over generations. Nucleic Acids Res 2019; 46:9524-9536. [PMID: 30312469 PMCID: PMC6182186 DOI: 10.1093/nar/gky761] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/22/2018] [Indexed: 11/14/2022] Open
Abstract
Transposable elements (TEs) are parasitic DNA sequences that threaten genome integrity by replicative transposition in host gonads. The Piwi-interacting RNAs (piRNAs) pathway is assumed to maintain Drosophila genome homeostasis by downregulating transcriptional and post-transcriptional TE expression in the ovary. However, the bursts of transposition that are expected to follow transposome derepression after piRNA pathway impairment have not yet been reported. Here, we show, at a genome-wide level, that piRNA loss in the ovarian somatic cells boosts several families of the endogenous retroviral subclass of TEs, at various steps of their replication cycle, from somatic transcription to germinal genome invasion. For some of these TEs, the derepression caused by the loss of piRNAs is backed up by another small RNA pathway (siRNAs) operating in somatic tissues at the post transcriptional level. Derepressed transposition during 70 successive generations of piRNA loss exponentially increases the genomic copy number by up to 10-fold.
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Affiliation(s)
| | - Marianne El-Barouk
- IGH, CNRS, Univ. Montpellier, Montpellier, France.,Institut Cochin, Paris, France
| | | | - Bruno Mugat
- IGH, CNRS, Univ. Montpellier, Montpellier, France
| | - Blaise Li
- IGH, CNRS, Univ. Montpellier, Montpellier, France.,Institut Pasteur, Bioinformatics and Biostatistics Hub, C3BI, USR 3756, IP CNRS, Paris France
| | | | | | - Marie Mirouze
- LGPD, CNRS, Univ Perpignan Via Domitia, Perpignan, France
| | - Marie Fablet
- Université de Lyon; Université Lyon 1; CNRS; UMR 5558, Laboratoire de Biométrie et Biologie Evolutive. 43 Boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France
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34
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Rogivue A, Choudhury RR, Zoller S, Joost S, Felber F, Kasser M, Parisod C, Gugerli F. Genome-wide variation in nucleotides and retrotransposons in alpine populations of Arabis alpina (Brassicaceae). Mol Ecol Resour 2019; 19:773-787. [PMID: 30636378 DOI: 10.1111/1755-0998.12991] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 02/01/2023]
Abstract
Advances in high-throughput sequencing have promoted the collection of reference genomes and genome-wide diversity. However, the assessment of genomic variation among populations has hitherto mainly been surveyed through single-nucleotide polymorphisms (SNPs) and largely ignored the often major fraction of genomes represented by transposable elements (TEs). Despite accumulating evidence supporting the evolutionary significance of TEs, comprehensive surveys remain scarce. Here, we sequenced the full genomes of 304 individuals of Arabis alpina sampled from four nearby natural populations to genotype SNPs as well as polymorphic long terminal repeat retrotransposons (polymorphic TEs; i.e., presence/absence of TE insertions at specific loci). We identified 291,396 SNPs and 20,548 polymorphic TEs, comparing their contributions to genomic diversity and divergence across populations. Few SNPs were shared among populations and overall showed high population-specific variation, whereas most polymorphic TEs segregated among populations. The genomic context of these two classes of variants further highlighted candidate adaptive loci having a putative impact on functional genes. In particular, 4.96% of the SNPs were identified as nonsynonymous or affecting start/stop codons. In contrast, 43% of the polymorphic TEs were present next to Arabis genes enriched in functional categories related to the regulation of reproduction and responses to biotic as well as abiotic stresses. This unprecedented data set, mapping variation gained from SNPs and complementary polymorphic TEs within and among populations, will serve as a rich resource for addressing microevolutionary processes shaping genome variation.
