1
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Blumenstiel JP. From the cauldron of conflict: Endogenous gene regulation by piRNA and other modes of adaptation enabled by selfish transposable elements. Semin Cell Dev Biol 2025; 164:1-12. [PMID: 38823219 DOI: 10.1016/j.semcdb.2024.05.001] [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: 10/10/2023] [Revised: 04/28/2024] [Accepted: 05/06/2024] [Indexed: 06/03/2024]
Abstract
Transposable elements (TEs) provide a prime example of genetic conflict because they can proliferate in genomes and populations even if they harm the host. However, numerous studies have shown that TEs, though typically harmful, can also provide fuel for adaptation. This is because they code functional sequences that can be useful for the host in which they reside. In this review, I summarize the "how" and "why" of adaptation enabled by the genetic conflict between TEs and hosts. In addition, focusing on mechanisms of TE control by small piwi-interacting RNAs (piRNAs), I highlight an indirect form of adaptation enabled by conflict. In this case, mechanisms of host defense that regulate TEs have been redeployed for endogenous gene regulation. I propose that the genetic conflict released by meiosis in early eukaryotes may have been important because, among other reasons, it spurred evolutionary innovation on multiple interwoven trajectories - on the part of hosts and also embedded genetic parasites. This form of evolution may function as a complexity generating engine that was a critical player in eukaryotic evolution.
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Affiliation(s)
- Justin P Blumenstiel
- Department of Ecology and Evolutionary Biology, University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, United States.
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2
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Lee DH, Park EG, Kim JM, Shin HJ, Lee YJ, Jeong HS, Roh HY, Kim WR, Ha H, Kim SW, Choi YH, Kim HS. Genomic analyses of intricate interaction of TE-lncRNA overlapping genes with miRNAs in human diseases. Genes Genomics 2024:10.1007/s13258-024-01547-1. [PMID: 39215947 DOI: 10.1007/s13258-024-01547-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 07/09/2024] [Indexed: 09/04/2024]
Abstract
BACKGROUND Transposable elements (TEs) are known to be inserted into genome to create transcript isoforms or to generate long non-coding RNA (lncRNA) sequences. The insertion of TEs generates a gene protein sequence within the genome, but also provides a microRNA (miRNA) regulatory region. OBJECTIVE To determine the effect of gene sequence changes caused by TE insertion on miRNA binding and to investigate the formation of an overlapping lncRNA that represses it. METHODS The distribution of overlapping regions between exons and TE regions with lncRNA was examined using the Bedtools. miRNAs that can bind to those overlapping regions were identified through the miRDB web program. For TE-lncRNA overlapping genes, bioinformatic analysis was conducted using DAVID web database. Differential expression analysis was conducted using data from the GEO dataset and TCGA. RESULTS Most TEs were distributed more frequently in untranslated regions than open reading frames. There were 30 annotated TE-lncRNA overlapping genes with same strand that could bind to the same miRNA. As a result of identifying the association between these 30 genes and diseases, TGFB2, FCGR2A, DCTN5, and IFI6 were associated with breast cancer, and HMGCS1, FRMD4A, EDNRB, and SNCA were associated with Alzheimer's disease. Analysis of the GEO and TCGA data showed that the relevant expression of miR-891a and miR-28, which bind to the TE overlapping region of DCTN5 and HMGCS1, decreased. CONCLUSION This study indicates that the interaction between TE-lncRNA overlapping genes and miRNAs can affect disease progression.
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Affiliation(s)
- Du Hyeong Lee
- Department of Integrated Biological Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Eun Gyung Park
- Department of Integrated Biological Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Jung-Min Kim
- Department of Integrated Biological Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Hae Jin Shin
- Department of Integrated Biological Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Yun Ju Lee
- Department of Integrated Biological Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Hyeon-Su Jeong
- Department of Integrated Biological Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Hyun-Young Roh
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea
| | - Woo Ryung Kim
- Department of Integrated Biological Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea
| | - Hongseok Ha
- Institute of Endemic Disease, Medical Research Center, Seoul National University, Seoul, 03080, Republic of Korea
| | - Sang-Woo Kim
- Department of Integrated Biological Sciences, Pusan National University, Busan, 46241, Republic of Korea
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea
| | - Yung Hyun Choi
- Department of Biochemistry, College of Oriental Medicine, Dong-Eui University, Busan, 47227, Republic of Korea
| | - Heui-Soo Kim
- Institute of Systems Biology, Pusan National University, Busan, 46241, Republic of Korea.
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea.
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3
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Hu C, Zhu XT, He MH, Shao Y, Qin Z, Wu ZJ, Zhou JQ. Elimination of subtelomeric repeat sequences exerts little effect on telomere essential functions in Saccharomyces cerevisiae. eLife 2024; 12:RP91223. [PMID: 38656297 DOI: 10.7554/elife.91223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Telomeres, which are chromosomal end structures, play a crucial role in maintaining genome stability and integrity in eukaryotes. In the baker's yeast Saccharomyces cerevisiae, the X- and Y'-elements are subtelomeric repetitive sequences found in all 32 and 17 telomeres, respectively. While the Y'-elements serve as a backup for telomere functions in cells lacking telomerase, the function of the X-elements remains unclear. This study utilized the S. cerevisiae strain SY12, which has three chromosomes and six telomeres, to investigate the role of X-elements (as well as Y'-elements) in telomere maintenance. Deletion of Y'-elements (SY12YΔ), X-elements (SY12XYΔ+Y), or both X- and Y'-elements (SY12XYΔ) did not impact the length of the terminal TG1-3 tracks or telomere silencing. However, inactivation of telomerase in SY12YΔ, SY12XYΔ+Y, and SY12XYΔ cells resulted in cellular senescence and the generation of survivors. These survivors either maintained their telomeres through homologous recombination-dependent TG1-3 track elongation or underwent microhomology-mediated intra-chromosomal end-to-end joining. Our findings indicate the non-essential role of subtelomeric X- and Y'-elements in telomere regulation in both telomerase-proficient and telomerase-null cells and suggest that these elements may represent remnants of S. cerevisiae genome evolution. Furthermore, strains with fewer or no subtelomeric elements exhibit more concise telomere structures and offer potential models for future studies in telomere biology.
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Affiliation(s)
- Can Hu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Xue-Ting Zhu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Ming-Hong He
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Yangyang Shao
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Zhongjun Qin
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Zhi-Jing Wu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
- Key Laboratory of Systems Health Science of Zhejiang Province, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
| | - Jin-Qiu Zhou
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
- Key Laboratory of Systems Health Science of Zhejiang Province, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
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4
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Lyčka M, Bubeník M, Závodník M, Peska V, Fajkus P, Demko M, Fajkus J, Fojtová M. TeloBase: a community-curated database of telomere sequences across the tree of life. Nucleic Acids Res 2024; 52:D311-D321. [PMID: 37602392 PMCID: PMC10767889 DOI: 10.1093/nar/gkad672] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/27/2023] [Accepted: 08/14/2023] [Indexed: 08/22/2023] Open
Abstract
Discoveries over the recent decade have demonstrated the unexpected diversity of telomere DNA motifs in nature. However, currently available resources, 'Telomerase database' and 'Plant rDNA database', contain just fragments of all relevant literature published over decades of telomere research as they have a different primary focus and limited updates. To fill this gap, we gathered data about telomere DNA sequences from a thorough literature screen as well as by analysing publicly available NGS data, and we created TeloBase (http://cfb.ceitec.muni.cz/telobase/) as a comprehensive database of information about telomere motif diversity. TeloBase is supplemented by internal taxonomy utilizing popular on-line taxonomic resources that enables in-house data filtration and graphical visualisation of telomere DNA evolutionary dynamics in the form of heat tree plots. TeloBase avoids overreliance on administrators for future data updates by having a simple form and community-curation system for application and approval, respectively, of new telomere sequences by users, which should ensure timeliness of the database and topicality. To demonstrate TeloBase utility, we examined telomere motif diversity in species from the fungal genus Aspergillus, and discovered (TTTATTAGGG)n sequence as a putative telomere motif in the plant family Chrysobalanaceae. This was bioinformatically confirmed by analysing template regions of identified telomerase RNAs.
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Affiliation(s)
- Martin Lyčka
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, BrnoCZ-62500, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, BrnoCZ-62500, Czech Republic
| | - Michal Bubeník
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, BrnoCZ-62500, Czech Republic
| | - Michal Závodník
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, BrnoCZ-62500, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, BrnoCZ-62500, Czech Republic
| | - Vratislav Peska
- Department of Cell Biology and Radiobiology, Institute of Biophysics, Academy of Sciences of the Czech Republic, BrnoCZ-61200, Czech Republic
| | - Petr Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, BrnoCZ-62500, Czech Republic
- Department of Cell Biology and Radiobiology, Institute of Biophysics, Academy of Sciences of the Czech Republic, BrnoCZ-61200, Czech Republic
| | - Martin Demko
- Core Facility Bioinformatics, Central European Institute of Technology (CEITEC), Masaryk University, BrnoCZ-62500, Czech Republic
- Faculty of Informatics, Masaryk University, BrnoCZ-62500, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, BrnoCZ-62500, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, BrnoCZ-62500, Czech Republic
- Department of Cell Biology and Radiobiology, Institute of Biophysics, Academy of Sciences of the Czech Republic, BrnoCZ-61200, Czech Republic
| | - Miloslava Fojtová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, BrnoCZ-62500, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, BrnoCZ-62500, Czech Republic
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5
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Dai D, Xie C, Zhou Y, Bo D, Zhang S, Mao S, Liao Y, Cui S, Zhu Z, Wang X, Li F, Peng D, Zheng J, Sun M. Unzipped chromosome-level genomes reveal allopolyploid nematode origin pattern as unreduced gamete hybridization. Nat Commun 2023; 14:7156. [PMID: 37935661 PMCID: PMC10630426 DOI: 10.1038/s41467-023-42700-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 10/19/2023] [Indexed: 11/09/2023] Open
Abstract
The formation and consequences of polyploidization in animals with clonal reproduction remain largely unknown. Clade I root-knot nematodes (RKNs), characterized by parthenogenesis and allopolyploidy, show a widespread geographical distribution and extensive agricultural destruction. Here, we generated 4 unzipped polyploid RKN genomes and identified a putative novel alternative telomeric element. Then we reconstructed 4 chromosome-level assemblies and resolved their genome structures as AAB for triploid and AABB for tetraploid. The phylogeny of subgenomes revealed polyploid RKN origin patterns as hybridization between haploid and unreduced gametes. We also observed extensive chromosomal fusions and homologous gene expression decrease after polyploidization, which might offset the disadvantages of clonal reproduction and increase fitness in polyploid RKNs. Our results reveal a rare pathway of polyploidization in parthenogenic polyploid animals and provide a large number of high-precision genetic resources that could be used for RKN prevention and control.
