51
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Abstract
The mechanisms by which DNA viruses adapt and evolve over time include minor accumulated changes associated with genetic drift – such as single nucleotide changes and small insertions or deletions – as well as more substantial changes equivalent to genetic shift. The latter case is most often driven by recombination between co-replicating genomes of the same or different species, but it can also include large segmental duplications and functionally tolerated deletions. Finally, instances of genetic exchange between virus and host or between virus species – i.e., horizontal gene transfer (HGT) – have driven the evolution of DNA viruses as well as their host organisms.
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52
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Fambrini M, Usai G, Vangelisti A, Mascagni F, Pugliesi C. The plastic genome: The impact of transposable elements on gene functionality and genomic structural variations. Genesis 2020; 58:e23399. [DOI: 10.1002/dvg.23399] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Marco Fambrini
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
| | - Gabriele Usai
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
| | - Alberto Vangelisti
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
| | - Flavia Mascagni
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
| | - Claudio Pugliesi
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
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53
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Abstract
Transposable elements (TEs) are mobile DNA sequences that propagate within genomes. Through diverse invasion strategies, TEs have come to occupy a substantial fraction of nearly all eukaryotic genomes, and they represent a major source of genetic variation and novelty. Here we review the defining features of each major group of eukaryotic TEs and explore their evolutionary origins and relationships. We discuss how the unique biology of different TEs influences their propagation and distribution within and across genomes. Environmental and genetic factors acting at the level of the host species further modulate the activity, diversification, and fate of TEs, producing the dramatic variation in TE content observed across eukaryotes. We argue that cataloging TE diversity and dissecting the idiosyncratic behavior of individual elements are crucial to expanding our comprehension of their impact on the biology of genomes and the evolution of species.
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Affiliation(s)
- Jonathan N Wells
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850; ,
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850; ,
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54
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de Melo ES, Wallau GL. Mosquito genomes are frequently invaded by transposable elements through horizontal transfer. PLoS Genet 2020; 16:e1008946. [PMID: 33253164 PMCID: PMC7728395 DOI: 10.1371/journal.pgen.1008946] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 12/10/2020] [Accepted: 10/19/2020] [Indexed: 12/28/2022] Open
Abstract
Transposable elements (TEs) are mobile genetic elements that parasitize basically all eukaryotic species genomes. Due to their complexity, an in-depth TE characterization is only available for a handful of model organisms. In the present study, we performed a de novo and homology-based characterization of TEs in the genomes of 24 mosquito species and investigated their mode of inheritance. More than 40% of the genome of Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus is composed of TEs, while it varied substantially among Anopheles species (0.13%-19.55%). Class I TEs are the most abundant among mosquitoes and at least 24 TE superfamilies were found. Interestingly, TEs have been extensively exchanged by horizontal transfer (172 TE families of 16 different superfamilies) among mosquitoes in the last 30 million years. Horizontally transferred TEs represents around 7% of the genome in Aedes species and a small fraction in Anopheles genomes. Most of these horizontally transferred TEs are from the three ubiquitous LTR superfamilies: Gypsy, Bel-Pao and Copia. Searching more than 32,000 genomes, we also uncovered transfers between mosquitoes and two different Phyla-Cnidaria and Nematoda-and two subphyla-Chelicerata and Crustacea, identifying a vector, the worm Wuchereria bancrofti, that enabled the horizontal spread of a Tc1-mariner element among various Anopheles species. These data also allowed us to reconstruct the horizontal transfer network of this TE involving more than 40 species. In summary, our results suggest that TEs are frequently exchanged by horizontal transfers among mosquitoes, influencing mosquito's genome size and variability.
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Affiliation(s)
- Elverson Soares de Melo
- Department of Entomology, Aggeu Magalhães Institute–Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
| | - Gabriel Luz Wallau
- Department of Entomology, Aggeu Magalhães Institute–Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
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55
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Yang J, Yuan B, Wu Y, Li M, Li J, Xu D, Gao ZH, Ma G, Zhou Y, Zuo Y, Wang J, Guo Y. The wide distribution and horizontal transfers of beta satellite DNA in eukaryotes. Genomics 2020; 112:5295-5304. [PMID: 33065245 DOI: 10.1016/j.ygeno.2020.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 09/08/2020] [Accepted: 10/10/2020] [Indexed: 01/12/2023]
Abstract
Beta satellite DNA (satDNA), also known as Sau3A sequences, are repetitive DNA sequences reported in human and primate genomes. It is previously thought that beta satDNAs originated in old world monkeys and bursted in great apes. In this study, we searched 7821 genome assemblies of 3767 eukaryotic species and found that beta satDNAs are widely distributed across eukaryotes. The four major branches of eukaryotes, animals, fungi, plants and Harosa/SAR, all have multiple clades containing beta satDNAs. These results were also confirmed by searching whole genome sequencing data (SRA) and PCR assay. Beta satDNA sequences were found in all the primate clades, as well as in Dermoptera and Scandentia, indicating that the beta satDNAs in primates might originate in the common ancestor of Primatomorpha or Euarchonta. In contrast, the widely patchy distribution of beta satDNAs across eukaryotes presents a typical scenario of multiple horizontal transfers.
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Affiliation(s)
- Jiawen Yang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, China.
| | - Bin Yuan
- Institute of Plant Protection and Soil Fertilizer, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Yu Wu
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, China.
| | - Meiyu Li
- Key Laboratory of Tropical Disease Control, Sun Yat-Sen University; Ministry of Education Experimental Teaching Center, Zhongshan School of Medicine, Sun Yat-sen University, China.
| | - Jian Li
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
| | - Donglin Xu
- Guangzhou Academy of Agricultural Sciences, Guangzhou, China
| | - Zeng-Hong Gao
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
| | - Guangwei Ma
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yiting Zhou
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
| | - Yachao Zuo
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, China.
| | - Jin Wang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
| | - Yabin Guo
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
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56
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Galbraith JD, Ludington AJ, Suh A, Sanders KL, Adelson DL. New Environment, New Invaders-Repeated Horizontal Transfer of LINEs to Sea Snakes. Genome Biol Evol 2020; 12:2370-2383. [PMID: 33022046 PMCID: PMC7846101 DOI: 10.1093/gbe/evaa208] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2020] [Indexed: 12/12/2022] Open
Abstract
Although numerous studies have found horizontal transposon transfer (HTT) to be widespread across metazoans, few have focused on HTT in marine ecosystems. To investigate potential recent HTTs into marine species, we searched for novel repetitive elements in sea snakes, a group of elapids which transitioned to a marine habitat at most 18 Ma. Our analysis uncovered repeated HTTs into sea snakes following their marine transition. The seven subfamilies of horizontally transferred LINE retrotransposons we identified in the olive sea snake (Aipysurus laevis) are transcribed, and hence are likely still active and expanding across the genome. A search of 600 metazoan genomes found all seven were absent from other amniotes, including terrestrial elapids, with the most similar LINEs present in fish and marine invertebrates. The one exception was a similar LINE found in sea kraits, a lineage of amphibious elapids which independently transitioned to a marine environment 25 Ma. Our finding of repeated horizontal transfer events into marine snakes greatly expands past findings that the marine environment promotes the transfer of transposons. Transposons are drivers of evolution as sources of genomic sequence and hence genomic novelty. We identified 13 candidate genes for HTT-induced adaptive change based on internal or neighboring HTT LINE insertions. One of these, ADCY4, is of particular interest as a part of the KEGG adaptation pathway “Circadian Entrainment.” This provides evidence of the ecological interactions between species influencing evolution of metazoans not only through specific selection pressures, but also by contributing novel genomic material.