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Affiliation(s)
- Aude Rogivue
- WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
| | - Rimjhim R Choudhury
- University of Neuchâtel, Neuchâtel, Switzerland.,Institute of Plant Sciences, University of Berne, Bern, Switzerland
| | - Stefan Zoller
- Genetic Diversity Centre, ETH Zürich, Zürich, Switzerland
| | - Stéphane Joost
- Laboratory of Geographic Information Systems (LASIG), School of Architecture, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - François Felber
- University of Neuchâtel, Neuchâtel, Switzerland.,Musée et Jardins botaniques cantonaux, Lausanne, Switzerland
| | | | | | - Felix Gugerli
- WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
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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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Erwin AA, Blumenstiel JP. Aging in the Drosophila ovary: contrasting changes in the expression of the piRNA machinery and mitochondria but no global release of transposable elements. BMC Genomics 2019; 20:305. [PMID: 31014230 PMCID: PMC6480902 DOI: 10.1186/s12864-019-5668-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 04/08/2019] [Indexed: 01/06/2023] Open
Abstract
Background Evolutionary theory indicates that the dynamics of aging in the soma and reproductive tissues may be distinct. This difference arises from the fact that only the germline lineage establishes future generations. In the soma, changes in the landscape of heterochromatin have been proposed to have an important role in aging. This is because redistribution of heterochromatin during aging has been linked to the derepression of transposable elements and an overall loss of somatic gene regulation. A role for changes in the chromatin landscape in the aging of reproductive tissues is less well established. Whether or not epigenetic factors, such as heterochromatin marks, are perturbed in aging reproductive tissues is of interest because, in special cases, epigenetic variation may be heritable. Using mRNA sequencing data from late-stage egg chambers in Drosophila melanogaster, we characterized the landscape of altered gene and transposable element expression in aged reproductive tissues. This allowed us to test the hypothesis that reproductive tissues may differ from somatic tissues in their response to aging. Results We show that age-related expression changes in late-stage egg chambers tend to occur in genes residing in heterochromatin, particularly on the largely heterochromatic 4th chromosome. However, these expression differences are seen as both decreases and increases during aging, inconsistent with a general loss of heterochromatic silencing. We also identify an increase in expression of the piRNA machinery, suggesting an age-related increased investment in the maintenance of genome stability. We further identify a strong age-related reduction in the expression of mitochondrial transcripts. However, we find no evidence for global TE derepression in reproductive tissues. Rather, the observed effects of aging on TEs are primarily strain and family specific. Conclusions These results identify unique responses in somatic versus reproductive tissue with regards to aging. As in somatic tissues, female reproductive tissues show reduced expression of mitochondrial genes. In contrast, the piRNA machinery shows increased expression during aging. Overall, these results also indicate that global loss of TE control observed in other studies may be unique to the soma and sensitive to genetic background and TE family. Electronic supplementary material The online version of this article (10.1186/s12864-019-5668-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexandra A Erwin
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA.
| | - Justin P Blumenstiel
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA.
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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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Guio L, González J. New Insights on the Evolution of Genome Content: Population Dynamics of Transposable Elements in Flies and Humans. Methods Mol Biol 2019; 1910:505-530. [PMID: 31278675 DOI: 10.1007/978-1-4939-9074-0_16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Understanding the abundance, diversity, and distribution of TEs in genomes is crucial to understand genome structure, function, and evolution. Advances in whole-genome sequencing techniques, as well as in bioinformatics tools, have increased our ability to detect and analyze the transposable element content in genomes. In addition to reference genomes, we now have access to population datasets in which multiple individuals within a species are sequenced. In this chapter, we highlight the recent advances in the study of TE population dynamics focusing on fruit flies and humans, which represent two extremes in terms of TE abundance, diversity, and activity. We review the most recent methodological approaches applied to the study of TE dynamics as well as the new knowledge on host factors involved in the regulation of TE activity. In addition to transposition rates, we also focus on TE deletion rates and on the selective forces that affect the dynamics of TEs in genomes.
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Affiliation(s)
- Lain Guio
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Josefa González
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain.