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Affiliation(s)
- Dadong Dai
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chuanshuai Xie
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yayi Zhou
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Dexin Bo
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shurong Zhang
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shengqiang Mao
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yucheng Liao
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Simeng Cui
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhaolu Zhu
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xueyu Wang
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Fanling Li
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Donghai Peng
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Jinshui Zheng
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
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6
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Liu M, Xie XJ, Li X, Ren X, Sun J, Lin Z, Hemba-Waduge RUS, Ji JY. Transcriptional coupling of telomeric retrotransposons with the cell cycle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.30.560321. [PMID: 37808851 PMCID: PMC10557779 DOI: 10.1101/2023.09.30.560321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Instead of employing telomerases to safeguard chromosome ends, dipteran species maintain their telomeres by transposition of telomeric-specific retrotransposons (TRs): in Drosophila , these are HeT-A , TART , and TAHRE . Previous studies have shown how these TRs create tandem repeats at chromosome ends, but the exact mechanism controlling TR transcription has remained unclear. Here we report the identification of multiple subunits of the transcription cofactor Mediator complex and transcriptional factors Scalloped (Sd, the TEAD homolog in flies) and E2F1-Dp as novel regulators of TR transcription and telomere length in Drosophila . Depletion of multiple Mediator subunits, Dp, or Sd increased TR expression and telomere length, while over-expressing E2F1-Dp or knocking down the E2F1 regulator Rbf1 (Retinoblastoma-family protein 1) stimulated TR transcription, with Mediator and Sd affecting TR expression through E2F1-Dp. The CUT&RUN analysis revealed direct binding of CDK8, Dp, and Sd to telomeric repeats. These findings highlight the essential role of the Mediator complex in maintaining telomere homeostasis by regulating TR transcription through E2F1-Dp and Sd, revealing the intricate coupling of TR transcription with the host cell-cycle machinery, thereby ensuring chromosome end protection and genomic stability during cell division.
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7
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Sung S, Kim E, Niida H, Kim C, Lee J. Distinct characteristics of two types of alternative lengthening of telomeres in mouse embryonic stem cells. Nucleic Acids Res 2023; 51:9122-9143. [PMID: 37496110 PMCID: PMC10516625 DOI: 10.1093/nar/gkad617] [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: 09/24/2022] [Revised: 06/27/2023] [Accepted: 07/13/2023] [Indexed: 07/28/2023] Open
Abstract
Telomere length must be maintained in actively dividing cells to avoid cellular arrest or death. In the absence of telomerase activity, activation of alternative lengthening of telomeres (ALT) allows the maintenance of telomeric length and prolongs the cellular lifespan. Our previous studies have established two types of ALT survivors from mouse embryonic stem cells. The key differences between these ALT survivors are telomere-constituting sequences: non-telomeric sequences and canonical telomeric repeats, with each type of ALT survivors being referred to as type I and type II, respectively. We explored how the characteristics of the two types of ALT lines reflect their fates using multi-omics approaches. The most notable gene expression signatures of type I and type II ALT cell lines were chromatin remodelling and DNA repair, respectively. Compared with type II cells, type I ALT cells accumulated more mutations and demonstrated persistent telomere instability. These findings indicate that cells of the same origin have separate routes for survival, thus providing insights into the plasticity of crisis-suffering cells and cancers.
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Affiliation(s)
- Sanghyun Sung
- Department of Biological Sciences, Seoul National University, Gwanak-ro 1, Seoul 08826, Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Gwanak-ro 1, Seoul 08826, Korea
| | - Eunkyeong Kim
- Department of Biological Sciences, Seoul National University, Gwanak-ro 1, Seoul 08826, Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Gwanak-ro 1, Seoul 08826, Korea
| | - Hiroyuki Niida
- Department of Molecular Biology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Chuna Kim
- Aging Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Gwahak-ro 125, Daejeon 34141, Korea
- Department of Bioinformatics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon 34113, Korea
| | - Junho Lee
- Department of Biological Sciences, Seoul National University, Gwanak-ro 1, Seoul 08826, Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Gwanak-ro 1, Seoul 08826, Korea
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8
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Sperling AL, Fabian DK, Garrison E, Glover DM. A genetic basis for facultative parthenogenesis in Drosophila. Curr Biol 2023; 33:3545-3560.e13. [PMID: 37516115 PMCID: PMC11044649 DOI: 10.1016/j.cub.2023.07.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/04/2023] [Accepted: 07/05/2023] [Indexed: 07/31/2023]
Abstract
Facultative parthenogenesis enables sexually reproducing organisms to switch between sexual and asexual parthenogenetic reproduction. To gain insights into this phenomenon, we sequenced the genomes of sexually reproducing and parthenogenetic strains of Drosophila mercatorum and identified differences in the gene expression in their eggs. We then tested whether manipulating the expression of candidate gene homologs identified in Drosophila mercatorum could lead to facultative parthenogenesis in the non-parthenogenetic species Drosophila melanogaster. This identified a polygenic system whereby increased expression of the mitotic protein kinase polo and decreased expression of a desaturase, Desat2, caused facultative parthenogenesis in the non-parthenogenetic species that was enhanced by increased expression of Myc. The genetically induced parthenogenetic Drosophila melanogaster eggs exhibit de novo centrosome formation, fusion of the meiotic products, and the onset of development to generate predominantly triploid offspring. Thus, we demonstrate a genetic basis for sporadic facultative parthenogenesis in an animal.
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Affiliation(s)
- Alexis L Sperling
- University of Cambridge, Department of Genetics, Downing Street, Cambridge CB2 3EH, UK.
| | - Daniel K Fabian
- University of Cambridge, Department of Genetics, Downing Street, Cambridge CB2 3EH, UK
| | - Erik Garrison
- University of Tennessee Health Science Center, S Manassas Street, Memphis, TN 38103, USA
| | - David M Glover
- University of Cambridge, Department of Genetics, Downing Street, Cambridge CB2 3EH, UK; Division of Biology and Biological Engineering, California Institute of Technology, East California Boulevard, Pasadena, CA 91125, USA.
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9
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Sloan DB, Warren JM, Williams AM, Kuster SA, Forsythe ES. Incompatibility and Interchangeability in Molecular Evolution. Genome Biol Evol 2023; 15:evac184. [PMID: 36583227 PMCID: PMC9839398 DOI: 10.1093/gbe/evac184] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 12/31/2022] Open
Abstract
There is remarkable variation in the rate at which genetic incompatibilities in molecular interactions accumulate. In some cases, minor changes-even single-nucleotide substitutions-create major incompatibilities when hybridization forces new variants to function in a novel genetic background from an isolated population. In other cases, genes or even entire functional pathways can be horizontally transferred between anciently divergent evolutionary lineages that span the tree of life with little evidence of incompatibilities. In this review, we explore whether there are general principles that can explain why certain genes are prone to incompatibilities while others maintain interchangeability. We summarize evidence pointing to four genetic features that may contribute to greater resistance to functional replacement: (1) function in multisubunit enzyme complexes and protein-protein interactions, (2) sensitivity to changes in gene dosage, (3) rapid rate of sequence evolution, and (4) overall importance to cell viability, which creates sensitivity to small perturbations in molecular function. We discuss the relative levels of support for these different hypotheses and lay out future directions that may help explain the striking contrasts in patterns of incompatibility and interchangeability throughout the history of molecular evolution.
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Affiliation(s)
- Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, Colorado
| | - Jessica M Warren
- Center for Mechanisms of Evolution, Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Alissa M Williams
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee
| | - Shady A Kuster
- Department of Biology, Colorado State University, Fort Collins, Colorado
| | - Evan S Forsythe
- Department of Biology, Colorado State University, Fort Collins, Colorado
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10
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Botto JM, Faulkner GJ. Endogenous retrovirus expression during fruitfly metamorphosis enhances adult viral immunity. Nat Genet 2022; 54:1765-1767. [PMID: 36396708 DOI: 10.1038/s41588-022-01209-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Juan M Botto
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland, Australia
| | - Geoffrey J Faulkner
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland, Australia. .,Mater Research Institute, University of Queensland, Woolloongabba, Queensland, Australia.
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11
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Takeuchi C, Yokoshi M, Kondo S, Shibuya A, Saito K, Fukaya T, Siomi H, Iwasaki Y. Mod(mdg4) variants repress telomeric retrotransposon HeT-A by blocking subtelomeric enhancers. Nucleic Acids Res 2022; 50:11580-11599. [PMID: 36373634 PMCID: PMC9723646 DOI: 10.1093/nar/gkac1034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/17/2022] [Accepted: 10/22/2022] [Indexed: 11/16/2022] Open
Abstract
Telomeres in Drosophila are composed of sequential non-LTR retrotransposons HeT-A, TART and TAHRE. Although they are repressed by the PIWI-piRNA pathway or heterochromatin in the germline, the regulation of these retrotransposons in somatic cells is poorly understood. In this study, we demonstrated that specific splice variants of Mod(mdg4) repress HeT-A by blocking subtelomeric enhancers in ovarian somatic cells. Among the variants, we found that the Mod(mdg4)-N variant represses HeT-A expression the most efficiently. Subtelomeric sequences bound by Mod(mdg4)-N block enhancer activity within subtelomeric TAS-R repeats. This enhancer-blocking activity is increased by the tandem association of Mod(mdg4)-N to repetitive subtelomeric sequences. In addition, the association of Mod(mdg4)-N couples with the recruitment of RNA polymerase II to the subtelomeres, which reinforces its enhancer-blocking function. Our findings provide novel insights into how telomeric retrotransposons are regulated by the specific variants of insulator proteins associated with subtelomeric sequences.
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Affiliation(s)
- Chikara Takeuchi
- Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Moe Yokoshi
- Laboratory of Transcription Dynamics, Research Center for Biological Visualization, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo 113-0032, Japan
| | - Shu Kondo
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Shizuoka 411-8540, Japan
| | - Aoi Shibuya
- Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Kuniaki Saito
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Shizuoka 411-8540, Japan
| | - Takashi Fukaya
- Laboratory of Transcription Dynamics, Research Center for Biological Visualization, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo 113-0032, Japan,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 113-0032, Japan
| | | | - Yuka W Iwasaki
- To whom correspondence should be addressed. Tel: +81 3 5363 3529; Fax: +81 3 5363 3266;
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12
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Telomeres and Their Neighbors. Genes (Basel) 2022; 13:genes13091663. [PMID: 36140830 PMCID: PMC9498494 DOI: 10.3390/genes13091663] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/21/2022] Open
Abstract
Telomeres are essential structures formed from satellite DNA repeats at the ends of chromosomes in most eukaryotes. Satellite DNA repeat sequences are useful markers for karyotyping, but have a more enigmatic role in the eukaryotic cell. Much work has been done to investigate the structure and arrangement of repetitive DNA elements in classical models with implications for species evolution. Still more is needed until there is a complete picture of the biological function of DNA satellite sequences, particularly when considering non-model organisms. Celebrating Gregor Mendel’s anniversary by going to the roots, this review is designed to inspire and aid new research into telomeres and satellites with a particular focus on non-model organisms and accessible experimental and in silico methods that do not require specialized equipment or expensive materials. We describe how to identify telomere (and satellite) repeats giving many examples of published (and some unpublished) data from these techniques to illustrate the principles behind the experiments. We also present advice on how to perform and analyse such experiments, including details of common pitfalls. Our examples are a selection of recent developments and underexplored areas of research from the past. As a nod to Mendel’s early work, we use many examples from plants and insects, especially as much recent work has expanded beyond the human and yeast models traditional in telomere research. We give a general introduction to the accepted knowledge of telomere and satellite systems and include references to specialized reviews for the interested reader.