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Affiliation(s)
| | | | - Alexander Suh
- Department of Ecology and Genetics-Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Sweden.,Department of Organismal Biology-Systematic Biology, Evolutionary Biology Centre, Uppsala University, Sweden.,School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Kate L Sanders
- School of Biological Sciences, University of Adelaide, Australia
| | - David L Adelson
- School of Biological Sciences, University of Adelaide, Australia
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57
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Amberger M, Ivics Z. Latest Advances for the Sleeping Beauty Transposon System: 23 Years of Insomnia but Prettier than Ever: Refinement and Recent Innovations of the Sleeping Beauty Transposon System Enabling Novel, Nonviral Genetic Engineering Applications. Bioessays 2020; 42:e2000136. [PMID: 32939778 DOI: 10.1002/bies.202000136] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/29/2020] [Indexed: 12/13/2022]
Abstract
The Sleeping Beauty transposon system is a nonviral DNA transfer tool capable of efficiently mediating transposition-based, stable integration of DNA sequences of choice into eukaryotic genomes. Continuous refinements of the system, including the emergence of hyperactive transposase mutants and novel approaches in vectorology, greatly improve upon transposition efficiency rivaling viral-vector-based methods for stable gene insertion. Current developments, such as reversible transgenesis and proof-of-concept RNA-guided transposition, further expand on possible applications in the future. In addition, innate advantages such as lack of preferential integration into genes reduce insertional mutagenesis-related safety concerns while comparably low manufacturing costs enable widespread implementation. Accordingly, the system is recognized as a powerful and versatile tool for genetic engineering and is playing a central role in an ever-expanding number of gene and cell therapy clinical trials with the potential to become a key technology to meet the growing demand for advanced therapy medicinal products.
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Affiliation(s)
- Maximilian Amberger
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, D-63225, Germany
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, D-63225, Germany
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58
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Courtier‐Orgogozo V, Danchin A, Gouyon P, Boëte C. Evaluating the probability of CRISPR-based gene drive contaminating another species. Evol Appl 2020; 13:1888-1905. [PMID: 32908593 PMCID: PMC7463340 DOI: 10.1111/eva.12939] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/03/2020] [Accepted: 02/07/2020] [Indexed: 12/27/2022] Open
Abstract
The probability D that a given clustered regularly interspaced short palindromic repeats (CRISPR)-based gene drive element contaminates another, nontarget species can be estimated by the following Drive Risk Assessment Quantitative Estimate (DRAQUE) Equation: D = h y b + t r a n s f × e x p r e s s × c u t × f l a n k × i m m u n e × n o n e x t i n c t with hyb = probability of hybridization between the target species and a nontarget species; transf = probability of horizontal transfer of a piece of DNA containing the gene drive cassette from the target species to a nontarget species (with no hybridization); express = probability that the Cas9 and guide RNA genes are expressed; cut = probability that the CRISPR-guide RNA recognizes and cuts at a DNA site in the new host; flank = probability that the gene drive cassette inserts at the cut site; immune = probability that the immune system does not reject Cas9-expressing cells; nonextinct = probability of invasion of the drive within the population. We discuss and estimate each of the seven parameters of the equation, with particular emphasis on possible transfers within insects, and between rodents and humans. We conclude from current data that the probability of a gene drive cassette to contaminate another species is not insignificant. We propose strategies to reduce this risk and call for more work on estimating all the parameters of the formula.
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Affiliation(s)
| | - Antoine Danchin
- Institut Cochin INSERM U1016 – CNRS UMR8104 – Université Paris DescartesParisFrance
| | - Pierre‐Henri Gouyon
- Institut de Systématique, Évolution, BiodiversitéMuséum National d'Histoire NaturelleCNRSSorbonne UniversitéEPHEUAParisFrance
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59
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Douglas AE. Housing microbial symbionts: evolutionary origins and diversification of symbiotic organs in animals. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190603. [PMID: 32772661 DOI: 10.1098/rstb.2019.0603] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In many animal hosts, microbial symbionts are housed within specialized structures known as symbiotic organs, but the evolutionary origins of these structures have rarely been investigated. Here, I adopt an evolutionary developmental (evo-devo) approach, specifically to apply knowledge of the development of symbiotic organs to gain insights into their evolutionary origins and diversification. In particular, host genetic changes associated with evolution of symbiotic organs can be inferred from studies to identify the host genes that orchestrate the development of symbiotic organs, recognizing that microbial products may also play a key role in triggering the developmental programme in some associations. These studies may also reveal whether higher animal taxonomic groups (order, class, phylum, etc.) possess a common genetic regulatory network for symbiosis that is latent in taxa lacking symbiotic organs, and activated at the origination of symbiosis in different host lineages. In this way, apparent instances of convergent evolution of symbiotic organs may be homologous in terms of a common genetic blueprint for symbiosis. Advances in genetic technologies, including reverse genetic tools and genome editing, will facilitate the application of evo-devo approaches to investigate the evolution of symbiotic organs in animals. This article is part of the theme issue 'The role of the microbiome in host evolution'.
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Affiliation(s)
- Angela E Douglas
- Department of Entomology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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60
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DNA methylation dynamics at transposable elements in mammals. Essays Biochem 2020; 63:677-689. [PMID: 31654072 DOI: 10.1042/ebc20190039] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 09/29/2019] [Accepted: 09/30/2019] [Indexed: 12/18/2022]
Abstract
Transposable elements dominate the mammalian genome, but their contribution to genetic and epigenetic regulation has been largely overlooked. This was in part due to technical limitations, which made the study of repetitive sequences at single copy resolution difficult. The advancement of next-generation sequencing assays in the last decade has greatly enhanced our understanding of transposable element function. In some instances, specific transposable elements are thought to have been co-opted into regulatory roles during both mouse and human development, while in disease such regulatory potential can contribute to malignancy. DNA methylation is arguably the best characterised regulator of transposable element activity. DNA methylation is associated with transposable element repression, and acts to limit their genotoxic potential. In specific developmental contexts, erasure of DNA methylation is associated with a burst of transposable element expression. Developmental regulation of DNA methylation enables transposon activation, ensuring their survival and propagation throughout the host genome, and also allows the host access to regulatory sequences encoded within the elements. Here I discuss DNA methylation at transposable elements, describing its function and dynamic regulation throughout murine and human development.