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Novel roles of Drosophila FUS and Aub responsible for piRNA biogenesis in neuronal disorders. Brain Res 2018; 1708:207-219. [PMID: 30578769 DOI: 10.1016/j.brainres.2018.12.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 11/16/2018] [Accepted: 12/19/2018] [Indexed: 02/08/2023]
Abstract
piRNAs, small non-coding RNAs, were considered to be restricted to germline cells. Although they have recently been detected in somatic cells including neurons, it remains unclear how piRNA biogenesis is involved in neuronal diseases. We herein examined the possible roles of Aubergine (Aub), a Piwi-family protein (PIWI) responsible for piRNA biogenesis, in the neuronal disorders, using the Cabeza (Caz) knockdown Drosophila. Caz is a Drosophila homologue of FUS, which is one of the genes causing amyotrophic lateral sclerosis (ALS). Aub overexpression enhanced the mobility defects accompanied by anatomical defects in motoneurons at neuromuscular junctions induced by the neuron-specific knockdown of Caz. In order to elucidate the underlying mechanisms, we examined pre-piRNA and mature-size piRNA levels under these conditions. qRT-PCR and RNA-seq analyses revealed that the Caz knockdown increased pre-piRNA levels, but reduced mature-size piRNA levels in the central nervous system (CNS), suggesting a role in the pre-piRNAs production. Aub overexpression did not increase mature-size piRNA levels. These results suggest that the accumulated pre-piRNAs are abnormal abortive pre-piRNAs that cannot be further processed by slicers, including Aub. We also demonstrated a relationship between Caz and pre-piRNAs in the CNS by RNA immunoprecipitation. Aub overexpression induced the abnormal cytoplasmic localization of Caz. Based on these results, we propose a model in which Caz knockdown-induced abnormal pre-piRNAs associate with Caz, then translocate and accumulate in the cytoplasm, a process that may be mediated by Aub. The novel roles for Caz and Aub demonstrated herein using the Caz-knockdown fly will contribute to a deeper understanding of the pathogenesis of ALS.
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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: 647] [Impact Index Per Article: 107.8] [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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41
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Pereira CM, Stoffel TJR, Callegari-Jacques SM, Hua-Van A, Capy P, Loreto ELS. The somatic mobilization of transposable element mariner-Mos1 during the Drosophila lifespan and its biological consequences. Gene 2018; 679:65-72. [PMID: 30171941 DOI: 10.1016/j.gene.2018.08.079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/08/2018] [Accepted: 08/29/2018] [Indexed: 11/17/2022]
Abstract
Transposable elements (TEs) are mobile DNA sequences on genomes. Some elements are able to transpose in somatic cells, a process known as somatic transposition (ST), which has been associated with detrimental biological effects. The mariner-Mos1 element of Drosophila promotes transposition in somatic and germline cells and is an excellent model for studies related to the biological consequence of somatic excision (SE). In this work, we used temperature stress to induce increasing transposition of mariner-Mos1 during different stages of the development of D. simulans, aiming to quantify SE during lifespan. Furthermore, strains of D. melanogaster exhibiting differential expression of mariner-Mos1 were employed for estimating some biological consequences of mariner mobilization. It is shown that SE of mariner-Mos1 was not constant during development; the larval phase had the highest rates while the pupal stage exhibited lower rates, and in the embryonic stage, no difference was detected. SE can be detrimental, as suggested by correlation in SE level and reduction in behavioral activities and embryonic viability. This study showed that mariner-Mos1 SE accumulates during the Drosophila life cycle, and can be involved in detrimental effects.
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Affiliation(s)
- Camila M Pereira
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Tailini J R Stoffel
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Sidia M Callegari-Jacques
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Estatística, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Aurélie Hua-Van
- Laboratoire Evolution, Génomes, Comportement, Ecologie CNRS, Univ. Paris-Sud, IRD, Université Paris-Saclay, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
| | - Pierre Capy
- Laboratoire Evolution, Génomes, Comportement, Ecologie CNRS, Univ. Paris-Sud, IRD, Université Paris-Saclay, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
| | - Elgion L S Loreto
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, Brazil; Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Dep. Biochemistry and Molecular Biology -Universidade Federal de Santa Maria, Av. Roraima 1000, 97105900 Santa Maria, Brazil.