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13
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Modzelewski AJ, Gan Chong J, Wang T, He L. Mammalian genome innovation through transposon domestication. Nat Cell Biol 2022; 24:1332-1340. [PMID: 36008480 PMCID: PMC9729749 DOI: 10.1038/s41556-022-00970-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 06/27/2022] [Indexed: 01/13/2023]
Abstract
Since the discovery of transposons, their sheer abundance in host genomes has puzzled many. While historically viewed as largely harmless 'parasitic' DNAs during evolution, transposons are not a mere record of ancient genome invasion. Instead, nearly every element of transposon biology has been integrated into host biology. Here we review how host genome sequences introduced by transposon activities provide raw material for genome innovation and document the distinct evolutionary path of each species.
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Affiliation(s)
- Andrew J Modzelewski
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, CA, USA
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Johnny Gan Chong
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, CA, USA
| | - Ting Wang
- Department of Genetics, Edison Family Center for Genome Science and System Biology, McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
| | - Lin He
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, CA, USA.
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14
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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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15
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Zhou Y, Wang Y, Xiong X, Appel AG, Zhang C, Wang X. Profiles of telomeric repeats in Insecta reveal diverse forms of telomeric motifs in Hymenopterans. Life Sci Alliance 2022; 5:5/7/e202101163. [PMID: 35365574 PMCID: PMC8977481 DOI: 10.26508/lsa.202101163] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 03/04/2022] [Accepted: 03/04/2022] [Indexed: 12/23/2022] Open
Abstract
Telomeres consist of highly conserved simple tandem telomeric repeat motif (TRM): (TTAGG)n in arthropods, (TTAGGG)n in vertebrates, and (TTTAGGG)n in most plants. TRM can be detected from chromosome-level assembly, which typically requires long-read sequencing data. To take advantage of short-read data, we developed an ultra-fast Telomeric Repeats Identification Pipeline and evaluated its performance on 91 species. With proven accuracy, we applied Telomeric Repeats Identification Pipeline in 129 insect species, using 7 Tbp of short-read sequences. We confirmed (TTAGG)n as the TRM in 19 orders, suggesting it is the ancestral form in insects. Systematic profiling in Hymenopterans revealed a diverse range of TRMs, including the canonical 5-bp TTAGG (bees, ants, and basal sawflies), three independent losses of tandem repeat form TRM (Ichneumonoids, hunting wasps, and gall-forming wasps), and most interestingly, a common 8-bp (TTATTGGG)n in Chalcid wasps with two 9-bp variants in the miniature wasp (TTACTTGGG) and fig wasps (TTATTGGGG). Our results identified extraordinary evolutionary fluidity of Hymenopteran TRMs, and rapid evolution of TRM and repeat abundance at all evolutionary scales, providing novel insights into telomere evolution.
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Affiliation(s)
- Yihang Zhou
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China.,Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA.,Auburn University Center for Advanced Science, Innovation, and Commerce, Alabama Agricultural Experiment Station, Auburn, AL, USA
| | - Yi Wang
- Ministry of Education Key Laboratory of Contemporary Anthropology, Department of Anthropology and Human Genetics, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
| | - Xiao Xiong
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China.,Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA.,Auburn University Center for Advanced Science, Innovation, and Commerce, Alabama Agricultural Experiment Station, Auburn, AL, USA
| | - Arthur G Appel
- Auburn University Center for Advanced Science, Innovation, and Commerce, Alabama Agricultural Experiment Station, Auburn, AL, USA.,Department of Entomology and Plant Pathology, Auburn University, AL, USA
| | - Chao Zhang
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xu Wang
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA.,Auburn University Center for Advanced Science, Innovation, and Commerce, Alabama Agricultural Experiment Station, Auburn, AL, USA.,Department of Entomology and Plant Pathology, Auburn University, AL, USA.,HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
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16
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Colonna Romano N, Fanti L. Transposable Elements: Major Players in Shaping Genomic and Evolutionary Patterns. Cells 2022; 11:cells11061048. [PMID: 35326499 PMCID: PMC8947103 DOI: 10.3390/cells11061048] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/04/2022] [Accepted: 03/18/2022] [Indexed: 02/04/2023] Open
Abstract
Transposable elements (TEs) are ubiquitous genetic elements, able to jump from one location of the genome to another, in all organisms. For this reason, on the one hand, TEs can induce deleterious mutations, causing dysfunction, disease and even lethality in individuals. On the other hand, TEs can increase genetic variability, making populations better equipped to respond adaptively to environmental change. To counteract the deleterious effects of TEs, organisms have evolved strategies to avoid their activation. However, their mobilization does occur. Usually, TEs are maintained silent through several mechanisms, but they can be reactivated during certain developmental windows. Moreover, TEs can become de-repressed because of drastic changes in the external environment. Here, we describe the ‘double life’ of TEs, being both ‘parasites’ and ‘symbionts’ of the genome. We also argue that the transposition of TEs contributes to two important evolutionary processes: the temporal dynamic of evolution and the induction of genetic variability. Finally, we discuss how the interplay between two TE-dependent phenomena, insertional mutagenesis and epigenetic plasticity, plays a role in the process of evolution.
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17
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Abstract
Repeat-enriched genomic regions evolve rapidly and yet support strictly conserved functions like faithful chromosome transmission and the preservation of genome integrity. The leading resolution to this paradox is that DNA repeat-packaging proteins evolve adaptively to mitigate deleterious changes in DNA repeat copy number, sequence, and organization. Exciting new research has tested this model of coevolution by engineering evolutionary mismatches between adaptively evolving chromatin proteins of one species and the DNA repeats of a close relative. Here, we review these innovative evolution-guided functional analyses. The studies demonstrate that vital, chromatin-mediated cellular processes, including transposon suppression, faithful chromosome transmission, and chromosome retention depend on species-specific versions of chromatin proteins that package species-specific DNA repeats. In many cases, the ever-evolving repeats are selfish genetic elements, raising the possibility that chromatin is a battleground of intragenomic conflict.
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Affiliation(s)
- Cara L Brand
- Department of Biology and Epigenetics Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Mia T Levine
- Department of Biology and Epigenetics Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
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18
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Modzelewski AJ, Shao W, Chen J, Lee A, Qi X, Noon M, Tjokro K, Sales G, Biton A, Anand A, Speed TP, Xuan Z, Wang T, Risso D, He L. A mouse-specific retrotransposon drives a conserved Cdk2ap1 isoform essential for development. Cell 2021; 184:5541-5558.e22. [PMID: 34644528 PMCID: PMC8787082 DOI: 10.1016/j.cell.2021.09.021] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/26/2021] [Accepted: 09/14/2021] [Indexed: 12/13/2022]
Abstract
Retrotransposons mediate gene regulation in important developmental and pathological processes. Here, we characterized the transient retrotransposon induction during preimplantation development of eight mammals. Induced retrotransposons exhibit similar preimplantation profiles across species, conferring gene regulatory activities, particularly through long terminal repeat (LTR) retrotransposon promoters. A mouse-specific MT2B2 retrotransposon promoter generates an N-terminally truncated Cdk2ap1ΔN that peaks in preimplantation embryos and promotes proliferation. In contrast, the canonical Cdk2ap1 peaks in mid-gestation and represses cell proliferation. This MT2B2 promoter, whose deletion abolishes Cdk2ap1ΔN production, reduces cell proliferation and impairs embryo implantation, is developmentally essential. Intriguingly, Cdk2ap1ΔN is evolutionarily conserved in sequence and function yet is driven by different promoters across mammals. The distinct preimplantation Cdk2ap1ΔN expression in each mammalian species correlates with the duration of its preimplantation development. Hence, species-specific transposon promoters can yield evolutionarily conserved, alternative protein isoforms, bestowing them with new functions and species-specific expression to govern essential biological divergence.
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Affiliation(s)
- Andrew J Modzelewski
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Wanqing Shao
- Department of Genetics, Edison Family Center for Genome Science and System Biology, McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jingqi Chen
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Angus Lee
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xin Qi
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Mackenzie Noon
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kristy Tjokro
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Gabriele Sales
- Department of Biology, University of Padova, Padova 35122, Italy
| | - Anne Biton
- Department of Statistics, University of California, Berkeley, Berkeley, CA 94720, USA; Bioinformatics and Biostatistics, Department of Computational Biology, USR 3756 CNRS, Institut Pasteur, Paris 75015, France
| | - Aparna Anand
- Department of Genetics, Edison Family Center for Genome Science and System Biology, McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Terence P Speed
- Bioinformatics Division, WEHI, Parkville, VIC 3052, Australia
| | - Zhenyu Xuan
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Ting Wang
- Department of Genetics, Edison Family Center for Genome Science and System Biology, McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Davide Risso
- Department of Statistical Sciences, University of Padova, Padova 35122, Italy.
| | - Lin He
- Division of Cellular and Developmental Biology, MCB Department, University of California, Berkeley, Berkeley, CA 94720, USA.
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19
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Murakami T, Paris C, Chirino M, Sasa C, Sakamoto H, Higashi S, Sato K. Unusual chromosome numbers and polyploidy in invasive fire ant populations. Genetica 2021; 149:203-215. [PMID: 34282482 DOI: 10.1007/s10709-021-00128-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 07/14/2021] [Indexed: 11/25/2022]
Abstract
Fire ants (Solenopsis invicta Buren in J Ga Entomol Soc 7:1-26, 1972), an invasive alien ant species, first spread from South America to the United States in the 1930s, the southern part of the United States by the end of the twentieth century, Oceania, Taiwan, and China in the twenty-first century, and finally to Japan and South Korea in 2017. As these ants have significant negative economic, human health, and environmental impacts, the purpose of this research was to accumulate cytogenetic information regarding fire ants and provide basic data for developing management strategies for their control. Fire ants were collected from invasive populations from Taiwan, Florida (USA), and Buenos Aires (Argentina), and a native population from Puerto Iguazu (Argentina), their point of origination, and analyzed with regard to chromosome number, morphology, and polyploidy, silver-stained nucleolar organizer regions (Ag-NORs), and 18S rDNA and telomere fluorescence in situ hybridization (FISH). The results showed that (1) fire ants from invaded populations differed in chromosome morphology compared to those from native populations; (2) the Florida and Taiwanese fire ant populations evinced greater variability in chromosome numbers and polyploidy variations; (3) the Taiwanese population exhibited significantly increased Ag-NOR signals in interphase cells, with signal number significantly positively correlating with distance from native populations; and (4) substantial diversity of signals was also apparent following 18S rDNA and telomere FISH analyses. Variation in these characteristics were hypothesized to be due to (1) the effect of hybridizations and interbreeding between closely related species or genetically distant populations, and (2) the potential effect of large amounts of insecticides sprayed for pest control.
