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Frangieh CJ, Wilkinson ME, Strebinger D, Strecker J, Walsh ML, Faure G, Yushenova IA, Macrae RK, Arkhipova IR, Zhang F. Internal initiation of reverse transcription in a Penelope-like retrotransposon. Mob DNA 2024; 15:12. [PMID: 38863000 PMCID: PMC11167929 DOI: 10.1186/s13100-024-00322-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 06/03/2024] [Indexed: 06/13/2024] Open
Abstract
Eukaryotic retroelements are generally divided into two classes: long terminal repeat (LTR) retrotransposons and non-LTR retrotransposons. A third class of eukaryotic retroelement, the Penelope-like elements (PLEs), has been well-characterized bioinformatically, but relatively little is known about the transposition mechanism of these elements. PLEs share some features with the R2 retrotransposon from Bombyx mori, which uses a target-primed reverse transcription (TPRT) mechanism, but their distinct phylogeny suggests PLEs may utilize a novel mechanism of mobilization. Using protein purified from E. coli, we report unique in vitro properties of a PLE from the green anole (Anolis carolinensis), revealing mechanistic aspects not shared by other retrotransposons. We found that reverse transcription is initiated at two adjacent sites within the transposon RNA that is not homologous to the cleaved DNA, a feature that is reflected in the genomic "tail" signature shared between and unique to PLEs. Our results for the first active PLE in vitro provide a starting point for understanding PLE mobilization and biology.
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Affiliation(s)
- Chris J Frangieh
- Howard Hughes Medical Institute, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Max E Wilkinson
- Howard Hughes Medical Institute, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Daniel Strebinger
- Howard Hughes Medical Institute, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Jonathan Strecker
- Howard Hughes Medical Institute, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Michelle L Walsh
- Howard Hughes Medical Institute, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Guilhem Faure
- Howard Hughes Medical Institute, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Irina A Yushenova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Rhiannon K Macrae
- Howard Hughes Medical Institute, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, 02543, USA.
| | - Feng Zhang
- Howard Hughes Medical Institute, Cambridge, MA, 02139, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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Craig RJ, Gallaher SD, Shu S, Salomé PA, Jenkins JW, Blaby-Haas CE, Purvine SO, O’Donnell S, Barry K, Grimwood J, Strenkert D, Kropat J, Daum C, Yoshinaga Y, Goodstein DM, Vallon O, Schmutz J, Merchant SS. The Chlamydomonas Genome Project, version 6: Reference assemblies for mating-type plus and minus strains reveal extensive structural mutation in the laboratory. THE PLANT CELL 2023; 35:644-672. [PMID: 36562730 PMCID: PMC9940879 DOI: 10.1093/plcell/koac347] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 10/12/2022] [Accepted: 12/16/2022] [Indexed: 05/20/2023]
Abstract
Five versions of the Chlamydomonas reinhardtii reference genome have been produced over the last two decades. Here we present version 6, bringing significant advances in assembly quality and structural annotations. PacBio-based chromosome-level assemblies for two laboratory strains, CC-503 and CC-4532, provide resources for the plus and minus mating-type alleles. We corrected major misassemblies in previous versions and validated our assemblies via linkage analyses. Contiguity increased over ten-fold and >80% of filled gaps are within genes. We used Iso-Seq and deep RNA-seq datasets to improve structural annotations, and updated gene symbols and textual annotation of functionally characterized genes via extensive manual curation. We discovered that the cell wall-less classical reference strain CC-503 exhibits genomic instability potentially caused by deletion of the helicase RECQ3, with major structural mutations identified that affect >100 genes. We therefore present the CC-4532 assembly as the primary reference, although this strain also carries unique structural mutations and is experiencing rapid proliferation of a Gypsy retrotransposon. We expect all laboratory strains to harbor gene-disrupting mutations, which should be considered when interpreting and comparing experimental results. Collectively, the resources presented here herald a new era of Chlamydomonas genomics and will provide the foundation for continued research in this important reference organism.
