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Harkess A, Bewick AJ, Lu Z, Fourounjian P, Michael TP, Schmitz RJ, Meyers BC. The unusual predominance of maintenance DNA methylation in Spirodela polyrhiza. G3 (BETHESDA, MD.) 2024; 14:jkae004. [PMID: 38190722 PMCID: PMC10989885 DOI: 10.1093/g3journal/jkae004] [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: 08/08/2023] [Revised: 10/28/2023] [Accepted: 11/06/2023] [Indexed: 01/10/2024]
Abstract
Duckweeds are among the fastest reproducing plants, able to clonally divide at exponential rates. However, the genetic and epigenetic impact of clonality on plant genomes is poorly understood. 5-methylcytosine (5mC) is a modified base often described as necessary for the proper regulation of certain genes and transposons and for the maintenance of genome integrity in plants. However, the extent of this dogma is limited by the current phylogenetic sampling of land plant species diversity. Here we analyzed DNA methylomes, small RNAs, mRNA-seq, and H3K9me2 histone modification for Spirodela polyrhiza. S. polyrhiza has lost highly conserved genes involved in de novo methylation of DNA at sites often associated with repetitive DNA, and within genes, however, symmetrical DNA methylation and heterochromatin are maintained during cell division at certain transposons and repeats. Consequently, small RNAs that normally guide methylation to silence repetitive DNA like retrotransposons are diminished. Despite the loss of a highly conserved methylation pathway, and the reduction of small RNAs that normally target repetitive DNA, transposons have not proliferated in the genome, perhaps due in part to the rapid, clonal growth lifestyle of duckweeds.
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Affiliation(s)
- Alex Harkess
- Donald Danforth Plant Science Center, St Louis, MO 63132, USA
| | - Adam J Bewick
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Zefu Lu
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Paul Fourounjian
- Waksman Institute of Microbiology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Todd P Michael
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St Louis, MO 63132, USA
- Division of Plant Sciences, University of Missouri—Columbia, Columbia, MO 65211, USA
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2
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Feng G, Jiao Y, Ma H, Bian H, Nie G, Huang L, Xie Z, Ran Q, Fan W, He W, Zhang X. The first two whole mitochondrial genomes for the genus Dactylis species: assembly and comparative genomics analysis. BMC Genomics 2024; 25:235. [PMID: 38438835 PMCID: PMC10910808 DOI: 10.1186/s12864-024-10145-0] [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: 09/16/2023] [Accepted: 02/19/2024] [Indexed: 03/06/2024] Open
Abstract
BACKGROUND Orchardgrass (Dactylis glomerata L.), a perennial forage, has the advantages of rich leaves, high yield, and good quality and is one of the most significant forage for grassland animal husbandry and ecological management in southwest China. Mitochondrial (mt) genome is one of the major genetic systems in plants. Studying the mt genome of the genus Dactylis could provide more genetic information in addition to the nuclear genome project of the genus. RESULTS In this study, we sequenced and assembled two mitochondrial genomes of Dactylis species of D. glomerata (597, 281 bp) and D. aschersoniana (613, 769 bp), based on a combination of PacBio and Illumina. The gene content in the mitochondrial genome of D. aschersoniana is almost identical to the mitochondrial genome of D. glomerata, which contains 22-23 protein-coding genes (PCGs), 8 ribosomal RNAs (rRNAs) and 30 transfer RNAs (tRNAs), while D. glomerata lacks the gene encoding the Ribosomal protein (rps1) and D. aschersoniana contains one pseudo gene (atp8). Twenty-three introns were found among eight of the 30 protein-coding genes, and introns of three genes (nad 1, nad2, and nad5) were trans-spliced in Dactylis aschersoniana. Further, our mitochondrial genome characteristics investigation of the genus Dactylis included codon usage, sequences repeats, RNA editing and selective pressure. The results showed that a large number of short repetitive sequences existed in the mitochondrial genome of D. aschersoniana, the size variation of two mitochondrial genomes is due largely to the presence of a large number of short repetitive sequences. We also identified 52-53 large fragments that were transferred from the chloroplast genome to the mitochondrial genome, and found that the similarity was more than 70%. ML and BI methods used in phylogenetic analysis revealed that the evolutionary status of the genus Dactylis. CONCLUSIONS Thus, this study reveals the significant rearrangements in the mt genomes of Pooideae species. The sequenced Dactylis mt genome can provide more genetic information and improve our evolutionary understanding of the mt genomes of gramineous plants.
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Affiliation(s)
- Guangyan Feng
- College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yongjuan Jiao
- College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Huizhen Ma
- Grassland Research Institute, Chongqing Academy of Animal Science, Chongqing, 402460, China
| | - Haoyang Bian
- College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Gang Nie
- College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Linkai Huang
- College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Zheni Xie
- College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Qifan Ran
- Grassland Research Institute, Chongqing Academy of Animal Science, Chongqing, 402460, China
| | - Wenwen Fan
- College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Wei He
- Grassland Research Institute, Chongqing Academy of Animal Science, Chongqing, 402460, China.
| | - Xinquan Zhang
- College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
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3
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Kovalchuk I. Role of Epigenetic Factors in Response to Stress and Establishment of Somatic Memory of Stress Exposure in Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:3667. [PMID: 37960024 PMCID: PMC10648063 DOI: 10.3390/plants12213667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/18/2023] [Accepted: 10/21/2023] [Indexed: 11/15/2023]
Abstract
All species are well adapted to their environment. Stress causes a magnitude of biochemical and molecular responses in plants, leading to physiological or pathological changes. The response to various stresses is genetically predetermined, but is also controlled on the epigenetic level. Most plants are adapted to their environments through generations of exposure to all elements. Many plant species have the capacity to acclimate or adapt to certain stresses using the mechanism of priming. In most cases, priming is a somatic response allowing plants to deal with the same or similar stress more efficiently, with fewer resources diverted from growth and development. Priming likely relies on multiple mechanisms, but the differential expression of non-coding RNAs, changes in DNA methylation, histone modifications, and nucleosome repositioning play a crucial role. Specifically, we emphasize the role of BRM/CHR17, BRU1, FGT1, HFSA2, and H2A.Z proteins as positive regulators, and CAF-1, MOM1, DDM1, and SGS3 as potential negative regulators of somatic stress memory. In this review, we will discuss the role of epigenetic factors in response to stress, priming, and the somatic memory of stress exposures.
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Affiliation(s)
- Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
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4
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Goeldel C, Johannes F. Stochasticity in gene body methylation. CURRENT OPINION IN PLANT BIOLOGY 2023; 75:102436. [PMID: 37597469 DOI: 10.1016/j.pbi.2023.102436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/30/2023] [Accepted: 07/10/2023] [Indexed: 08/21/2023]
Abstract
Gene body methylation (gbM) is a widely conserved epigenetic feature of plant genomes. Efforts to delineate the mechanisms by which gbM contributes to transcriptional regulation remain largely inconclusive, and its evolutionary significance continues to be debated. Curiously, although steady-state gbM levels are remarkably stable across mitotic and meiotic cell divisions, the methylation status of individual CG dinucleotides in gbM genes is highly stochastic. How can these two seemingly contradictory observations be reconciled? Here, we discuss how stochastic processes relate to gbM maintenance dynamics. We show that a quantitative understanding of these processes can shed deeper insights into the molecular and evolutionary biology of this enigmatic epigenetic trait.
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Affiliation(s)
| | - Frank Johannes
- Plant Epigenomics, Technical University of Munich, Germany.
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5
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Xi F, Zhang Z, Wu L, Wang B, Gao P, Chen K, Zhao L, Gao J, Gu L, Zhang H. Insight into gene expression associated with DNA methylation and small RNA in the rhizome-root system of Moso bamboo. Int J Biol Macromol 2023; 248:125921. [PMID: 37499707 DOI: 10.1016/j.ijbiomac.2023.125921] [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: 05/11/2023] [Revised: 07/07/2023] [Accepted: 07/19/2023] [Indexed: 07/29/2023]
Abstract
Moso bamboo (Phyllostachys edulis), typically a monopodial scattering bamboo, is famous for its rapid growth. The rhizome-root system of Moso bamboo plays a crucial role in its clonal growth and spatial distribution. However, few studies have focused on rhizome-root systems. Here we collected LBs, RTs, and RGFNSs, the most important parts of the rhizome-root system, to study the molecular basis of the rapid growth of Moso bamboo due to epigenetic changes, such as DNA modifications and small RNAs. The angle of the shoot apical meristem of LB gradually decreased with increasing distance from the mother plant, and the methylation levels of LB were much higher than those of RT and RGFNS. 24 nt small RNAs and mCHH exhibited similar distribution patterns in transposable elements, suggesting a potential association between these components. The miRNA abundance of LB gradually increased with increasing distance from the mother plant, and a negative correlation was observed between gene expression levels and mCG and mCHG levels in the gene body. This study paves the way for further exploring the effects of epigenetic factors on the physiology of Moso bamboo.
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Affiliation(s)
- Feihu Xi
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zeyu Zhang
- College of Forestry, Basic Forestry and Proteomics Research Center, School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lin Wu
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Baijie Wang
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Pengfei Gao
- College of Forestry, Basic Forestry and Proteomics Research Center, School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Kai Chen
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Liangzhen Zhao
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jian Gao
- International Center for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, State Forestry Administration, Beijing, China.
| | - Lianfeng Gu
- College of Forestry, Basic Forestry and Proteomics Research Center, School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Hangxiao Zhang
- College of Forestry, Basic Forestry and Proteomics Research Center, School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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6
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Lyons DB, Briffa A, He S, Choi J, Hollwey E, Colicchio J, Anderson I, Feng X, Howard M, Zilberman D. Extensive de novo activity stabilizes epigenetic inheritance of CG methylation in Arabidopsis transposons. Cell Rep 2023; 42:112132. [PMID: 36827183 DOI: 10.1016/j.celrep.2023.112132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 11/10/2022] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
Cytosine methylation within CG dinucleotides (mCG) can be epigenetically inherited over many generations. Such inheritance is thought to be mediated by a semiconservative mechanism that produces binary present/absent methylation patterns. However, we show here that, in Arabidopsis thaliana h1ddm1 mutants, intermediate heterochromatic mCG is stably inherited across many generations and is quantitatively associated with transposon expression. We develop a mathematical model that estimates the rates of semiconservative maintenance failure and de novo methylation at each transposon, demonstrating that mCG can be stably inherited at any level via a dynamic balance of these activities. We find that DRM2-the core methyltransferase of the RNA-directed DNA methylation pathway-catalyzes most of the heterochromatic de novo mCG, with de novo rates orders of magnitude higher than previously thought, whereas chromomethylases make smaller contributions. Our results demonstrate that stable epigenetic inheritance of mCG in plant heterochromatin is enabled by extensive de novo methylation.