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Affiliation(s)
- Takahiro Murakami
- Institution of Decision Science for a Sustainable Society, Kyushu University, Motooka 744, Fukuoka, 8190395, Japan.
| | | | | | - Chifune Sasa
- Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Hironori Sakamoto
- Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan
- Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, Ibaraki, 305-0053, Japan
| | - Seigo Higashi
- Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan
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20
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Thakur J, Packiaraj J, Henikoff S. Sequence, Chromatin and Evolution of Satellite DNA. Int J Mol Sci 2021; 22:ijms22094309. [PMID: 33919233 PMCID: PMC8122249 DOI: 10.3390/ijms22094309] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/15/2022] Open
Abstract
Satellite DNA consists of abundant tandem repeats that play important roles in cellular processes, including chromosome segregation, genome organization and chromosome end protection. Most satellite DNA repeat units are either of nucleosomal length or 5–10 bp long and occupy centromeric, pericentromeric or telomeric regions. Due to high repetitiveness, satellite DNA sequences have largely been absent from genome assemblies. Although few conserved satellite-specific sequence motifs have been identified, DNA curvature, dyad symmetries and inverted repeats are features of various satellite DNAs in several organisms. Satellite DNA sequences are either embedded in highly compact gene-poor heterochromatin or specialized chromatin that is distinct from euchromatin. Nevertheless, some satellite DNAs are transcribed into non-coding RNAs that may play important roles in satellite DNA function. Intriguingly, satellite DNAs are among the most rapidly evolving genomic elements, such that a large fraction is species-specific in most organisms. Here we describe the different classes of satellite DNA sequences, their satellite-specific chromatin features, and how these features may contribute to satellite DNA biology and evolution. We also discuss how the evolution of functional satellite DNA classes may contribute to speciation in plants and animals.
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Affiliation(s)
- Jitendra Thakur
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
- Correspondence:
| | - Jenika Packiaraj
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
- Fred Hutchinson Cancer Research Center, Howard Hughes Medical Institute, Seattle, WA 98109, USA
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21
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Comprehensive mapping of transposable elements reveals distinct patterns of element accumulation on chromosomes of wild beetles. Chromosome Res 2021; 29:203-218. [PMID: 33638119 DOI: 10.1007/s10577-021-09655-4] [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: 10/05/2020] [Revised: 02/01/2021] [Accepted: 02/10/2021] [Indexed: 10/22/2022]
Abstract
Over the past decades, transposable elements (TEs) have been shown to play important roles shaping genome architecture and as major promoters of genetic diversification and evolution of species. Likewise, TE accumulation is tightly linked to heterochromatinization and centromeric dynamics, which can ultimately contribute to speciation. Despite growing efforts to characterize the repeat landscape of species, few studies have focused on mapping the accumulation profiles of TEs on chromosomes. The few studies on repeat accumulation profiles in populations are biased towards model organisms and inbred lineages. Here, we present a cytomolecular analysis of six mobilome-extracted elements on multiple individuals from a population of a species of wild-captured beetle, Dichotomius schiffleri, aiming to investigate patterns of TE accumulation and uncover possible trends of their chromosomal distribution. Compiling TE distribution data from several individuals allowed us to make generalizations regarding variation of TEs at the gross chromosome level unlikely to have been achieved using a single individual, or even from a whole-genome assembly. We found that (1) transposable elements have differential accumulation profiles on D. schiffleri chromosomes and (2) specific chromosomes have their own TE accumulation landscape. The remarkable variability of their genomic distribution suggests that TEs are likely candidates to contribute to the evolution of heterochromatin architecture and promote high genetic variability in species that otherwise display conserved karyotypes. Therefore, this variation likely contributed to genome evolution and species diversification in Dichotomius.
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22
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McGurk MP, Dion-Côté AM, Barbash DA. Rapid evolution at the Drosophila telomere: transposable element dynamics at an intrinsically unstable locus. Genetics 2021; 217:iyaa027. [PMID: 33724410 PMCID: PMC8045721 DOI: 10.1093/genetics/iyaa027] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/03/2020] [Indexed: 12/26/2022] Open
Abstract
Drosophila telomeres have been maintained by three families of active transposable elements (TEs), HeT-A, TAHRE, and TART, collectively referred to as HTTs, for tens of millions of years, which contrasts with an unusually high degree of HTT interspecific variation. While the impacts of conflict and domestication are often invoked to explain HTT variation, the telomeres are unstable structures such that neutral mutational processes and evolutionary tradeoffs may also drive HTT evolution. We leveraged population genomic data to analyze nearly 10,000 HTT insertions in 85 Drosophila melanogaster genomes and compared their variation to other more typical TE families. We observe that occasional large-scale copy number expansions of both HTTs and other TE families occur, highlighting that the HTTs are, like their feral cousins, typically repressed but primed to take over given the opportunity. However, large expansions of HTTs are not caused by the runaway activity of any particular HTT subfamilies or even associated with telomere-specific TE activity, as might be expected if HTTs are in strong genetic conflict with their hosts. Rather than conflict, we instead suggest that distinctive aspects of HTT copy number variation and sequence diversity largely reflect telomere instability, with HTT insertions being lost at much higher rates than other TEs elsewhere in the genome. We extend previous observations that telomere deletions occur at a high rate, and surprisingly discover that more than one-third do not appear to have been healed with an HTT insertion. We also report that some HTT families may be preferentially activated by the erosion of whole telomeres, implying the existence of HTT-specific host control mechanisms. We further suggest that the persistent telomere localization of HTTs may reflect a highly successful evolutionary strategy that trades away a stable insertion site in order to have reduced impact on the host genome. We propose that HTT evolution is driven by multiple processes, with niche specialization and telomere instability being previously underappreciated and likely predominant.
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Affiliation(s)
- Michael P McGurk
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Anne-Marie Dion-Côté
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36 Uppsala, Sweden
| | - Daniel A Barbash
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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23
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Peona V, Blom MPK, Xu L, Burri R, Sullivan S, Bunikis I, Liachko I, Haryoko T, Jønsson KA, Zhou Q, Irestedt M, Suh A. Identifying the causes and consequences of assembly gaps using a multiplatform genome assembly of a bird-of-paradise. Mol Ecol Resour 2021; 21:263-286. [PMID: 32937018 PMCID: PMC7757076 DOI: 10.1111/1755-0998.13252] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 01/09/2023]
Abstract
Genome assemblies are currently being produced at an impressive rate by consortia and individual laboratories. The low costs and increasing efficiency of sequencing technologies now enable assembling genomes at unprecedented quality and contiguity. However, the difficulty in assembling repeat-rich and GC-rich regions (genomic "dark matter") limits insights into the evolution of genome structure and regulatory networks. Here, we compare the efficiency of currently available sequencing technologies (short/linked/long reads and proximity ligation maps) and combinations thereof in assembling genomic dark matter. By adopting different de novo assembly strategies, we compare individual draft assemblies to a curated multiplatform reference assembly and identify the genomic features that cause gaps within each assembly. We show that a multiplatform assembly implementing long-read, linked-read and proximity sequencing technologies performs best at recovering transposable elements, multicopy MHC genes, GC-rich microchromosomes and the repeat-rich W chromosome. Telomere-to-telomere assemblies are not a reality yet for most organisms, but by leveraging technology choice it is now possible to minimize genome assembly gaps for downstream analysis. We provide a roadmap to tailor sequencing projects for optimized completeness of both the coding and noncoding parts of nonmodel genomes.
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Affiliation(s)
- Valentina Peona
- Department of Ecology and Genetics—Evolutionary BiologyScience for Life LaboratoriesUppsala UniversityUppsalaSweden
- Department of Organismal Biology—Systematic BiologyScience for Life LaboratoriesUppsala UniversityUppsalaSweden
| | - Mozes P. K. Blom
- Department of Bioinformatics and GeneticsSwedish Museum of Natural HistoryStockholmSweden
- Museum für NaturkundeLeibniz Institut für Evolutions‐ und BiodiversitätsforschungBerlinGermany
| | - Luohao Xu
- Department of Neurosciences and Developmental BiologyUniversity of ViennaViennaAustria
| | - Reto Burri
- Department of Population EcologyInstitute of Ecology and EvolutionFriedrich‐Schiller‐University JenaJenaGermany
| | | | - Ignas Bunikis
- Department of Immunology, Genetics and PathologyScience for Life LaboratoryUppsala Genome CenterUppsala UniversityUppsalaSweden
| | | | - Tri Haryoko
- Research Centre for BiologyMuseum Zoologicum BogorienseIndonesian Institute of Sciences (LIPI)CibinongIndonesia
| | - Knud A. Jønsson
- Natural History Museum of DenmarkUniversity of CopenhagenCopenhagenDenmark
| | - Qi Zhou
- Department of Neurosciences and Developmental BiologyUniversity of ViennaViennaAustria
- MOE Laboratory of Biosystems Homeostasis & ProtectionLife Sciences InstituteZhejiang UniversityHangzhouChina
- Center for Reproductive MedicineThe 2nd Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouChina
| | - Martin Irestedt
- Department of Bioinformatics and GeneticsSwedish Museum of Natural HistoryStockholmSweden
| | - Alexander Suh
- Department of Ecology and Genetics—Evolutionary BiologyScience for Life LaboratoriesUppsala UniversityUppsalaSweden
- Department of Organismal Biology—Systematic BiologyScience for Life LaboratoriesUppsala UniversityUppsalaSweden
- School of Biological Sciences—Organisms and the EnvironmentUniversity of East AngliaNorwichUK
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Červenák F, Sepšiová R, Nosek J, Tomáška Ľ. Step-by-Step Evolution of Telomeres: Lessons from Yeasts. Genome Biol Evol 2020; 13:6127219. [PMID: 33537752 PMCID: PMC7857110 DOI: 10.1093/gbe/evaa268] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2020] [Indexed: 12/23/2022] Open
Abstract
In virtually every eukaryotic species, the ends of nuclear chromosomes are protected by telomeres, nucleoprotein structures counteracting the end-replication problem and suppressing recombination and undue DNA repair. Although in most cases, the primary structure of telomeric DNA is conserved, there are several exceptions to this rule. One is represented by the telomeric repeats of ascomycetous yeasts, which encompass a great variety of sequences, whose evolutionary origin has been puzzling for several decades. At present, the key questions concerning the driving force behind their rapid evolution and the means of co-evolution of telomeric repeats and telomere-binding proteins remain largely unanswered. Previously published studies addressed mostly the general concepts of the evolutionary origin of telomeres, key properties of telomeric proteins as well as the molecular mechanisms of telomere maintenance; however, the evolutionary process itself has not been analyzed thoroughly. Here, we aimed to inspect the evolution of telomeres in ascomycetous yeasts from the subphyla Saccharomycotina and Taphrinomycotina, with special focus on the evolutionary origin of species-specific telomeric repeats. We analyzed the sequences of telomeric repeats from 204 yeast species classified into 20 families and as a result, we propose a step-by-step model, which integrates the diversity of telomeric repeats, telomerase RNAs, telomere-binding protein complexes and explains a propensity of certain species to generate the repeat heterogeneity within a single telomeric array.
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Affiliation(s)
- Filip Červenák
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Bratislava, Slovakia
| | - Regina Sepšiová
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Bratislava, Slovakia
| | - Jozef Nosek
- Department of Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Bratislava, Slovakia
| | - Ľubomír Tomáška
- Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Bratislava, Slovakia
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Ellison CE, Kagda MS, Cao W. Telomeric TART elements target the piRNA machinery in Drosophila. PLoS Biol 2020; 18:e3000689. [PMID: 33347429 PMCID: PMC7785250 DOI: 10.1371/journal.pbio.3000689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 01/05/2021] [Accepted: 12/10/2020] [Indexed: 11/23/2022] Open
Abstract
Coevolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by reestablishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. The TART-A TE functions as an important component of Drosophila telomeres but has also reportedly inserted into the Drosophila melanogaster nuclear export factor gene nxf2. We find that, rather than inserting into nxf2, TART-A has actually captured a portion of nxf2 sequence. We show that TART-A produces abundant Piwi-interacting small RNAs (piRNAs), some of which are antisense to the nxf2 transcript, and that the TART-like region of nxf2 is evolving rapidly. Furthermore, in D. melanogaster, TART-A is present at higher copy numbers, and nxf2 shows reduced expression, compared to the closely related species Drosophila simulans. We propose that capturing nxf2 sequence allowed TART-A to target the nxf2 gene for piRNA-mediated repression and that these 2 elements are engaged in antagonistic coevolution despite the fact that TART-A is serving a critical role for its host genome. Co-evolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by re-establishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. This study shows that a specialized Drosophila retrotransposon that functions as a telomere has captured a portion of a host piRNA gene which may allow it to evade silencing.
