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Zhang H, Gu Z, Zeng Y, Zhang Y. Mechanism of heterochromatin remodeling revealed by the DDM1 bound nucleosome structures. Structure 2024; 32:1222-1230.e4. [PMID: 38870940 DOI: 10.1016/j.str.2024.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 04/07/2024] [Accepted: 05/17/2024] [Indexed: 06/15/2024]
Abstract
The SWI/SNF2 chromatin remodeling factor decreased DNA methylation 1 (DDM1) is essential for the silencing of transposable elements (TEs) in both euchromatic and heterochromatic regions. Here, we determined the cryo-EM structures of DDM1-nucleosomeH2A and DDM1-nucleosomeH2A.W complexes at near-atomic resolution in the presence of the ATP analog ADP-BeFx. The structures show that nucleosomal DNA is unwrapped more on the surface of the histone octamer containing histone H2A than that containing histone H2A.W. DDM1 embraces one DNA gyre of the nucleosome and interacts with the N-terminal tails of histone H4. Although we did not observe DDM1-H2A.W interactions in our structures, the results of the pull-down experiments suggest a direct interaction between DDM1 and the core region of histone H2A.W. Our work provides mechanistic insights into the heterochromatin remodeling process driven by DDM1 in plants.
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Affiliation(s)
- Hongwei Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.
| | - Zhanxi Gu
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Zeng
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.
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2
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Osakabe A, Takizawa Y, Horikoshi N, Hatazawa S, Negishi L, Sato S, Berger F, Kakutani T, Kurumizaka H. Molecular and structural basis of the chromatin remodeling activity by Arabidopsis DDM1. Nat Commun 2024; 15:5187. [PMID: 38992002 PMCID: PMC11239853 DOI: 10.1038/s41467-024-49465-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 06/05/2024] [Indexed: 07/13/2024] Open
Abstract
The histone H2A variant H2A.W occupies transposons and thus prevents access to them in Arabidopsis thaliana. H2A.W is deposited by the chromatin remodeler DDM1, which also promotes the accessibility of chromatin writers to heterochromatin by an unknown mechanism. To shed light on this question, we solve the cryo-EM structures of nucleosomes containing H2A and H2A.W, and the DDM1-H2A.W nucleosome complex. These structures show that the DNA end flexibility of the H2A nucleosome is higher than that of the H2A.W nucleosome. In the DDM1-H2A.W nucleosome complex, DDM1 binds to the N-terminal tail of H4 and the nucleosomal DNA and increases the DNA end flexibility of H2A.W nucleosomes. Based on these biochemical and structural results, we propose that DDM1 counters the low accessibility caused by nucleosomes containing H2A.W to enable the maintenance of repressive epigenetic marks on transposons and prevent their activity.
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Affiliation(s)
- Akihisa Osakabe
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan.
| | - Yoshimasa Takizawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Naoki Horikoshi
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Suguru Hatazawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Lumi Negishi
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Shoko Sato
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Tetsuji Kakutani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Hitoshi Kurumizaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan.
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3
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Nandety RS, Oh S, Lee HK, Krom N, Gupta R, Mysore KS. Genome-wide methylation landscape during somatic embryogenesis in Medicago truncatula reveals correlation between Tnt1 retrotransposition and hyperactive methylation regions. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:557-576. [PMID: 38627952 DOI: 10.1111/tpj.16744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 02/27/2024] [Accepted: 03/14/2024] [Indexed: 07/01/2024]
Abstract
Medicago truncatula is a model legume for fundamental research on legume biology and symbiotic nitrogen fixation. Tnt1, a retrotransposon from tobacco, was used to generate insertion mutants in M. truncatula R108. Approximately 21 000 insertion lines have been generated and publicly available. Tnt1 retro-transposition event occurs during somatic embryogenesis (SE), a pivotal process that triggers massive methylation changes. We studied the SE of M. truncatula R108 using leaf explants and explored the dynamic shifts in the methylation landscape from leaf explants to callus formation and finally embryogenesis. Higher cytosine methylation in all three contexts of CG, CHG, and CHH patterns was observed during SE compared to the controls. Higher methylation patterns were observed in assumed promoter regions (~2-kb upstream regions of transcription start site) of the genes, while lowest was recorded in the untranslated regions. Differentially methylated promoter region analysis showed a higher CHH methylation in embryogenesis tissue samples when compared to CG and CHG methylation. Strong correlation (89.71%) was identified between the differentially methylated regions (DMRs) and the site of Tnt1 insertions in M. truncatula R108 and stronger hypermethylation of genes correlated with higher number of Tnt1 insertions in all contexts of CG, CHG, and CHH methylation. Gene ontology enrichment and KEGG pathway enrichment analysis identified genes and pathways enriched in the signal peptide processing, ATP hydrolysis, RNA polymerase activity, transport, secondary metabolites, and nitrogen metabolism pathways. Combined gene expression analysis and methylation profiling showed an inverse relationship between methylation in the DMRs (regions spanning genes) and the expression of genes. Our results show that a dynamic shift in methylation happens during the SE process in the context of CG, CHH and CHG methylation, and the Tnt1 retrotransposition correlates with the hyperactive methylation regions.
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Affiliation(s)
- Raja Sekhar Nandety
- Noble Research Institute, Ardmore, Oklahoma, 73401, USA
- Department of Plant Sciences, North Dakota State University, Fargo, North Dakota, 58102, USA
- Cereal Crops Research Unit, USDA-ARS, Edward T. Schafer Agricultural Research Center, Fargo, North Dakota, 58102, USA
| | - Sunhee Oh
- Noble Research Institute, Ardmore, Oklahoma, 73401, USA
| | - Hee-Kyung Lee
- Noble Research Institute, Ardmore, Oklahoma, 73401, USA
| | - Nick Krom
- Noble Research Institute, Ardmore, Oklahoma, 73401, USA
| | - Rajeev Gupta
- Department of Plant Sciences, North Dakota State University, Fargo, North Dakota, 58102, USA
- Cereal Crops Research Unit, USDA-ARS, Edward T. Schafer Agricultural Research Center, Fargo, North Dakota, 58102, USA
| | - Kirankumar S Mysore
- Noble Research Institute, Ardmore, Oklahoma, 73401, USA
- Institute for Agricultural Biosciences, Oklahoma State University, Ardmore, Oklahoma, 73401, USA
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, 74078, USA
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4
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Bradamante G, Nguyen VH, Incarbone M, Meir Z, Bente H, Donà M, Lettner N, Scheid OM, Gutzat R. Two ARGONAUTE proteins loaded with transposon-derived small RNAs are associated with the reproductive cell lineage in Arabidopsis. THE PLANT CELL 2024; 36:863-880. [PMID: 38060984 PMCID: PMC10980394 DOI: 10.1093/plcell/koad295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 11/23/2023] [Indexed: 04/01/2024]
Abstract
In sexually propagating organisms, genetic, and epigenetic mutations are evolutionarily relevant only if they occur in the germline and are hence transmitted to the next generation. In contrast to most animals, plants are considered to lack an early segregating germline, implying that somatic cells can contribute genetic information to progeny. Here we demonstrate that 2 ARGONAUTE proteins, AGO5 and AGO9, mark cells associated with sexual reproduction in Arabidopsis (Arabidopsis thaliana) throughout development. Both AGOs are loaded with dynamically changing small RNA populations derived from highly methylated, pericentromeric, long transposons. Sequencing of single stem cell nuclei revealed that many of these transposons are co-expressed within an AGO5/9 expression domain in the shoot apical meristem (SAM). Co-occurrence of transposon expression and specific ARGONAUTE (AGO) expression in the SAM is reminiscent of germline features in animals and supports the existence of an early segregating germline in plants. Our results open the path to investigating transposon biology and epigenome dynamics at cellular resolution in the SAM stem cell niche.
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Affiliation(s)
- Gabriele Bradamante
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Vu Hoang Nguyen
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Marco Incarbone
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Zohar Meir
- Faculty of Mathematics and Computer Science & Department of Plant and Environmental Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Heinrich Bente
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Mattia Donà
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Nicole Lettner
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Ortrun Mittelsten Scheid
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Ruben Gutzat
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
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5
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Mierziak J, Wojtasik W. Epigenetic weapons of plants against fungal pathogens. BMC PLANT BIOLOGY 2024; 24:175. [PMID: 38443788 PMCID: PMC10916060 DOI: 10.1186/s12870-024-04829-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 02/16/2024] [Indexed: 03/07/2024]
Abstract
In the natural environment, plants face constant exposure to biotic stress caused by fungal attacks. The plant's response to various biotic stresses relies heavily on its ability to rapidly adjust the transcriptome. External signals are transmitted to the nucleus, leading to activation of transcription factors that subsequently enhance the expression of specific defense-related genes. Epigenetic mechanisms, including histone modifications and DNA methylation, which are closely linked to chromatin states, regulate gene expression associated with defense against biotic stress. Additionally, chromatin remodelers and non-coding RNA play a significant role in plant defense against stressors. These molecular modifications enable plants to exhibit enhanced resistance and productivity under diverse environmental conditions. Epigenetic mechanisms also contribute to stress-induced environmental epigenetic memory and priming in plants, enabling them to recall past molecular experiences and utilize this stored information for adaptation to new conditions. In the arms race between fungi and plants, a significant aspect is the cross-kingdom RNAi mechanism, whereby sRNAs can traverse organismal boundaries. Fungi utilize sRNA as an effector molecule to silence plant resistance genes, while plants transport sRNA, primarily through extracellular vesicles, to pathogens in order to suppress virulence-related genes. In this review, we summarize contemporary knowledge on epigenetic mechanisms of plant defense against attack by pathogenic fungi. The role of epigenetic mechanisms during plant-fungus symbiotic interactions is also considered.
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Affiliation(s)
- Justyna Mierziak
- Department of Genetic Biochemistry, Faculty of Biotechnology, University of Wroclaw, Przybyszewskiego 63, Wroclaw, 51-148, Poland
| | - Wioleta Wojtasik
- Department of Genetic Biochemistry, Faculty of Biotechnology, University of Wroclaw, Przybyszewskiego 63, Wroclaw, 51-148, Poland.
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6
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Hassan AH, Mokhtar MM, El Allali A. Transposable elements: multifunctional players in the plant genome. FRONTIERS IN PLANT SCIENCE 2024; 14:1330127. [PMID: 38239225 PMCID: PMC10794571 DOI: 10.3389/fpls.2023.1330127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024]
Abstract
Transposable elements (TEs) are indispensable components of eukaryotic genomes that play diverse roles in gene regulation, recombination, and environmental adaptation. Their ability to mobilize within the genome leads to gene expression and DNA structure changes. TEs serve as valuable markers for genetic and evolutionary studies and facilitate genetic mapping and phylogenetic analysis. They also provide insight into how organisms adapt to a changing environment by promoting gene rearrangements that lead to new gene combinations. These repetitive sequences significantly impact genome structure, function and evolution. This review takes a comprehensive look at TEs and their applications in biotechnology, particularly in the context of plant biology, where they are now considered "genomic gold" due to their extensive functionalities. The article addresses various aspects of TEs in plant development, including their structure, epigenetic regulation, evolutionary patterns, and their use in gene editing and plant molecular markers. The goal is to systematically understand TEs and shed light on their diverse roles in plant biology.