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Affiliation(s)
| | | | | | | | - Elizabeth Hollwey
- John Innes Centre, Norwich NR4 7UH, UK; Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | - Jack Colicchio
- Department of Plant & Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ian Anderson
- Department of Plant & Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xiaoqi Feng
- John Innes Centre, Norwich NR4 7UH, UK; Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | | | - Daniel Zilberman
- John Innes Centre, Norwich NR4 7UH, UK; Institute of Science and Technology, 3400 Klosterneuburg, Austria.
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7
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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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8
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Fukagawa T, Kakutani T. Transgenerational epigenetic control of constitutive heterochromatin, transposons, and centromeres. Curr Opin Genet Dev 2023; 78:102021. [PMID: 36716679 DOI: 10.1016/j.gde.2023.102021] [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: 10/12/2022] [Revised: 12/20/2022] [Accepted: 01/04/2023] [Indexed: 01/30/2023]
Abstract
Epigenetic mechanisms are important not only for development but also for genome stability and chromosome dynamics. The latter types of epigenetic controls can often be transgenerational. Here, we review recent progress in two examples of transgenerational epigenetic control: i) the control of constitutive heterochromatin and transposable elements and ii) epigenetic mechanisms that regulate centromere specification and functions. We also discuss the biological significance of enigmatic associations among centromeres, transposons, and constitutive heterochromatin.
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Affiliation(s)
- Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan. https://twitter.com/tatsuofukagawa1
| | - Tetsuji Kakutani
- Department of Biological Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
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9
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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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10
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Cheng J, Xu L, Bergér V, Bruckmann A, Yang C, Schubert V, Grasser KD, Schnittger A, Zheng B, Jiang H. H3K9 demethylases IBM1 and JMJ27 are required for male meiosis in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2022; 235:2252-2269. [PMID: 35638341 DOI: 10.1111/nph.18286] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Dimethylation of histone H3 lysine 9 (H3K9me2), a crucial modification for heterochromatin formation and transcriptional silencing, is essential for proper meiotic prophase progression in mammals. We analyzed meiotic defects and generated genome-wide profiles of H3K9me2 and transcriptomes for the mutants of H3K9 demethylases. Moreover, we also identified proteins interacting with H3K9 demethylases. H3K9me2 is usually found at transposable elements and repetitive sequences but is absent from the bodies of protein-coding genes. In this study, we show that the Arabidopsis thaliana H3K9 demethylases IBM1 and JMJ27 cooperatively regulate crossover formation and chromosome segregation. They protect thousands of protein-coding genes from ectopic H3K9me2, including genes essential for meiotic prophase progression. In addition to removing H3K9me2, IBM1 and JMJ27 interact with the Precocious Dissociation of Sisters 5 (PDS5) cohesin complex cofactors. The pds5 mutant shared similar transcriptional alterations with ibm1 jmj27, including meiosis-essential genes, yet without affecting H3K9me2 levels. Hence, PDS5s, together with IBM1 and JMJ27, regulate male meiosis and gene expression independently of H3K9 demethylation. These findings uncover a novel role of H3K9me2 removal in meiosis and a new function of H3K9 demethylases and cohesin cofactors in meiotic transcriptional regulation.
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Affiliation(s)
- Jinping Cheng
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, 06466, Germany
| | - Linhao Xu
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, 06466, Germany
| | - Valentin Bergér
- Cell Biology & Plant Biochemistry, Biochemistry Center, University of Regensburg, Regensburg, 93053, Germany
| | - Astrid Bruckmann
- Department of Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, 93053, Germany
| | - Chao Yang
- Department of Developmental Biology, University of Hamburg, Hamburg, 20146, Germany
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, 06466, Germany
| | - Klaus D Grasser
- Cell Biology & Plant Biochemistry, Biochemistry Center, University of Regensburg, Regensburg, 93053, Germany
| | - Arp Schnittger
- Department of Developmental Biology, University of Hamburg, Hamburg, 20146, Germany
| | - Binglian Zheng
- State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Hua Jiang
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, 06466, Germany
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11
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To TK, Kakutani T. Crosstalk among pathways to generate DNA methylome. CURRENT OPINION IN PLANT BIOLOGY 2022; 68:102248. [PMID: 35724481 DOI: 10.1016/j.pbi.2022.102248] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/19/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Cytosine is methylated in both CpG and non-CpG contexts (mCG and mCH, respectively) in plant genomes. Although mCG and mCH are almost independent in regard to their "maintenance," recent studies uncovered crosstalk between them during their "establishment," which unexpectedly functions in both RNAi-dependent and -independent pathways. In addition, the importance of linker histone H1 and variants of histone H2A to DNA methylation dynamics is starting to be understood. We summarize these new aspects of mechanisms to generate DNA methylomes and discuss future prospects.
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Affiliation(s)
- Taiko Kim To
- Department of Biological Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tetsuji Kakutani
- Department of Biological Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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12
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Local and global crosstalk among heterochromatin marks drives DNA methylome patterning in Arabidopsis. Nat Commun 2022; 13:861. [PMID: 35165291 PMCID: PMC8844080 DOI: 10.1038/s41467-022-28468-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 01/26/2022] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) are robustly silenced by multiple epigenetic marks, but dynamics of crosstalk among these marks remains enigmatic. In Arabidopsis, TEs are silenced by cytosine methylation in both CpG and non-CpG contexts (mCG and mCH) and histone H3 lysine 9 methylation (H3K9me). While mCH and H3K9me are mutually dependent for their maintenance, mCG and mCH/H3K9me are independently maintained. Here, we show that establishment, rather than maintenance, of mCH depends on mCG, accounting for the synergistic colocalization of these silent marks in TEs. When mCG is lost, establishment of mCH is abolished in TEs. mCG also guides mCH in active genes, though the resulting mCH/H3K9me is removed thereafter. Unexpectedly, targeting efficiency of mCH depends on relative, rather than absolute, levels of mCG within the genome, suggesting underlying global negative controls. We propose that local positive feedback in heterochromatin dynamics, together with global negative feedback, drive robust and balanced DNA methylome patterning. In plant genomes, both mCG and H3K9me2/mCH are important for silencing transposable elements (TEs). Here, the authors show that establishment of mCH is abolished in both TE and active genes when mCG is lost and targeting efficiency of mCH depends on relative levels of mCG within the genome.
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13
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Hazarika RR, Serra M, Zhang Z, Zhang Y, Schmitz RJ, Johannes F. Molecular properties of epimutation hotspots. NATURE PLANTS 2022; 8:146-156. [PMID: 35087209 PMCID: PMC8866225 DOI: 10.1038/s41477-021-01086-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Mistakes in the maintenance of CG methylation are a source of heritable epimutations in plants. Multigenerational surveys indicate that the rate of these stochastic events varies substantially across the genome, with some regions harbouring localized 'epimutation hotspots'. Using Arabidopsis as a model, we show that epimutation hotspots are indexed by a specific set of chromatin states that map to subregions of gene body methylation genes. Although these regions comprise only ~12% of all CGs in the genome, they account for ~63% of all epimutation events per unit time. Molecular profiling revealed that these regions contain unique sequence features, harbour steady-state intermediate methylation levels and act as putative targets of antagonistic DNA methylation pathways. We further demonstrate that experimentally induced shifts in steady-state methylation in these hotspot regions are sufficient to significantly alter local epimutation intensities. Our work lays the foundation for dissecting the molecular mechanisms and evolutionary consequences of epimutation hotspots in plants.
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Affiliation(s)
- Rashmi R Hazarika
- Department of Molecular Life Sciences, Technical University of Munich, Freising, Germany
- TUM Institute for Advanced Study, Garching, Germany
| | - Michele Serra
- Department of Molecular Life Sciences, Technical University of Munich, Freising, Germany
| | - Zhilin Zhang
- Department of Molecular Life Sciences, Technical University of Munich, Freising, Germany
| | - Yinwen Zhang
- Department of Genetics, The University of Georgia, Athens, GA, USA
| | - Robert J Schmitz
- TUM Institute for Advanced Study, Garching, Germany.
- Department of Genetics, The University of Georgia, Athens, GA, USA.
| | - Frank Johannes
- Department of Molecular Life Sciences, Technical University of Munich, Freising, Germany.
- TUM Institute for Advanced Study, Garching, Germany.
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14
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Chen X, Li Y, Rubio K, Deng B, Li Y, Tang Q, Mao C, Liu S, Xiao D, Barreto G, Tao Y. Lymphoid-specific helicase in epigenetics, DNA repair and cancer. Br J Cancer 2022; 126:165-173. [PMID: 34493821 PMCID: PMC8770686 DOI: 10.1038/s41416-021-01543-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/26/2021] [Accepted: 08/25/2021] [Indexed: 02/07/2023] Open
Abstract
Lymphoid-specific helicase (LSH) is a member of the SNF2 helicase family of chromatin-remodelling proteins. Dysfunctions or mutations in LSH causes an autosomal recessive disease known as immunodeficiency-centromeric instability-facial anomaly (ICF) syndrome. Interestingly, LSH participates in various aspects of epigenetic regulation, including nucleosome remodelling, DNA methylation, histone modifications and heterochromatin formation. Further, LSH plays a crucial role during DNA-damage repair, specifically during double-strand break (DSB) repair, since murine LSH was shown to be essential for non-homologous end joining (NHEJ) and homologous recombination (HR). Accordingly, overexpression of LSH drives tumorigenesis and malignancy. On the other hand, LSH homologs stabilise the genome. Thus, LSH might be implemented as a biomarker for various cancer types and potential target molecule to develop therapeutic strategies against them. In this review, we focus on the role of LSH in orchestrating chromatin rearrangements, such as DNA methylation and histone modifications, as well as in DNA-damage repair. Changes in chromatin structure may facilitate gene expression signatures that cause malignant transformation. We summarise recent findings of LSH in cancers and raise critical open questions for further studies.