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61
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Koonin EV, Dolja VV, Krupovic M, Varsani A, Wolf YI, Yutin N, Zerbini FM, Kuhn JH. Global Organization and Proposed Megataxonomy of the Virus World. Microbiol Mol Biol Rev 2020; 84:e00061-19. [PMID: 32132243 PMCID: PMC7062200 DOI: 10.1128/mmbr.00061-19] [Citation(s) in RCA: 324] [Impact Index Per Article: 81.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Viruses and mobile genetic elements are molecular parasites or symbionts that coevolve with nearly all forms of cellular life. The route of virus replication and protein expression is determined by the viral genome type. Comparison of these routes led to the classification of viruses into seven "Baltimore classes" (BCs) that define the major features of virus reproduction. However, recent phylogenomic studies identified multiple evolutionary connections among viruses within each of the BCs as well as between different classes. Due to the modular organization of virus genomes, these relationships defy simple representation as lines of descent but rather form complex networks. Phylogenetic analyses of virus hallmark genes combined with analyses of gene-sharing networks show that replication modules of five BCs (three classes of RNA viruses and two classes of reverse-transcribing viruses) evolved from a common ancestor that encoded an RNA-directed RNA polymerase or a reverse transcriptase. Bona fide viruses evolved from this ancestor on multiple, independent occasions via the recruitment of distinct cellular proteins as capsid subunits and other structural components of virions. The single-stranded DNA (ssDNA) viruses are a polyphyletic class, with different groups evolving by recombination between rolling-circle-replicating plasmids, which contributed the replication protein, and positive-sense RNA viruses, which contributed the capsid protein. The double-stranded DNA (dsDNA) viruses are distributed among several large monophyletic groups and arose via the combination of distinct structural modules with equally diverse replication modules. Phylogenomic analyses reveal the finer structure of evolutionary connections among RNA viruses and reverse-transcribing viruses, ssDNA viruses, and large subsets of dsDNA viruses. Taken together, these analyses allow us to outline the global organization of the virus world. Here, we describe the key aspects of this organization and propose a comprehensive hierarchical taxonomy of viruses.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Valerian V Dolja
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Mart Krupovic
- Institut Pasteur, Archaeal Virology Unit, Department of Microbiology, Paris, France
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Structural Biology Research Unit, Department of Clinical Laboratory Sciences, University of Cape Town, Observatory, Cape Town, South Africa
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - F Murilo Zerbini
- Departamento de Fitopatologia/Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, USA
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62
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Abstract
Transposons are major genome constituents that can mobilize and trigger mutations, DNA breaks and chromosome rearrangements. Transposon silencing is particularly important in the germline, which is dedicated to transmission of the inherited genome. Piwi-interacting RNAs (piRNAs) guide a host defence system that transcriptionally and post-transcriptionally silences transposons during germline development. While germline control of transposons by the piRNA pathway is conserved, many piRNA pathway genes are evolving rapidly under positive selection, and the piRNA biogenesis machinery shows remarkable phylogenetic diversity. Conservation of core function combined with rapid gene evolution is characteristic of a host–pathogen arms race, suggesting that transposons and the piRNA pathway are engaged in an evolutionary tug of war that is driving divergence of the biogenesis machinery. Recent studies suggest that this process may produce biochemical incompatibilities that contribute to reproductive isolation and species divergence.
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Affiliation(s)
- Swapnil S Parhad
- Program in Molecular Medicine, University of Massachusetts Medical School , 373 Plantation Street, Worcester, MA 01605 , USA
| | - William E Theurkauf
- Program in Molecular Medicine, University of Massachusetts Medical School , 373 Plantation Street, Worcester, MA 01605 , USA
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63
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Zhang HH, Peccoud J, Xu MRX, Zhang XG, Gilbert C. Horizontal transfer and evolution of transposable elements in vertebrates. Nat Commun 2020; 11:1362. [PMID: 32170101 PMCID: PMC7070016 DOI: 10.1038/s41467-020-15149-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 02/20/2020] [Indexed: 11/13/2022] Open
Abstract
Horizontal transfer of transposable elements (HTT) is an important process shaping eukaryote genomes, yet very few studies have quantified this phenomenon on a large scale or have evaluated the selective constraints acting on transposable elements (TEs) during vertical and horizontal transmission. Here we screen 307 vertebrate genomes and infer a minimum of 975 independent HTT events between lineages that diverged more than 120 million years ago. HTT distribution greatly differs from null expectations, with 93.7% of these transfers involving ray-finned fishes and less than 3% involving mammals and birds. HTT incurs purifying selection (conserved protein evolution) on all TEs, confirming that producing functional transposition proteins is required for a TE to invade new genomes. In the absence of HTT, DNA transposons appear to evolve neutrally within genomes, unlike most retrotransposons, which evolve under purifying selection. This selection regime indicates that proteins of most retrotransposon families tend to process their own encoding RNA (cis-preference), which helps retrotransposons to persist within host lineages over long time periods. Horizontal transfer (HT) and evolution of transposable elements (TEs) has rarely been quantified on a large scale. Here, the authors screen 307 vertebrate genomes and infer 975 HT events (93% in ray-finned fishes); all TEs involved in HT evolve within genomes under purifying selection, as do most retrotransposons.
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Affiliation(s)
- Hua-Hao Zhang
- College of Pharmacy and Life Science, Jiujiang University, 332000, Jiujiang, China
| | - Jean Peccoud
- UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Université de Poitiers, 86073, Poitiers, France
| | - Min-Rui-Xuan Xu
- College of Pharmacy and Life Science, Jiujiang University, 332000, Jiujiang, China
| | - Xiao-Gu Zhang
- College of Pharmacy and Life Science, Jiujiang University, 332000, Jiujiang, China.
| | - Clément Gilbert
- Laboratoire Evolution, Génomes, Comportement, Écologie, UMR 9191 CNRS, UMR 247 IRD, Université Paris-Saclay, 91198, Gif-sur-Yvette, France.
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64
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Abstract
Since Barbara McClintock’s groundbreaking discovery of mobile DNA sequences some 70 years ago, transposable elements have come to be recognized as important mutagenic agents impacting genome composition, genome evolution, and human health. Transposable elements are a major constituent of prokaryotic and eukaryotic genomes, and the transposition mechanisms enabling transposon proliferation over evolutionary time remain engaging topics for study, suggesting complex interactions with the host, both antagonistic and mutualistic. The impact of transposition is profound, as over 100 human heritable diseases have been attributed to transposon insertions. Transposition can be highly mutagenic, perturbing genome integrity and gene expression in a wide range of organisms. This mutagenic potential has been exploited in the laboratory, where transposons have long been utilized for phenotypic screening and the generation of defined mutant libraries. More recently, barcoding applications and methods for RNA-directed transposition are being used towards new phenotypic screens and studies relevant for gene therapy. Thus, transposable elements are significant in affecting biology both
in vivo and in the laboratory, and this review will survey advances in understanding the biological role of transposons and relevant laboratory applications of these powerful molecular tools.