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Affiliation(s)
- Christopher E. Ellison
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
| | - Meenakshi S. Kagda
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Weihuan Cao
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
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Identification and Characterization of Breakpoints and Mutations on Drosophila melanogaster Balancer Chromosomes. G3-GENES GENOMES GENETICS 2020; 10:4271-4285. [PMID: 32972999 PMCID: PMC7642927 DOI: 10.1534/g3.120.401559] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Balancers are rearranged chromosomes used in Drosophila melanogaster to maintain deleterious mutations in stable populations, preserve sets of linked genetic elements and construct complex experimental stocks. Here, we assess the phenotypes associated with breakpoint-induced mutations on commonly used third chromosome balancers and show remarkably few deleterious effects. We demonstrate that a breakpoint in p53 causes loss of radiation-induced apoptosis and a breakpoint in Fucosyltransferase A causes loss of fucosylation in nervous and intestinal tissue—the latter study providing new markers for intestinal cell identity and challenging previous conclusions about the regulation of fucosylation. We also describe thousands of potentially harmful mutations shared among X or third chromosome balancers, or unique to specific balancers, including an Ankyrin 2 mutation present on most TM3 balancers, and reiterate the risks of using balancers as experimental controls. We used long-read sequencing to confirm or refine the positions of two inversions with breakpoints lying in repetitive sequences and provide evidence that one of the inversions, In(2L)Cy, arose by ectopic recombination between foldback transposon insertions and the other, In(3R)C, cleanly separates subtelomeric and telomeric sequences and moves the subtelomeric sequences to an internal chromosome position. In addition, our characterization of In(3R)C shows that balancers may be polymorphic for terminal deletions. Finally, we present evidence that extremely distal mutations on balancers can add to the stability of stocks whose purpose is to maintain homologous chromosomes carrying mutations in distal genes. Overall, these studies add to our understanding of the structure, diversity and effectiveness of balancer chromosomes.
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The Beginning of the End: A Chromosomal Assembly of the New World Malaria Mosquito Ends with a Novel Telomere. G3-GENES GENOMES GENETICS 2020; 10:3811-3819. [PMID: 32883756 PMCID: PMC7534423 DOI: 10.1534/g3.120.401654] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Chromosome level assemblies are accumulating in various taxonomic groups including mosquitoes. However, even in the few reference-quality mosquito assemblies, a significant portion of the heterochromatic regions including telomeres remain unresolved. Here we produce a de novo assembly of the New World malaria mosquito, Anopheles albimanus by integrating Oxford Nanopore sequencing, Illumina, Hi-C and optical mapping. This 172.6 Mbps female assembly, which we call AalbS3, is obtained by scaffolding polished large contigs (contig N50 = 13.7 Mbps) into three chromosomes. All chromosome arms end with telomeric repeats, which is the first in mosquito assemblies and represents a significant step toward the completion of a genome assembly. These telomeres consist of tandem repeats of a novel 30-32 bp Telomeric Repeat Unit (TRU) and are confirmed by analyzing the termini of long reads and through both chromosomal in situ hybridization and a Bal31 sensitivity assay. The AalbS3 assembly included previously uncharacterized centromeric and rDNA clusters and more than doubled the content of transposable elements and other repetitive sequences. This telomere-to-telomere assembly, although still containing gaps, represents a significant step toward resolving biologically important but previously hidden genomic components. The comparison of different scaffolding methods will also inform future efforts to obtain reference-quality genomes for other mosquito species.
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Mérel V, Boulesteix M, Fablet M, Vieira C. Transposable elements in Drosophila. Mob DNA 2020; 11:23. [PMID: 32636946 PMCID: PMC7334843 DOI: 10.1186/s13100-020-00213-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 04/14/2020] [Indexed: 12/25/2022] Open
Abstract
Drosophila has been studied as a biological model for many years and many discoveries in biology rely on this species. Research on transposable elements (TEs) is not an exception. Drosophila has contributed significantly to our knowledge on the mechanisms of transposition and their regulation, but above all, it was one of the first organisms on which genetic and genomic studies of populations were done. In this review article, in a very broad way, we will approach the TEs of Drosophila with a historical hindsight as well as recent discoveries in the field.
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Affiliation(s)
- Vincent Mérel
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Matthieu Boulesteix
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Marie Fablet
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Cristina Vieira
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
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29
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Hocher A, Taddei A. Subtelomeres as Specialized Chromatin Domains. Bioessays 2020; 42:e1900205. [PMID: 32181520 DOI: 10.1002/bies.201900205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/19/2020] [Indexed: 12/26/2022]
Abstract
Specificities associated with chromosomal linearity are not restricted to telomeres. Here, recent results obtained on fission and budding yeast are summarized and an attempt is made to define subtelomeres using chromatin features extending beyond the heterochromatin emanating from telomeres. Subtelomeres, the chromosome domains adjacent to telomeres, differ from the rest of the genome by their gene content, rapid evolution, and chromatin features that together contribute to organism adaptation. However, current definitions of subtelomeres are generally based on synteny and are largely gene-centered. Taking into consideration both the peculiar gene content and dynamics as well as the chromatin properties of those domains, it is discussed how chromatin features can contribute to subtelomeric properties and functions, and play a pivotal role in the emergence of subtelomeres.
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Affiliation(s)
- Antoine Hocher
- MRC London Institute of Medical Sciences (LMS), Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Angela Taddei
- Institut Curie, PSL Research University, CNRS, UMR3664, Paris, F-75005, France.,Sorbonne Université, UPMC University Paris 06, CNRS, UMR3664, Paris, F-75005, France
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Markova DN, Christensen SM, Betrán E. Telomere-Specialized Retroelements in Drosophila: Adaptive Symbionts of the Genome, Neutral, or in Conflict? Bioessays 2019; 42:e1900154. [PMID: 31815300 DOI: 10.1002/bies.201900154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/31/2019] [Indexed: 12/17/2022]
Abstract
Linear chromosomes shorten in every round of replication. In Drosophila, telomere-specialized long interspersed retrotransposable elements (LINEs) belonging to the jockey clade offset this shortening by forming head-to-tail arrays at Drosophila telomere ends. As such, these telomeric LINEs have been considered adaptive symbionts of the genome, protecting it from premature decay, particularly as Drosophila lacks a conventional telomerase holoenzyme. However, as reviewed here, recent work reveals a high degree of variation and turnover in the telomere-specialized LINE lineages across Drosophila. There appears to be no absolute requirement for LINE activity to maintain telomeres in flies, hence the suggestion that the telomere-specialized LINEs may instead be neutral or in conflict with the host, rather than adaptive.
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Affiliation(s)
- Dragomira N Markova
- Department of Biology, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Shawn M Christensen
- Department of Biology, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Esther Betrán
- Department of Biology, University of Texas at Arlington, Arlington, TX, 76019, USA
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31
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Kuznetsova V, Grozeva S, Gokhman V. Telomere structure in insects: A review. J ZOOL SYST EVOL RES 2019. [DOI: 10.1111/jzs.12332] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Valentina Kuznetsova
- Department of Karyosystematics, Zoological Institute Russian Academy of Sciences St. Petersburg Russia
| | - Snejana Grozeva
- Cytotaxonomy and Evolution Research Group, Institute of Biodiversity and Ecosystem Research Bulgarian Academy of Sciences Sofia Bulgaria
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32
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Sándor S, Kubinyi E. Genetic Pathways of Aging and Their Relevance in the Dog as a Natural Model of Human Aging. Front Genet 2019; 10:948. [PMID: 31681409 PMCID: PMC6813227 DOI: 10.3389/fgene.2019.00948] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 09/05/2019] [Indexed: 12/15/2022] Open
Abstract
Aging research has experienced a burst of scientific efforts in the last decades as the growing ratio of elderly people has begun to pose an increased burden on the healthcare and pension systems of developed countries. Although many breakthroughs have been reported in understanding the cellular mechanisms of aging, the intrinsic and extrinsic factors that contribute to senescence on higher biological levels are still barely understood. The dog, Canis familiaris, has already served as a valuable model of human physiology and disease. The possible role the dog could play in aging research is still an open question, although utilization of dogs may hold great promises as they naturally develop age-related cognitive decline, with behavioral and histological characteristics very similar to those of humans. In this regard, family dogs may possess unmatched potentials as models for investigations on the complex interactions between environmental, behavioral, and genetic factors that determine the course of aging. In this review, we summarize the known genetic pathways in aging and their relevance in dogs, putting emphasis on the yet barely described nature of certain aging pathways in canines. Reasons for highlighting the dog as a future aging and gerontology model are also discussed, ranging from its unique evolutionary path shared with humans, its social skills, and the fact that family dogs live together with their owners, and are being exposed to the same environmental effects.
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Affiliation(s)
- Sára Sándor
- Department of Ethology, Eötvös Loránd University, Budapest, Hungary
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33
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Hjelmen CE, Blackmon H, Holmes VR, Burrus CG, Johnston JS. Genome Size Evolution Differs Between Drosophila Subgenera with Striking Differences in Male and Female Genome Size in Sophophora. G3 (BETHESDA, MD.) 2019; 9:3167-3179. [PMID: 31358560 PMCID: PMC6778784 DOI: 10.1534/g3.119.400560] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 07/26/2019] [Indexed: 11/29/2022]
Abstract
Genome size varies across the tree of life, with no clear correlation to organismal complexity or coding sequence, but with differences in non-coding regions. Phylogenetic methods have recently been incorporated to further disentangle this enigma, yet most of these studies have focused on widely diverged species. Few have compared patterns of genome size change in closely related species with known structural differences in the genome. As a consequence, the relationship between genome size and differences in chromosome number or inter-sexual differences attributed to XY systems are largely unstudied. We hypothesize that structural differences associated with chromosome number and X-Y chromosome differentiation, should result in differing rates and patterns of genome size change. In this study, we utilize the subgenera within the Drosophila to ask if patterns and rates of genome size change differ between closely related species with differences in chromosome numbers and states of the XY system. Genome sizes for males and females of 152 species are used to answer these questions (with 92 newly added or updated estimates). While we find no relationship between chromosome number and genome size or chromosome number and inter-sexual differences in genome size, we find evidence for differing patterns of genome size change between the subgenera, and increasing rates of change throughout time. Estimated shifts in rates of change in sex differences in genome size occur more often in Sophophora and correspond to known neo-sex events.