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Affiliation(s)
- Xiangyu Chen
- Department of Pathology, Xiangya Hospital, Central South University; Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Hunan, China
- NHC Key Laboratory of Carcinogenesis of Ministry of Health (Central South University); Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Yamei Li
- Department of Pathology, Xiangya Hospital, Central South University; Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Hunan, China
- NHC Key Laboratory of Carcinogenesis of Ministry of Health (Central South University); Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Karla Rubio
- Université de Lorraine, CNRS, Laboratoire IMoPA, UMR 7365, Nancy, France
- Univ Paris Est Creteil, Gly-CRRET, Brain and Lung Epigenetics (BLUE), Creteil, France
- Lung Cancer Epigenetic, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
- International Laboratory EPIGEN, Universidad de la Salud del Estado de Puebla, Puebla, Mexico
| | - Bi Deng
- Department of Pathology, Xiangya Hospital, Central South University; Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Hunan, China
- NHC Key Laboratory of Carcinogenesis of Ministry of Health (Central South University); Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Yuyi Li
- Department of Pathology, Xiangya Hospital, Central South University; Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Hunan, China
- NHC Key Laboratory of Carcinogenesis of Ministry of Health (Central South University); Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Qinwei Tang
- Department of Pathology, Xiangya Hospital, Central South University; Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Hunan, China
- NHC Key Laboratory of Carcinogenesis of Ministry of Health (Central South University); Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Chao Mao
- Department of Pathology, Xiangya Hospital, Central South University; Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Hunan, China
- NHC Key Laboratory of Carcinogenesis of Ministry of Health (Central South University); Cancer Research Institute, Central South University, Changsha, Hunan, China
| | - Shuang Liu
- Department of Oncology, Institute of Medical Sciences, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Desheng Xiao
- Department of Pathology, Xiangya Hospital, Central South University; Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Hunan, China.
- NHC Key Laboratory of Carcinogenesis of Ministry of Health (Central South University); Cancer Research Institute, Central South University, Changsha, Hunan, China.
| | - Guillermo Barreto
- Université de Lorraine, CNRS, Laboratoire IMoPA, UMR 7365, Nancy, France.
- Univ Paris Est Creteil, Gly-CRRET, Brain and Lung Epigenetics (BLUE), Creteil, France.
- Lung Cancer Epigenetic, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany.
- International Laboratory EPIGEN, Universidad de la Salud del Estado de Puebla, Puebla, Mexico.
| | - Yongguang Tao
- Department of Pathology, Xiangya Hospital, Central South University; Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Hunan, China.
- NHC Key Laboratory of Carcinogenesis of Ministry of Health (Central South University); Cancer Research Institute, Central South University, Changsha, Hunan, China.
- Department of Thoracic Surgery, Hunan Key Laboratory of Early Diagnosis and Precision Therapy in Lung Cancer and Second Xiangya Hospital, Central South University, Changsha, China.
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15
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Choi J, Lyons DB, Zilberman D. Histone H1 prevents non-CG methylation-mediated small RNA biogenesis in Arabidopsis heterochromatin. eLife 2021; 10:72676. [PMID: 34850679 PMCID: PMC8828055 DOI: 10.7554/elife.72676] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 11/30/2021] [Indexed: 11/27/2022] Open
Abstract
Flowering plants utilize small RNA (sRNA) molecules to guide DNA methyltransferases to genomic sequences. This RNA-directed DNA methylation (RdDM) pathway preferentially targets euchromatic transposable elements. However, RdDM is thought to be recruited by methylation of histone H3 at lysine 9 (H3K9me), a hallmark of heterochromatin. How RdDM is targeted to euchromatin despite an affinity for H3K9me is unclear. Here, we show that loss of histone H1 enhances heterochromatic RdDM, preferentially at nucleosome linker DNA. Surprisingly, this does not require SHH1, the RdDM component that binds H3K9me. Furthermore, H3K9me is dispensable for RdDM, as is CG DNA methylation. Instead, we find that non-CG methylation is specifically associated with sRNA biogenesis, and without H1 sRNA production quantitatively expands to non-CG-methylated loci. Our results demonstrate that H1 enforces the separation of euchromatic and heterochromatic DNA methylation pathways by excluding the sRNA-generating branch of RdDM from non-CG-methylated heterochromatin. Cells adapt to different roles by turning different groups of genes on and off. One way cells control which genes are on or off is by creating regions of active and inactive DNA, which are created and maintained by different groups of proteins. Genes in active DNA regions can be turned on, while genes in inactive regions are switched off or silenced. Silenced DNA regions also turn off ‘transposable elements’: pieces of DNA that can copy themselves and move to other regions of the genome if they become active. Transposons can be dangerous if they are activated, because they can disrupt genes or regulatory sequences when they move. There are different types of active and inactive DNA, but it is not always clear why these differences exist, or how they are maintained over time. In plants, such as the commonly-studied weed Arabidopsis thaliana, there are two types of inactive DNA, called E and H, that can silence transposons. In both types, DNA has small chemicals called methyl groups attached to it, which help inactivate the DNA. Type E DNA is methylated by a process called RNA-directed DNA methylation (RdDM), but RdDM is rarely seen in type H DNA. Choi, Lyons and Zilberman showed that RdDM is attracted to E and H regions by previously existing methylated DNA. However, in the H regions, a protein called histone H1 blocks RdDM from attaching methyl groups. This helps focus RdDM onto E regions where it is most needed, because E regions contain the types of transposons RdDM is best suited to silence. When Choi, Lyons and Zilberman examined genetically modified A. thaliana plants that do not produce histone H1, they found that RdDM happened in both E and H regions. There are many more H regions than E regions, so stretching RdDM across both made it less effective at silencing DNA. This work shows how different DNA silencing processes are focused onto specific genetic regions, helping explain why there are different types of active and inactive DNA within cells. RdDM has been studied as a way to affect crop growth and yield by altering DNA methylation. These results may help such studies by explaining how RdDM is naturally targeted.
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Affiliation(s)
- Jaemyung Choi
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - David B Lyons
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Daniel Zilberman
- Department of Cell and Developmental Biology, John Innes Centre, Klosterneuburg, Austria
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16
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Zhang Y, Jang H, Xiao R, Kakoulidou I, Piecyk RS, Johannes F, Schmitz RJ. Heterochromatin is a quantitative trait associated with spontaneous epiallele formation. Nat Commun 2021; 12:6958. [PMID: 34845222 PMCID: PMC8630088 DOI: 10.1038/s41467-021-27320-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 11/15/2021] [Indexed: 11/09/2022] Open
Abstract
Epialleles are meiotically heritable variations in expression states that are independent from changes in DNA sequence. Although they are common in plant genomes, their molecular origins are unknown. Here we show, using mutant and experimental populations, that epialleles in Arabidopsis thaliana that result from ectopic hypermethylation are due to feedback regulation of pathways that primarily function to maintain DNA methylation at heterochromatin. Perturbations to maintenance of heterochromatin methylation leads to feedback regulation of DNA methylation in genes. Using single base resolution methylomes from epigenetic recombinant inbred lines (epiRIL), we show that epiallelic variation is abundant in euchromatin, yet, associates with QTL primarily in heterochromatin regions. Mapping three-dimensional chromatin contacts shows that genes that are hotspots for ectopic hypermethylation have increases in contact frequencies with regions possessing H3K9me2. Altogether, these data show that feedback regulation of pathways that have evolved to maintain heterochromatin silencing leads to the origins of spontaneous hypermethylated epialleles.
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Affiliation(s)
- Yinwen Zhang
- Institute of Bioinformatics, University of Georgia, Athens, GA, USA
| | - Hosung Jang
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - Rui Xiao
- Institute of Bioinformatics, University of Georgia, Athens, GA, USA
| | - Ioanna Kakoulidou
- Department of Plant Sciences, Technical University of Munich, Freising, Germany
| | - Robert S Piecyk
- Department of Plant Sciences, Technical University of Munich, Freising, Germany
| | - Frank Johannes
- Department of Plant Sciences, Technical University of Munich, Freising, Germany.
- Institute for Advanced Study (IAS), Technical University of Munich, Garching, Germany.
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA, USA.
- Institute for Advanced Study (IAS), Technical University of Munich, Garching, Germany.
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17
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Inagaki S. Silencing and anti-silencing mechanisms that shape the epigenome in plants. Genes Genet Syst 2021; 96:217-228. [PMID: 34719532 DOI: 10.1266/ggs.21-00041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Epigenome information mediates genome function and maintenance by regulating gene expression and chromatin organization. Because the epigenome pattern can change in response to internal and external environments, it may underlie an adaptive genome response that modulates phenotypes during development and in changing environments. Here I summarize recent progress in our understanding of how epigenome patterns are shaped and modulated by concerted actions of silencing and anti-silencing factors mainly in Arabidopsis thaliana. I discuss the dynamic nature of epigenome regulation, which is realized by cooperation and counteraction among silencing and anti-silencing factors, and how the dynamic epigenome mediates robust and plastic responses of plants to fluctuating environments.
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Affiliation(s)
- Soichi Inagaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo.,PRESTO, Japan Science and Technology Agency
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18
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Sow MD, Le Gac AL, Fichot R, Lanciano S, Delaunay A, Le Jan I, Lesage-Descauses MC, Citerne S, Caius J, Brunaud V, Soubigou-Taconnat L, Cochard H, Segura V, Chaparro C, Grunau C, Daviaud C, Tost J, Brignolas F, Strauss SH, Mirouze M, Maury S. RNAi suppression of DNA methylation affects the drought stress response and genome integrity in transgenic poplar. THE NEW PHYTOLOGIST 2021; 232:80-97. [PMID: 34128549 DOI: 10.1111/nph.17555] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/08/2021] [Indexed: 05/27/2023]
Abstract
Trees are long-lived organisms that continuously adapt to their environments, a process in which epigenetic mechanisms are likely to play a key role. Via downregulation of the chromatin remodeler DECREASED IN DNA METHYLATION 1 (DDM1) in poplar (Populus tremula × Populus alba) RNAi lines, we examined how DNA methylation coordinates genomic and physiological responses to moderate water deficit. We compared the growth and drought response of two RNAi-ddm1 lines to wild-type (WT) trees under well-watered and water deficit/rewatering conditions, and analyzed their methylomes, transcriptomes, mobilomes and phytohormone contents in the shoot apical meristem. The RNAi-ddm1 lines were more tolerant to drought-induced cavitation but did not differ in height or stem diameter growth. About 5000 differentially methylated regions were consistently detected in both RNAi-ddm1 lines, colocalizing with 910 genes and 89 active transposable elements. Under water deficit conditions, 136 differentially expressed genes were found, including many involved in phytohormone pathways; changes in phytohormone concentrations were also detected. Finally, the combination of hypomethylation and drought led to the mobility of two transposable elements. Our findings suggest major roles for DNA methylation in regulation of genes involved in hormone-related stress responses, and the maintenance of genome integrity through repression of transposable elements.