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Affiliation(s)
- Anuj Kumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.,Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, USA
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65
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Chalmers TJ, Wu LE. Transposable Elements Cross Kingdom Boundaries and Contribute to Inflammation and Ageing: Somatic Acquisition of Foreign Transposable Elements as a Catalyst of Genome Instability, Epigenetic Dysregulation, Inflammation, Senescence, and Ageing. Bioessays 2020; 42:e1900197. [PMID: 31994769 DOI: 10.1002/bies.201900197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/23/2019] [Indexed: 01/07/2023]
Abstract
The de-repression of transposable elements (TEs) in mammalian genomes is thought to contribute to genome instability, inflammation, and ageing, yet is viewed as a cell-autonomous event. In contrast to mammalian cells, prokaryotes constantly exchange genetic material through TEs, crossing both cell and species barriers, contributing to rapid microbial evolution and diversity in complex communities such as the mammalian gut. Here, it is proposed that TEs released from prokaryotes in the microbiome or from pathogenic infections regularly cross the kingdom barrier to the somatic cells of their eukaryotic hosts. It is proposed this horizontal transfer of TEs from microbe to host is a stochastic, ongoing catalyst of genome destabilization, resulting in structural and epigenetic variations, and activation of well-evolved host defense mechanisms contributing to inflammation, senescence, and biological ageing. It is proposed that innate immunity pathways defend against the horizontal acquisition of microbial TEs, and that activation of this pathway during horizontal transposon transfer promotes chronic inflammation during ageing. Finally, it is suggested that horizontal acquisition of prokaryotic TEs into mammalian genomes has been masked and subsequently under-reported due to flaws in current sequencing pipelines, and new strategies to uncover these events are proposed.
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Affiliation(s)
| | - Lindsay E Wu
- School of Medical Sciences, UNSW, Sydney, NSW, 2052, Australia
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66
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Tambones IL, Haudry A, Simão MC, Carareto CMA. High frequency of horizontal transfer in Jockey families (LINE order) of drosophilids. Mob DNA 2019; 10:43. [PMID: 31709017 PMCID: PMC6829985 DOI: 10.1186/s13100-019-0184-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 10/09/2019] [Indexed: 11/30/2022] Open
Abstract
Background The use of large-scale genomic analyses has resulted in an improvement of transposable element sampling and a significant increase in the number of reported HTT (horizontal transfer of transposable elements) events by expanding the sampling of transposable element sequences in general and of specific families of these elements in particular, which were previously poorly sampled. In this study, we investigated the occurrence of HTT events in a group of elements that, until recently, were uncommon among the HTT records in Drosophila – the Jockey elements, members of the LINE (long interspersed nuclear element) order of non-LTR (long terminal repeat) retrotransposons. The sequences of 111 Jockey families deposited in Repbase that met the criteria of the analysis were used to identify Jockey sequences in 48 genomes of Drosophilidae (genus Drosophila, subgenus Sophophora: melanogaster, obscura and willistoni groups; subgenus Drosophila: immigrans, melanica, repleta, robusta, virilis and grimshawi groups; subgenus Dorsilopha: busckii group; genus/subgenus Zaprionus and genus Scaptodrosophila). Results Phylogenetic analyses revealed 72 Jockey families in 41 genomes. Combined analyses revealed 15 potential HTT events between species belonging to different genera and species groups of Drosophilidae, providing evidence for the flow of genetic material favoured by the spatio-temporal sharing of these species present in the Palaeartic or Afrotropical region. Conclusions Our results provide phylogenetic, biogeographic and temporal evidence of horizontal transfers of the Jockey elements, increase the number of rare records of HTT in specific families of LINE elements, increase the number of known occurrences of these events, and enable a broad understanding of the evolutionary dynamics of these elements and the host species.
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Affiliation(s)
- Izabella L Tambones
- 1Department of Biology, Institute of Biosciences, Humanities and Exact Sciences (IBILCE), UNESP - São Paulo State University, Campus São José do Rio Preto, São Paulo, SP 15054-000 Brazil
| | - Annabelle Haudry
- 2Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, F-69622 Villeurbanne, France
| | - Maryanna C Simão
- 1Department of Biology, Institute of Biosciences, Humanities and Exact Sciences (IBILCE), UNESP - São Paulo State University, Campus São José do Rio Preto, São Paulo, SP 15054-000 Brazil
| | - Claudia M A Carareto
- 1Department of Biology, Institute of Biosciences, Humanities and Exact Sciences (IBILCE), UNESP - São Paulo State University, Campus São José do Rio Preto, São Paulo, SP 15054-000 Brazil
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Dechaud C, Volff JN, Schartl M, Naville M. Sex and the TEs: transposable elements in sexual development and function in animals. Mob DNA 2019; 10:42. [PMID: 31700550 PMCID: PMC6825717 DOI: 10.1186/s13100-019-0185-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/21/2019] [Indexed: 12/23/2022] Open
Abstract
Transposable elements are endogenous DNA sequences able to integrate into and multiply within genomes. They constitute a major source of genetic innovations, as they can not only rearrange genomes but also spread ready-to-use regulatory sequences able to modify host gene expression, and even can give birth to new host genes. As their evolutionary success depends on their vertical transmission, transposable elements are intrinsically linked to reproduction. In organisms with sexual reproduction, this implies that transposable elements have to manifest their transpositional activity in germ cells or their progenitors. The control of sexual development and function can be very versatile, and several studies have demonstrated the implication of transposable elements in the evolution of sex. In this review, we report the functional and evolutionary relationships between transposable elements and sexual reproduction in animals. In particular, we highlight how transposable elements can influence expression of sexual development genes, and how, reciprocally, they are tightly controlled in gonads. We also review how transposable elements contribute to the organization, expression and evolution of sexual development genes and sex chromosomes. This underscores the intricate co-evolution between host functions and transposable elements, which regularly shift from a parasitic to a domesticated status useful to the host.
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Affiliation(s)
- Corentin Dechaud
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d’Italie, F-69364 Lyon, France
| | - Jean-Nicolas Volff
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d’Italie, F-69364 Lyon, France
| | - Manfred Schartl
- Entwicklungsbiochemie, Biozentrum, Universität Würzburg, Würzburg, Germany
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX USA
| | - Magali Naville
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d’Italie, F-69364 Lyon, France
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68
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Cordeiro J, Carvalho TL, Valente VLDS, Robe LJ. Evolutionary history and classification of Micropia retroelements in Drosophilidae species. PLoS One 2019; 14:e0220539. [PMID: 31622354 PMCID: PMC6797199 DOI: 10.1371/journal.pone.0220539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/04/2019] [Indexed: 11/19/2022] Open
Abstract
Transposable elements (TEs) have the main role in shaping the evolution of genomes and host species, contributing to the creation of new genes and promoting rearrangements frequently associated with new regulatory networks. Support for these hypotheses frequently results from studies with model species, and Drosophila provides a great model organism to the study of TEs. Micropia belongs to the Ty3/Gypsy group of long terminal repeats (LTR) retroelements and comprises one of the least studied Drosophila transposable elements. In this study, we assessed the evolutionary history of Micropia within Drosophilidae, while trying to assist in the classification of this TE. At first, we performed searches of Micropia presence in the genome of natural populations from several species. Then, based on searches within online genomic databases, we retrieved Micropia-like sequences from the genomes of distinct Drosophilidae species. We expanded the knowledge of Micropia distribution within Drosophila species. The Micropia retroelements we detected consist of an array of divergent sequences, which we subdivided into 20 subfamilies. Even so, a patchy distribution of Micropia sequences within the Drosophilidae phylogeny could be identified, with incongruences between the species phylogeny and the Micropia phylogeny. Comparing the pairwise synonymous distance (dS) values between Micropia and three host nuclear sequences, we found several cases of unexpectedly high levels of similarity between Micropia sequences in divergent species. All these findings provide a hypothesis to the evolution of Micropia within Drosophilidae, which include several events of vertical and horizontal transposon transmission, associated with ancestral polymorphisms and recurrent Micropia sequences diversification.