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Affiliation(s)
- Asmaa H. Hassan
- Bioinformatics Laboratory, College of Computing, Mohammed VI Polytechnic University, Ben Guerir, Morocco
- Agricultural Genetic Engineering Research Institute, Agriculture Research Center, Giza, Egypt
| | - Morad M. Mokhtar
- Bioinformatics Laboratory, College of Computing, Mohammed VI Polytechnic University, Ben Guerir, Morocco
- Agricultural Genetic Engineering Research Institute, Agriculture Research Center, Giza, Egypt
| | - Achraf El Allali
- Bioinformatics Laboratory, College of Computing, Mohammed VI Polytechnic University, Ben Guerir, Morocco
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7
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Chakrabarty P, Sen R, Sengupta S. From parasites to partners: exploring the intricacies of host-transposon dynamics and coevolution. Funct Integr Genomics 2023; 23:278. [PMID: 37610667 DOI: 10.1007/s10142-023-01206-w] [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: 06/14/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 08/24/2023]
Abstract
Transposable elements, often referred to as "jumping genes," have long been recognized as genomic parasites due to their ability to integrate and disrupt normal gene function and induce extensive genomic alterations, thereby compromising the host's fitness. To counteract this, the host has evolved a plethora of mechanisms to suppress the activity of the transposons. Recent research has unveiled the host-transposon relationships to be nuanced and complex phenomena, resulting in the coevolution of both entities. Transposition increases the mutational rate in the host genome, often triggering physiological pathways such as immune and stress responses. Current gene transfer technologies utilizing transposable elements have potential drawbacks, including off-target integration, induction of mutations, and modifications of cellular machinery, which makes an in-depth understanding of the host-transposon relationship imperative. This review highlights the dynamic interplay between the host and transposable elements, encompassing various factors and components of the cellular machinery. We provide a comprehensive discussion of the strategies employed by transposable elements for their propagation, as well as the mechanisms utilized by the host to mitigate their parasitic effects. Additionally, we present an overview of recent research identifying host proteins that act as facilitators or inhibitors of transposition. We further discuss the evolutionary outcomes resulting from the genetic interactions between the host and the transposable elements. Finally, we pose open questions in this field and suggest potential avenues for future research.
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Affiliation(s)
- Prayas Chakrabarty
- Department of Life Sciences, Presidency University Kolkata, 86/1 College Street, Kolkata, 700073, India
| | - Raneet Sen
- Department of Life Sciences, Presidency University Kolkata, 86/1 College Street, Kolkata, 700073, India
- Institute of Bioorganic Chemistry, Department of RNA Metabolism, Polish Academy of Sciences, Poznan, Poland
| | - Sugopa Sengupta
- Department of Life Sciences, Presidency University Kolkata, 86/1 College Street, Kolkata, 700073, India.
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8
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Pegler JL, Oultram JMJ, Mann CWG, Carroll BJ, Grof CPL, Eamens AL. Miniature Inverted-Repeat Transposable Elements: Small DNA Transposons That Have Contributed to Plant MICRORNA Gene Evolution. PLANTS (BASEL, SWITZERLAND) 2023; 12:1101. [PMID: 36903960 PMCID: PMC10004981 DOI: 10.3390/plants12051101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Angiosperms form the largest phylum within the Plantae kingdom and show remarkable genetic variation due to the considerable difference in the nuclear genome size of each species. Transposable elements (TEs), mobile DNA sequences that can amplify and change their chromosome position, account for much of the difference in nuclear genome size between individual angiosperm species. Considering the dramatic consequences of TE movement, including the complete loss of gene function, it is unsurprising that the angiosperms have developed elegant molecular strategies to control TE amplification and movement. Specifically, the RNA-directed DNA methylation (RdDM) pathway, directed by the repeat-associated small-interfering RNA (rasiRNA) class of small regulatory RNA, forms the primary line of defense to control TE activity in the angiosperms. However, the miniature inverted-repeat transposable element (MITE) species of TE has at times avoided the repressive effects imposed by the rasiRNA-directed RdDM pathway. MITE proliferation in angiosperm nuclear genomes is due to their preference to transpose within gene-rich regions, a pattern of transposition that has enabled MITEs to gain further transcriptional activity. The sequence-based properties of a MITE results in the synthesis of a noncoding RNA (ncRNA), which, after transcription, folds to form a structure that closely resembles those of the precursor transcripts of the microRNA (miRNA) class of small regulatory RNA. This shared folding structure results in a MITE-derived miRNA being processed from the MITE-transcribed ncRNA, and post-maturation, the MITE-derived miRNA can be used by the core protein machinery of the miRNA pathway to regulate the expression of protein-coding genes that harbor homologous MITE insertions. Here, we outline the considerable contribution that the MITE species of TE have made to expanding the miRNA repertoire of the angiosperms.
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Affiliation(s)
- Joseph L. Pegler
- Centre for Plant Science, School of Environmental and Life Sciences, College of Engineering, Science and Environment, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Jackson M. J. Oultram
- Centre for Plant Science, School of Environmental and Life Sciences, College of Engineering, Science and Environment, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Christopher W. G. Mann
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Bernard J. Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Christopher P. L. Grof
- Centre for Plant Science, School of Environmental and Life Sciences, College of Engineering, Science and Environment, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Andrew L. Eamens
- School of Health, University of the Sunshine Coast, Maroochydore, QLD 4558, Australia
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9
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Berger F, Muegge K, Richards EJ. Seminars in cell and development biology on histone variants remodelers of H2A variants associated with heterochromatin. Semin Cell Dev Biol 2023; 135:93-101. [PMID: 35249811 PMCID: PMC9440159 DOI: 10.1016/j.semcdb.2022.02.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 01/04/2023]
Abstract
Variants of the histone H2A occupy distinct locations in the genome. There is relatively little known about the mechanisms responsible for deposition of specific H2A variants. Notable exceptions are chromatin remodelers that control the dynamics of H2A.Z at promoters. Here we review the steps that identified the role of a specific class of chromatin remodelers, including LSH and DDM1 that deposit the variants macroH2A in mammals and H2A.W in plants, respectively. The function of these remodelers in heterochromatin is discussed together with their multiple roles in genome stability.
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Affiliation(s)
- Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
| | - Kathrin Muegge
- Epigenetics Section, Frederick National Laboratory for Cancer Research in the Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD, USA.
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10
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Akinmusola RY, Wilkins CA, Doughty J. DDM1-Mediated TE Silencing in Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:437. [PMID: 36771522 PMCID: PMC9919755 DOI: 10.3390/plants12030437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
Epigenetic modifications are indispensable for regulating gene bodies and TE silencing. DECREASE IN DNA METHYLATION 1 (DDM1) is a chromatin remodeller involved in histone modifications and DNA methylation. Apart from maintaining the epigenome, DDM1 also maintains key plant traits such as flowering time and heterosis. The role of DDM1 in epigenetic regulation is best characterised in plants, especially arabidopsis, rice, maize and tomato. The epigenetic changes induced by DDM1 establish the stable inheritance of many plant traits for at least eight generations, yet DDM1 does not methylate protein-coding genes. The DDM1 TE silencing mechanism is distinct and has evolved independently of other silencing pathways. Unlike the RNA-directed DNA Methylation (RdDM) pathway, DDM1 does not depend on siRNAs to enforce the heterochromatic state of TEs. Here, we review DDM1 TE silencing activity in the RdDM and non-RdDM contexts. The DDM1 TE silencing machinery is strongly associated with the histone linker H1 and histone H2A.W. While the linker histone H1 excludes the RdDM factors from methylating the heterochromatin, the histone H2A.W variant prevents TE mobility. The DDM1-H2A.W strategy alone silences nearly all the mobile TEs in the arabidopsis genome. Thus, the DDM1-directed TE silencing essentially preserves heterochromatic features and abolishes mobile threats to genome stability.
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11
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Ramakrishnan M, Papolu PK, Mullasseri S, Zhou M, Sharma A, Ahmad Z, Satheesh V, Kalendar R, Wei Q. The role of LTR retrotransposons in plant genetic engineering: how to control their transposition in the genome. PLANT CELL REPORTS 2023; 42:3-15. [PMID: 36401648 DOI: 10.1007/s00299-022-02945-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
We briefly discuss that the similarity of LTR retrotransposons to retroviruses is a great opportunity for the development of a genetic engineering tool that exploits intragenic elements in the plant genome for plant genetic improvement. Long terminal repeat (LTR) retrotransposons are very similar to retroviruses but do not have the property of being infectious. While spreading between its host cells, a retrovirus inserts a DNA copy of its genome into the cells. The ability of retroviruses to cause infection with genome integration allows genes to be delivered to cells and tissues. Retrovirus vectors are, however, only specific to animals and insects, and, thus, are not relevant to plant genetic engineering. However, the similarity of LTR retrotransposons to retroviruses is an opportunity to explore the former as a tool for genetic engineering. Although recent long-read sequencing technologies have advanced the knowledge about transposable elements (TEs), the integration of TEs is still unable either to control them or to direct them to specific genomic locations. The use of existing intragenic elements to achieve the desired genome composition is better than using artificial constructs like vectors, but it is not yet clear how to control the process. Moreover, most LTR retrotransposons are inactive and unable to produce complete proteins. They are also highly mutable. In addition, it is impossible to find a full active copy of a LTR retrotransposon out of thousands of its own copies. Theoretically, if these elements were directly controlled and turned on or off using certain epigenetic mechanisms (inducing by stress or infection), LTR retrotransposons could be a great opportunity to develop a genetic engineering tool using intragenic elements in the plant genome. In this review, the recent developments in uncovering the nature of LTR retrotransposons and the possibility of using these intragenic elements as a tool for plant genetic engineering are briefly discussed.
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Affiliation(s)
- Muthusamy Ramakrishnan
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Key Laboratory of National Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Pradeep K Papolu
- State Key Laboratory of Subtropical Silviculture, Institute of Bamboo Research, Zhejiang A&F University, Lin'an, Hangzhou, 311300, Zhejiang, China
| | - Sileesh Mullasseri
- Department of Zoology, St. Albert's College (Autonomous), Kochi, 682018, Kerala, India
| | - Mingbing Zhou
- State Key Laboratory of Subtropical Silviculture, Institute of Bamboo Research, Zhejiang A&F University, Lin'an, Hangzhou, 311300, Zhejiang, China
- Zhejiang Provincial Collaborative Innovation Center for Bamboo Resources and High-Efficiency Utilization, Zhejiang A&F University, Lin'an, Hangzhou, 311300, Zhejiang, China
| | - Anket Sharma
- State Key Laboratory of Subtropical Silviculture, Institute of Bamboo Research, Zhejiang A&F University, Lin'an, Hangzhou, 311300, Zhejiang, China
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, USA
| | - Zishan Ahmad
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Key Laboratory of National Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Viswanathan Satheesh
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Ruslan Kalendar
- Helsinki Institute of Life Science HiLIFE, University of Helsinki, Biocenter 3, Viikinkaari 1, F1-00014, Helsinki, Finland.
- Institute of Plant Biology and Biotechnology (IPBB), Timiryazev Street 45, 050040, Almaty, Kazakhstan.
| | - Qiang Wei
- Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Key Laboratory of National Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China.
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12
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Cerbin S, Ou S, Li Y, Sun Y, Jiang N. Distinct composition and amplification dynamics of transposable elements in sacred lotus (Nelumbo nucifera Gaertn.). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:172-192. [PMID: 35959634 PMCID: PMC9804982 DOI: 10.1111/tpj.15938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/19/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Sacred lotus (Nelumbo nucifera Gaertn.) is a basal eudicot plant with a unique lifestyle, physiological features, and evolutionary characteristics. Here we report the unique profile of transposable elements (TEs) in the genome, using a manually curated repeat library. TEs account for 59% of the genome, and hAT (Ac/Ds) elements alone represent 8%, more than in any other known plant genome. About 18% of the lotus genome is comprised of Copia LTR retrotransposons, and over 25% of them are associated with non-canonical termini (non-TGCA). Such high abundance of non-canonical LTR retrotransposons has not been reported for any other organism. TEs are very abundant in genic regions, with retrotransposons enriched in introns and DNA transposons primarily in flanking regions of genes. The recent insertion of TEs in introns has led to significant intron size expansion, with a total of 200 Mb in the 28 455 genes. This is accompanied by declining TE activity in intergenic regions, suggesting distinct control efficacy of TE amplification in different genomic compartments. Despite the prevalence of TEs in genic regions, some genes are associated with fewer TEs, such as those involved in fruit ripening and stress responses. Other genes are enriched with TEs, and genes in epigenetic pathways are the most associated with TEs in introns, indicating a dynamic interaction between TEs and the host surveillance machinery. The dramatic differential abundance of TEs with genes involved in different biological processes as well as the variation of target preference of different TEs suggests the composition and activity of TEs influence the path of evolution.