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Affiliation(s)
- Mamadou D Sow
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Anne-Laure Le Gac
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Régis Fichot
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Sophie Lanciano
- IRD, UMR 232 DIADE, Université de Montpellier, Montpellier, 34090, France
- Laboratory of Plant Genome and Development, Université de Perpignan, Perpignan, 66860, France
| | - Alain Delaunay
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Isabelle Le Jan
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | | | - Sylvie Citerne
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, 78000, France
| | - Jose Caius
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université Evry, Orsay, 91405, France
| | - Véronique Brunaud
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université Evry, Orsay, 91405, France
| | - Ludivine Soubigou-Taconnat
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université Evry, Orsay, 91405, France
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, Clermont-Ferrand, 63000, France
| | - Vincent Segura
- BioForA, INRAE, ONF, UMR 0588, Orléans, 45075, France
- UMR AGAP Institut, Université Montpellier, CIRAD, INRAE, Institut Montpellier SupAgro, UMR 1334, Montpellier, F-34398, France
| | | | - Christoph Grunau
- UMR 5244, IHPE, Université de Perpignan, Perpignan, 66100, France
| | - Christian Daviaud
- Laboratory for Epigenetics and Environment Centre National de Recherche en Génomique Humaine, CEA- Institut de Biologie Francois Jacob, Université Paris-Saclay, Evry, 91057, France
| | - Jörg Tost
- Laboratory for Epigenetics and Environment Centre National de Recherche en Génomique Humaine, CEA- Institut de Biologie Francois Jacob, Université Paris-Saclay, Evry, 91057, France
| | - Franck Brignolas
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Steven H Strauss
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331-5752, USA
| | - Marie Mirouze
- IRD, UMR 232 DIADE, Université de Montpellier, Montpellier, 34090, France
- Laboratory of Plant Genome and Development, Université de Perpignan, Perpignan, 66860, France
| | - Stéphane Maury
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
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19
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Pathway conversion enables a double-lock mechanism to maintain DNA methylation and genome stability. Proc Natl Acad Sci U S A 2021; 118:2107320118. [PMID: 34453006 DOI: 10.1073/pnas.2107320118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The CMT2 and RNA-directed DNA methylation (RdDM) pathways have been proposed to separately maintain CHH methylation in specific regions of the Arabidopsis thaliana genome. Here, we show that dysfunction of the chromatin remodeler DDM1 causes hundreds of genomic regions to switch from CMT2 dependency to RdDM dependency in DNA methylation. These converted loci are enriched at the edge regions of long transposable elements (TEs). Furthermore, we found that dysfunction in both DDM1 and RdDM causes strong reactivation of TEs and a burst of TE transposition in the first generation of mutant plants, indicating that the DDM1 and RdDM pathways together are critical to maintaining TE repression and protecting genomic stability. Our findings reveal the existence of a pathway conversion-based backup mechanism to guarantee the maintenance of DNA methylation and genome integrity.
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20
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Papareddy RK, Páldi K, Smolka AD, Hüther P, Becker C, Nodine MD. Repression of CHROMOMETHYLASE 3 prevents epigenetic collateral damage in Arabidopsis. eLife 2021; 10:e69396. [PMID: 34296996 PMCID: PMC8352596 DOI: 10.7554/elife.69396] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/21/2021] [Indexed: 01/14/2023] Open
Abstract
DNA methylation has evolved to silence mutagenic transposable elements (TEs) while typically avoiding the targeting of endogenous genes. Mechanisms that prevent DNA methyltransferases from ectopically methylating genes are expected to be of prime importance during periods of dynamic cell cycle activities including plant embryogenesis. However, virtually nothing is known regarding how DNA methyltransferase activities are precisely regulated during embryogenesis to prevent the induction of potentially deleterious and mitotically stable genic epimutations. Here, we report that microRNA-mediated repression of CHROMOMETHYLASE 3 (CMT3) and the chromatin features that CMT3 prefers help prevent ectopic methylation of thousands of genes during embryogenesis that can persist for weeks afterwards. Our results are also consistent with CMT3-induced ectopic methylation of promoters or bodies of genes undergoing transcriptional activation reducing their expression. Therefore, the repression of CMT3 prevents epigenetic collateral damage on endogenous genes. We also provide a model that may help reconcile conflicting viewpoints regarding the functions of gene-body methylation that occurs in nearly all flowering plants.
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Affiliation(s)
- Ranjith K Papareddy
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3ViennaAustria
| | - Katalin Páldi
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3ViennaAustria
| | - Anna D Smolka
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3ViennaAustria
| | - Patrick Hüther
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3ViennaAustria
- Genetics, LMU Biocenter, Ludwig-Maximilians UniversityMartinsriedGermany
| | - Claude Becker
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3ViennaAustria
- Genetics, LMU Biocenter, Ludwig-Maximilians UniversityMartinsriedGermany
| | - Michael D Nodine
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3ViennaAustria
- Laboratory of Molecular Biology, Wageningen UniversityWageningenNetherlands
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21
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Wang Z, Butel N, Santos-González J, Simon L, Wärdig C, Köhler C. Transgenerational effect of mutants in the RNA-directed DNA methylation pathway on the triploid block in Arabidopsis. Genome Biol 2021; 22:141. [PMID: 33957942 PMCID: PMC8101200 DOI: 10.1186/s13059-021-02359-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 04/22/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Hybridization of plants that differ in number of chromosome sets (ploidy) frequently causes endosperm failure and seed arrest, a phenomenon referred to as triploid block. In Arabidopsis, loss of function of NRPD1, encoding the largest subunit of the plant-specific RNA polymerase IV (Pol IV), can suppress the triploid block. Pol IV generates short RNAs required to guide de novo methylation in the RNA-directed DNA methylation (RdDM) pathway. Recent work suggests that suppression of the triploid block by mutants in RdDM components differs, depending on whether the diploid pollen is derived from tetraploid plants or from the omission in second division 1 (osd1) mutant. This study aims to understand this difference. RESULTS In this study, we find that the ability of mutants in the RdDM pathway to suppress the triploid block depends on their degree of inbreeding. While first homozygous generation mutants in RdDM components NRPD1, RDR2, NRPE1, and DRM2 have weak or no ability to rescue the triploid block, they are able to suppress the triploid block with successive generations of inbreeding. Inbreeding of nrpd1 was connected with a transgenerational loss of non-CG DNA methylation on sites jointly regulated by CHROMOMETHYLASES 2 and 3. CONCLUSIONS Our data reveal that loss of RdDM function differs in its effect in early and late generations, which has important implications when interpreting the effect of RdDM mutants.
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Affiliation(s)
- Zhenxing Wang
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007 Uppsala, Sweden
- Present address: College of Horticulture, Nanjing Agricultural University and State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing, 210095 China
| | - Nicolas Butel
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Juan Santos-González
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Lauriane Simon
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Cecilia Wärdig
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007 Uppsala, Sweden
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
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22
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Inagaki S, Takahashi M, Takashima K, Oya S, Kakutani T. Chromatin-based mechanisms to coordinate convergent overlapping transcription. NATURE PLANTS 2021; 7:295-302. [PMID: 33649596 DOI: 10.1038/s41477-021-00868-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
In eukaryotic genomes, the transcription units of genes often overlap with other protein-coding and/or noncoding transcription units1,2. In such intertwined genomes, the coordinated transcription of nearby or overlapping genes would be important to ensure the integrity of genome function3-6; however, the mechanisms underlying this coordination are largely unknown. Here, we show in Arabidopsis thaliana that genes with convergent orientation of transcription are major sources of antisense transcripts and that these genes transcribed on both strands are regulated by a putative Lysine-Specific Demethylase 1 family histone demethylase, FLOWERING LOCUS D (FLD)7,8. Our genome-wide chromatin profiling revealed that FLD, as well as its associating factor LUMINIDEPENDENS9, downregulates histone H3K4me1 in regions with convergent overlapping transcription. FLD localizes to actively transcribed genes, where it colocalizes with elongating RNA polymerase II phosphorylated at the Ser2 or Ser5 sites. Genome-wide transcription analyses suggest that FLD-mediated H3K4me1 removal negatively regulates the transcription of genes with high levels of antisense transcription. Furthermore, the effect of FLD on transcription dynamics is antagonized by DNA topoisomerase I. Our study reveals chromatin-based mechanisms to cope with overlapping transcription, which may occur by modulating DNA topology. This global mechanism to cope with overlapping transcription could be co-opted for specific epigenetic processes, such as cellular memory of responses to the environment10.
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Affiliation(s)
- Soichi Inagaki
- Department of Biological Sciences, Faculty of Science, The University of Tokyo, Tokyo, Japan.
- National Institute of Genetics, Mishima, Japan.
- Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Shonankokusaimura, Hayama, Japan.
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan.
| | | | | | - Satoyo Oya
- Department of Biological Sciences, Faculty of Science, The University of Tokyo, Tokyo, Japan
| | - Tetsuji Kakutani
- Department of Biological Sciences, Faculty of Science, The University of Tokyo, Tokyo, Japan
- National Institute of Genetics, Mishima, Japan
- Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Shonankokusaimura, Hayama, Japan
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23
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Bhadouriya SL, Mehrotra S, Basantani MK, Loake GJ, Mehrotra R. Role of Chromatin Architecture in Plant Stress Responses: An Update. FRONTIERS IN PLANT SCIENCE 2021; 11:603380. [PMID: 33510748 PMCID: PMC7835326 DOI: 10.3389/fpls.2020.603380] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/07/2020] [Indexed: 05/08/2023]
Abstract
Sessile plants possess an assembly of signaling pathways that perceive and transmit environmental signals, ultimately resulting in transcriptional reprogramming. Histone is a key feature of chromatin structure. Numerous histone-modifying proteins act under different environmental stress conditions to help modulate gene expression. DNA methylation and histone modification are crucial for genome reprogramming for tissue-specific gene expression and global gene silencing. Different classes of chromatin remodelers including SWI/SNF, ISWI, INO80, and CHD are reported to act upon chromatin in different organisms, under diverse stresses, to convert chromatin from a transcriptionally inactive to a transcriptionally active state. The architecture of chromatin at a given promoter is crucial for determining the transcriptional readout. Further, the connection between somatic memory and chromatin modifications may suggest a mechanistic basis for a stress memory. Studies have suggested that there is a functional connection between changes in nuclear organization and stress conditions. In this review, we discuss the role of chromatin architecture in different stress responses and the current evidence on somatic, intergenerational, and transgenerational stress memory.