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Affiliation(s)
- Juliana Cordeiro
- Departamento de Ecologia, Zoologia e Genética, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas, RS, Brazil
| | - Tuane Letícia Carvalho
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Vera Lúcia da Silva Valente
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre; Rio Grande do Sul; Brazil
| | - Lizandra Jaqueline Robe
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Departamento de Ecologia e Evolução, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
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69
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Benoit M, Drost HG, Catoni M, Gouil Q, Lopez-Gomollon S, Baulcombe D, Paszkowski J. Environmental and epigenetic regulation of Rider retrotransposons in tomato. PLoS Genet 2019; 15:e1008370. [PMID: 31525177 PMCID: PMC6762207 DOI: 10.1371/journal.pgen.1008370] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/26/2019] [Accepted: 08/14/2019] [Indexed: 11/18/2022] Open
Abstract
Transposable elements in crop plants are the powerful drivers of phenotypic variation that has been selected during domestication and breeding programs. In tomato, transpositions of the LTR (long terminal repeat) retrotransposon family Rider have contributed to various phenotypes of agronomical interest, such as fruit shape and colour. However, the mechanisms regulating Rider activity are largely unknown. We have developed a bioinformatics pipeline for the functional annotation of retrotransposons containing LTRs and defined all full-length Rider elements in the tomato genome. Subsequently, we showed that accumulation of Rider transcripts and transposition intermediates in the form of extrachromosomal DNA is triggered by drought stress and relies on abscisic acid signalling. We provide evidence that residual activity of Rider is controlled by epigenetic mechanisms involving siRNAs and the RNA-dependent DNA methylation pathway. Finally, we demonstrate the broad distribution of Rider-like elements in other plant species, including crops. Our work identifies Rider as an environment-responsive element and a potential source of genetic and epigenetic variation in plants. Transposons are major constituents of plant genomes and represent a powerful source of internal genetic and epigenetic variation. For example, domestication of maize has been facilitated by a dramatic change in plant architecture, the consequence of a transposition event. Insertion of transposons near genes often confers quantitative phenotypic variation linked to changes in transcriptional patterns, as documented for blood oranges and grapes. In tomato, the most widely grown fruit crop and model for fleshy fruit biology, occurrences of several beneficial traits related to fruit shape and plant architecture are due to the activity of the transposon family Rider. While Rider represents a unique endogenous source of genetic and epigenetic variation, mechanisms regulating Rider activity remain unexplored. By achieving experimentally-controlled activation of the Rider family, we shed light on the regulation of these transposons by drought stress, signalling by phytohormones, as well as epigenetic pathways. Furthermore, we reveal the presence of Rider-like elements in other economically important crops such as rapeseed, beetroot and quinoa. This suggests that drought-inducible Rider activation could be further harnessed to generate genetic and epigenetic variation for crop breeding, and highlights the potential of transposon-directed mutagenesis for crop improvement.
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Affiliation(s)
- Matthias Benoit
- The Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
| | - Hajk-Georg Drost
- The Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Marco Catoni
- The Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Quentin Gouil
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Sara Lopez-Gomollon
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - David Baulcombe
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Jerzy Paszkowski
- The Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
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70
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Abstract
Transposable elements (TEs) are mobile DNA sequences that colonize genomes and threaten genome integrity. As a result, several mechanisms appear to have emerged during eukaryotic evolution to suppress TE activity. However, TEs are ubiquitous and account for a prominent fraction of most eukaryotic genomes. We argue that the evolutionary success of TEs cannot be explained solely by evasion from host control mechanisms. Rather, some TEs have evolved commensal and even mutualistic strategies that mitigate the cost of their propagation. These coevolutionary processes promote the emergence of complex cellular activities, which in turn pave the way for cooption of TE sequences for organismal function.
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Affiliation(s)
- Rachel L Cosby
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Ni-Chen Chang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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71
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Abstract
Maintenance of genome stability requires control over the expression of transposable elements (TEs), whose activity can have substantial deleterious effects on the host. Chemical modification of DNA is a commonly used strategy to achieve this, and it has long been argued that the emergence of 5-methylcytosine (5mC) in many species was driven by the requirement to silence TEs. Potential roles in TE regulation have also been suggested for other DNA modifications, such as N6-methyladenine and oxidation derivatives of 5mC, although the underlying mechanistic relationships are poorly understood. Here, we discuss current evidence implicating DNA modifications and DNA-modifying enzymes in TE regulation across different species.
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Affiliation(s)
- Özgen Deniz
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, UK
| | - Jennifer M Frost
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, UK
| | - Miguel R Branco
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, UK.
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72
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Patterson K, Shavarebi F, Magnan C, Chang I, Qi X, Baldi P, Bilanchone V, Sandmeyer SB. Local features determine Ty3 targeting frequency at RNA polymerase III transcription start sites. Genome Res 2019; 29:1298-1309. [PMID: 31249062 PMCID: PMC6673722 DOI: 10.1101/gr.240861.118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 06/12/2019] [Indexed: 12/27/2022]
Abstract
Retroelement integration into host genomes affects chromosome structure and function. A goal of a considerable number of investigations is to elucidate features influencing insertion site selection. The Saccharomyces cerevisiae Ty3 retrotransposon inserts proximal to the transcription start sites (TSS) of genes transcribed by RNA polymerase III (RNAP3). In this study, differential patterns of insertion were profiled genome-wide using a random barcode-tagged Ty3. Saturation transposition showed that tRNA genes (tDNAs) are targeted at widely different frequencies even within isoacceptor families. Ectopic expression of Ty3 integrase (IN) showed that it localized to targets independent of other Ty3 proteins and cDNA. IN, RNAP3, and transcription factor Brf1 were enriched at tDNA targets with high frequencies of transposition. To examine potential effects of cis-acting DNA features on transposition, targeting was tested on high-copy plasmids with restricted amounts of 5′ flanking sequence plus tDNA. Relative activity of targets was reconstituted in these constructions. Weighting of genomic insertions according to frequency identified an A/T-rich sequence followed by C as the dominant site of strand transfer. This site lies immediately adjacent to the adenines previously implicated in the RNAP3 TSS motif (CAA). In silico DNA structural analysis upstream of this motif showed that targets with elevated DNA curvature coincide with reduced integration. We propose that integration mediated by the Ty3 intasome complex (IN and cDNA) is subject to inputs from a combination of host factor occupancy and insertion site architecture, and that this results in the wide range of Ty3 targeting frequencies.