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Affiliation(s)
- Stefan Cerbin
- Department of HorticultureMichigan State University1066 Bogue StreetEast LansingMI48824USA
- Present address:
Department of Ecology & Evolutionary BiologyUniversity of Kansas1200 Sunnyside AvenueLawrenceKS66045USA
| | - Shujun Ou
- Department of HorticultureMichigan State University1066 Bogue StreetEast LansingMI48824USA
- Present address:
Department of Computer ScienceJohns Hopkins UniversityBaltimoreMD21218USA
| | - Yang Li
- Department of Electrical EngineeringCity University of Hong KongKowloonHong Kong SARChina
| | - Yanni Sun
- Department of Electrical EngineeringCity University of Hong KongKowloonHong Kong SARChina
| | - Ning Jiang
- Department of HorticultureMichigan State University1066 Bogue StreetEast LansingMI48824USA
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13
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Li SF, She HB, Yang LL, Lan LN, Zhang XY, Wang LY, Zhang YL, Li N, Deng CL, Qian W, Gao WJ. Impact of LTR-Retrotransposons on Genome Structure, Evolution, and Function in Curcurbitaceae Species. Int J Mol Sci 2022; 23:ijms231710158. [PMID: 36077556 PMCID: PMC9456015 DOI: 10.3390/ijms231710158] [Citation(s) in RCA: 6] [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: 08/05/2022] [Revised: 09/02/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
Long terminal repeat (LTR)-retrotransposons (LTR-RTs) comprise a major portion of many plant genomes and may exert a profound impact on genome structure, function, and evolution. Although many studies have focused on these elements in an individual species, their dynamics on a family level remains elusive. Here, we investigated the abundance, evolutionary dynamics, and impact on associated genes of LTR-RTs in 16 species in an economically important plant family, Cucurbitaceae. Results showed that full-length LTR-RT numbers and LTR-RT content varied greatly among different species, and they were highly correlated with genome size. Most of the full-length LTR-RTs were amplified after the speciation event, reflecting the ongoing rapid evolution of these genomes. LTR-RTs highly contributed to genome size variation via species-specific distinct proliferations. The Angela and Tekay lineages with a greater evolutionary age were amplified in Trichosanthes anguina, whereas a recent activity burst of Reina and another ancient round of Tekay activity burst were examined in Sechium edule. In addition, Tekay and Retand lineages belonging to the Gypsy superfamily underwent a recent burst in Gynostemma pentaphyllum. Detailed investigation of genes with intronic and promoter LTR-RT insertion showed diverse functions, but the term of metabolism was enriched in most species. Further gene expression analysis in G.pentaphyllum revealed that the LTR-RTs within introns suppress the corresponding gene expression, whereas the LTR-RTs within promoters exert a complex influence on the downstream gene expression, with the main function of promoting gene expression. This study provides novel insights into the organization, evolution, and function of LTR-RTs in Cucurbitaceae genomes.
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Affiliation(s)
- Shu-Fen Li
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Hong-Bing She
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Long-Long Yang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Li-Na Lan
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Xin-Yu Zhang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Li-Ying Wang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Yu-Lan Zhang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Ning Li
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Chuan-Liang Deng
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Wei Qian
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- Correspondence: (W.Q.); (W.-J.G.)
| | - Wu-Jun Gao
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
- Correspondence: (W.Q.); (W.-J.G.)
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14
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Chen TH, Winefield C. Comprehensive analysis of both long and short read transcriptomes of a clonal and a seed-propagated model species reveal the prerequisites for transcriptional activation of autonomous and non-autonomous transposons in plants. Mob DNA 2022; 13:16. [PMID: 35549762 PMCID: PMC9097378 DOI: 10.1186/s13100-022-00271-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 04/13/2022] [Indexed: 11/29/2022] Open
Abstract
Background Transposable element (TE) transcription is a precursor to its mobilisation in host genomes. However, the characteristics of expressed TE loci, the identification of self-competent transposon loci contributing to new insertions, and the genomic conditions permitting their mobilisation remain largely unknown. Results Using Vitis vinifera embryogenic callus, we explored the impact of biotic stressors on transposon transcription through the exposure of the callus to live cultures of an endemic grapevine yeast, Hanseniaspora uvarum. We found that only 1.7–2.5% of total annotated TE loci were transcribed, of which 5–10% of these were full-length, and the expressed TE loci exhibited a strong location bias towards expressed genes. These trends in transposon transcription were also observed in RNA-seq data from Arabidopsis thaliana wild-type plants but not in epigenetically compromised Arabidopsis ddm1 mutants. Moreover, differentially expressed TE loci in the grapevine tended to share expression patterns with co-localised differentially expressed genes. Utilising nanopore cDNA sequencing, we found a strong correlation between the inclusion of intronic TEs in gene transcripts and the presence of premature termination codons in these transcripts. Finally, we identified low levels of full-length transcripts deriving from structurally intact TE loci in the grapevine model. Conclusion Our observations in two disparate plant models representing clonally and seed propagated plant species reveal a closely connected transcriptional relationship between TEs and co-localised genes, particularly when epigenetic silencing is not compromised. We found that the stress treatment alone was insufficient to induce large-scale full-length transcription from structurally intact TE loci, a necessity for non-autonomous and autonomous mobilisation. Supplementary Information The online version contains supplementary material available at 10.1186/s13100-022-00271-5.
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Affiliation(s)
- Ting-Hsuan Chen
- Department of Wine, Food, and Molecular Biosciences, Lincoln University, Lincoln, 7647, New Zealand.,Present address: The New Zealand Institute for Plant and Food Research Ltd, Lincoln, 7608, New Zealand
| | - Christopher Winefield
- Department of Wine, Food, and Molecular Biosciences, Lincoln University, Lincoln, 7647, New Zealand.
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15
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Specificities and Dynamics of Transposable Elements in Land Plants. BIOLOGY 2022; 11:biology11040488. [PMID: 35453688 PMCID: PMC9033089 DOI: 10.3390/biology11040488] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/10/2022] [Accepted: 03/18/2022] [Indexed: 01/27/2023]
Abstract
Simple Summary Transposable elements are dynamic components of plant genomes, and display a high diversity of lineages and distribution as the result of evolutionary driving forces and overlapping mechanisms of genetic and epigenetic regulation. They are now regarded as main contributors for genome evolution and function, and important regulators of endogenous gene expression. In this review, we survey recent progress and current challenges in the identification and classification of transposon lineages in complex plant genomes, highlighting the molecular specificities that may explain the expansion and diversification of mobile genetic elements in land plants. Abstract Transposable elements (TEs) are important components of most plant genomes. These mobile repetitive sequences are highly diverse in terms of abundance, structure, transposition mechanisms, activity and insertion specificities across plant species. This review will survey the different mechanisms that may explain the variability of TE patterns in land plants, highlighting the tight connection between TE dynamics and host genome specificities, and their co-evolution to face and adapt to a changing environment. We present the current TE classification in land plants, and describe the different levels of genetic and epigenetic controls originating from the plant, the TE itself, or external environmental factors. Such overlapping mechanisms of TE regulation might be responsible for the high diversity and dynamics of plant TEs observed in nature.
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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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Oberlin S, Rajeswaran R, Trasser M, Barragán-Borrero V, Schon MA, Plotnikova A, Loncsek L, Nodine MD, Marí-Ordóñez A, Voinnet O. Innate, translation-dependent silencing of an invasive transposon in Arabidopsis. EMBO Rep 2021; 23:e53400. [PMID: 34931432 PMCID: PMC8892269 DOI: 10.15252/embr.202153400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 12/05/2021] [Accepted: 12/06/2021] [Indexed: 11/25/2022] Open
Abstract
Co‐evolution between hosts’ and parasites’ genomes shapes diverse pathways of acquired immunity based on silencing small (s)RNAs. In plants, sRNAs cause heterochromatinization, sequence degeneration, and, ultimately, loss of autonomy of most transposable elements (TEs). Recognition of newly invasive plant TEs, by contrast, involves an innate antiviral‐like silencing response. To investigate this response’s activation, we studied the single‐copy element EVADÉ (EVD), one of few representatives of the large Ty1/Copia family able to proliferate in Arabidopsis when epigenetically reactivated. In Ty1/Copia elements, a short subgenomic mRNA (shGAG) provides the necessary excess of structural GAG protein over the catalytic components encoded by the full‐length genomic flGAG‐POL. We show here that the predominant cytosolic distribution of shGAG strongly favors its translation over mostly nuclear flGAG‐POL. During this process, an unusually intense ribosomal stalling event coincides with mRNA breakage yielding unconventional 5’OH RNA fragments that evade RNA quality control. The starting point of sRNA production by RNA‐DEPENDENT‐RNA‐POLYMERASE‐6 (RDR6), exclusively on shGAG, occurs precisely at this breakage point. This hitherto‐unrecognized “translation‐dependent silencing” (TdS) is independent of codon usage or GC content and is not observed on TE remnants populating the Arabidopsis genome, consistent with their poor association, if any, with polysomes. We propose that TdS forms a primal defense against EVD de novo invasions that underlies its associated sRNA pattern.
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Affiliation(s)
- Stefan Oberlin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Rajendran Rajeswaran
- Department of Biology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Marieke Trasser
- Gregor Mendel Institute of Molecular Plant Biology (GMI) of the Austrian Academy of Sciences, Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Verónica Barragán-Borrero
- Department of Biology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland.,Gregor Mendel Institute of Molecular Plant Biology (GMI) of the Austrian Academy of Sciences, Vienna, Austria
| | - Michael A Schon
- Gregor Mendel Institute of Molecular Plant Biology (GMI) of the Austrian Academy of Sciences, Vienna, Austria
| | - Alexandra Plotnikova
- Gregor Mendel Institute of Molecular Plant Biology (GMI) of the Austrian Academy of Sciences, Vienna, Austria
| | - Lukas Loncsek
- Gregor Mendel Institute of Molecular Plant Biology (GMI) of the Austrian Academy of Sciences, Vienna, Austria
| | - Michael D Nodine
- Gregor Mendel Institute of Molecular Plant Biology (GMI) of the Austrian Academy of Sciences, Vienna, Austria.,Laboratory of Molecular Biology, Wageningen University, Wageningen, The Netherlands
| | - Arturo Marí-Ordóñez
- Department of Biology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland.,Gregor Mendel Institute of Molecular Plant Biology (GMI) of the Austrian Academy of Sciences, Vienna, Austria
| | - Olivier Voinnet
- Department of Biology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
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18
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Taming, Domestication and Exaptation: Trajectories of Transposable Elements in Genomes. Cells 2021; 10:cells10123590. [PMID: 34944100 PMCID: PMC8700633 DOI: 10.3390/cells10123590] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 02/06/2023] Open
Abstract
During evolution, several types of sequences pass through genomes. Along with mutations and internal genetic tinkering, they are a useful source of genetic variability for adaptation and evolution. Most of these sequences are acquired by horizontal transfers (HT), but some of them may come from the genomes themselves. If they are not lost or eliminated quickly, they can be tamed, domesticated, or even exapted. Each of these processes results from a series of events, depending on the interactions between these sequences and the host genomes, but also on environmental constraints, through their impact on individuals or population fitness. After a brief reminder of the characteristics of each of these states (taming, domestication, exaptation), the evolutionary trajectories of these new or acquired sequences will be presented and discussed, emphasizing that they are not totally independent insofar as the first can constitute a step towards the second, and the second is another step towards the third.
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19
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Gebert D, Neubert LK, Lloyd C, Gui J, Lehmann R, Teixeira FK. Large Drosophila germline piRNA clusters are evolutionarily labile and dispensable for transposon regulation. Mol Cell 2021; 81:3965-3978.e5. [PMID: 34352205 PMCID: PMC8516431 DOI: 10.1016/j.molcel.2021.07.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/23/2021] [Accepted: 07/10/2021] [Indexed: 12/13/2022]
Abstract
PIWI proteins and their guiding Piwi-interacting small RNAs (piRNAs) are crucial for fertility and transposon defense in the animal germline. In most species, the majority of piRNAs are produced from distinct large genomic loci, called piRNA clusters. It is assumed that germline-expressed piRNA clusters, particularly in Drosophila, act as principal regulators to control transposons dispersed across the genome. Here, using synteny analysis, we show that large clusters are evolutionarily labile, arise at loci characterized by recurrent chromosomal rearrangements, and are mostly species-specific across the Drosophila genus. By engineering chromosomal deletions in D. melanogaster, we demonstrate that the three largest germline clusters, which account for the accumulation of >40% of all transposon-targeting piRNAs in ovaries, are neither required for fertility nor for transposon regulation in trans. We provide further evidence that dispersed elements, rather than the regulatory action of large Drosophila germline clusters in trans, may be central for transposon defense.