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Affiliation(s)
- Sneha Lata Bhadouriya
- Department of Biological Sciences, Birla Institute of Technology and Sciences, Sancoale, India
| | - Sandhya Mehrotra
- Department of Biological Sciences, Birla Institute of Technology and Sciences, Sancoale, India
| | - Mahesh K. Basantani
- Institute of Bioscience and Technology, Shri Ramswaroop Memorial University, Lucknow, India
| | - Gary J. Loake
- School of Biological Sciences, Institute of Molecular Plant Sciences, University of Edinburg, Edinburg, United Kingdom
| | - Rajesh Mehrotra
- Department of Biological Sciences, Birla Institute of Technology and Sciences, Sancoale, India
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To TK, Nishizawa Y, Inagaki S, Tarutani Y, Tominaga S, Toyoda A, Fujiyama A, Berger F, Kakutani T. RNA interference-independent reprogramming of DNA methylation in Arabidopsis. NATURE PLANTS 2020; 6:1455-1467. [PMID: 33257860 DOI: 10.1038/s41477-020-00810-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/16/2020] [Indexed: 06/12/2023]
Abstract
DNA methylation is important for silencing transposable elements (TEs) in diverse eukaryotes, including plants. In plant genomes, TEs are silenced by methylation of histone H3 lysine 9 (H3K9) and cytosines in both CG and non-CG contexts. The role of RNA interference (RNAi) in establishing TE-specific silent marks has been extensively studied, but the importance of RNAi-independent pathways remains largely unexplored. Here, we directly investigated transgenerational de novo DNA methylation of TEs after the loss of silent marks. Our analyses uncovered potent and precise RNAi-independent pathways for recovering non-CG methylation and H3K9 methylation in most TE genes (that is, coding regions within TEs). Characterization of a subset of TE genes without the recovery revealed the effects of H3K9 demethylation, replacement of histone H2A variants and their interaction with CG methylation, together with feedback from transcription. These chromatin components are conserved among eukaryotes and may contribute to chromatin reprogramming in a conserved manner.
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Affiliation(s)
- Taiko Kim To
- Department of Biological Sciences, The University of Tokyo, Tokyo, Japan.
| | - Yuichiro Nishizawa
- Department of Biological Sciences, The University of Tokyo, Tokyo, Japan
| | - Soichi Inagaki
- Department of Biological Sciences, The University of Tokyo, Tokyo, Japan
- Department of Integrated Genetics, National Institute of Genetics (NIG), Mishima, Shizuoka, Japan
- PREST, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Yoshiaki Tarutani
- Department of Integrated Genetics, National Institute of Genetics (NIG), Mishima, Shizuoka, Japan
| | - Sayaka Tominaga
- Department of Biological Sciences, The University of Tokyo, Tokyo, Japan
| | - Atsushi Toyoda
- Center for Genetic Resource Information, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Asao Fujiyama
- Center for Genetic Resource Information, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna, Austria
| | - Tetsuji Kakutani
- Department of Biological Sciences, The University of Tokyo, Tokyo, Japan.
- Department of Integrated Genetics, National Institute of Genetics (NIG), Mishima, Shizuoka, Japan.
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25
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Williams BP, Gehring M. Principles of Epigenetic Homeostasis Shared Between Flowering Plants and Mammals. Trends Genet 2020; 36:751-763. [PMID: 32711945 DOI: 10.1016/j.tig.2020.06.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 12/18/2022]
Abstract
In diverse eukaryotes, epigenetic information such as DNA methylation is stably propagated over many cell divisions and generations, and can remain the same over thousands or millions of years. However, this stability is the product of dynamic processes that add and remove DNA methylation by specialized enzymatic pathways. The activities of these dynamic pathways must therefore be finely orchestrated in order to ensure that the DNA methylation landscape is maintained with high fidelity - a concept we term epigenetic homeostasis. In this review, we summarize recent insights into epigenetic homeostasis mechanisms in flowering plants and mammals, highlighting analogous mechanisms that have independently evolved to achieve the same goal of stabilizing the epigenetic landscape.
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Affiliation(s)
- Ben P Williams
- Whitehead Institute for Biomedical Research, 455 Main St, Cambridge, MA 02142, USA.
| | - Mary Gehring
- Whitehead Institute for Biomedical Research, 455 Main St, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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26
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Natural variation in DNA methylation homeostasis and the emergence of epialleles. Proc Natl Acad Sci U S A 2020; 117:4874-4884. [PMID: 32071208 DOI: 10.1073/pnas.1918172117] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In plants and mammals, DNA methylation plays a critical role in transcriptional silencing by delineating heterochromatin from transcriptionally active euchromatin. A homeostatic balance between heterochromatin and euchromatin is essential to genomic stability. This is evident in many diseases and mutants for heterochromatin maintenance, which are characterized by global losses of DNA methylation coupled with localized ectopic gains of DNA methylation that alter transcription. Furthermore, we have shown that genome-wide methylation patterns in Arabidopsis thaliana are highly stable over generations, with the exception of rare epialleles. However, the extent to which natural variation in the robustness of targeting DNA methylation to heterochromatin exists, and the phenotypic consequences of such variation, remain to be fully explored. Here we describe the finding that heterochromatin and genic DNA methylation are highly variable among 725 A. thaliana accessions. We found that genic DNA methylation is inversely correlated with that in heterochromatin, suggesting that certain methylation pathway(s) may be redirected to genes upon the loss of heterochromatin. This redistribution likely involves a feedback loop involving the DNA methyltransferase, CHROMOMETHYLASE 3 (CMT3), H3K9me2, and histone turnover, as highly expressed, long genes with a high density of CMT3-preferred CWG sites are more likely to be methylated. Importantly, although the presence of CG methylation in genes alone may not affect transcription, genes containing CG methylation are more likely to become methylated at non-CG sites and silenced. These findings are consistent with the hypothesis that natural variation in DNA methylation homeostasis may underlie the evolution of epialleles that alter phenotypes.
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Srikant T, Drost HG. How Stress Facilitates Phenotypic Innovation Through Epigenetic Diversity. FRONTIERS IN PLANT SCIENCE 2020; 11:606800. [PMID: 33519857 PMCID: PMC7843580 DOI: 10.3389/fpls.2020.606800] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/16/2020] [Indexed: 05/14/2023]
Abstract
Climate adaptation through phenotypic innovation will become the main challenge for plants during global warming. Plants exhibit a plethora of mechanisms to achieve environmental and developmental plasticity by inducing dynamic alterations of gene regulation and by maximizing natural variation through large population sizes. While successful over long evolutionary time scales, most of these mechanisms lack the short-term adaptive responsiveness that global warming will require. Here, we review our current understanding of the epigenetic regulation of plant genomes, with a focus on stress-response mechanisms and transgenerational inheritance. Field and laboratory-scale experiments on plants exposed to stress have revealed a multitude of temporally controlled, mechanistic strategies integrating both genetic and epigenetic changes on the genome level. We analyze inter- and intra-species population diversity to discuss how methylome differences and transposon activation can be harnessed for short-term adaptive efforts to shape co-evolving traits in response to qualitatively new climate conditions and environmental stress.
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28
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Sarkies P. Molecular mechanisms of epigenetic inheritance: Possible evolutionary implications. Semin Cell Dev Biol 2020; 97:106-115. [PMID: 31228598 PMCID: PMC6945114 DOI: 10.1016/j.semcdb.2019.06.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/04/2019] [Accepted: 06/18/2019] [Indexed: 12/30/2022]
Abstract
Recently interest in multi-generational epigenetic phenomena have been fuelled by highly reproducible intergenerational and transgenerational inheritance paradigms in several model organisms. Such paradigms are essential in order to begin to use genetics to unpick the mechanistic bases of how epigenetic information may be transmitted between generations; indeed great strides have been made towards understanding these mechanisms. Far less well understood is the relationship between epigenetic inheritance, ecology and evolution. In this review I focus on potential connections between laboratory studies of transgenerational epigenetic inheritance phenomena and evolutionary processes that occur in natural populations. In the first section, I consider whether transgenerational epigenetic inheritance might provide an advantage to organisms over the short term in adapting to their environment. Second, I consider whether epigenetic changes can contribute to the evolution of species by contributing to stable phenotypic variation within a population. Finally I discuss whether epigenetic changes could influence evolution by either directly or indirectly promoting DNA sequence changes that could impact phenotypic divergence. Additionally, I will discuss how epigenetic changes could influence the evolution of human cancer and thus be directly relevant for the development of this disease.
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Affiliation(s)
- Peter Sarkies
- MRC London Institute of Medical Sciences, Du Cane Road, London, W120NN, United Kingdom; Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W120NN, United Kingdom.
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Transposition favors the generation of large effect mutations that may facilitate rapid adaption. Nat Commun 2019; 10:3421. [PMID: 31366887 PMCID: PMC6668482 DOI: 10.1038/s41467-019-11385-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) are mobile parasitic sequences that have been repeatedly coopted during evolution to generate new functions and rewire gene regulatory networks. Yet, the contribution of active TEs to the creation of heritable mutations remains unknown. Using TE accumulation lines in Arabidopsis thaliana we show that once initiated, transposition produces an exponential spread of TE copies, which rapidly leads to high mutation rates. Most insertions occur near or within genes and targets differ between TE families. Furthermore, we uncover an essential role of the histone variant H2A.Z in the preferential integration of Ty1/copia retrotransposons within environmentally responsive genes and away from essential genes. We also show that epigenetic silencing of new Ty1/copia copies can affect their impact on major fitness-related traits, including flowering time. Our findings demonstrate that TEs are potent episodic (epi)mutagens that, thanks to marked chromatin tropisms, limit the mutation load and increase the potential for rapid adaptation.
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Johannes F, Schmitz RJ. Spontaneous epimutations in plants. THE NEW PHYTOLOGIST 2019; 221:1253-1259. [PMID: 30216456 DOI: 10.1111/nph.15434] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/01/2018] [Indexed: 05/22/2023]
Abstract
Contents Summary 1253 I. Introduction 1253 II. What is the rate and molecular spectrum of spontaneous epimutations? 1254 III. Do spontaneous epimutations have phenotypic consequences? 1257 IV. Conclusion and discussion 1258 Acknowledgements 1258 References 1258 SUMMARY: Heritable gains or losses of cytosine methylation can arise stochastically in plant genomes independently of DNA sequence changes. These so-called 'spontaneous epimutations' appear to be a byproduct of imperfect DNA methylation maintenance and epigenome reinforcement events that occur in specialized cell types. There is continued interest in the plant epigenetics community in trying to understand the broader implications of these stochastic events, as some have been shown to induce heritable gene expression changes, shape patterns of methylation diversity within and among plant populations, and appear to be responsive to multi-generational environmental stressors. In this paper we synthesized our current knowledge of the molecular basis and functional consequences of spontaneous epimutations in plants, discuss technical and conceptual challenges, and highlight emerging research directions.