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Affiliation(s)
- Carl E Hjelmen
- Department of Biology and
- Department of Entomology, Texas A&M University, College Station, TX 77843
| | - Heath Blackmon
- Department of Entomology, Texas A&M University, College Station, TX 77843
| | | | - Crystal G Burrus
- Department of Entomology, Texas A&M University, College Station, TX 77843
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Abstract
Conventional approaches to identify a telomere motif in a new genome are laborious and time-intensive. An efficient new methodology based on next-generation sequencing (NGS), de novo sequence repeat finder (SERF) and fluorescence in situ hybridization (FISH) is presented. Unlike existing heuristic approaches, SERF utilizes an exhaustive analysis of raw NGS reads or assembled contigs for rapid de novo detection of conserved tandem repeats representing telomere motifs. SERF was validated using the NGS data from Ipheion uniflorum and Allium cepa with known telomere motifs. The analysis program was then used on NGS data to investigate the telomere motifs in several additional plant species and together with FISH proved to be an efficient approach to identify as yet unknown telomere motifs.
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35
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Maurer-Alcalá XX, Nowacki M. Evolutionary origins and impacts of genome architecture in ciliates. Ann N Y Acad Sci 2019; 1447:110-118. [PMID: 31074010 PMCID: PMC6767857 DOI: 10.1111/nyas.14108] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 03/18/2019] [Accepted: 04/03/2019] [Indexed: 01/24/2023]
Abstract
Genome architecture is well diversified among eukaryotes in terms of size and content, with many being radically shaped by ancient and ongoing genome conflicts with transposable elements (e.g., the large transposon‐rich genomes common among plants). In ciliates, a group of microbial eukaryotes with distinct somatic and germ‐line genomes present in a single cell, the consequences of these genome conflicts are most apparent in their developmentally programmed genome rearrangements. This complicated developmental phenomenon has largely overshadowed and outpaced our understanding of how germ‐line and somatic genome architectures have influenced the evolutionary dynamism and potential in these taxa. In our review, we highlight three central concepts: how the evolution of atypical ciliate germ‐line genome architectures is linked to ancient genome conflicts; how the complex, epigenetically guided transformation of germline to soma during development can generate widespread genetic variation; and how these features, coupled with their unusual life cycle, have increased the rate of molecular evolution linked to genome architecture in these taxa.
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Affiliation(s)
| | - Mariusz Nowacki
- Institute of Cell Biology, University of Bern, Bern, Switzerland
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36
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Aksenova AY, Mirkin SM. At the Beginning of the End and in the Middle of the Beginning: Structure and Maintenance of Telomeric DNA Repeats and Interstitial Telomeric Sequences. Genes (Basel) 2019; 10:genes10020118. [PMID: 30764567 PMCID: PMC6410037 DOI: 10.3390/genes10020118] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 02/07/2023] Open
Abstract
Tandem DNA repeats derived from the ancestral (TTAGGG)n run were first detected at chromosome ends of the majority of living organisms, hence the name telomeric DNA repeats. Subsequently, it has become clear that telomeric motifs are also present within chromosomes, and they were suitably called interstitial telomeric sequences (ITSs). It is well known that telomeric DNA repeats play a key role in chromosome stability, preventing end-to-end fusions and precluding the recurrent DNA loss during replication. Recent data suggest that ITSs are also important genomic elements as they confer its karyotype plasticity. In fact, ITSs appeared to be among the most unstable microsatellite sequences as they are highly length polymorphic and can trigger chromosomal fragility and gross chromosomal rearrangements. Importantly, mechanisms responsible for their instability appear to be similar to the mechanisms that maintain the length of genuine telomeres. This review compares the mechanisms of maintenance and dynamic properties of telomeric repeats and ITSs and discusses the implications of these dynamics on genome stability.
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Affiliation(s)
- Anna Y Aksenova
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia.
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02421, USA.
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37
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Petersen M, Armisén D, Gibbs RA, Hering L, Khila A, Mayer G, Richards S, Niehuis O, Misof B. Diversity and evolution of the transposable element repertoire in arthropods with particular reference to insects. BMC Evol Biol 2019; 19:11. [PMID: 30626321 PMCID: PMC6327564 DOI: 10.1186/s12862-018-1324-9] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 12/11/2018] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Transposable elements (TEs) are a major component of metazoan genomes and are associated with a variety of mechanisms that shape genome architecture and evolution. Despite the ever-growing number of insect genomes sequenced to date, our understanding of the diversity and evolution of insect TEs remains poor. RESULTS Here, we present a standardized characterization and an order-level comparison of arthropod TE repertoires, encompassing 62 insect and 11 outgroup species. The insect TE repertoire contains TEs of almost every class previously described, and in some cases even TEs previously reported only from vertebrates and plants. Additionally, we identified a large fraction of unclassifiable TEs. We found high variation in TE content, ranging from less than 6% in the antarctic midge (Diptera), the honey bee and the turnip sawfly (Hymenoptera) to more than 58% in the malaria mosquito (Diptera) and the migratory locust (Orthoptera), and a possible relationship between the content and diversity of TEs and the genome size. CONCLUSION While most insect orders exhibit a characteristic TE composition, we also observed intraordinal differences, e.g., in Diptera, Hymenoptera, and Hemiptera. Our findings shed light on common patterns and reveal lineage-specific differences in content and evolution of TEs in insects. We anticipate our study to provide the basis for future comparative research on the insect TE repertoire.
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Affiliation(s)
- Malte Petersen
- University of Bonn, Bonn, Germany
- Zoological Research Museum Alexander Koenig, Center for Molecular Biodiversity Research, Adenauerallee 160, Bonn, 53113 Germany
- Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt, 60325 Germany
| | - David Armisén
- Université de Lyon, Institut de Génomique Fonctionnelle de Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 allée d’Italie, Lyon, 69364 France
| | - Richard A. Gibbs
- Human Genome Sequencing Center, Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, 77030 TX USA
| | - Lars Hering
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Str. 40, Kassel, 34132 Germany
| | - Abderrahman Khila
- Université de Lyon, Institut de Génomique Fonctionnelle de Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 allée d’Italie, Lyon, 69364 France
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, Heinrich-Plett-Str. 40, Kassel, 34132 Germany
| | - Stephen Richards
- Human Genome Sequencing Center, Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, 77030 TX USA
| | - Oliver Niehuis
- Department of Evolutionary Biology and Ecology, Institute for Biology I (Zoology), University of Freiburg, Freiburg (Brsg.), 79104 Germany
| | - Bernhard Misof
- Zoological Research Museum Alexander Koenig, Center for Molecular Biodiversity Research, Adenauerallee 160, Bonn, 53113 Germany
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Chromatin Loop Formation Induced by a Subtelomeric Protosilencer Represses EPA Genes in Candida glabrata. Genetics 2018; 210:113-128. [PMID: 30002080 DOI: 10.1534/genetics.118.301202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/09/2018] [Indexed: 01/05/2023] Open
Abstract
Adherence, an important virulence factor, is mediated by the EPA (Epithelial Adhesin) genes in the opportunistic pathogen Candida glabrata Expression of adhesin-encoding genes requires tight regulation to respond to harsh environmental conditions within the host. The majority of EPA genes are localized in subtelomeric regions regulated by subtelomeric silencing, which depends mainly on Rap1 and the Sir proteins. In vitro adhesion to epithelial cells is primarily mediated by Epa1. EPA1 forms a cluster with EPA2 and EPA3 in the right telomere of chromosome E (E-R). This telomere contains a cis-acting regulatory element, the protosilencer Sil2126 between EPA3 and the telomere. Interestingly, Sil2126 is only active in the context of its native telomere. Replacement of the intergenic regions between EPA genes in E-R revealed that cis-acting elements between EPA2 and EPA3 are required for Sil2126 activity when placed 32 kb away from the telomere (Sil@-32kb). Sil2126 contains several putative binding sites for Rap1 and Abf1, and its activity depends on these proteins. Indeed, Sil2126 binds Rap1 and Abf1 at its native position and also when inserted at -32 kb, a silencing-free environment in the parental strain. In addition, we found that Sil@-32kb and Sil2126 at its native position can physically interact with the intergenic regions between EPA1-EPA2 and EPA2-EPA3 respectively, by chromosome conformation capture assays. We speculate that Rap1 and Abf1 bound to Sil2126 can recruit the Silent Information Regulator complex, and together mediate silencing in this region, probably through the formation of a chromatin loop.
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Berthelier J, Casse N, Daccord N, Jamilloux V, Saint-Jean B, Carrier G. A transposable element annotation pipeline and expression analysis reveal potentially active elements in the microalga Tisochrysis lutea. BMC Genomics 2018. [PMID: 29783941 DOI: 10.17882/52231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
Abstract
BACKGROUND Transposable elements (TEs) are mobile DNA sequences known as drivers of genome evolution. Their impacts have been widely studied in animals, plants and insects, but little is known about them in microalgae. In a previous study, we compared the genetic polymorphisms between strains of the haptophyte microalga Tisochrysis lutea and suggested the involvement of active autonomous TEs in their genome evolution. RESULTS To identify potentially autonomous TEs, we designed a pipeline named PiRATE (Pipeline to Retrieve and Annotate Transposable Elements, download: https://doi.org/10.17882/51795 ), and conducted an accurate TE annotation on a new genome assembly of T. lutea. PiRATE is composed of detection, classification and annotation steps. Its detection step combines multiple, existing analysis packages representing all major approaches for TE detection and its classification step was optimized for microalgal genomes. The efficiency of the detection and classification steps was evaluated with data on the model species Arabidopsis thaliana. PiRATE detected 81% of the TE families of A. thaliana and correctly classified 75% of them. We applied PiRATE to T. lutea genomic data and established that its genome contains 15.89% Class I and 4.95% Class II TEs. In these, 3.79 and 17.05% correspond to potentially autonomous and non-autonomous TEs, respectively. Annotation data was combined with transcriptomic and proteomic data to identify potentially active autonomous TEs. We identified 17 expressed TE families and, among these, a TIR/Mariner and a TIR/hAT family were able to synthesize their transposase. Both these TE families were among the three highest expressed genes in a previous transcriptomic study and are composed of highly similar copies throughout the genome of T. lutea. This sum of evidence reveals that both these TE families could be capable of transposing or triggering the transposition of potential related MITE elements. CONCLUSION This manuscript provides an example of a de novo transposable element annotation of a non-model organism characterized by a fragmented genome assembly and belonging to a poorly studied phylum at genomic level. Integration of multi-omics data enabled the discovery of potential mobile TEs and opens the way for new discoveries on the role of these repeated elements in genomic evolution of microalgae.
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Affiliation(s)
- Jérémy Berthelier
- IFREMER, Physiology and Biotechnology of Algae Laboratory, rue de l'Ile d'Yeu, 44311, Nantes, France.