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Affiliation(s)
- Kurt Patterson
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California 92697, USA
| | - Farbod Shavarebi
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California 92697, USA
| | - Christophe Magnan
- School of Information and Computer Sciences, University of California, Irvine, Irvine, California 92697, USA
| | - Ivan Chang
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California 92697, USA
| | - Xiaojie Qi
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California 92697, USA
| | - Pierre Baldi
- School of Information and Computer Sciences, University of California, Irvine, Irvine, California 92697, USA
| | - Virginia Bilanchone
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California 92697, USA
| | - Suzanne B Sandmeyer
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California 92697, USA
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73
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Han G, Zhang N, Xu J, Jiang H, Ji C, Zhang Z, Song Q, Stanley D, Fang J, Wang J. Characterization of a novel Helitron family in insect genomes: insights into classification, evolution and horizontal transfer. Mob DNA 2019; 10:25. [PMID: 31164927 PMCID: PMC6544945 DOI: 10.1186/s13100-019-0165-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 04/30/2019] [Indexed: 01/09/2023] Open
Abstract
Background Helitrons play an important role in shaping eukaryotic genomes due to their ability to transfer horizontally between distantly related species and capture gene fragments during the transposition. However, the mechanisms of horizontal transfer (HT) and the process of gene fragment capturing of Helitrons still remain to be further clarified. Results Here, we characterized a novel Helitron family discontinuously distributed in 27 out of 256 insect genomes. The most prominent characteristic of Hel1 family is its high sequence similarity among species of different insect orders. Related elements were also identified in two spiders, representing the first report of spider Helitrons. All these elements were classified into 2 families, 9 subfamilies and 35 exemplars based on our new classification criteria. Autonomous partners of Helitron were reconstructed in the genomes of three insects and one spider. Integration pattern analysis showed that majority of Hel1A elements in Papilio xuthus and Pieris rapae inserted into introns. Consistent with filler DNA model, stepwise sequence acquisition was observed in Sfru_Hel1Aa, Sfru_Hel1Ab and Sfru_Hel1Ac in Spodoptera frugiperda. Remarkably, the evidence that Prap_Hel1Aa in a Lepdidoptera insect, Pieris rapae, was derived from Cves_Hel1Aa in a parasitoid wasp, Cotesia vestalis, suggested the role of nonregular host-parasite interactions in HT of Helitrons. Conclusions We proposed a modified classification criteria of Helitrons based on the important role of the 5′-end of Helitrons in transposition, and provided evidence for stepwise sequence acquisition and recurrent HT of a novel Helitron family. Our findings of the nonregular host-parasite interactions may be more conducive to the HT of transposons. Electronic supplementary material The online version of this article (10.1186/s13100-019-0165-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guangjie Han
- 1College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, 225009 China.,Jiangsu Lixiahe Institute of Agricultural Sciences, Yangzhou, 225007 China
| | - Nan Zhang
- 1College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, 225009 China
| | - Jian Xu
- Jiangsu Lixiahe Institute of Agricultural Sciences, Yangzhou, 225007 China
| | - Heng Jiang
- 1College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, 225009 China
| | - Caihong Ji
- 1College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, 225009 China
| | - Ze Zhang
- 3School of Life Sciences, Chongqing University, Chongqing, 400044 China
| | - Qisheng Song
- 4Division of Plant Sciences, University of Missouri, Columbia, MO USA
| | - David Stanley
- 5USDA/Agricultural Research Service, Biological Control of Insects Research Laboratory, Columbia, MO USA
| | - Jichao Fang
- 6Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014 China
| | - Jianjun Wang
- 1College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, 225009 China
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74
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Dunemann SM, Wasmuth JD. Horizontal transfer of a retrotransposon between parasitic nematodes and the common shrew. Mob DNA 2019; 10:24. [PMID: 31160924 PMCID: PMC6542046 DOI: 10.1186/s13100-019-0166-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 05/09/2019] [Indexed: 01/09/2023] Open
Abstract
Background As the genomes of more metazoan species are sequenced, reports of horizontal transposon transfers (HTT) have increased. Our understanding of the mechanisms of such events is at an early stage. The close physical relationship between a parasite and its host could facilitate horizontal transfer. To date, two studies have identified horizontal transfer of RTEs, a class of retrotransposable elements, involving parasites: ticks might act as vector for BovB between ruminants and squamates, and AviRTE was transferred between birds and parasitic nematodes. Results We searched for RTEs shared between nematode and mammalian genomes. Given their physical proximity, it was necessary to detect and remove sequence contamination from the genome datasets, which would otherwise distort the signal of horizontal transfer. We developed an approach that is based on reads instead of genomic sequences to reliably detect contamination. From comparison of 43 RTEs across 197 genomes, we identified a single putative case of horizontal transfer: we detected RTE1_Sar from Sorex araneus, the common shrew, in parasitic nematodes. From the taxonomic distribution and evolutionary analysis, we show that RTE1_Sar was horizontally transferred. Conclusion We identified a new horizontal RTE transfer in host-parasite interactions, which suggests that it is not uncommon. Further, we present and provide the workflow a read-based method to distinguish between contamination and horizontal transfer. Electronic supplementary material The online version of this article (10.1186/s13100-019-0166-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sonja M Dunemann
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, T2N 4Z6 Canada
| | - James D Wasmuth
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, T2N 4Z6 Canada
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75
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Yang L, Scott L, Wichman HA. Tracing the history of LINE and SINE extinction in sigmodontine rodents. Mob DNA 2019; 10:22. [PMID: 31139266 PMCID: PMC6530004 DOI: 10.1186/s13100-019-0164-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/30/2019] [Indexed: 12/18/2022] Open
Abstract
Background L1 retrotransposons have co-evolved with their mammalian hosts for the entire history of mammals and currently compose ~ 20% of a mammalian genome. B1 retrotransposons are dependent on L1 for retrotransposition and span the evolutionary history of rodents since their radiation. L1s were found to have lost their activity in a group of South American rodents, the Sigmodontinae, and B1 inactivation preceded the extinction of L1 in the same group. Consequently, a basal group of sigmodontines have active L1s but inactive B1s and a derived clade have both inactive L1s and B1s. It has been suggested that B1s became extinct during a long period of L1 quiescence and that L1s subsequently reemerged in the basal group. Results Here we investigate the evolutionary histories of L1 and B1 in the sigmodontine rodents and show that L1 activity continued until after the L1-extinct clade and the basal group diverged. After the split, L1 had a small burst of activity in the former group, followed by extinction. In the basal group, activity was initially low but was followed by a dramatic increase in L1 activity. We found the last wave of B1 retrotransposition was large and probably preceded the split between the two rodent clades. Conclusions Given that L1s had been steadily retrotransposing during the time corresponding to B1 extinction and that the burst of B1 activity preceding B1 extinction was large, we conclude that B1 extinction was not a result of L1 quiescence. Rather, the burst of B1 activity may have contributed to L1 extinction both by competition with L1 and by putting strong selective pressure on the host to control retrotransposition. Electronic supplementary material The online version of this article (10.1186/s13100-019-0164-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lei Yang
- 1Department of Biological Sciences, University of Idaho, Moscow, ID USA.,2Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID USA
| | - LuAnn Scott
- 1Department of Biological Sciences, University of Idaho, Moscow, ID USA.,2Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID USA
| | - Holly A Wichman
- 1Department of Biological Sciences, University of Idaho, Moscow, ID USA.,2Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID USA
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76
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Wu C, Lu J. Diversification of Transposable Elements in Arthropods and Its Impact on Genome Evolution. Genes (Basel) 2019; 10:genes10050338. [PMID: 31064091 PMCID: PMC6562904 DOI: 10.3390/genes10050338] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/09/2019] [Accepted: 04/26/2019] [Indexed: 12/22/2022] Open
Abstract
Transposable elements (TEs) are ubiquitous in arthropods. However, analyses of large-scale and long-term coevolution between TEs and host genomes remain scarce in arthropods. Here, we choose 14 representative Arthropoda species from eight orders spanning more than 500 million years of evolution. By developing an unbiased TE annotation pipeline, we obtained 87 to 2266 TE reference sequences in a species, which is a considerable improvement compared to the reference TEs previously annotated in Repbase. We find that TE loads are diversified among species and were previously underestimated. The highly species- and time-specific expansions and contractions, and intraspecific sequence diversification are the leading driver of long terminal repeat (LTR) dynamics in Lepidoptera. Terminal inverted repeats (TIRs) proliferated substantially in five species with large genomes. A phylogenetic comparison reveals that the loads of multiple TE subfamilies are positively correlated with genome sizes. We also identified a few horizontally transferred TE candidates across nine species. In addition, we set up the Arthropod Transposable Elements database (ArTEdb) to provide TE references and annotations. Collectively, our results provide high-quality TE references and uncover that TE loads and expansion histories vary greatly among arthropods, which implies that TEs are an important driving force shaping the evolution of genomes through gain and loss.