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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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43
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Croset V, Treiber CD, Waddell S. Cellular diversity in the Drosophila midbrain revealed by single-cell transcriptomics. eLife 2018; 7:34550. [PMID: 29671739 PMCID: PMC5927767 DOI: 10.7554/elife.34550] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/18/2018] [Indexed: 12/12/2022] Open
Abstract
To understand the brain, molecular details need to be overlaid onto neural wiring diagrams so that synaptic mode, neuromodulation and critical signaling operations can be considered. Single-cell transcriptomics provide a unique opportunity to collect this information. Here we present an initial analysis of thousands of individual cells from Drosophila midbrain, that were acquired using Drop-Seq. A number of approaches permitted the assignment of transcriptional profiles to several major brain regions and cell-types. Expression of biosynthetic enzymes and reuptake mechanisms allows all the neurons to be typed according to the neurotransmitter or neuromodulator that they produce and presumably release. Some neuropeptides are preferentially co-expressed in neurons using a particular fast-acting transmitter, or monoamine. Neuromodulatory and neurotransmitter receptor subunit expression illustrates the potential of these molecules in generating complexity in neural circuit function. This cell atlas dataset provides an important resource to link molecular operations to brain regions and complex neural processes.
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Affiliation(s)
- Vincent Croset
- Centre for Neural Circuits and Behaviour, The University of Oxford, Oxford, United Kingdom
| | - Christoph D Treiber
- Centre for Neural Circuits and Behaviour, The University of Oxford, Oxford, United Kingdom
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, The University of Oxford, Oxford, United Kingdom
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Kofler R. SimulaTE: simulating complex landscapes of transposable elements of populations. Bioinformatics 2018; 34:1419-1420. [PMID: 29186298 PMCID: PMC5905622 DOI: 10.1093/bioinformatics/btx772] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/11/2017] [Accepted: 11/25/2017] [Indexed: 11/14/2022] Open
Abstract
Motivation Estimating the abundance of transposable elements (TEs) in populations (or tissues) promises to answer many open research questions. However, progress is hampered by the lack of concordance between different approaches for TE identification and thus potentially unreliable results. Results To address this problem, we developed SimulaTE a tool that generates TE landscapes for populations using a newly developed domain specific language (DSL). The simple syntax of our DSL allows for easily building even complex TE landscapes that have, for example, nested, truncated and highly diverged TE insertions. Reads may be simulated for the populations using different sequencing technologies (PacBio, Illumina paired-ends) and strategies (sequencing individuals and pooled populations). The comparison between the expected (i.e. simulated) and the observed results will guide researchers in finding the most suitable approach for a particular research question. Availability and implementation SimulaTE is implemented in Python and available at https://sourceforge.net/projects/simulates/. Manual https://sourceforge.net/p/simulates/wiki/Home/#manual; Test data and tutorials https://sourceforge.net/p/simulates/wiki/Home/#walkthrough; Validation https://sourceforge.net/p/simulates/wiki/Home/#validation. Contact robert.kofler@vetmeduni.ac.at.
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Affiliation(s)
- Robert Kofler
- Institute für Populationsgenetik, Vetmeduni Vienna, Wien, Austria
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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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46
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Treiber CD, Waddell S. Resolving the prevalence of somatic transposition in Drosophila. eLife 2017; 6. [PMID: 28742021 PMCID: PMC5553932 DOI: 10.7554/elife.28297] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/21/2017] [Indexed: 11/13/2022] Open
Abstract
Somatic transposition in mammals and insects could increase cellular diversity and neural mobilization has been implicated in age-dependent decline. To understand the impact of transposition in somatic cells it is essential to reliably measure the frequency and map locations of new insertions. Here we identified thousands of putative somatic transposon insertions in neurons from individual Drosophila melanogaster using whole-genome sequencing. However, the number of de novo insertions did not correlate with transposon expression or fly age. Analysing our data with exons as 'immobile genetic elements' revealed a similar frequency of unexpected exon translocations. A new sequencing strategy that recovers transposon: chromosome junction information revealed most putative de novo transposon and exon insertions likely result from unavoidable chimeric artefacts. Reanalysis of other published data suggests similar artefacts are often mistaken for genuine somatic transposition. We conclude that somatic transposition is less prevalent in Drosophila than previously envisaged.
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Affiliation(s)
- Christoph D Treiber
- Centre for Neural Circuits and Behaviour, The University of Oxford, Oxford, United Kingdom
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, The University of Oxford, Oxford, United Kingdom
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