- Mer Molécules Santé, EA 2160 IUML - FR 3473 CNRS, Le Mans University, Le Mans, France.
| | - Nathalie Casse
- Mer Molécules Santé, EA 2160 IUML - FR 3473 CNRS, Le Mans University, Le Mans, France
| | - Nicolas Daccord
- Institut de Recherche en Horticulture et Semences, INRA of Angers, AGROCAMPUS-Ouest, SFR4207 QUASAV, Université d'Angers, Angers, France
- Université Bretagne Loire, Angers, France
| | | | - Bruno Saint-Jean
- IFREMER, Physiology and Biotechnology of Algae Laboratory, rue de l'Ile d'Yeu, 44311, Nantes, France
| | - Grégory Carrier
- IFREMER, Physiology and Biotechnology of Algae Laboratory, rue de l'Ile d'Yeu, 44311, Nantes, France
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Berthelier J, Casse N, Daccord N, Jamilloux V, Saint-Jean B, Carrier G. A transposable element annotation pipeline and expression analysis reveal potentially active elements in the microalga Tisochrysis lutea. BMC Genomics 2018; 19:378. [PMID: 29783941 PMCID: PMC5963040 DOI: 10.1186/s12864-018-4763-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/07/2018] [Indexed: 01/01/2023] Open
Abstract
Background Transposable elements (TEs) are mobile DNA sequences known as drivers of genome evolution. Their impacts have been widely studied in animals, plants and insects, but little is known about them in microalgae. In a previous study, we compared the genetic polymorphisms between strains of the haptophyte microalga Tisochrysis lutea and suggested the involvement of active autonomous TEs in their genome evolution. Results To identify potentially autonomous TEs, we designed a pipeline named PiRATE (Pipeline to Retrieve and Annotate Transposable Elements, download: 10.17882/51795), and conducted an accurate TE annotation on a new genome assembly of T. lutea. PiRATE is composed of detection, classification and annotation steps. Its detection step combines multiple, existing analysis packages representing all major approaches for TE detection and its classification step was optimized for microalgal genomes. The efficiency of the detection and classification steps was evaluated with data on the model species Arabidopsis thaliana. PiRATE detected 81% of the TE families of A. thaliana and correctly classified 75% of them. We applied PiRATE to T. lutea genomic data and established that its genome contains 15.89% Class I and 4.95% Class II TEs. In these, 3.79 and 17.05% correspond to potentially autonomous and non-autonomous TEs, respectively. Annotation data was combined with transcriptomic and proteomic data to identify potentially active autonomous TEs. We identified 17 expressed TE families and, among these, a TIR/Mariner and a TIR/hAT family were able to synthesize their transposase. Both these TE families were among the three highest expressed genes in a previous transcriptomic study and are composed of highly similar copies throughout the genome of T. lutea. This sum of evidence reveals that both these TE families could be capable of transposing or triggering the transposition of potential related MITE elements. Conclusion This manuscript provides an example of a de novo transposable element annotation of a non-model organism characterized by a fragmented genome assembly and belonging to a poorly studied phylum at genomic level. Integration of multi-omics data enabled the discovery of potential mobile TEs and opens the way for new discoveries on the role of these repeated elements in genomic evolution of microalgae. Electronic supplementary material The online version of this article (10.1186/s12864-018-4763-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jérémy Berthelier
- IFREMER, Physiology and Biotechnology of Algae Laboratory, rue de l'Ile d'Yeu, 44311, Nantes, France. .,Mer Molécules Santé, EA 2160 IUML - FR 3473 CNRS, Le Mans University, Le Mans, France.
| | - Nathalie Casse
- Mer Molécules Santé, EA 2160 IUML - FR 3473 CNRS, Le Mans University, Le Mans, France
| | - Nicolas Daccord
- Institut de Recherche en Horticulture et Semences, INRA of Angers, AGROCAMPUS-Ouest, SFR4207 QUASAV, Université d'Angers, Angers, France.,Université Bretagne Loire, Angers, France
| | | | - Bruno Saint-Jean
- IFREMER, Physiology and Biotechnology of Algae Laboratory, rue de l'Ile d'Yeu, 44311, Nantes, France
| | - Grégory Carrier
- IFREMER, Physiology and Biotechnology of Algae Laboratory, rue de l'Ile d'Yeu, 44311, Nantes, France
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Li P, Wang L, Bennett BD, Wang J, Li J, Qin Y, Takaku M, Wade PA, Wong J, Hu G. Rif1 promotes a repressive chromatin state to safeguard against endogenous retrovirus activation. Nucleic Acids Res 2018; 45:12723-12738. [PMID: 29040764 PMCID: PMC5727408 DOI: 10.1093/nar/gkx884] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 10/05/2017] [Indexed: 12/29/2022] Open
Abstract
Transposable elements, including endogenous retroviruses (ERVs), constitute a large fraction of the mammalian genome. They are transcriptionally silenced during early development to protect genome integrity and aberrant transcription. However, the mechanisms that control their repression are not fully understood. To systematically study ERV repression, we carried out an RNAi screen in mouse embryonic stem cells (ESCs) and identified a list of novel regulators. Among them, Rif1 displays the strongest effect. Rif1 depletion by RNAi or gene deletion led to increased transcription and increased chromatin accessibility at ERV regions and their neighboring genes. This transcriptional de-repression becomes more severe when DNA methylation is lost. On the mechanistic level, Rif1 directly occupies ERVs and is required for repressive histone mark H3K9me3 and H3K27me3 assembly and DNA methylation. It interacts with histone methyltransferases and facilitates their recruitment to ERV regions. Importantly, Rif1 represses ERVs in human ESCs as well, and the evolutionally-conserved HEAT-like domain is essential for its function. Finally, Rif1 acts as a barrier during somatic cell reprogramming, and its depletion significantly enhances reprogramming efficiency. Together, our study uncovered many previously uncharacterized repressors of ERVs, and defined an essential role of Rif1 in the epigenetic defense against ERV activation.
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Affiliation(s)
- Pishun Li
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, RTP, NC 27709, USA
| | - Li Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Brian D. Bennett
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, RTP, NC 27709, USA
| | - Jiajia Wang
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, RTP, NC 27709, USA
| | - Jialun Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yufeng Qin
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, RTP, NC 27709, USA
| | - Motoki Takaku
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, RTP, NC 27709, USA
| | - Paul A. Wade
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, RTP, NC 27709, USA
| | - Jiemin Wong
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Guang Hu
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, RTP, NC 27709, USA
- To whom correspondence should be addressed. Tel: +1 919 541 4755; Fax: +1 919 541 0146;
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Penke TJR, McKay DJ, Strahl BD, Matera AG, Duronio RJ. Functional Redundancy of Variant and Canonical Histone H3 Lysine 9 Modification in Drosophila. Genetics 2018; 208:229-244. [PMID: 29133298 PMCID: PMC5753860 DOI: 10.1534/genetics.117.300480] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/10/2017] [Indexed: 01/07/2023] Open
Abstract
Histone post-translational modifications (PTMs) and differential incorporation of variant and canonical histones into chromatin are central modes of epigenetic regulation. Despite similar protein sequences, histone variants are enriched for different suites of PTMs compared to their canonical counterparts. For example, variant histone H3.3 occurs primarily in transcribed regions and is enriched for "active" histone PTMs like Lys9 acetylation (H3.3K9ac), whereas the canonical histone H3 is enriched for Lys9 methylation (H3K9me), which is found in transcriptionally silent heterochromatin. To determine the functions of K9 modification on variant vs. canonical H3, we compared the phenotypes caused by engineering H3.3K9R and H3K9R mutant genotypes in Drosophila melanogaster Whereas most H3.3K9R , and a small number of H3K9R , mutant animals are capable of completing development and do not have substantially altered protein-coding transcriptomes, all H3.3K9R H3K9R combined mutants die soon after embryogenesis and display decreased expression of genes enriched for K9ac. These data suggest that the role of K9ac in gene activation during development can be provided by either H3 or H3.3. Conversely, we found that H3.3K9 is methylated at telomeric transposons and that this mark contributes to repressive chromatin architecture, supporting a role for H3.3 in heterochromatin that is distinct from that of H3. Thus, our genetic and molecular analyses demonstrate that K9 modification of variant and canonical H3 have overlapping roles in development and transcriptional regulation, though to differing extents in euchromatin and heterochromatin.
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Affiliation(s)
- Taylor J R Penke
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, North Carolina 27599
| | - Daniel J McKay
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, North Carolina 27599
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, North Carolina 27599
- Department of Genetics, The University of North Carolina at Chapel Hill, North Carolina 27599
- Department of Biology, The University of North Carolina at Chapel Hill, North Carolina 27599
| | - Brian D Strahl
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, North Carolina 27599
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, North Carolina 27599
| | - A Gregory Matera
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, North Carolina 27599
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, North Carolina 27599
- Department of Genetics, The University of North Carolina at Chapel Hill, North Carolina 27599
- Department of Biology, The University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, North Carolina 27599
| | - Robert J Duronio
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, North Carolina 27599
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, North Carolina 27599
- Department of Genetics, The University of North Carolina at Chapel Hill, North Carolina 27599
- Department of Biology, The University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, North Carolina 27599
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Laricchia KM, Zdraljevic S, Cook DE, Andersen EC. Natural Variation in the Distribution and Abundance of Transposable Elements Across the Caenorhabditis elegans Species. Mol Biol Evol 2017; 34:2187-2202. [PMID: 28486636 PMCID: PMC5850821 DOI: 10.1093/molbev/msx155] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Transposons are mobile DNA elements that generate both adaptive and deleterious phenotypic variation thereby driving genome evolution. For these reasons, genomes have mechanisms to regulate transposable element (TE) activity. Approximately 12–16% of the Caenorhabditis elegans genome is composed of TEs, of which the majority are likely inactive. However, most studies of TE activity have been conducted in the laboratory strain N2, which limits our knowledge of the effects of these mobile elements across natural populations. We analyzed the distribution and abundance of TEs in 208 wild C. elegans strains to better understand how transposons contribute to variation in natural populations. We identified 3,397 TEs as compared with the reference strain, of which 2,771 are novel insertions and 241 are TEs that have been excised in at least one wild strain. Likely because of their hypothesized deleterious effects, we find that TEs are found at low allele frequencies throughout the population, and we predict functional effects of TE insertions. The abundances of TEs reflect their activities, and these data allowed us to perform both genome-wide association mappings and rare variant correlations to reveal several candidate genes that impact TE regulation, including small regulatory piwi-interacting RNAs and chromatin factors. Because TE variation in natural populations could underlie phenotypic variation for organismal and behavioral traits, the transposons that we identified and their regulatory mechanisms can be used in future studies to explore the genomics of complex traits and evolutionary changes.
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Affiliation(s)
- K M Laricchia
- Department of Molecular Biosciences, Northwestern University, Evanston, IL
| | - S Zdraljevic
- Department of Molecular Biosciences, Northwestern University, Evanston, IL.,Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL
| | - D E Cook
- Department of Molecular Biosciences, Northwestern University, Evanston, IL.,Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL
| | - E C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL.,Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL.,Chemistry of Life Processes Institute, Northwestern University, Evanston, IL.,Northwestern Institute on Complex Systems, Northwestern University, Evanston, IL
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Malicki M, Iliopoulou M, Hammann C. Retrotransposon Domestication and Control in Dictyostelium discoideum. Front Microbiol 2017; 8:1869. [PMID: 29051748 PMCID: PMC5633606 DOI: 10.3389/fmicb.2017.01869] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/13/2017] [Indexed: 01/22/2023] Open
Abstract
Transposable elements, identified in all eukaryotes, are mobile genetic units that can change their genomic position. Transposons usually employ an excision and reintegration mechanism, by which they change position, but not copy number. In contrast, retrotransposons amplify via RNA intermediates, increasing their genomic copy number. Hence, they represent a particular threat to the structural and informational integrity of the invaded genome. The social amoeba Dictyostelium discoideum, model organism of the evolutionary Amoebozoa supergroup, features a haploid, gene-dense genome that offers limited space for damage-free transposition. Several of its contemporary retrotransposons display intrinsic integration preferences, for example by inserting next to transfer RNA genes or other retroelements. Likely, any retrotransposons that invaded the genome of the amoeba in a non-directed manner were lost during evolution, as this would result in decreased fitness of the organism. Thus, the positional preference of the Dictyostelium retroelements might represent a domestication of the selfish elements. Likewise, the reduced danger of such domesticated transposable elements led to their accumulation, and they represent about 10% of the current genome of D. discoideum. To prevent the uncontrolled spreading of retrotransposons, the amoeba employs control mechanisms including RNA interference and heterochromatization. Here, we review TRE5-A, DIRS-1 and Skipper-1, as representatives of the three retrotransposon classes in D. discoideum, which make up 5.7% of the Dictyostelium genome. We compile open questions with respect to their mobility and cellular regulation, and suggest strategies, how these questions might be addressed experimentally.