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Affiliation(s)
- Changcheng Wu
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing 100871, China.
| | - Jian Lu
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing 100871, China.
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77
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Blumenstiel JP. Birth, School, Work, Death, and Resurrection: The Life Stages and Dynamics of Transposable Element Proliferation. Genes (Basel) 2019; 10:genes10050336. [PMID: 31058854 PMCID: PMC6562965 DOI: 10.3390/genes10050336] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/18/2022] Open
Abstract
Transposable elements (TEs) can be maintained in sexually reproducing species even if they are harmful. However, the evolutionary strategies that TEs employ during proliferation can modulate their impact. In this review, I outline the different life stages of a TE lineage, from birth to proliferation to extinction. Through their interactions with the host, TEs can exploit diverse strategies that range from long-term coexistence to recurrent movement across species boundaries by horizontal transfer. TEs can also engage in a poorly understood phenomenon of TE resurrection, where TE lineages can apparently go extinct, only to proliferate again. By determining how this is possible, we may obtain new insights into the evolutionary dynamics of TEs and how they shape the genomes of their hosts.
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Affiliation(s)
- Justin P Blumenstiel
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66049, USA.
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78
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Palazzo A, Lorusso P, Miskey C, Walisko O, Gerbino A, Marobbio CMT, Ivics Z, Marsano RM. Transcriptionally promiscuous "blurry" promoters in Tc1/ mariner transposons allow transcription in distantly related genomes. Mob DNA 2019; 10:13. [PMID: 30988701 PMCID: PMC6446368 DOI: 10.1186/s13100-019-0155-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/26/2019] [Indexed: 12/04/2022] Open
Abstract
Background We have recently described a peculiar feature of the promoters in two Drosophila Tc1-like elements, Bari1 and Bari3. The AT-richness and the presence of weak core-promoter motifs make these promoters, that we have defined “blurry”, able to activate transcription of a reporter gene in cellular systems as diverse as fly, human, yeast and bacteria. In order to clarify whether the blurry promoter is a specific feature of the Bari transposon family, we have extended this study to promoters isolated from three additional DNA transposon and from two additional LTR retrotransposons. Results Here we show that the blurry promoter is also a feature of two vertebrate transposable elements, Sleeping Beauty and Hsmar1, belonging to the Tc1/mariner superfamily. In contrast, this feature is not shared by the promoter of the hobo transposon, which belongs to the hAT superfamily, nor by LTR retrotransposon-derived promoters, which, in general, do not activate transcription when introduced into non-related genomes. Conclusions Our results suggest that the blurry promoter could be a shared feature of the members of the Tc1/mariner superfamily with possible evolutionary and biotechnological implications. Electronic supplementary material The online version of this article (10.1186/s13100-019-0155-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Antonio Palazzo
- 1Department of Biology, University of Bari "Aldo Moro", via Orabona 4, 70125 Bari, Italy.,Present address: Laboratory of Translational Nanotechnology, "Istituto Tumori Giovanni Paolo II" I.R.C.C.S, Viale Orazio Flacco 65, 70125 Bari, Italy
| | - Patrizio Lorusso
- 1Department of Biology, University of Bari "Aldo Moro", via Orabona 4, 70125 Bari, Italy
| | - Csaba Miskey
- 2Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Oliver Walisko
- 2Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Andrea Gerbino
- 3Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | | | - Zoltán Ivics
- 2Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
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79
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Abstract
Transposable elements (TEs) are ubiquitous in both prokaryotes and eukaryotes, and the dynamic character of their interaction with host genomes brings about numerous evolutionary innovations and shapes genome structure and function in a multitude of ways. In traditional classification systems, TEs are often being depicted in simplistic ways, based primarily on the key enzymes required for transposition, such as transposases/recombinases and reverse transcriptases. Recent progress in whole-genome sequencing and long-read assembly, combined with expansion of the familiar range of model organisms, resulted in identification of unprecedentedly long transposable units spanning dozens or even hundreds of kilobases, initially in prokaryotic and more recently in eukaryotic systems. Here, we focus on such oversized eukaryotic TEs, including retrotransposons and DNA transposons, outline their complex and often combinatorial nature and closely intertwined relationship with viruses, and discuss their potential for participating in transfer of long stretches of DNA in eukaryotes.
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Affiliation(s)
- Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, Massachusetts
- Corresponding author: E-mail:
| | - Irina A Yushenova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, Massachusetts
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80
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Pischedda E, Scolari F, Valerio F, Carballar-Lejarazú R, Catapano PL, Waterhouse RM, Bonizzoni M. Insights Into an Unexplored Component of the Mosquito Repeatome: Distribution and Variability of Viral Sequences Integrated Into the Genome of the Arboviral Vector Aedes albopictus. Front Genet 2019; 10:93. [PMID: 30809249 PMCID: PMC6379468 DOI: 10.3389/fgene.2019.00093] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 01/29/2019] [Indexed: 01/01/2023] Open
Abstract
The Asian tiger mosquito Aedes albopictus is an invasive mosquito and a competent vector for public-health relevant arboviruses such as Chikungunya (Alphavirus), Dengue and Zika (Flavivirus) viruses. Unexpectedly, the sequencing of the genome of this mosquito revealed an unusually high number of integrated sequences with similarities to non-retroviral RNA viruses of the Flavivirus and Rhabdovirus genera. These Non-retroviral Integrated RNA Virus Sequences (NIRVS) are enriched in piRNA clusters and coding sequences and have been proposed to constitute novel mosquito immune factors. However, given the abundance of NIRVS and their variable viral origin, their relative biological roles remain unexplored. Here we used an analytical approach that intersects computational, evolutionary and molecular methods to study the genomic landscape of mosquito NIRVS. We demonstrate that NIRVS are differentially distributed across mosquito genomes, with a core set of seemingly the oldest integrations with similarity to Rhabdoviruses. Additionally, we compare the polymorphisms of NIRVS with respect to that of fast and slow-evolving genes within the Ae. albopictus genome. Overall, NIRVS appear to be less polymorphic than slow-evolving genes, with differences depending on whether they occur in intergenic regions or in piRNA clusters. Finally, two NIRVS that map within the coding sequences of genes annotated as Rhabdovirus RNA-dependent RNA polymerase and the nucleocapsid-encoding gene, respectively, are highly polymorphic and are expressed, suggesting exaptation possibly to enhance the mosquito's antiviral responses. These results greatly advance our understanding of the complexity of the mosquito repeatome and the biology of viral integrations in mosquito genomes.