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Affiliation(s)
- Frank Johannes
- Department of Plant Sciences, Technical University of Munich, Liesel-Beckmann-Str. 2, Freising, 85354, Germany
- Institute for Advanced Study (IAS), Technical University of Munich, Lichtenbergstr. 2a, Garching, 85748, Germany
| | - Robert J Schmitz
- Institute for Advanced Study (IAS), Technical University of Munich, Lichtenbergstr. 2a, Garching, 85748, Germany
- Department of Genetics, The University of Georgia, 120 East Green Street, Athens, GA, 30602, USA
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Furci L, Jain R, Stassen J, Berkowitz O, Whelan J, Roquis D, Baillet V, Colot V, Johannes F, Ton J. Identification and characterisation of hypomethylated DNA loci controlling quantitative resistance in Arabidopsis. eLife 2019; 8:40655. [PMID: 30608232 PMCID: PMC6342528 DOI: 10.7554/elife.40655] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/03/2019] [Indexed: 12/12/2022] Open
Abstract
Variation in DNA methylation enables plants to inherit traits independently of changes to DNA sequence. Here, we have screened an Arabidopsis population of epigenetic recombinant inbred lines (epiRILs) for resistance against Hyaloperonospora arabidopsidis (Hpa). These lines share the same genetic background, but show variation in heritable patterns of DNA methylation. We identified four epigenetic quantitative trait loci (epiQTLs) that provide quantitative resistance without reducing plant growth or resistance to other (a)biotic stresses. Phenotypic characterisation and RNA-sequencing analysis revealed that Hpa-resistant epiRILs are primed to activate defence responses at the relatively early stages of infection. Collectively, our results show that hypomethylation at selected pericentromeric regions is sufficient to provide quantitative disease resistance, which is associated with genome-wide priming of defence-related genes. Based on comparisons of global gene expression and DNA methylation between the wild-type and resistant epiRILs, we discuss mechanisms by which the pericentromeric epiQTLs could regulate the defence-related transcriptome. In plants, animals and microbes genetic information is encoded by DNA, which are made up of sequences of building blocks, called nucleotide bases. These sequences can be separated into sections known as genes that each encode specific traits. It was previously thought that only changes to the sequence of bases in a DNA molecule could alter the traits passed on to future generations. However, it has recently become clear that some traits can also be inherited through modifications to the DNA that do not alter its sequence. One such modification is to attach a tag, known as a methyl group, to a nucleotide base known as cytosine. These methyl tags can be added to, or removed from, DNA to create different patterns of methylation. Previous studies have shown that plants whose DNA is less methylated than normal (‘hypo-methylated’) are more resistant to plant diseases. However, the location and identity of the hypo-methylated DNA regions controlling this resistance remained unknown. To address this problem, Furci, Jain et al. studied how DNA methylation in a small weed known as Arabidopsis thaliana affects how well the plants can resist a disease known as downy mildew. Furci, Jain et al. studied a population of over 100 A. thaliana lines that have the same DNA sequences but different patterns of DNA methylation. The experiments identified four DNA locations that were less methylated in lines with enhanced resistance to downy mildew. Importantly, this form of resistance did not appear to reduce how well the plants grew, or make them less able to resist other diseases or environmental stresses. The results of further experiments suggested that reduced methylation at the four DNA regions prime the plant’s immune system, enabling a faster and stronger activation of a multitude of defence genes across the genome after attack by downy mildew. The next steps following on from this work are to investigate exactly how the four DNA regions with reduced methylation can prime so many different defence genes in the plant. Further research is also needed to determine whether it is possible to breed crop plants with lower levels of methylation at specific DNA locations to improve disease resistance, but without decreasing the amount and quality of food produced.
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Affiliation(s)
- Leonardo Furci
- P3 Centre for Plant and Soil Biology, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Ritushree Jain
- P3 Centre for Plant and Soil Biology, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Joost Stassen
- P3 Centre for Plant and Soil Biology, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Oliver Berkowitz
- Department of Animal, Plant and Soil Science, ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Melbourne, Australia
| | - James Whelan
- Department of Animal, Plant and Soil Science, ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Melbourne, Australia
| | - David Roquis
- Department of Plant Sciences, Technical University of Munich, Freising, Germany.,Institute for Advanced Study, Technical University of Munich, Garching, Germany
| | - Victoire Baillet
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), PSL Université Paris, Paris, France
| | - Vincent Colot
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), PSL Université Paris, Paris, France
| | - Frank Johannes
- Department of Plant Sciences, Technical University of Munich, Freising, Germany.,Institute for Advanced Study, Technical University of Munich, Garching, Germany
| | - Jurriaan Ton
- P3 Centre for Plant and Soil Biology, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
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Yoshida T, Tarutani Y, Kakutani T, Kawabe A. DNA Methylation Diversification at the Integrated Organellar DNA-Like Sequence. Genes (Basel) 2018; 9:genes9120602. [PMID: 30513997 PMCID: PMC6316516 DOI: 10.3390/genes9120602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/20/2018] [Accepted: 11/28/2018] [Indexed: 12/29/2022] Open
Abstract
Plants have a lot of diversity in epigenetic modifications such as DNA methylation in their natural populations or cultivars. Although many studies observing the epigenetic diversity within and among species have been reported, the mechanisms how these variations are generated are still not clear. In addition to the de novo spontaneous epi-mutation, the intra- and inter-specific crossing can also cause a change of epigenetic modifications in their progenies. Here we report an example of diversification of DNA methylation by crossing and succeeding selfing. We traced the inheritance pattern of epigenetic modification during the crossing experiment between two natural strains Columbia (Col), and Landsberg electa (Ler) in model plant Arabidopsis thaliana to observe the inheritance of DNA methylation in two organellar DNA-like sequence regions in the nuclear genome. Because organellar DNA integration to the nuclear genome is common in flowering plants and these sequences are occasionally methylated, such DNA could be the novel source of plant genome evolution. The amplicon sequencing, using bisulfite-converted DNA and a next-generation auto-sequencer, was able to efficiently track the heredity of DNA methylation in F1 and F2 populations. One region showed hypomethylation in the F1 population and succeeding elevation of DNA methylation with large variance in the F2 population. The methylation level of Col and Ler alleles in F2 heterozygotes showed a significant positive correlation, implying the trans-chromosomal effect on DNA methylation. The results may suggest the possible mechanism causing the natural epigenetic diversity within plant populations.
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Affiliation(s)
- Takanori Yoshida
- Faculty of Life Science, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555, Japan.
| | - Yoshiaki Tarutani
- Department of Integrated Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
- Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan.
| | - Tetsuji Kakutani
- Department of Integrated Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
- Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan.
- Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Akira Kawabe
- Faculty of Life Science, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555, Japan.
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Tan F, Lu Y, Jiang W, Wu T, Zhang R, Zhao Y, Zhou DX. DDM1 Represses Noncoding RNA Expression and RNA-Directed DNA Methylation in Heterochromatin. PLANT PHYSIOLOGY 2018; 177:1187-1197. [PMID: 29794169 PMCID: PMC6052999 DOI: 10.1104/pp.18.00352] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/17/2018] [Indexed: 05/16/2023]
Abstract
C methylation of DNA, which occurs at CG, CHG, and CHH (H = A, C, or T) sequences in plants, is a hallmark for the epigenetic repression of repetitive sequences. The chromatin-remodeling factor DECREASE IN DNA METHYLATION1 (DDM1) is essential for DNA methylation, especially at CG and CHG sequences. However, its potential roles in RNA-directed DNA methylation (RdDM) and in chromatin function are not completely understood in rice (Oryza sativa). In this work, we used high-throughput approaches to study the function of rice DDM1 (OsDDM1) in RdDM and the expression of noncoding RNA. We show that loss of function of OsDDM1 results in ectopic CHH methylation of transposable elements and repeats. The ectopic CHH methylation was dependent on rice DOMAINS REARRANGED METHYLTRANSFERASE2, a DNA methyltransferase involved in RdDM. Mutations in OsDDM1 lead to decreases of histone H3K9me2 and increases in the levels of heterochromatic small RNA and long noncoding RNA. In particular, OsDDM1 was found to be essential to repress the transcription of the two repetitive sequences, Centromeric Retrotransposons of Rice1 and the dominant centromeric CentO repeats. These results suggest that OsDDM1 antagonizes RdDM at heterochromatin and represses the tissue-specific expression of noncoding RNA from repetitive sequences in the rice genome.
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Affiliation(s)
- Feng Tan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Yue Lu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Wei Jiang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Tian Wu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Ruoyu Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
- Institute of Plant Science Paris-Saclay, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Paris-Sud 11, Université Paris-Saclay, 91405 Orsay, France
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34
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Corem S, Doron-Faigenboim A, Jouffroy O, Maumus F, Arazi T, Bouché N. Redistribution of CHH Methylation and Small Interfering RNAs across the Genome of Tomato ddm1 Mutants. THE PLANT CELL 2018; 30:1628-1644. [PMID: 29875274 PMCID: PMC6096599 DOI: 10.1105/tpc.18.00167] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/01/2018] [Accepted: 05/31/2018] [Indexed: 05/18/2023]
Abstract
In plants, cytosine methylation, an epigenetic mark critical for transposon silencing, is maintained over generations by key enzymes that directly methylate DNA and is facilitated by chromatin remodelers, like DECREASE IN DNA METHYLATION1 (DDM1). Short-interfering RNAs (siRNAs) also mediate transposon DNA methylation through a process called RNA-directed DNA methylation (RdDM). In tomato (Solanum lycopersicum), siRNAs are primarily mapped to gene-rich chromosome arms, and not to pericentromeric regions as in Arabidopsis thaliana Tomato encodes two DDM1 genes. To better understand their functions and interaction with the RdDM pathway, we targeted the corresponding genes via the CRISPR/Cas9 technology, resulting in the isolation of Slddm1a and Slddm1b knockout mutants. Unlike the single mutants, Slddm1a Slddm1b double mutant plants display pleiotropic vegetative and reproductive phenotypes, associated with severe hypomethylation of the heterochromatic transposons in both the CG and CHG methylation contexts. The methylation in the CHH context increased for some heterochromatic transposons and conversely decreased for others localized in euchromatin. We found that the number of heterochromatin-associated siRNAs, including RdDM-specific small RNAs, increased significantly, likely limiting the transcriptional reactivation of transposons in Slddm1a Slddm1b Taken together, we propose that the global production of siRNAs and the CHH methylation mediated by the RdDM pathway are restricted to chromosome arms in tomato. Our data suggest that both pathways are greatly enhanced in heterochromatin when DDM1 functions are lost, at the expense of silencing mechanisms normally occurring in euchromatin.