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Affiliation(s)
- Daniel Gebert
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Lena K Neubert
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Catrin Lloyd
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Jinghua Gui
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Ruth Lehmann
- Howard Hughes Medical Institute (HHMI) and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.
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20
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Casati P, Gomez MS. Chromatin dynamics during DNA damage and repair in plants: new roles for old players. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4119-4131. [PMID: 33206978 DOI: 10.1093/jxb/eraa551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/12/2020] [Indexed: 06/11/2023]
Abstract
The genome of plants is organized into chromatin. The chromatin structure regulates the rates of DNA metabolic processes such as replication, transcription, DNA recombination, and repair. Different aspects of plant growth and development are regulated by changes in chromatin status by the action of chromatin-remodeling activities. Recent data have also shown that many of these chromatin-associated proteins participate in different aspects of the DNA damage response, regulating DNA damage and repair, cell cycle progression, programmed cell death, and entry into the endocycle. In this review, we present different examples of proteins and chromatin-modifying enzymes with roles during DNA damage responses, demonstrating that rapid changes in chromatin structure are essential to maintain genome stability.
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Affiliation(s)
- Paula Casati
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), Universidad Nacional de Rosario, Suipacha, Rosario, Argentina
| | - Maria Sol Gomez
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera, Cantoblanco, Madrid, Spain
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21
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Baduel P, Colot V. The epiallelic potential of transposable elements and its evolutionary significance in plants. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200123. [PMID: 33866816 PMCID: PMC8059525 DOI: 10.1098/rstb.2020.0123] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
DNA provides the fundamental framework for heritability, yet heritable trait variation need not be completely ‘hard-wired’ into the DNA sequence. In plants, the epigenetic machinery that controls transposable element (TE) activity, and which includes DNA methylation, underpins most known cases of inherited trait variants that are independent of DNA sequence changes. Here, we review our current knowledge of the extent, mechanisms and potential adaptive contribution of epiallelic variation at TE-containing alleles in this group of species. For the purpose of this review, we focus mainly on DNA methylation, as it provides an easily quantifiable readout of such variation. The picture that emerges is complex. On the one hand, pronounced differences in DNA methylation at TE sequences can either occur spontaneously or be induced experimentally en masse across the genome through genetic means. Many of these epivariants are stably inherited over multiple sexual generations, thus leading to transgenerational epigenetic inheritance. Functional consequences can be significant, yet they are typically of limited magnitude and although the same epivariants can be found in nature, the factors involved in their generation in this setting remain to be determined. On the other hand, moderate DNA methylation variation at TE-containing alleles can be reproducibly induced by the environment, again usually with mild effects, and most of this variation tends to be lost across generations. Based on these considerations, we argue that TE-containing alleles, rather than their inherited epiallelic variants, are the main targets of natural selection. Thus, we propose that the adaptive contribution of TE-associated epivariation, whether stable or not, lies predominantly in its capacity to modulate TE mobilization in response to the environment, hence providing hard-wired opportunities for the flexible exploration of the phenotypic space. This article is part of the theme issue ‘How does epigenetics influence the course of evolution?’
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Affiliation(s)
- Pierre Baduel
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Ecole Normale Supérieure, PSL Research University, 75005 Paris, France
| | - Vincent Colot
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Ecole Normale Supérieure, PSL Research University, 75005 Paris, France
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22
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Osakabe A, Jamge B, Axelsson E, Montgomery SA, Akimcheva S, Kuehn AL, Pisupati R, Lorković ZJ, Yelagandula R, Kakutani T, Berger F. The chromatin remodeler DDM1 prevents transposon mobility through deposition of histone variant H2A.W. Nat Cell Biol 2021; 23:391-400. [PMID: 33833428 DOI: 10.1038/s41556-021-00658-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 03/01/2021] [Indexed: 12/16/2022]
Abstract
Mobile transposable elements (TEs) not only participate in genome evolution but also threaten genome integrity. In healthy cells, TEs that encode all of the components that are necessary for their mobility are specifically silenced, yet the precise mechanism remains unknown. Here, we characterize the mechanism used by a conserved class of chromatin remodelers that prevent TE mobility. In the Arabidopsis chromatin remodeler DECREASE IN DNA METHYLATION 1 (DDM1), we identify two conserved binding domains for the histone variant H2A.W, which marks plant heterochromatin. DDM1 is necessary and sufficient for the deposition of H2A.W onto potentially mobile TEs, yet does not act on TE fragments or host protein-coding genes. DDM1-mediated H2A.W deposition changes the properties of chromatin, resulting in the silencing of TEs and, therefore, prevents their mobility. This distinct mechanism provides insights into the interplay between TEs and their host in the contexts of evolution and disease, and potentiates innovative strategies for targeted gene silencing.
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Affiliation(s)
- Akihisa Osakabe
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Bhagyshree Jamge
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Elin Axelsson
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Sean A Montgomery
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Svetlana Akimcheva
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Annika Luisa Kuehn
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Rahul Pisupati
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Zdravko J Lorković
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Ramesh Yelagandula
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Tetsuji Kakutani
- National Institute of Genetics, Mishima, Japan
- Department of Genetics, School of Life science, The Graduate University of Advanced Studies (SOKENDAI), Mishima, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
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23
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Panda K, Slotkin RK. Long-Read cDNA Sequencing Enables a "Gene-Like" Transcript Annotation of Transposable Elements. THE PLANT CELL 2020; 32:2687-2698. [PMID: 32647069 PMCID: PMC7474280 DOI: 10.1105/tpc.20.00115] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/11/2020] [Accepted: 06/25/2020] [Indexed: 05/05/2023]
Abstract
Transcript-based annotations of genes facilitate both genome-wide analyses and detailed single-locus research. In contrast, transposable element (TE) annotations are rudimentary, consisting of information only on TE location and type. The repetitiveness and limited annotation of TEs prevent the ability to distinguish between potentially functional expressed elements and degraded copies. To improve genome-wide TE bioinformatics, we performed long-read sequencing of cDNAs from Arabidopsis (Arabidopsis thaliana) lines deficient in multiple layers of TE repression. These uniquely mapping transcripts were used to identify the set of TEs able to generate polyadenylated RNAs and create a new transcript-based annotation of TEs that we have layered upon the existing high-quality community standard annotation. We used this annotation to reduce the bioinformatic complexity associated with multimapping reads from short-read RNA sequencing experiments, and we show that this improvement is expanded in a TE-rich genome such as maize (Zea mays). Our TE annotation also enables the testing of specific standing hypotheses in the TE field. We demonstrate that inaccurate TE splicing does not trigger small RNA production, and the cell more strongly targets DNA methylation to TEs that have the potential to make mRNAs. This work provides a transcript-based TE annotation for Arabidopsis and maize, which serves as a blueprint to reduce the bioinformatic complexity associated with repetitive TEs in any organism.
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Affiliation(s)
- Kaushik Panda
- Donald Danforth Plant Science Center, St. Louis, 63132 Missouri
| | - R Keith Slotkin
- Donald Danforth Plant Science Center, St. Louis, 63132 Missouri
- Division of Biological Sciences, University of Missouri, Columbia, 63132 Missouri
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Gutzat R, Rembart K, Nussbaumer T, Hofmann F, Pisupati R, Bradamante G, Daubel N, Gaidora A, Lettner N, Donà M, Nordborg M, Nodine M, Mittelsten Scheid O. Arabidopsis shoot stem cells display dynamic transcription and DNA methylation patterns. EMBO J 2020; 39:e103667. [PMID: 32815560 PMCID: PMC7560203 DOI: 10.15252/embj.2019103667] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
In plants, aerial organs originate continuously from stem cells in the center of the shoot apical meristem. Descendants of stem cells in the subepidermal layer are progenitors of germ cells, giving rise to male and female gametes. In these cells, mutations, including insertions of transposable elements or viruses, must be avoided to preserve genome integrity across generations. To investigate the molecular characteristics of stem cells in Arabidopsis, we isolated their nuclei and analyzed stage‐specific gene expression and DNA methylation in plants of different ages. Stem cell expression signatures are largely defined by developmental stage but include a core set of stem cell‐specific genes, among which are genes implicated in epigenetic silencing. Transiently increased expression of transposable elements in meristems prior to flower induction correlates with increasing CHG methylation during development and decreased CHH methylation, before stem cells enter the reproductive lineage. These results suggest that epigenetic reprogramming may occur at an early stage in this lineage and could contribute to genome protection in stem cells during germline development.
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Affiliation(s)
- Ruben Gutzat
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Klaus Rembart
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Thomas Nussbaumer
- Division of Computational Systems Biology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Falko Hofmann
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Rahul Pisupati
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Gabriele Bradamante
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Nina Daubel
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Angelika Gaidora
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Nicole Lettner
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Mattia Donà
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Magnus Nordborg
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Michael Nodine
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Ortrun Mittelsten Scheid
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
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Nandety RS, Serrani‐Yarce JC, Gill US, Oh S, Lee H, Zhang X, Dai X, Zhang W, Krom N, Wen J, Zhao PX, Mysore KS. Insertional mutagenesis of Brachypodium distachyon using the Tnt1 retrotransposable element. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1924-1936. [PMID: 32410353 PMCID: PMC7496502 DOI: 10.1111/tpj.14813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 04/29/2020] [Accepted: 05/05/2020] [Indexed: 06/11/2023]
Abstract
Brachypodium distachyon is an annual C3 grass used as a monocot model system in functional genomics research. Insertional mutagenesis is a powerful tool for both forward and reverse genetics studies. In this study, we explored the possibility of using the tobacco retrotransposon Tnt1 to create a transposon-based insertion mutant population in B. distachyon. We developed transgenic B. distachyon plants expressing Tnt1 (R0) and in the subsequent regenerants (R1) we observed that Tnt1 actively transposed during somatic embryogenesis, generating an average of 6.37 insertions per line in a population of 19 independent R1 regenerant plants analyzed. In seed-derived progeny of R1 plants, Tnt1 segregated in a Mendelian ratio of 3:1 and no new Tnt1 transposition was observed. A total of 126 flanking sequence tags (FSTs) were recovered from the analyzed R0 and R1 lines. Analysis of the FSTs showed a uniform pattern of insertion in all the chromosomes (1-5) without any preference for a particular chromosome region. Considering the average length of a gene transcript to be 3.37 kb, we estimated that 29 613 lines are required to achieve a 90% possibility of tagging a given gene in the B. distachyon genome using the Tnt1-based mutagenesis approach. Our results show the possibility of using Tnt1 to achieve near-saturation mutagenesis in B. distachyon, which will aid in functional genomics studies of other C3 grasses.
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Affiliation(s)
| | - Juan C. Serrani‐Yarce
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
- Present address:
Department of Biological SciencesUniversity of North TexasDentonTX76203USA
| | - Upinder S. Gill
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
- Present address:
Department of Plant PathologyNorth Dakota State UniversityFargoND58102USA
| | - Sunhee Oh
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
| | - Hee‐Kyung Lee
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
| | - Xinji Zhang
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
| | - Xinbin Dai
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
| | - Wenchao Zhang
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
| | - Nick Krom
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
| | - Jiangqi Wen
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
| | - Patrick X. Zhao
- Noble Research InstituteLLC.2510 Sam Noble ParkwayArdmoreOK73401USA
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Choi JY, Lee YCG. Double-edged sword: The evolutionary consequences of the epigenetic silencing of transposable elements. PLoS Genet 2020; 16:e1008872. [PMID: 32673310 PMCID: PMC7365398 DOI: 10.1371/journal.pgen.1008872] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Transposable elements (TEs) are genomic parasites that selfishly replicate at the expense of host fitness. Fifty years of evolutionary studies of TEs have concentrated on the deleterious genetic effects of TEs, such as their effects on disrupting genes and regulatory sequences. However, a flurry of recent work suggests that there is another important source of TEs' harmful effects-epigenetic silencing. Host genomes typically silence TEs by the deposition of repressive epigenetic marks. While this silencing reduces the selfish replication of TEs and should benefit hosts, a picture is emerging that the epigenetic silencing of TEs triggers inadvertent spreading of repressive marks to otherwise expressed neighboring genes, ultimately jeopardizing host fitness. In this Review, we provide a long-overdue overview of the recent genome-wide evidence for the presence and prevalence of TEs' epigenetic effects, highlighting both the similarities and differences across mammals, insects, and plants. We lay out the current understanding of the functional and fitness consequences of TEs' epigenetic effects, and propose possible influences of such effects on the evolution of both hosts and TEs themselves. These unique evolutionary consequences indicate that TEs' epigenetic effect is not only a crucial component of TE biology but could also be a significant contributor to genome function and evolution.