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Affiliation(s)
- Rory J Craig
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Sean D Gallaher
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
| | - Shengqiang Shu
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - Patrice A Salomé
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
- Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095, USA
| | - Jerry W Jenkins
- HudsonAlpha Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA
| | - Crysten E Blaby-Haas
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Samuel O Purvine
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - Samuel O’Donnell
- Laboratory of Computational and Quantitative Biology, UMR 7238, CNRS, Institut de Biologie Paris-Seine, Sorbonne Université, Paris 75005, France
| | - Kerrie Barry
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - Jane Grimwood
- HudsonAlpha Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA
| | - Daniela Strenkert
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
| | - Janette Kropat
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Chris Daum
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - Yuko Yoshinaga
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - David M Goodstein
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - Olivier Vallon
- Unité Mixte de Recherche 7141, CNRS, Institut de Biologie Physico-Chimique, Sorbonne Université, Paris 75005, France
| | - Jeremy Schmutz
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
- HudsonAlpha Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA
| | - Sabeeha S Merchant
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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López-Cortegano E, Craig RJ, Chebib J, Balogun EJ, Keightley PD. Rates and spectra of de novo structural mutations in Chlamydomonas reinhardtii. Genome Res 2023; 33:45-60. [PMID: 36617667 PMCID: PMC9977147 DOI: 10.1101/gr.276957.122] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022]
Abstract
Genetic variation originates from several types of spontaneous mutation, including single-nucleotide substitutions, short insertions and deletions (indels), and larger structural changes. Structural mutations (SMs) drive genome evolution and are thought to play major roles in evolutionary adaptation, speciation, and genetic disease, including cancers. Sequencing of mutation accumulation (MA) lines has provided estimates of rates and spectra of single-nucleotide and indel mutations in many species, yet the rate of new SMs is largely unknown. Here, we use long-read sequencing to determine the full mutation spectrum in MA lines derived from two strains (CC-1952 and CC-2931) of the green alga Chlamydomonas reinhardtii The SM rate is highly variable between strains and between MA lines, and SMs represent a substantial proportion of all mutations in both strains (CC-1952 6%; CC-2931 12%). The SM spectra differ considerably between the two strains, with almost all inversions and translocations occurring in CC-2931 MA lines. This variation is associated with heterogeneity in the number and type of active transposable elements (TEs), which comprise major proportions of SMs in both strains (CC-1952 22%; CC-2931 38%). In CC-2931, a Crypton and a previously undescribed type of DNA element have caused 71% of chromosomal rearrangements, whereas in CC-1952, a Dualen LINE is associated with 87% of duplications. Other SMs, notably large duplications in CC-2931, are likely products of various double-strand break repair pathways. Our results show that diverse types of SMs occur at substantial rates, and support prominent roles for SMs and TEs in evolution.
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Affiliation(s)
- Eugenio López-Cortegano
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Rory J. Craig
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom;,California Institute for Quantitative Biosciences, UC Berkeley, Berkeley, California 94720, USA
| | - Jobran Chebib
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Eniolaye J. Balogun
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario ON M5S 3B2, Canada;,Department of Biology, University of Toronto Mississauga, Mississauga ON L5L 1C6, Canada
| | - Peter D. Keightley
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
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Goubert C, Craig RJ, Bilat AF, Peona V, Vogan AA, Protasio AV. A beginner's guide to manual curation of transposable elements. Mob DNA 2022; 13:7. [PMID: 35354491 PMCID: PMC8969392 DOI: 10.1186/s13100-021-00259-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/17/2021] [Indexed: 12/11/2022] Open
Abstract
Background In the study of transposable elements (TEs), the generation of a high confidence set of consensus sequences that represent the diversity of TEs found in a given genome is a key step in the path to investigate these fascinating genomic elements. Many algorithms and pipelines are available to automatically identify putative TE families present in a genome. Despite the availability of these valuable resources, producing a library of high-quality full-length TE consensus sequences largely remains a process of manual curation. This know-how is often passed on from mentor-to-mentee within research groups, making it difficult for those outside the field to access this highly specialised skill. Results Our manuscript attempts to fill this gap by providing a set of detailed computer protocols, software recommendations and video tutorials for those aiming to manually curate TEs. Detailed step-by-step protocols, aimed at the complete beginner, are presented in the Supplementary Methods. Conclusions The proposed set of programs and tools presented here will make the process of manual curation achievable and amenable to all researchers and in special to those new to the field of TEs. Supplementary Information The online version contains supplementary material available at 10.1186/s13100-021-00259-7.
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Affiliation(s)
- Clement Goubert
- Canadian Center for Computational Genomics, McGill University, Montreal, Québec, Canada.,Department of Human Genetics, McGill University, Montreal, Québec, Canada
| | - Rory J Craig
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Agustin F Bilat
- Departamento de Genética, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Valentina Peona
- Department of Organismal Biology, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden
| | - Aaron A Vogan
- Department of Organismal Biology, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden
| | - Anna V Protasio
- Department of Pathology, Tennis Court Road, Cambridge, CB1 2PQ, UK. .,Christ's College, St Andrews Street, Cambridge, CB2 3BU, UK.
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