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Affiliation(s)
- Shira Corem
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion 7505101, Israel
| | - Adi Doron-Faigenboim
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion 7505101, Israel
| | | | - Florian Maumus
- URGI, INRA, Université Paris-Saclay, 78000 Versailles, France
| | - Tzahi Arazi
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion 7505101, Israel
| | - Nicolas Bouché
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
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Shea DJ, Tomaru Y, Itabashi E, Nakamura Y, Miyazaki T, Kakizaki T, Naher TN, Shimizu M, Fujimoto R, Fukai E, Okazaki K. The production and characterization of a BoFLC2 introgressed Brassica rapa by repeated backcrossing to an F 1. BREEDING SCIENCE 2018; 68:316-325. [PMID: 30100798 PMCID: PMC6081295 DOI: 10.1270/jsbbs.17115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 02/13/2018] [Indexed: 05/25/2023]
Abstract
Flowering time is an important agronomic trait for Brassica rapa crops, and previous breeding work in Brassica has successfully transmitted other important agronomic traits from donor species. However, there has been no previous attempts to produce hybrids replacing the original Brassica FLC alleles with alien FLC alleles. In this paper, we introduce the creation of a chromosome substitution line (CSSL) containing a homozygous introgression of Flowering Locus C from Brassica oleracea (BoFLC2) into a B. rapa genomic background, and characterize the CSSL line with respect to the parental cultivars. The preferential transmission of alien chromosome inheritance and the pattern of transmission observed during the production of the CSSLs are also discussed.
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Affiliation(s)
- Daniel J. Shea
- Laboratory of Plant Breeding, Graduate School of Science and Technology, Niigata University,
2-8050 Ikarashi, Nishi-ku, Niigata 950-2181,
Japan
| | - Yuki Tomaru
- Laboratory of Plant Breeding, Graduate School of Science and Technology, Niigata University,
2-8050 Ikarashi, Nishi-ku, Niigata 950-2181,
Japan
| | - Etsuko Itabashi
- National Institute of Vegetable and Tea Science,
360 Kusawa, Ano, Tsu, Mie 514-2392,
Japan
| | - Yuri Nakamura
- Laboratory of Plant Breeding, Graduate School of Science and Technology, Niigata University,
2-8050 Ikarashi, Nishi-ku, Niigata 950-2181,
Japan
| | - Toshio Miyazaki
- Nippon Norin Seed Co.,
6-6-5 Takinogawa, Kita-ku, Tokyo 114-0023,
Japan
| | - Tomohiro Kakizaki
- National Institute of Vegetable and Tea Science,
360 Kusawa, Ano, Tsu, Mie 514-2392,
Japan
| | | | - Motoki Shimizu
- Iwate Biotechnology Research Center,
22-174-4 Narita, Kitakami, Iwate 024-0003,
Japan
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University,
Rokkodai, Nada-ku, Kobe, Hyogo 657-8501,
Japan
| | - Eigo Fukai
- Laboratory of Plant Breeding, Graduate School of Science and Technology, Niigata University,
2-8050 Ikarashi, Nishi-ku, Niigata 950-2181,
Japan
| | - Keiichi Okazaki
- Laboratory of Plant Breeding, Graduate School of Science and Technology, Niigata University,
2-8050 Ikarashi, Nishi-ku, Niigata 950-2181,
Japan
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36
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The correlation between pulmonary fibrosis and methylation of peripheral Smad3 in cases of pigeon breeder's lung in a Chinese Uygur population. Oncotarget 2018; 8:43104-43113. [PMID: 28562330 PMCID: PMC5522131 DOI: 10.18632/oncotarget.17763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 04/06/2017] [Indexed: 11/25/2022] Open
Abstract
Smad3 is a key protein in the transforming growth factor-beta (TGF-β)/Smad signaling pathway, which is involved in fibrosis in many organs. We investigated the relationship between Smad3 gene methylation and pulmonary fibrosis in pigeon breeder's lung (PBL). Twenty Uygur PBL patients with pulmonary fibrosis in Kashi between October 2015 and March 2016 were enrolled. Twenty PBL-free pigeon breeders and 20 healthy non-pigeon breeders enrolled during the same period constituted the negative and normal control groups, respectively. Participants’ data and peripheral blood samples were collected, and three Smad3 CpG loci were examined. Distributions of CpG_2 and CpG_4 methylation rates did not differ across groups, whereas distributions of CpG_3 methylation rates were significantly different among the three groups. The CpG_3 methylation rate was significantly lower in the patient group than in the negative control group. Smad3 mRNA expression was significantly higher in the patient group than in the negative control group but did not differ between the two control groups. TGF-βlevels were significantly higher in the patient group than in either control group (both P<0.01). Smad3 gene methylation and Smad3 mRNA expression were negatively correlated, with a correlation coefficient of -0.84. The number of pigeons bred during the preceding three months was positively correlated with Smad3 mRNA expression, with a correlation coefficient of 0.77. Smad3 gene hypomethylation might promote pulmonary fibrosis in Uygur PBL patients via increased Smad3 mRNA expression. Smad3 methylation, Smad3 mRNA expression and TGF-β level were correlated with the number of pigeons bred by patients.
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Hosaka A, Saito R, Takashima K, Sasaki T, Fu Y, Kawabe A, Ito T, Toyoda A, Fujiyama A, Tarutani Y, Kakutani T. Evolution of sequence-specific anti-silencing systems in Arabidopsis. Nat Commun 2017; 8:2161. [PMID: 29255196 PMCID: PMC5735166 DOI: 10.1038/s41467-017-02150-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 11/09/2017] [Indexed: 01/13/2023] Open
Abstract
The arms race between parasitic sequences and their hosts is a major driving force for evolution of gene control systems. Since transposable elements (TEs) are potentially deleterious, eukaryotes silence them by epigenetic mechanisms such as DNA methylation. Little is known about how TEs counteract silencing to propagate during evolution. Here, we report behavior of sequence-specific anti-silencing proteins used by Arabidopsis TEs and evolution of those proteins and their target sequences. We show that VANC, a TE-encoded anti-silencing protein, induces extensive DNA methylation loss throughout TEs. Related VANC proteins have evolved to hypomethylate TEs of completely different spectra. Targets for VANC proteins often form tandem repeats, which vary considerably between related TEs. We propose that evolution of VANC proteins and their targets allow propagation of TEs while causing minimal host damage. Our findings provide insight into the evolutionary dynamics of these apparently "selfish" sequences. They also provide potential tools to edit epigenomes in a sequence-specific manner.
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Affiliation(s)
- Aoi Hosaka
- Department of Integrated Genetics, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan.
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Yata 1111, Shizuoka, 411-8540, Japan.
| | - Raku Saito
- Department of Integrated Genetics, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Yata 1111, Shizuoka, 411-8540, Japan
| | - Kazuya Takashima
- Department of Integrated Genetics, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan
| | - Taku Sasaki
- Department of Integrated Genetics, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yu Fu
- Department of Integrated Genetics, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Yata 1111, Shizuoka, 411-8540, Japan
| | - Akira Kawabe
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Motoyama Kamigamo, Kyoto, 606-8555, Japan
| | - Tasuku Ito
- Department of Integrated Genetics, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Atsushi Toyoda
- Center for Information Biology, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan
| | - Asao Fujiyama
- Center for Information Biology, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan
| | - Yoshiaki Tarutani
- Department of Integrated Genetics, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Yata 1111, Shizuoka, 411-8540, Japan
| | - Tetsuji Kakutani
- Department of Integrated Genetics, National Institute of Genetics, Yata 1111, Shizuoka, 411-8540, Japan.
- Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Yata 1111, Shizuoka, 411-8540, Japan.
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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Lyons DB, Zilberman D. DDM1 and Lsh remodelers allow methylation of DNA wrapped in nucleosomes. eLife 2017; 6:e30674. [PMID: 29140247 PMCID: PMC5728721 DOI: 10.7554/elife.30674] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 11/14/2017] [Indexed: 12/17/2022] Open
Abstract
Cytosine methylation regulates essential genome functions across eukaryotes, but the fundamental question of whether nucleosomal or naked DNA is the preferred substrate of plant and animal methyltransferases remains unresolved. Here, we show that genetic inactivation of a single DDM1/Lsh family nucleosome remodeler biases methylation toward inter-nucleosomal linker DNA in Arabidopsis thaliana and mouse. We find that DDM1 enables methylation of DNA bound to the nucleosome, suggesting that nucleosome-free DNA is the preferred substrate of eukaryotic methyltransferases in vivo. Furthermore, we show that simultaneous mutation of DDM1 and linker histone H1 in Arabidopsis reproduces the strong linker-specific methylation patterns of species that diverged from flowering plants and animals over a billion years ago. Our results indicate that in the absence of remodeling, nucleosomes are strong barriers to DNA methyltransferases. Linker-specific methylation can evolve simply by breaking the connection between nucleosome remodeling and DNA methylation.
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Affiliation(s)
- David B Lyons
- Department of Plant and Microbial BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Daniel Zilberman
- Department of Plant and Microbial BiologyUniversity of California, BerkeleyBerkeleyUnited States
- Department of Cell and Developmental BiologyJohn Innes CentreNorwichUnited Kingdom
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39
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Stroud LK, McGinnis KM. Altered nucleosome positions in maize haplotypes and mutants of a subset of SWI/SNF-like proteins. PLANT DIRECT 2017; 1:e00019. [PMID: 31245667 PMCID: PMC6508530 DOI: 10.1002/pld3.19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/07/2017] [Accepted: 09/25/2017] [Indexed: 06/09/2023]
Abstract
Chromatin remodelers alter DNA-histone interactions in eukaryotic organisms and have been well characterized in yeast and Arabidopsis. While there are maize proteins with similar domains as known remodelers, the ability of the maize proteins to alter nucleosome position has not been reported. Mutant alleles of several maize proteins (RMR1, CHR101, CHR106, CHR127, and CHR156) with similar functional domains to known chromatin remodelers were identified. Altered gene expression of Chr101, Chr106, Chr127, and Chr156 was demonstrated in plants homozygous for the mutant alleles. These mutant genotypes were subjected to nucleosome position analysis to determine whether misregulation of putative maize chromatin proteins would lead to altered DNA-histone interactions. Nucleosome position changes were observed in plants homozygous for chr101, chr106, chr127, and chr156 mutant alleles, suggesting that CHR101, CHR106, CHR127, and CHR156 may affect chromatin structure. The role of RNA polymerases in altering DNA-histone interactions was also tested. Changes in nucleosome position were demonstrated in homozygous mop2-1 individuals. These changes were demonstrated at the b1 tandem repeats and at newly identified loci. Additionally, differential DNA-histone interactions and altered gene expression of putative chromatin remodelers were demonstrated between different maize haplotypes.