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Affiliation(s)
- Jae Young Choi
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, New York State, United States of America
| | - Yuh Chwen G. Lee
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, United States of America
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27
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Champigny MJ, Unda F, Skyba O, Soolanayakanahally RY, Mansfield SD, Campbell MM. Learning from methylomes: epigenomic correlates of Populus balsamifera traits based on deep learning models of natural DNA methylation. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:1361-1375. [PMID: 31742813 PMCID: PMC7207000 DOI: 10.1111/pbi.13299] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 10/29/2019] [Indexed: 06/10/2023]
Abstract
Epigenomes have remarkable potential for the estimation of plant traits. This study tested the hypothesis that natural variation in DNA methylation can be used to estimate industrially important traits in a genetically diverse population of Populus balsamifera L. (balsam poplar) trees grown at two common garden sites. Statistical learning experiments enabled by deep learning models revealed that plant traits in novel genotypes can be modelled transparently using small numbers of methylated DNA predictors. Using this approach, tissue type, a nonheritable attribute, from which DNA methylomes were derived was assigned, and provenance, a purely heritable trait and an element of population structure, was determined. Significant proportions of phenotypic variance in quantitative wood traits, including total biomass (57.5%), wood density (40.9%), soluble lignin (25.3%) and cell wall carbohydrate (mannose: 44.8%) contents, were also explained from natural variation in DNA methylation. Modelling plant traits using DNA methylation can capture tissue-specific epigenetic mechanisms underlying plant phenotypes in natural environments. DNA methylation-based models offer new insight into natural epigenetic influence on plants and can be used as a strategy to validate the identity, provenance or quality of agroforestry products.
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Affiliation(s)
- Marc J. Champigny
- Department of Molecular and Cellular BiologyUniversity of GuelphGuelphONCanada
- Department of Biological SciencesUniversity of Toronto ScarboroughTorontoONCanada
| | - Faride Unda
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
| | - Oleksandr Skyba
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
| | | | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
| | - Malcolm M. Campbell
- Department of Molecular and Cellular BiologyUniversity of GuelphGuelphONCanada
- Department of Biological SciencesUniversity of Toronto ScarboroughTorontoONCanada
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28
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Azizi P, Hanafi MM, Sahebi M, Harikrishna JA, Taheri S, Yassoralipour A, Nasehi A. Epigenetic changes and their relationship to somaclonal variation: a need to monitor the micropropagation of plantation crops. FUNCTIONAL PLANT BIOLOGY : FPB 2020; 47:508-523. [PMID: 32349860 DOI: 10.1071/fp19077] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 02/23/2020] [Indexed: 06/11/2023]
Abstract
Chromatin modulation plays important roles in gene expression regulation and genome activities. In plants, epigenetic changes, including variations in histone modification and DNA methylation, are linked to alterations in gene expression. Despite the significance and potential of in vitro cell and tissue culture systems in fundamental research and marketable applications, these systems threaten the genetic and epigenetic networks of intact plant organs and tissues. Cell and tissue culture applications can lead to DNA variations, methylation alterations, transposon activation, and finally, somaclonal variations. In this review, we discuss the status of the current understanding of epigenomic changes that occur under in vitro conditions in plantation crops, including coconut, oil palm, rubber, cotton, coffee and tea. It is hoped that comprehensive knowledge of the molecular basis of these epigenomic variations will help researchers develop strategies to enhance the totipotent and embryogenic capabilities of tissue culture systems for plantation crops.
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Affiliation(s)
- Parisa Azizi
- Laboratory of Plantation Science and Technology, Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; and Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Mohamed M Hanafi
- Laboratory of Plantation Science and Technology, Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; and Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; and Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; and Corresponding author.
| | - Mahbod Sahebi
- Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Jennifer A Harikrishna
- Centre of Research in Biotechnology for Agriculture (CEBAR), University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Sima Taheri
- Centre of Research in Biotechnology for Agriculture (CEBAR), University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Ali Yassoralipour
- Department of Agricultural and Food Science, Faculty of Science (Kampar Campus), Universiti Tunku Abdul Rahman (UTAR), Jalan Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - Abbas Nasehi
- Laboratory of Plantation Science and Technology, Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
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29
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Böhrer M, Rymen B, Himber C, Gerbaud A, Pflieger D, Laudencia-Chingcuanco D, Cartwright A, Vogel J, Sibout R, Blevins T. Integrated Genome-Scale Analysis and Northern Blot Detection of Retrotransposon siRNAs Across Plant Species. Methods Mol Biol 2020; 2166:387-411. [PMID: 32710422 DOI: 10.1007/978-1-0716-0712-1_23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Cells have sophisticated RNA-directed mechanisms to regulate genes, destroy viruses, or silence transposable elements (TEs). In terrestrial plants, a specialized non-coding RNA machinery involving RNA polymerase IV (Pol IV) and small interfering RNAs (siRNAs) targets DNA methylation and silencing to TEs. Here, we present a bioinformatics protocol for annotating and quantifying siRNAs that derive from long terminal repeat (LTR) retrotransposons. The approach was validated using small RNA northern blot analyses, comparing the species Arabidopsis thaliana and Brachypodium distachyon. To assist hybridization probe design, we configured a genome browser to show small RNA-seq mappings in distinct colors and shades according to their nucleotide lengths and abundances, respectively. Samples from wild-type and pol IV mutant plants, cross-species negative controls, and a conserved microRNA control validated the detected siRNA signals, confirming their origin from specific TEs and their Pol IV-dependent biogenesis. Moreover, an optimized labeling method yielded probes that could detect low-abundance siRNAs from B. distachyon TEs. The integration of de novo TE annotation, small RNA-seq profiling, and northern blotting, as outlined here, will facilitate the comparative genomic analysis of RNA silencing in crop plants and non-model species.
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Affiliation(s)
- Marcel Böhrer
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Bart Rymen
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Christophe Himber
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Aude Gerbaud
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - David Pflieger
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | | | - Amy Cartwright
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - John Vogel
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Richard Sibout
- INRAE, UR BIA, Nantes, France.,Institut Jean-Pierre Bourgin, UMR 1318, INRAE, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Todd Blevins
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France.
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30
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Vondras AM, Minio A, Blanco-Ulate B, Figueroa-Balderas R, Penn MA, Zhou Y, Seymour D, Ye Z, Liang D, Espinoza LK, Anderson MM, Walker MA, Gaut B, Cantu D. The genomic diversification of grapevine clones. BMC Genomics 2019; 20:972. [PMID: 31830913 PMCID: PMC6907202 DOI: 10.1186/s12864-019-6211-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 10/22/2019] [Indexed: 12/14/2022] Open
Abstract
Background Vegetatively propagated clones accumulate somatic mutations. The purpose of this study was to better appreciate clone diversity and involved defining the nature of somatic mutations throughout the genome. Fifteen Zinfandel winegrape clone genomes were sequenced and compared to one another using a highly contiguous genome reference produced from one of the clones, Zinfandel 03. Results Though most heterozygous variants were shared, somatic mutations accumulated in individual and subsets of clones. Overall, heterozygous mutations were most frequent in intergenic space and more frequent in introns than exons. A significantly larger percentage of CpG, CHG, and CHH sites in repetitive intergenic space experienced transition mutations than in genic and non-repetitive intergenic spaces, likely because of higher levels of methylation in the region and because methylated cytosines often spontaneously deaminate. Of the minority of mutations that occurred in exons, larger proportions of these were putatively deleterious when they occurred in relatively few clones. Conclusions These data support three major conclusions. First, repetitive intergenic space is a major driver of clone genome diversification. Second, clones accumulate putatively deleterious mutations. Third, the data suggest selection against deleterious variants in coding regions or some mechanism by which mutations are less frequent in coding than noncoding regions of the genome.
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Affiliation(s)
- Amanda M Vondras
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Andrea Minio
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Barbara Blanco-Ulate
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA.,Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Rosa Figueroa-Balderas
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Michael A Penn
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Yongfeng Zhou
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92617, USA
| | - Danelle Seymour
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92617, USA
| | - Zirou Ye
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Dingren Liang
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Lucero K Espinoza
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Michael M Anderson
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - M Andrew Walker
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Brandon Gaut
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92617, USA
| | - Dario Cantu
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA.
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31
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Zhang Y, Ramming A, Heinke L, Altschmied L, Slotkin RK, Becker JD, Kappel C, Lenhard M. The poly(A) polymerase PAPS1 interacts with the RNA-directed DNA-methylation pathway in sporophyte and pollen development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 99:655-672. [PMID: 31009115 DOI: 10.1111/tpj.14348] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 03/21/2019] [Accepted: 04/08/2019] [Indexed: 05/28/2023]
Abstract
RNA-based processes play key roles in the regulation of eukaryotic gene expression. This includes both the processing of pre-mRNAs into mature mRNAs ready for translation and RNA-based silencing processes, such as RNA-directed DNA methylation (RdDM). Polyadenylation of pre-mRNAs is one important step in their processing and is carried out by three functionally specialized canonical nuclear poly(A) polymerases in Arabidopsis thaliana. Null mutations in one of these, termed PAPS1, result in a male gametophytic defect. Using a fluorescence-labelling strategy, we have characterized this defect in more detail using RNA and small-RNA sequencing. In addition to global defects in the expression of pollen-differentiation genes, paps1 null-mutant pollen shows a strong overaccumulation of transposable element (TE) transcripts, yet a depletion of 21- and particularly 24-nucleotide-long short interfering RNAs (siRNAs) and microRNAs (miRNAs) targeting the corresponding TEs. Double-mutant analyses support a specific functional interaction between PAPS1 and components of the RdDM pathway, as evident from strong synergistic phenotypes in mutant combinations involving paps1, but not paps2 paps4, mutations. In particular, the double-mutant of paps1 and rna-dependent rna polymerase 6 (rdr6) shows a synergistic developmental phenotype disrupting the formation of the transmitting tract in the female gynoecium. Thus, our findings in A. thaliana uncover a potentially general link between canonical poly(A) polymerases as components of mRNA processing and RdDM, reflecting an analogous interaction in fission yeast.
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Affiliation(s)
- Yunming Zhang
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany
| | - Anna Ramming
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany
| | - Lisa Heinke
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany
| | - Lothar Altschmied
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung, Corrensstrasse 3, D-06466 Seeland, OT, Gatersleben, Germany
| | - R Keith Slotkin
- Donald Danforth Plant Science Center, 975 North Warson Road, St Louis, MO, 63132, USA
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Jörg D Becker
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156, Oeiras, Portugal
| | - Christian Kappel
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany
| | - Michael Lenhard
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany
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32
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Long JC, Xia AA, Liu JH, Jing JL, Wang YZ, Qi CY, He Y. Decrease in DNA methylation 1 (DDM1) is required for the formation of m CHH islands in maize. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:749-764. [PMID: 30387549 DOI: 10.1111/jipb.12733] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/23/2018] [Indexed: 05/26/2023]
Abstract
DNA methylation plays a crucial role in suppressing mobilization of transposable elements and regulation of gene expression. A number of studies have indicated that DNA methylation pathways and patterns exhibit distinct properties in different species, including Arabidopsis, rice, and maize. Here, we characterized the function of DDM1 in regulating genome-wide DNA methylation in maize. Two homologs of ZmDDM1 are abundantly expressed in the embryo and their simultaneous disruption caused embryo lethality with abnormalities in cell proliferation from the early stage of kernel development. We establish that ZmDDM1 is critical for DNA methylation, at CHG sites, and to a lesser extent at CG sites, in heterochromatic regions, and unexpectedly, it is required for the formation of m CHH islands. In addition, ZmDDM1 is indispensable for the presence of 24-nt siRNA, suggesting its involvement in the RdDM pathway. Our results provide novel insight into the role of ZmDDM1 in regulating the formation of m CHH islands, via the RdDM pathway maize, suggesting that, in comparison to Arabidopsis, maize may have adopted distinct mechanisms for regulating m CHH.