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Affiliation(s)
- Marek Malicki
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Maro Iliopoulou
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Christian Hammann
- Ribogenetics Biochemistry Lab, Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
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Asif-Laidin A, Delmarre V, Laurentie J, Miller WJ, Ronsseray S, Teysset L. Short and long-term evolutionary dynamics of subtelomeric piRNA clusters in Drosophila. DNA Res 2017; 24:459-472. [PMID: 28459978 PMCID: PMC5737368 DOI: 10.1093/dnares/dsx017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 03/29/2017] [Indexed: 12/31/2022] Open
Abstract
Two Telomeric Associated Sequences, TAS-R and TAS-L, form the principal subtelomeric repeat families identified in Drosophila melanogaster. They are PIWI-interacting RNA (piRNA) clusters involved in repression of Transposable Elements. In this study, we revisited TAS structural and functional dynamics in D. melanogaster and in related species. In silico analysis revealed that TAS-R family members are composed of previously uncharacterized domains. This analysis also showed that TAS-L repeats are composed of arrays of a region we have named "TAS-L like" (TLL) identified specifically in one TAS-R family member, X-TAS. TLL were also present in other species of the melanogaster subgroup. Therefore, it is possible that TLL represents an ancestral subtelomeric piRNA core-cluster. Furthermore, all D. melanogaster genomes tested possessed at least one TAS-R locus, whereas TAS-L can be absent. A screen of 110 D. melanogaster lines showed that X-TAS is always present in flies living in the wild, but often absent in long-term laboratory stocks and that natural populations frequently lost their X-TAS within 2 years upon lab conditioning. Therefore, the unexpected structural and temporal dynamics of subtelomeric piRNA clusters demonstrated here suggests that genome organization is subjected to distinct selective pressures in the wild and upon domestication in the laboratory.
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Affiliation(s)
- Amna Asif-Laidin
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Valérie Delmarre
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Jeanne Laurentie
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Wolfgang J. Miller
- Lab Genome Dynamics, Department for Cell & Developmental Biology, Center of Anatomy and Cell Biology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Stéphane Ronsseray
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
| | - Laure Teysset
- Sorbonne Universités, UPMC University of Paris 06, CNRS, Biologie du Développement Paris-Seine, Institut de Biologie Paris-Seine (LBD-IBPS), 75005 Paris, France
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Chromosome Healing Is Promoted by the Telomere Cap Component Hiphop in Drosophila. Genetics 2017; 207:949-959. [PMID: 28942425 DOI: 10.1534/genetics.117.300317] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/21/2017] [Indexed: 11/18/2022] Open
Abstract
The addition of a new telomere onto a chromosome break, a process termed healing, has been studied extensively in organisms that utilize telomerase to maintain their telomeres. In comparison, relatively little is known about how new telomeres are constructed on broken chromosomes in organisms that do not use telomerase. Chromosome healing was studied in somatic and germline cells of Drosophila melanogaster, a nontelomerase species. We observed, for the first time, that broken chromosomes can be healed in somatic cells. In addition, overexpression of the telomere cap component Hiphop increased the survival of somatic cells with broken chromosomes, while the cap component HP1 did not, and overexpression of the cap protein HOAP decreased their survival. In the male germline, Hiphop overexpression greatly increased the transmission of healed chromosomes. These results indicate that Hiphop can stimulate healing of a chromosome break. We suggest that this reflects a unique function of Hiphop: it is capable of seeding formation of a new telomeric cap on a chromosome end that lacks a telomere.
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Ryazansky S, Radion E, Mironova A, Akulenko N, Abramov Y, Morgunova V, Kordyukova MY, Olovnikov I, Kalmykova A. Natural variation of piRNA expression affects immunity to transposable elements. PLoS Genet 2017; 13:e1006731. [PMID: 28448516 PMCID: PMC5407775 DOI: 10.1371/journal.pgen.1006731] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 03/31/2017] [Indexed: 11/25/2022] Open
Abstract
In the Drosophila germline, transposable elements (TEs) are silenced by PIWI-interacting RNA (piRNA) that originate from distinct genomic regions termed piRNA clusters and are processed by PIWI-subfamily Argonaute proteins. Here, we explore the variation in the ability to restrain an alien TE in different Drosophila strains. The I-element is a retrotransposon involved in the phenomenon of I-R hybrid dysgenesis in Drosophila melanogaster. Genomes of R strains do not contain active I-elements, but harbour remnants of ancestral I-related elements. The permissivity to I-element activity of R females, called reactivity, varies considerably in natural R populations, indicating the existence of a strong natural polymorphism in defense systems targeting transposons. To reveal the nature of such polymorphisms, we compared ovarian small RNAs between R strains with low and high reactivity and show that reactivity negatively correlates with the ancestral I-element-specific piRNA content. Analysis of piRNA clusters containing remnants of I-elements shows increased expression of the piRNA precursors and enrichment by the Heterochromatin Protein 1 homolog, Rhino, in weak R strains, which is in accordance with stronger piRNA expression by these regions. To explore the nature of the differences in piRNA production, we focused on two R strains, weak and strong, and showed that the efficiency of maternal inheritance of piRNAs as well as the I-element copy number are very similar in both strains. At the same time, germline and somatic uni-strand piRNA clusters generate more piRNAs in strains with low reactivity, suggesting the relationship between the efficiency of primary piRNA production and variable response to TE invasions. The strength of adaptive genome defense is likely driven by naturally occurring polymorphisms in the rapidly evolving piRNA pathway proteins. We hypothesize that hyper-efficient piRNA production is contributing to elimination of a telomeric retrotransposon HeT-A, which we have observed in one particular transposon-resistant R strain. Transposon activity in the germline is suppressed by the PIWI-interacting RNA (piRNA) pathway. The resistance of natural Drosophila strains to transposon invasion varies considerably, but the nature of this variability is unknown. We discovered that natural variation in the efficiency of primary piRNA production in the germline causes dramatic differences in the susceptibility to expansion of a newly invaded transposon. A high level of piRNA production in the germline is achieved by increased expression of piRNA precursors. In one of the most transposon-resistant strains, increased content of primary piRNA is observed in both the germline and ovarian somatic cells. We suggest that polymorphisms in piRNA pathway factors are responsible for increased piRNA production. piRNA pathway proteins have been shown to be evolving rapidly under selective pressure. Our data are the first to describe a phenotype that might be caused by this kind of polymorphism. We also demonstrate a likely explanation as to why an overly active piRNA pathway can cause more harm than good in Drosophila: Highly efficient piRNA processing leads to elimination of domesticated telomeric retrotransposons essential for telomere elongation, an effect which has been observed in a natural strain that is extremely resistant to transposon invasion.
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Affiliation(s)
- Sergei Ryazansky
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Elizaveta Radion
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Anastasia Mironova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Natalia Akulenko
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Yuri Abramov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Valeriya Morgunova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Maria Y. Kordyukova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Ivan Olovnikov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Alla Kalmykova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
- * E-mail:
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Lee YCG, Leek C, Levine MT. Recurrent Innovation at Genes Required for Telomere Integrity in Drosophila. Mol Biol Evol 2017; 34:467-482. [PMID: 27836984 PMCID: PMC6307840 DOI: 10.1093/molbev/msw248] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Telomeres are nucleoprotein complexes at the ends of linear chromosomes. These specialized structures ensure genome integrity and faithful chromosome inheritance. Recurrent addition of repetitive, telomere-specific DNA elements to chromosome ends combats end-attrition, while specialized telomere-associated proteins protect naked, double-stranded chromosome ends from promiscuous repair into end-to-end fusions. Although telomere length homeostasis and end-protection are ubiquitous across eukaryotes, there is sporadic but building evidence that the molecular machinery supporting these essential processes evolves rapidly. Nevertheless, no global analysis of the evolutionary forces that shape these fast-evolving proteins has been performed on any eukaryote. The abundant population and comparative genomic resources of Drosophila melanogaster and its close relatives offer us a unique opportunity to fill this gap. Here we leverage population genetics, molecular evolution, and phylogenomics to define the scope and evolutionary mechanisms driving fast evolution of genes required for telomere integrity. We uncover evidence of pervasive positive selection across multiple evolutionary timescales. We also document prolific expansion, turnover, and expression evolution in gene families founded by telomeric proteins. Motivated by the mutant phenotypes and molecular roles of these fast-evolving genes, we put forward four alternative, but not mutually exclusive, models of intra-genomic conflict that may play out at very termini of eukaryotic chromosomes. Our findings set the stage for investigating both the genetic causes and functional consequences of telomere protein evolution in Drosophila and beyond.
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Affiliation(s)
- Yuh Chwen G Lee
- Department of Ecology and Evolution, University of Chicago, Chicago, IL
| | - Courtney Leek
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA
| | - Mia T Levine
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA
- Epigenetics Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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Sotero-Caio CG, Platt RN, Suh A, Ray DA. Evolution and Diversity of Transposable Elements in Vertebrate Genomes. Genome Biol Evol 2017; 9:161-177. [PMID: 28158585 PMCID: PMC5381603 DOI: 10.1093/gbe/evw264] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2016] [Indexed: 12/21/2022] Open
Abstract
Transposable elements (TEs) are selfish genetic elements that mobilize in genomes via transposition or retrotransposition and often make up large fractions of vertebrate genomes. Here, we review the current understanding of vertebrate TE diversity and evolution in the context of recent advances in genome sequencing and assembly techniques. TEs make up 4-60% of assembled vertebrate genomes, and deeply branching lineages such as ray-finned fishes and amphibians generally exhibit a higher TE diversity than the more recent radiations of birds and mammals. Furthermore, the list of taxa with exceptional TE landscapes is growing. We emphasize that the current bottleneck in genome analyses lies in the proper annotation of TEs and provide examples where superficial analyses led to misleading conclusions about genome evolution. Finally, recent advances in long-read sequencing will soon permit access to TE-rich genomic regions that previously resisted assembly including the gigantic, TE-rich genomes of salamanders and lungfishes.
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Affiliation(s)
| | - Roy N. Platt
- Department of Biological Sciences, Texas Tech University, Lubbock, TX
| | - Alexander Suh
- Department of Evolutionary Biology (EBC), Uppsala University, Uppsala, Sweden
| | - David A. Ray
- Department of Biological Sciences, Texas Tech University, Lubbock, TX
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