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Affiliation(s)
- Linda K. Stroud
- Department of Biological ScienceFlorida State UniversityTallahasseeFLUSA
| | - Karen M. McGinnis
- Department of Biological ScienceFlorida State UniversityTallahasseeFLUSA
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40
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Inagaki S, Takahashi M, Hosaka A, Ito T, Toyoda A, Fujiyama A, Tarutani Y, Kakutani T. Gene-body chromatin modification dynamics mediate epigenome differentiation in Arabidopsis. EMBO J 2017; 36:970-980. [PMID: 28100676 DOI: 10.15252/embj.201694983] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 12/14/2016] [Accepted: 12/16/2016] [Indexed: 11/09/2022] Open
Abstract
Heterochromatin is marked by methylation of lysine 9 on histone H3 (H3K9me). A puzzling feature of H3K9me is that this modification localizes not only in promoters but also in internal regions (bodies) of silent transcription units. Despite its prevalence, the biological significance of gene-body H3K9me remains enigmatic. Here we show that H3K9me-associated removal of H3K4 monomethylation (H3K4me1) in gene bodies mediates transcriptional silencing. Mutations in an Arabidopsis H3K9 demethylase gene IBM1 induce ectopic H3K9me2 accumulation in gene bodies, with accompanying severe developmental defects. Through suppressor screening of the ibm1-induced developmental defects, we identified the LDL2 gene, which encodes a homolog of conserved H3K4 demethylases. The ldl2 mutation suppressed the developmental defects, without suppressing the ibm1-induced ectopic H3K9me2. The ectopic H3K9me2 mark directed removal of gene-body H3K4me1 and caused transcriptional repression in an LDL2-dependent manner. Furthermore, mutations of H3K9 methylases increased the level of H3K4me1 in the gene bodies of various transposable elements, and this H3K4me1 increase is a prerequisite for their transcriptional derepression. Our results uncover an unexpected role of gene-body H3K9me2/H3K4me1 dynamics as a mediator of heterochromatin silencing and epigenome differentiation.
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Affiliation(s)
- Soichi Inagaki
- National Institute of Genetics, Mishima, Shizuoka, Japan .,Department of Genetics, School of Life science, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan
| | | | - Aoi Hosaka
- National Institute of Genetics, Mishima, Shizuoka, Japan.,Department of Genetics, School of Life science, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan
| | - Tasuku Ito
- National Institute of Genetics, Mishima, Shizuoka, Japan.,Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Atsushi Toyoda
- National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Asao Fujiyama
- National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Yoshiaki Tarutani
- National Institute of Genetics, Mishima, Shizuoka, Japan.,Department of Genetics, School of Life science, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan
| | - Tetsuji Kakutani
- National Institute of Genetics, Mishima, Shizuoka, Japan .,Department of Genetics, School of Life science, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan.,Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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41
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Li S, Xia Q, Wang F, Yu X, Ma J, Kou H, Lin X, Gao X, Liu B. Laser Irradiation-Induced DNA Methylation Changes Are Heritable and Accompanied with Transpositional Activation of mPing in Rice. FRONTIERS IN PLANT SCIENCE 2017; 8:363. [PMID: 28377781 PMCID: PMC5359294 DOI: 10.3389/fpls.2017.00363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/01/2017] [Indexed: 05/05/2023]
Abstract
DNA methylation is an integral component of the epigenetic code in most higher eukaryotes. Exploring the extent to which DNA methylation can be altered under a specific condition and its heritability is important for elucidating the biological functions of this epigenetic modification. Here, we conducted MSAP analysis of rice plants with altered phenotypes subsequent to a low-dose Nd3+YAG laser irradiation. We found that all four methylation patterns at the 5'-CCGG sites that are analyzable by MSAP showed substantial changes in the immediately treated M0 plants. Interestingly, the frequencies of hypo- and hypermethylation were of similar extents, which largely offset each other and render the total methylation levels unchanged. Further analysis revealed that the altered methylation patterns were meiotically heritable to at least the M2 generation but accompanied with further changes in each generation. The methylation changes and their heritability of the metastable epigenetic state were verified by bisulfite sequencing of portion of the retrotranspon, Tos17, an established locus for assessing DNA methylation liability in rice. Real-time PCR assay indicated that the expression of various methylation-related chromatin genes was perturbed, and a Pearson correlation analysis showed that many of these genes, especially two AGOs (AGO4-1 and AGO4-2), were significantly correlated with the methylation pattern alterations. In addition, excisions of a MITE transposon, mPing, occurred rampantly in the laser irradiated plants and their progenies. Together, our results indicate that heritable DNA methylation changes can be readily induced by low-dose laser irradiation, and which can be accompanied by transpostional activation of transposable elements.
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Affiliation(s)
- Siyuan Li
- Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal UniversityChangchun, China
- School of Life Sciences, Jilin Agricultural UniversityChangchun, China
| | - Qiong Xia
- Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal UniversityChangchun, China
| | - Fang Wang
- College of Oceanology & Food Science, Quanzhou Normal UniversityQuanzhou, China
- *Correspondence: Fang Wang
| | - Xiaoming Yu
- Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal UniversityChangchun, China
| | - Jian Ma
- College of Agronomy, Jilin Agricultural UniversityChangchun, China
| | - Hongping Kou
- College of Agronomy, Jilin Agricultural UniversityChangchun, China
| | - Xiuyun Lin
- Jilin Academy of Agricultural SciencesChangchun, China
| | - Xiang Gao
- Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal UniversityChangchun, China
- Xiang Gao
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal UniversityChangchun, China
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42
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Affiliation(s)
| | - Vincent Colot
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), F-75005 Paris, France;
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43
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Velanis CN, Herzyk P, Jenkins GI. Regulation of transcription by the Arabidopsis UVR8 photoreceptor involves a specific histone modification. PLANT MOLECULAR BIOLOGY 2016; 92:425-443. [PMID: 27534420 PMCID: PMC5080334 DOI: 10.1007/s11103-016-0522-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 08/02/2016] [Indexed: 05/21/2023]
Abstract
The photoreceptor UV RESISTANCE LOCUS 8 (UVR8) specifically mediates photomorphogenic responses to UV-B wavelengths. UVR8 acts by regulating transcription of a set of genes, but the underlying mechanisms are unknown. Previous research indicated that UVR8 can associate with chromatin, but the specificity and functional significance of this interaction are not clear. Here we show, by chromatin immunoprecipitation, that UV-B exposure of Arabidopsis increases acetylation of lysines K9 and/or K14 of histone H3 at UVR8-regulated gene loci in a UVR8-dependent manner. The transcription factors HY5 and/or HYH, which mediate UVR8-regulated transcription, are also required for this chromatin modification, at least for the ELIP1 gene. Furthermore, sequencing of the immunoprecipitated DNA revealed that all UV-B-induced enrichments in H3K9,14diacetylation across the genome are UVR8-dependent, and approximately 40 % of the enriched loci contain known UVR8-regulated genes. In addition, inhibition of histone acetylation by anacardic acid reduces the UV-B induced, UVR8 mediated expression of ELIP1 and CHS. No evidence was obtained in yeast 2-hybrid assays for a direct interaction between either UVR8 or HY5 and several proteins involved in light-regulated histone modification, nor for the involvement of these proteins in UVR8-mediated responses in plants, although functional redundancy between proteins could influence the results. In summary, this study shows that UVR8 regulates a specific chromatin modification associated with transcriptional regulation of a set of UVR8-target genes.
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Affiliation(s)
- Christos N Velanis
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK
| | - Pawel Herzyk
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, University of Glasgow, Garscube Estate, Switchback Road, Bearsden, G61 1QH, UK
| | - Gareth I Jenkins
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK.
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44
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Kawanabe T, Ishikura S, Miyaji N, Sasaki T, Wu LM, Itabashi E, Takada S, Shimizu M, Takasaki-Yasuda T, Osabe K, Peacock WJ, Dennis ES, Fujimoto R. Role of DNA methylation in hybrid vigor in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2016; 113:E6704-E6711. [PMID: 27791039 PMCID: PMC5087013 DOI: 10.1073/pnas.1613372113] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Hybrid vigor or heterosis refers to the superior performance of F1 hybrid plants over their parents. Heterosis is particularly important in the production systems of major crops. Recent studies have suggested that epigenetic regulation such as DNA methylation is involved in heterosis, but the molecular mechanism of heterosis is still unclear. To address the epigenetic contribution to heterosis in Arabidopsis thaliana, we used mutant genes that have roles in DNA methylation. Hybrids between C24 and Columbia-0 (Col) without RNA polymerase IV (Pol IV) or methyltransferase I (MET1) function did not reduce the level of biomass heterosis (as evaluated by rosette diameter). Hybrids with a mutation in decrease in dna methylation 1 (ddm1) showed a decreased heterosis level. Vegetative heterosis in the ddm1 mutant hybrid was reduced but not eliminated; a complete reduction could result if there was a change in methylation at all loci critical for generating the level of heterosis, whereas if only a proportion of the loci have methylation changes there may only be a partial reduction in heterosis.
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Affiliation(s)
- Takahiro Kawanabe
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Sonoko Ishikura
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Naomi Miyaji
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Taku Sasaki
- Department of Integrated Genetics, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Li Min Wu
- Commonwealth Scientific and Industrial Research Organisation Agriculture and Food, Canberra, ACT 2601, Australia
| | - Etsuko Itabashi
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Satoko Takada
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Motoki Shimizu
- Iwate Biotechnology Research Center, 22-174-4, Narita, Kitakami, Iwate, 024-0003, Japan
| | - Takeshi Takasaki-Yasuda
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Kenji Osabe
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
| | - W James Peacock
- Commonwealth Scientific and Industrial Research Organisation Agriculture and Food, Canberra, ACT 2601, Australia; University of Technology, Sydney, Broadway, NSW 2007, Australia;
| | - Elizabeth S Dennis
- Commonwealth Scientific and Industrial Research Organisation Agriculture and Food, Canberra, ACT 2601, Australia; University of Technology, Sydney, Broadway, NSW 2007, Australia
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Saitama, 332-0012 Japan
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45
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Abstract
The formation of spontaneous epialleles is poorly understood. A new study describes how the formation of epihybrids can lead to the appearance of novel epialleles.
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Affiliation(s)
- William T Jordan
- Department of Genetics, University of Georgia, 120 East Green Street, Athens, GA, 30602, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, 120 East Green Street, Athens, GA, 30602, USA.
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