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Affiliation(s)
- Jin Cheng Long
- National Maize Improvement Center of China, China Agricultural University, Beijing 100094, China
| | - Ai Ai Xia
- National Maize Improvement Center of China, China Agricultural University, Beijing 100094, China
| | - Jing Han Liu
- National Maize Improvement Center of China, China Agricultural University, Beijing 100094, China
| | - Ju Li Jing
- National Maize Improvement Center of China, China Agricultural University, Beijing 100094, China
| | - Ya Zhong Wang
- National Maize Improvement Center of China, China Agricultural University, Beijing 100094, China
| | - Chuang Ye Qi
- National Maize Improvement Center of China, China Agricultural University, Beijing 100094, China
| | - Yan He
- National Maize Improvement Center of China, China Agricultural University, Beijing 100094, China
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33
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Li SF, Guo YJ, Li JR, Zhang DX, Wang BX, Li N, Deng CL, Gao WJ. The landscape of transposable elements and satellite DNAs in the genome of a dioecious plant spinach ( Spinacia oleracea L.). Mob DNA 2019; 10:3. [PMID: 30675191 PMCID: PMC6337768 DOI: 10.1186/s13100-019-0147-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/07/2019] [Indexed: 11/10/2022] Open
Abstract
Background Repetitive sequences, including transposable elements (TEs) and satellite DNAs, occupy a considerable portion of plant genomes. Analysis of the repeat fraction benefits the understanding of genome structure and evolution. Spinach (Spinacia oleracea L.), an important vegetable crop, is also a model dioecious plant species for studying sex determination and sex chromosome evolution. However, the repetitive sequences of the spinach genome have not been fully investigated. Results We extensively analyzed the repetitive components of draft spinach genome, especially TEs and satellites, by different strategies. A total of 16,002 full-length TEs were identified. Among the most abundant long terminal repeat (LTR) retrotransposons (REs), Copia elements were overrepresented compared with Gypsy ones. Angela was the most dominating Copia lineage; Ogre/Tat was the most abundant Gypsy lineage. The mean insertion age of LTR-REs was 1.42 million years; approximately 83.7% of these elements were retrotransposed during the last two million years. RepeatMasker totally masked about 64.05% of the spinach genome, with LTR-REs, non-LTR-REs, and DNA transposons occupying 49.2, 2.4, and 5.6%, respectively. Fluorescence in situ hybridization (FISH) analysis showed that most LTR-REs dispersed all over the chromosomes, by contrast, elements of CRM lineage were distributed at the centromeric region of all chromosomes. In addition, Ogre/Tat lineage mainly accumulated on sex chromosomes, and satellites Spsat2 and Spsat3 were exclusively located at the telomeric region of the short arm of sex chromosomes. Conclusions We reliably annotated the TE fraction of the draft genome of spinach. FISH analysis indicates that Ogre/Tat lineage and the sex chromosome-specific satellites DNAs might participate in sex chromosome formation and evolution. Based on FISH signals of microsatellites, together with 45S rDNA, a fine karyotype of spinach was established. This study improves our knowledge of repetitive sequence organization in spinach genome and aids in accurate spinach karyotype construction. Electronic supplementary material The online version of this article (10.1186/s13100-019-0147-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shu-Fen Li
- 1College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Yu-Jiao Guo
- 1College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Jia-Rong Li
- 1College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Dong-Xu Zhang
- 2College of Life Science, Shanxi Datong University, Datong, 037009 China
| | - Bing-Xiao Wang
- 1College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Ning Li
- 1College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Chuan-Liang Deng
- 1College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
| | - Wu-Jun Gao
- 1College of Life Sciences, Henan Normal University, Xinxiang, 453007 China
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Yadav NS, Khadka J, Domb K, Zemach A, Grafi G. CMT3 and SUVH4/KYP silence the exonic Evelknievel retroelement to allow for reconstitution of CMT1 mRNA. Epigenetics Chromatin 2018; 11:69. [PMID: 30446008 PMCID: PMC6238269 DOI: 10.1186/s13072-018-0240-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 11/09/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The Chromomethylase 1 (CMT1) has long been considered a nonessential gene because, in certain Arabidopsis ecotypes, the CMT1 gene is disrupted by the Evelknievel (EK) retroelement, inserted within exon 13, or contains frameshift mutations, resulting in a truncated, non-functional protein. In contrast to other transposable elements, no transcriptional activation of EK was observed under stress conditions (e.g., protoplasting). RESULTS We wanted to explore the regulatory pathway responsible for EK silencing in the Ler ecotype and its effect on CMT1 transcription. Methylome databases confirmed that EK retroelement is heavily methylated and methylation is extended toward CMT1 downstream region. Strong transcriptional activation of EK accompanied by significant reduction in non-CG methylation was found in cmt3 and kyp2, but not in ddm1 or RdDM mutants. EK activation in cmt3 and kyp2 did not interfere with upstream CMT1 expression but abolish transcription through the EK. We identified, in wild-type Ler, three spliced variants in which the entire EK is spliced out; one variant (25% of splicing incidents) facilitates proper reconstitution of an intact CMT1 mRNA. We could recover very low amount of the full-length CMT1 mRNA from WT Ler and Col, but not from cmt3 mutant. CONCLUSIONS Our findings highlight CMT3-SUVH4/KYP as the major pathway silencing the intragenic EK via inducing non-CG methylation. Furthermore, retroelement insertion within exons (e.g., CMT1) may not lead to a complete abolishment of the gene product when the element is kept silent. Rather the element can be spliced out to bring about reconstruction of an intact, functional mRNA and possibly retrieval of an active protein.
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Affiliation(s)
- Narendra Singh Yadav
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben Gurion, Israel
| | - Janardan Khadka
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben Gurion, Israel
| | - Katherine Domb
- The School of Plant Sciences and Food Security, Tel-Aviv University, 69978, Tel Aviv, Israel
| | - Assaf Zemach
- The School of Plant Sciences and Food Security, Tel-Aviv University, 69978, Tel Aviv, Israel
| | - Gideon Grafi
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben Gurion, Israel.
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Shaping Plant Adaptability, Genome Structure and Gene Expression through Transposable Element Epigenetic Control: Focus on Methylation. AGRONOMY-BASEL 2018. [DOI: 10.3390/agronomy8090180] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In plants, transposable elements (TEs) represent a large fraction of the genome, with potential to alter gene expression and produce genomic rearrangements. Epigenetic control of TEs is often used to stop unrestricted movement of TEs that would result in detrimental effects due to insertion in essential genes. The current review focuses on the effects of methylation on TEs and their genomic context, and how this type of epigenetic control affects plant adaptability when plants are faced with different stresses and changes. TEs mobilize in response to stress elicitors, including biotic and abiotic cues, but also developmental transitions and ‘genome shock’ events like polyploidization. These events transitionally lift TE repression, allowing TEs to move to new genomic locations. When TEs fall close to genes, silencing through methylation can spread to nearby genes, resulting in lower gene expression. The presence of TEs in gene promoter regions can also confer stress inducibility modulated through alternative methylation and demethylation of the TE. Bursts of transposition triggered by events of genomic shock can increase genome size and account for differences seen during polyploidization or species divergence. Finally, TEs have evolved several mechanisms to suppress their own repression, including the use of microRNAs to control genes that promote methylation. The interplay between silencing, transient TE activation, and purifying selection allows the genome to use TEs as a reservoir of potential beneficial modifications but also keeps TEs under control to stop uncontrolled detrimental transposition.
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Lee J, Yang EC, Graf L, Yang JH, Qiu H, Zelzion U, Chan CX, Stephens TG, Weber APM, Boo GH, Boo SM, Kim KM, Shin Y, Jung M, Lee SJ, Yim HS, Lee JH, Bhattacharya D, Yoon HS. Analysis of the Draft Genome of the Red Seaweed Gracilariopsis chorda Provides Insights into Genome Size Evolution in Rhodophyta. Mol Biol Evol 2018; 35:1869-1886. [DOI: 10.1093/molbev/msy081] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- JunMo Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Korea
| | - Eun Chan Yang
- Marine Ecosystem Research Center, Korea Institute of Ocean Science and Technology, Busan, Korea
| | - Louis Graf
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Korea
| | - Ji Hyun Yang
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Korea
| | - Huan Qiu
- Department of Ecology Evolution and Natural Resources, Rutgers University, New Brunswick, NJ
| | - Udi Zelzion
- Department of Ecology Evolution and Natural Resources, Rutgers University, New Brunswick, NJ
| | - Cheong Xin Chan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy G Stephens
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Andreas P M Weber
- Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine-University, Duesseldorf, Germany
| | - Ga Hun Boo
- Department of Biology, Chungnam National University, Daejeon, Korea
| | - Sung Min Boo
- Department of Biology, Chungnam National University, Daejeon, Korea
| | - Kyeong Mi Kim
- National Marine Biodiversity Institute of Korea, Seocheon, Korea
| | - Younhee Shin
- Bioinformatics Group, R&D Center, Insilicogen, Inc., Suwon, Korea
| | - Myunghee Jung
- Bioinformatics Group, R&D Center, Insilicogen, Inc., Suwon, Korea
| | | | - Hyung-Soon Yim
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, Korea
| | - Jung-Hyun Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, Korea
| | | | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Korea
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Xie X, Shippen DE. DDM1 guards against telomere truncation in Arabidopsis. PLANT CELL REPORTS 2018; 37:501-513. [PMID: 29392401 PMCID: PMC5880217 DOI: 10.1007/s00299-017-2245-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/26/2017] [Indexed: 05/20/2023]
Abstract
Prolonged hypomethylation of DNA leads to telomere truncation correlated with increased telomere recombination, transposon mobilization and stem cell death. Epigenetic pathways, including DNA methylation, are crucial for telomere maintenance. Deficient in DNA Methylation 1 (DDM1) encodes a nucleosome remodeling protein, required to maintain DNA methylation in Arabidopsis thaliana. Plants lacking DDM1 can be self-propagated, but in the sixth generation (G6) hypomethylation leads to rampant transposon activation and infertility. Here we examine the role of DDM1 in telomere length homeostasis through a longitudinal study of successive generations of ddm1-2 mutants. We report that bulk telomere length remains within the wild-type range for the first five generations (G1-G5), and then precipitously drops in G6. While telomerase activity becomes more variable in later generation ddm1-2 mutants, there is no correlation between enzyme activity and telomere length. Plants lacking DDM1 also exhibit no dysregulation of several known telomere-associated transcripts, including TERRA. Instead, telomere shortening coincides with increased G-overhangs and extra-chromosomal circles, consistent with deletional recombination. Telomere shortening also correlates with transcriptional activation of retrotransposons, and a hypersensitive DNA damage response in root apical meristems. Since abiotic stresses, including DNA damage, stimulate homologous recombination, we hypothesize that telomere deletion in G6 ddm1-2 mutants is a by-product of elevated genome-wide recombination in response to transposon mobilization. Further, we speculate that telomere truncation may be beneficial in adverse environmental conditions by accelerating the elimination of stem cells with aberrant genomes.
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Affiliation(s)
- Xiaoyuan Xie
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843-2128, USA
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843-2128, USA.
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Cardelli M. The epigenetic alterations of endogenous retroelements in aging. Mech Ageing Dev 2018; 174:30-46. [PMID: 29458070 DOI: 10.1016/j.mad.2018.02.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/05/2018] [Accepted: 02/08/2018] [Indexed: 02/06/2023]
Abstract
Endogenous retroelements, transposons that mobilize through RNA intermediates, include some of the most abundant repetitive sequences of the human genome, such as Alu and LINE-1 sequences, and human endogenous retroviruses. Recent discoveries demonstrate that these mobile genetic elements not only act as intragenomic parasites, but also exert regulatory roles in living cells. The risk of genomic instability represented by endogenous retroelements is normally counteracted by a series of epigenetic control mechanisms which include, among the most important, CpG DNA methylation. Indeed, most of the genomic CpG sites subjected to DNA methylation in the nuclear DNA are carried by these repetitive elements. As other parts of the genome, endogenous retroelements and other transposable elements are subjected to deep epigenetic alterations during aging, repeatedly observed in the context of organismal and cellular senescence, in human and other species. This review summarizes the current status of knowledge about the epigenetic alterations occurring in this large, non-genic portion of the genome in aging and age-related conditions, with a focus on the causes and the possible functional consequences of these alterations.