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Affiliation(s)
- Elisa Pischedda
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Francesca Scolari
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Federica Valerio
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Rebeca Carballar-Lejarazú
- Department of Microbiology & Molecular Genetics, University of California, Irvine, Irvine, CA, United States
| | | | - Robert M. Waterhouse
- Department of Ecology and Evolution, University of Lausanne and Swiss Institute of Bioinformatics, Lausanne, Switzerland
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81
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Global survey of mobile DNA horizontal transfer in arthropods reveals Lepidoptera as a prime hotspot. PLoS Genet 2019; 15:e1007965. [PMID: 30707693 PMCID: PMC6373975 DOI: 10.1371/journal.pgen.1007965] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 02/13/2019] [Accepted: 01/16/2019] [Indexed: 12/24/2022] Open
Abstract
More than any other genome components, Transposable Elements (TEs) have the capacity to move across species barriers through Horizontal Transfer (HT), with substantial evolutionary consequences. Previous large-scale surveys, based on full-genomes comparisons, have revealed the transposition mode as an important predictor of HT rates variation across TE superfamilies. However, host biology could represent another major explanatory factor, one that needs to be investigated through extensive taxonomic sampling. Here we test this hypothesis using a field collection of 460 arthropod species from Tahiti and surrounding islands. Through targeted massive parallel sequencing, we uncover patterns of HT in three widely-distributed TE superfamilies with contrasted modes of transposition. In line with earlier findings, the DNA transposons under study (TC1-Mariner) were found to transfer horizontally at the highest frequency, closely followed by the LTR superfamily (Copia), in contrast with the non-LTR superfamily (Jockey), that mostly diversifies through vertical inheritance and persists longer within genomes. Strikingly, across all superfamilies, we observe a marked excess of HTs in Lepidoptera, an insect order that also commonly hosts baculoviruses, known for their ability to transport host TEs. These results turn the spotlight on baculoviruses as major potential vectors of TEs in arthropods, and further emphasize the importance of non-vertical TE inheritance in genome evolution. Transposable elements are chunks of DNA that can produce copies of themselves. New copies usually insert in the genome of their carrier but are occasionally subject to horizontal transmission between organisms, sometimes belonging to evolutionarily-distant lineages. Previous surveys have established that the probability of such events is largely conditioned by the transposition mechanism. For example, elements with an RNA intermediate tend to be less frequently involved in horizontal transfers. Here we investigate host taxa as another potential explanatory factor of variation in horizontal transfer rates. Using targeted sequencing in hundreds of insects and other arthropod species collected in South Pacific islands, we found that butterflies and moths (Lepidoptera) show an abnormally elevated rate of horizontal transfers. Previous studies have established that Lepidoptera are also commonly attacked by baculoviruses, large viruses that can transport host DNA. Taken together, these findings point to baculoviruses as a major suspect for transposable elements transfers across arthropod species.
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82
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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: 659] [Impact Index Per Article: 109.8] [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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83
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Ivancevic AM, Kortschak RD, Bertozzi T, Adelson DL. Horizontal transfer of BovB and L1 retrotransposons in eukaryotes. Genome Biol 2018; 19:85. [PMID: 29983116 PMCID: PMC6036668 DOI: 10.1186/s13059-018-1456-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 05/23/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Transposable elements (TEs) are mobile DNA sequences, colloquially known as jumping genes because of their ability to replicate to new genomic locations. TEs can jump between organisms or species when given a vector of transfer, such as a tick or virus, in a process known as horizontal transfer. Here, we propose that LINE-1 (L1) and Bovine-B (BovB), the two most abundant TE families in mammals, were initially introduced as foreign DNA via ancient horizontal transfer events. RESULTS Using analyses of 759 plant, fungal and animal genomes, we identify multiple possible L1 horizontal transfer events in eukaryotic species, primarily involving Tx-like L1s in marine eukaryotes. We also extend the BovB paradigm by increasing the number of estimated transfer events compared to previous studies, finding new parasite vectors of transfer such as bed bug, leech and locust, and BovB occurrences in new lineages such as bat and frog. Given that these transposable elements have colonised more than half of the genome sequence in today's mammals, our results support a role for horizontal transfer in causing long-term genomic change in new host organisms. CONCLUSIONS We describe extensive horizontal transfer of BovB retrotransposons and provide the first evidence that L1 elements can also undergo horizontal transfer. With the advancement of genome sequencing technologies and bioinformatics tools, we anticipate our study to be a valuable resource for inferring horizontal transfer from large-scale genomic data.
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Affiliation(s)
- Atma M Ivancevic
- Department of Genetics and Evolution, Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
- Neurogenetics Research Program, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - R Daniel Kortschak
- Department of Genetics and Evolution, Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Terry Bertozzi
- Department of Genetics and Evolution, Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
- Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, Australia
| | - David L Adelson
- Department of Genetics and Evolution, Biological Sciences, The University of Adelaide, Adelaide, SA, Australia.
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84
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Hill T, Betancourt AJ. Extensive exchange of transposable elements in the Drosophila pseudoobscura group. Mob DNA 2018; 9:20. [PMID: 29946370 PMCID: PMC6006672 DOI: 10.1186/s13100-018-0123-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/01/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND As species diverge, so does their transposable element (TE) content. Within a genome, TE families may eventually become dormant due to host-silencing mechanisms, natural selection and the accumulation of inactive copies. The transmission of active copies from a TE families, both vertically and horizontally between species, can allow TEs to escape inactivation if it occurs often enough, as it may allow TEs to temporarily escape silencing in a new host. Thus, the contribution of horizontal exchange to TE persistence has been of increasing interest. RESULTS Here, we annotated TEs in five species with sequenced genomes from the D. pseudoobscura species group, and curated a set of TE families found in these species. We found that, compared to host genes, many TE families showed lower neutral divergence between species, consistent with recent transmission of TEs between species. Despite these transfers, there are differences in the TE content between species in the group. CONCLUSIONS The TE content is highly dynamic in the D. pseudoobscura species group, frequently transferring between species, keeping TEs active. This result highlights how frequently transposable elements are transmitted between sympatric species and, despite these transfers, how rapidly species TE content can diverge.
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Affiliation(s)
- Tom Hill
- The Department of Molecular Biosciences, University of Kansas, 4055 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS 66045 USA
| | - Andrea J. Betancourt
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB UK
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