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Affiliation(s)
- Maurizio Cardelli
- Advanced Technology Center for Aging Research, Scientific Technological Area, Italian National Research Center on Aging (INRCA), via Birarelli 8, 60121 Ancona, Italy.
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Paz RC, Kozaczek ME, Rosli HG, Andino NP, Sanchez-Puerta MV. Diversity, distribution and dynamics of full-length Copia and Gypsy LTR retroelements in Solanum lycopersicum. Genetica 2017; 145:417-430. [PMID: 28776161 DOI: 10.1007/s10709-017-9977-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/26/2017] [Indexed: 12/18/2022]
Abstract
Transposable elements are the most abundant components of plant genomes and can dramatically induce genetic changes and impact genome evolution. In the recently sequenced genome of tomato (Solanum lycopersicum), the estimated fraction of elements corresponding to retrotransposons is nearly 62%. Given that tomato is one of the most important vegetable crop cultivated and consumed worldwide, understanding retrotransposon dynamics can provide insight into its evolution and domestication processes. In this study, we performed a genome-wide in silico search of full-length LTR retroelements in the tomato nuclear genome and annotated 736 full-length Gypsy and Copia retroelements. The dispersion level across the 12 chromosomes, the diversity and tissue-specific expression of those elements were estimated. Phylogenetic analysis based on the retrotranscriptase region revealed the presence of 12 major lineages of LTR retroelements in the tomato genome. We identified 97 families, of which 77 and 20 belong to the superfamilies Copia and Gypsy, respectively. Each retroelement family was characterized according to their element size, relative frequencies and insertion time. These analyses represent a valuable resource for comparative genomics within the Solanaceae, transposon-tagging and for the design of cultivar-specific molecular markers in tomato.
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Affiliation(s)
- Rosalía Cristina Paz
- CIGEOBIO (FCEFyN, UNSJ/CONICET), Av. Ignacio de la Roza 590 (Oeste), J5402DCS, Rivadavia, San Juan, Argentina.
| | - Melisa Eliana Kozaczek
- Facultad de Ciencias Exactas, Químicas y Naturales, Universidad Nacional de Misiones, Posadas, Misiones, Argentina
| | - Hernán Guillermo Rosli
- Instituto de Fisiología Vegetal, INFIVE, Universidad Nacional de La Plata, CONICET, La Plata, Buenos Aires, Argentina
| | - Natalia Pilar Andino
- Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan, San Juan, Argentina
| | - Maria Virginia Sanchez-Puerta
- IBAM, Universidad Nacional de Cuyo, CONICET, FCA and FCEN, Almirante Brown 500, M5528AHB, Chacras de Coria, Argentina
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Fultz D, Slotkin RK. Exogenous Transposable Elements Circumvent Identity-Based Silencing, Permitting the Dissection of Expression-Dependent Silencing. THE PLANT CELL 2017; 29:360-376. [PMID: 28193737 PMCID: PMC5354191 DOI: 10.1105/tpc.16.00718] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/19/2016] [Accepted: 02/10/2017] [Indexed: 05/09/2023]
Abstract
The propagation of epigenetic marks has received a great deal of attention, yet the initiation of epigenetic silencing of a new transgene, virus, or transposable element (TE) remains enigmatic. The overlapping and simultaneous function of multiple silencing mechanisms has obscured this area of investigation. Here, we revealed two broad mechanisms that can initiate silencing independently: identity-based and expression-dependent silencing. We found that identity-based silencing is targeted by 21- to 22-nucleotide or 24-nucleotide small interfering RNAs (siRNAs) generated from previously silenced regions of the genome. By transforming exogenous TEs into Arabidopsis thaliana, we circumvented identity-based silencing, allowing us to isolate and investigate the molecular mechanism of expression-dependent silencing. We found that several siRNA-generating mechanisms all trigger de novo expression-dependent RNA-directed DNA methylation (RdDM) through RNA Polymerase V. In addition, while full-length TEs quickly progress beyond RdDM to heterochromatin formation and the final maintenance methylation state, TE fragments stall at the RdDM phase. Lastly, we found that transformation into a mutant genotype followed by introgression into the wild type does not result in the same level of silencing as direct transformation into the wild type. This demonstrates that the plant genotype during a narrow window of time at TE insertion (or transgene transformation) is key for establishing the transgenerational extent of epigenetic silencing.
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Affiliation(s)
- Dalen Fultz
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210
- Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio 43210
| | - R Keith Slotkin
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210
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Kalinka A, Achrem M, Poter P. The DNA methylation level against the background of the genome size and t-heterochromatin content in some species of the genus Secale L. PeerJ 2017; 5:e2889. [PMID: 28149679 PMCID: PMC5267573 DOI: 10.7717/peerj.2889] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 12/08/2016] [Indexed: 01/05/2023] Open
Abstract
Methylation of cytosine in DNA is one of the most important epigenetic modifications in eukaryotes and plays a crucial role in the regulation of gene activity and the maintenance of genomic integrity. DNA methylation and other epigenetic mechanisms affect the development, differentiation or the response of plants to biotic and abiotic stress. This study compared the level of methylation of cytosines on a global (ELISA) and genomic scale (MSAP) between the species of the genus Secale. We analyzed whether the interspecific variation of cytosine methylation was associated with the size of the genome (C-value) and the content of telomeric heterochromatin. MSAP analysis showed that S. sylvestre was the most distinct species among the studied rye taxa; however, the results clearly indicated that these differences were not statistically significant. The total methylation level of the studied loci was very similar in all taxa and ranged from 60% in S. strictum ssp. africanum to 66% in S. cereale ssp. segetale, which confirmed the lack of significant differences in the sequence methylation pattern between the pairs of rye taxa. The level of global cytosine methylation in the DNA was not significantly associated with the content of t-heterochromatin and did not overlap with the existing taxonomic rye relationships. The highest content of 5-methylcytosine was found in S. cereale ssp. segetale (83%), while very low in S. strictum ssp. strictum (53%), which was significantly different from the methylation state of all taxa, except for S. sylvestre. The other studied taxa of rye had a similar level of methylated cytosine ranging from 66.42% (S. vavilovii) to 74.41% in (S. cereale ssp. afghanicum). The results obtained in this study are evidence that the percentage of methylated cytosine cannot be inferred solely based on the genome size or t-heterochromatin. This is a significantly more complex issue.
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Affiliation(s)
- Anna Kalinka
- Department of Cell Biology, Faculty of Biology, University of Szczecin, Szczecin, Poland; Molecular Biology and Biotechnology Center, Faculty of Biology, University of Szczecin, Szczecin, Poland
| | - Magdalena Achrem
- Department of Cell Biology, Faculty of Biology, University of Szczecin, Szczecin, Poland; Molecular Biology and Biotechnology Center, Faculty of Biology, University of Szczecin, Szczecin, Poland
| | - Paulina Poter
- Department of Cell Biology, Faculty of Biology, University of Szczecin , Szczecin , Poland
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Khan A, Yadav NS, Morgenstern Y, Zemach A, Grafi G. Activation of Tag1 transposable elements in Arabidopsis dedifferentiating cells and their regulation by CHROMOMETHYLASE 3-mediated CHG methylation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:1289-98. [PMID: 27475038 DOI: 10.1016/j.bbagrm.2016.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 07/13/2016] [Accepted: 07/25/2016] [Indexed: 12/11/2022]
Abstract
Dedifferentiation, that is, the acquisition of stem cell-like state, commonly induced by stress (e.g., protoplasting), is characterized by open chromatin conformation, a chromatin state that could lead to activation of transposable elements (TEs). Here, we studied the activation of the Arabidopsis class II TE Tag1, in which two copies, situated close to each other (near genes) on chromosome 1 are found in Landsberg erecta (Ler) but not in Columbia (Col). We first transformed protoplasts with a construct in which a truncated Tag1 (ΔTag1 non-autonomous) blocks the expression of a reporter gene AtMBD5-GFP and found a relatively high ectopic excision of ΔTag1 accompanied by expression of AtMBD5-GFP in protoplasts derived from Ler compared to Col; further increase was observed in ddm1 (decrease in DNA methylation1) protoplasts (Ler background). Ectopic excision was associated with transcription of the endogenous Tag1 and changes in histone H3 methylation at the promoter region. Focusing on the endogenous Tag1 elements we found low level of excision in Ler protoplasts, which was slightly and strongly enhanced in ddm1 and cmt3 (chromomethylase3) protoplasts, respectively, concomitantly with reduction in Tag1 gene body (GB) CHG methylation and increased Tag1 transcription; strong activation of Tag1 was also observed in cmt3 leaves. Notably, in cmt3, but not in ddm1, Tag1 elements were excised out from their original sites and transposed elsewhere in the genome. Our results suggest that dedifferentiation is associated with Tag1 activation and that CMT3 rather than DDM1 plays a central role in restraining Tag1 activation via inducing GB CHG methylation.
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Affiliation(s)
- Asif Khan
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel
| | - Narendra Singh Yadav
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel
| | - Yaakov Morgenstern
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel
| | - Assaf Zemach
- Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, 69978 Tel Aviv, Israel
| | - Gideon Grafi
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben Gurion 84990, Israel.
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Jiang S, Cai D, Sun Y, Teng Y. Isolation and characterization of putative functional long terminal repeat retrotransposons in the Pyrus genome. Mob DNA 2016; 7:1. [PMID: 26779288 PMCID: PMC4715297 DOI: 10.1186/s13100-016-0058-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/05/2016] [Indexed: 01/28/2023] Open
Abstract
Background Long terminal repeat (LTR)-retrotransposons constitute 42.4 % of the genome of the ‘Suli’ pear (Pyrus pyrifolia white pear group), implying that retrotransposons have played important roles in Pyrus evolution. Therefore, further analysis of retrotransposons will enhance our understanding of the evolutionary history of Pyrus. Results We identified 1836 LTR-retrotransposons in the ‘Suli’ pear genome, of which 440 LTR-retrotransposons were predicted to contain at least two of three gene models (gag, integrase and reverse transcriptase). Because these were most likely to be functional transposons, we focused our analyses on this set of 440. Most of the LTR-retrotransposons were estimated to have inserted into the genome less than 2.5 million years ago. Sequence analysis showed that the reverse transcriptase component of the identified LTR-retrotransposons was highly heterogeneous. Analyses of transcripts assembled from RNA-Seq databases of two cultivars of Pyrus species showed that LTR-retrotransposons were expressed in the buds and fruit of Pyrus. A total of 734 coding sequences in the ‘Suli’ genome were disrupted by the identified LTR-retrotransposons. Five high-copy-number LTR-retrotransposon families were identified in Pyrus. These families were rarely found in the genomes of Malus and Prunus, but were distributed extensively in Pyrus and abundance varied between species. Conclusions We identified potentially functional, full-length LTR-retrotransposons with three gene models in the ‘Suli’ genome. The analysis of RNA-seq data demonstrated that these retrotransposons are expressed in the organs of pears. The differential copy number of LTR-retrotransposon families between Pyrus species suggests that the transposition of retrotransposons is an important evolutionary force driving the genetic divergence of species within the genus. Electronic supplementary material The online version of this article (doi:10.1186/s13100-016-0058-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shuang Jiang
- Department of Horticulture, Zhejiang University, Hangzhou, Zhejiang 310058 China ; Forest & Fruit Tree Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403 China
| | - Danying Cai
- Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang 310021 China
| | - Yongwang Sun
- Department of Horticulture, Zhejiang University, Hangzhou, Zhejiang 310058 China ; The Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, The Ministry of Agriculture of China, Hangzhou, Zhejiang 310058 China ; Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, Zhejiang 310058 China
| | - Yuanwen Teng
- Department of Horticulture, Zhejiang University, Hangzhou, Zhejiang 310058 China ; The Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, The Ministry of Agriculture of China, Hangzhou, Zhejiang 310058 China ; Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, Zhejiang 310058 China
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Gebert D, Rosenkranz D. RNA-based regulation of transposon expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:687-708. [DOI: 10.1002/wrna.1310] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/08/2015] [Accepted: 09/13/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Daniel Gebert
- Institute of Anthropology; Johannes Gutenberg University; Mainz Germany
| | - David Rosenkranz
- Institute of Anthropology; Johannes Gutenberg University; Mainz Germany
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De-la-Peña C, Nic-Can GI, Galaz-Ávalos RM, Avilez-Montalvo R, Loyola-Vargas VM. The role of chromatin modifications in somatic embryogenesis in plants. FRONTIERS IN PLANT SCIENCE 2015; 6:635. [PMID: 26347757 PMCID: PMC4539545 DOI: 10.3389/fpls.2015.00635] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/31/2015] [Indexed: 05/20/2023]
Abstract
Somatic embryogenesis (SE) is a powerful tool for plant genetic improvement when used in combination with traditional agricultural techniques, and it is also an important technique to understand the different processes that occur during the development of plant embryogenesis. SE onset depends on a complex network of interactions among plant growth regulators, mainly auxins and cytokinins, during the proembryogenic early stages, and ethylene and gibberellic and abscisic acids later in the development of the somatic embryos. These growth regulators control spatial and temporal regulation of multiple genes in order to initiate change in the genetic program of somatic cells, as well as moderating the transition between embryo developmental stages. In recent years, epigenetic mechanisms have emerged as critical factors during SE. Some early reports indicate that auxins and in vitro conditions modify the levels of DNA methylation in embryogenic cells. The changes in DNA methylation patterns are associated with the regulation of several genes involved in SE, such as WUS, BBM1, LEC, and several others. In this review, we highlight the more recent discoveries in the understanding of the role of epigenetic regulation of SE. In addition, we include a survey of different approaches to the study of SE, and new opportunities to focus SE studies.
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Affiliation(s)
- Clelia De-la-Peña
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, MéridaMexico
| | - Geovanny I. Nic-Can
- Facultad de Ingeniería Química, Campus de Ciencias Exactas e Ingeniería, Universidad Autónoma de Yucatán, MéridaMexico
| | - Rosa M. Galaz-Ávalos
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, MéridaMexico
| | - Randy Avilez-Montalvo
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, MéridaMexico
| | - Víctor M. Loyola-Vargas
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, MéridaMexico
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El Baidouri M, Kim KD, Abernathy B, Arikit S, Maumus F, Panaud O, Meyers BC, Jackson SA. A new approach for annotation of transposable elements using small RNA mapping. Nucleic Acids Res 2015; 43:e84. [PMID: 25813049 PMCID: PMC4513842 DOI: 10.1093/nar/gkv257] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 03/10/2015] [Accepted: 03/15/2015] [Indexed: 12/31/2022] Open
Abstract
Transposable elements (TEs) are mobile genomic DNA sequences found in most organisms. They so densely populate the genomes of many eukaryotic species that they are often the major constituents. With the rapid generation of many plant genome sequencing projects over the past few decades, there is an urgent need for improved TE annotation as a prerequisite for genome-wide studies. Analogous to the use of RNA-seq for gene annotation, we propose a new method for de novo TE annotation that uses as a guide 24 nt-siRNAs that are a part of TE silencing pathways. We use this new approach, called TASR (for Transposon Annotation using Small RNAs), for de novo annotation of TEs in Arabidopsis, rice and soybean and demonstrate that this strategy can be successfully applied for de novo TE annotation in plants.Executable PERL is available for download from: http://tasr-pipeline.sourceforge.net/.
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Affiliation(s)
- Moaine El Baidouri
- Center for Applied Genetic Technologies. University of Georgia, 111, Riverbend Dr., Athens, GA 30602, USA
| | - Kyung Do Kim
- Center for Applied Genetic Technologies. University of Georgia, 111, Riverbend Dr., Athens, GA 30602, USA
| | - Brian Abernathy
- Center for Applied Genetic Technologies. University of Georgia, 111, Riverbend Dr., Athens, GA 30602, USA
| | - Siwaret Arikit
- Delaware Biotechnology Institute and Department of Plant & Soil Sciences, University of Delaware, Newark, DE 19711, USA
| | - Florian Maumus
- INRA, UR1164 URGI-Research Unit in Genomics-Info, INRA de Versailles-Grignon, Route de Saint-Cyr, Versailles 78026, France
| | - Olivier Panaud
- Université de Perpignan Via Domitia. Laboratoire Génome et Développement des Plantes. UMR5096 CNRS/UPVD., 52, avenue Paul Alduy. 66860 Perpignan Cedex, France
| | - Blake C Meyers
- Delaware Biotechnology Institute and Department of Plant & Soil Sciences, University of Delaware, Newark, DE 19711, USA
| | - Scott A Jackson
- Center for Applied Genetic Technologies. University of Georgia, 111, Riverbend Dr., Athens, GA 30602, USA
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Paz RC, Rendina González AP, Ferrer MS, Masuelli RW. Short-term hybridisation activates Tnt1 and Tto1 Copia retrotransposons in wild tuber-bearing Solanum species. PLANT BIOLOGY (STUTTGART, GERMANY) 2015; 17:860-869. [PMID: 25556397 DOI: 10.1111/plb.12301] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/17/2014] [Indexed: 06/04/2023]
Abstract
Interspecific hybridisation in tuber-bearing species of Solanum is a common phenomenon and represents an important source of variability, crucial for adaptation and speciation of potato species. In this regard, the effects of interspecific hybridisation on retrotransposon families present in the genomes, and their consequent effects on generation of genetic variability in wild tuber-bearing Solanum species, are poorly characterised. The aim of this study was to analyse the activity of retrotransposons in inter- and intraspecific hybrids between S. kurtzianum and S. microdontum, obtained by controlled crosses, and the effects on morphological, genetic and epigenetic variability. For genetic and epigenetic analysis, S-SAP (sequence-specific amplification polymorphism) and TMD (transposon methylation display) techniques were used, respectively, with specific primers for Tnt1 and Tto1 retrotransposon families (Order LTR, Superfamily Copia). The results indicate that at morphological level, interspecific hybrid genotypes differ from their parental species, whereas derived intraspecific hybrids do not. In both cases, we observed significant reductions in pollen grain viability, and a negative correlation with Tnt1 mobility. Both retrotransposons, Tto1 and Tnt1, were mobilised in the genotypes analysed, with mobility ranging from 0 to 7.8%. Furthermore, at the epigenetic level, demethylation was detected in the vicinity of Tnt1 and Tto1 in the hybrids compared with the parental genotypes. These patterns were positively correlated with the activity of the retrotransposons. The results suggest a possible mechanism through which hybridisation events generate genetic variability in tuber-bearing species of Solanum through retrotranposon activation.
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Affiliation(s)
- R C Paz
- Dpto. de Biología, Grupo INTERBIODES (Biological Interactions of Desert), CIGEOBIO (FCEFyN, UNSJ/CONICET), Rivadavia, San Juan, Argentina
| | - A P Rendina González
- Facultad de Ciencias Exactas, Químicas y Naturales, Universidad Nacional de Misiones, Posadas, Misiones, Argentina
| | - M S Ferrer
- Laboratorio de Biología Molecular, Instituto de Biología Agrícola de Mendoza (IBAM), Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Chacras de Coria, Mendoza, Argentina
| | - R W Masuelli
- Laboratorio de Biología Molecular, Instituto de Biología Agrícola de Mendoza (IBAM), Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Chacras de Coria, Mendoza, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA), La Consulta, San Carlos, Mendoza, Argentina
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Rodríguez-Mega E, Piñeyro-Nelson A, Gutierrez C, García-Ponce B, Sánchez MDLP, Zluhan-Martínez E, Álvarez-Buylla ER, Garay-Arroyo A. Role of transcriptional regulation in the evolution of plant phenotype: A dynamic systems approach. Dev Dyn 2015; 244:1074-1095. [PMID: 25733163 DOI: 10.1002/dvdy.24268] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 02/24/2015] [Accepted: 02/24/2015] [Indexed: 12/20/2022] Open
Abstract
A growing body of evidence suggests that alterations in transcriptional regulation of genes involved in modulating development are an important part of phenotypic evolution, and this can be documented among species and within populations. While the effects of differential transcriptional regulation in organismal development have been preferentially studied in animal systems, this phenomenon has also been addressed in plants. In this review, we summarize evidence for cis-regulatory mutations, trans-regulatory changes and epigenetic modifications as molecular events underlying important phenotypic alterations, and thus shaping the evolution of plant development. We postulate that a mechanistic understanding of why such molecular alterations have a key role in development, morphology and evolution will have to rely on dynamic models of complex regulatory networks that consider the concerted action of genetic and nongenetic components, and that also incorporate the restrictions underlying the genotype to phenotype mapping process. Developmental Dynamics 244:1074-1095, 2015. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Emiliano Rodríguez-Mega
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, México
| | - Alma Piñeyro-Nelson
- Department of Plant and Microbial Biology, University of California, Berkeley, California
| | - Crisanto Gutierrez
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, Cantoblanco, 28049, Madrid, Spain
| | - Berenice García-Ponce
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, México
| | - María De La Paz Sánchez
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, México
| | - Estephania Zluhan-Martínez
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, México
| | - Elena R Álvarez-Buylla
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, México
| | - Adriana Garay-Arroyo
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, México.,Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, Cantoblanco, 28049, Madrid, Spain
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Grandbastien MA. LTR retrotransposons, handy hitchhikers of plant regulation and stress response. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:403-16. [DOI: 10.1016/j.bbagrm.2014.07.017] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/21/2014] [Accepted: 07/23/2014] [Indexed: 11/30/2022]
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Jung CH, O'Brien M, Singh MB, Bhalla PL. Epigenetic landscape of germline specific genes in the sporophyte cells of Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2015; 6:328. [PMID: 26029228 PMCID: PMC4429549 DOI: 10.3389/fpls.2015.00328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 04/27/2015] [Indexed: 05/15/2023]
Abstract
In plants, the germline lineages arise in later stages of life cycle as opposed to animals where both male and female germlines are set aside early in development. This developmental divergence is associated with germline specific or preferential expression of a subset of genes that are normally repressed for the rest of plant life cycle. The gene regulatory mechanisms involved in such long-term suppression and short-term activation in plant germline remain vague. Thus, we explored the nature of epigenetic marks that are likely associated with long-term gene repression in the non-germline cells. We accessed available Arabidopsis genome-wide DNA methylation and histone modification data and queried it for epigenetic marks associated with germline genes: genes preferentially expressed in sperm cells, egg cells, synergid cells, central cells, antipodal cells or embryo sac or genes that are with enriched expression in two or more of female germline tissues. The vast majority of germline genes are associated with repression-related epigenetic histone modifications in one or more non-germline tissues, among which H3K9me2 and H3K27me3 are the most widespread repression-related marks. Interestingly, we show here that the repressive epigenetic mechanisms differ between male and female germline genes. We also highlight the diverse states of epigenetic marks in different non-germline tissues. Some germline genes also have activation-related marks in non-germline tissues, and the proportion of such genes is higher for female germline genes. Germline genes include 30 transposable element (TE) loci, to which a large number of 24-nt long small interfering RNAs were mapped, suggesting that these small RNAs take a role in suppressing them in non-germline tissues. The data presented here suggest that the majority of Arabidopsis gamete-preferentially/-enriched genes bear repressive epigenetic modifications or regulated by small RNAs.
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Affiliation(s)
- Chol Hee Jung
- Plant Molecular Biology and Biotechnology Laboratory, Melbourne School of Land and Environment, The University of MelbourneParkville, VIC, Australia
- VLSCI Life Sciences Computation Centre, The University of MelbourneParkville, VIC, Australia
| | - Martin O'Brien
- Plant Molecular Biology and Biotechnology Laboratory, Melbourne School of Land and Environment, The University of MelbourneParkville, VIC, Australia
| | - Mohan B. Singh
- Plant Molecular Biology and Biotechnology Laboratory, Melbourne School of Land and Environment, The University of MelbourneParkville, VIC, Australia
| | - Prem L. Bhalla
- Plant Molecular Biology and Biotechnology Laboratory, Melbourne School of Land and Environment, The University of MelbourneParkville, VIC, Australia
- *Correspondence: Prem L. Bhalla, Melbourne School of Land and Environment, The University of Melbourne, Building 142, Royal Parade, Parkville, VIC 3010, Australia
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