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Briffa A, Menon G, Movilla Miangolarra A, Howard M. Dissecting Mechanisms of Epigenetic Memory Through Computational Modeling. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:265-290. [PMID: 38424070 DOI: 10.1146/annurev-arplant-070523-041445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Understanding the mechanistic basis of epigenetic memory has proven to be a difficult task due to the underlying complexity of the systems involved in its establishment and maintenance. Here, we review the role of computational modeling in helping to unlock this complexity, allowing the dissection of intricate feedback dynamics. We focus on three forms of epigenetic memory encoded in gene regulatory networks, DNA methylation, and histone modifications and discuss the important advantages offered by plant systems in their dissection. We summarize the main modeling approaches involved and highlight the principal conceptual advances that the modeling has enabled through iterative cycles of predictive modeling and experiments. Lastly, we discuss remaining gaps in our understanding and how intertwined theory and experimental approaches might help in their resolution.
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Affiliation(s)
- Amy Briffa
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom;
- Epigenetics Programme, Babraham Institute, Cambridge, United Kingdom
| | - Govind Menon
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom;
| | - Ander Movilla Miangolarra
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom;
| | - Martin Howard
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom;
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2
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Frost JM, Rhee JH, Choi Y. Dynamics of DNA methylation and its impact on plant embryogenesis. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102593. [PMID: 38941722 DOI: 10.1016/j.pbi.2024.102593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 06/08/2024] [Accepted: 06/09/2024] [Indexed: 06/30/2024]
Abstract
Flowering plants exhibit unique DNA methylation dynamics during development. Particular attention can be focused on seed development and the embryo, which represents the starting point of the sporophytic life cycle. A build-up of CHH methylation is now recognized as highly characteristic of embryo development. This process is thought to occur in order to silence potentially harmful transposable element expression, though roles in promoting seed dormancy and dessication tolerance have also been revealed. Recent studies show that increased CHH methylation in embryos inhabits both novel loci, unmethylated elsewhere in the plant, as well as shared loci, exhibiting more dense methylation. The role of DNA methylation in cis-regulatory gene regulation in plants is less well established compared to mammals, and here we discuss both transposable element regulation and the potential role of DNA methylation in dynamic gene expression.
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Affiliation(s)
- Jennifer M Frost
- Medical and Molecular Genetics, King's College London, St Thomas' Street, London SE1 9RT, UK.
| | - Ji Hoon Rhee
- Department of Biological Sciences, Seoul National University, Seoul, South Korea; Research Center for Plant Plasticity, Seoul National University, Seoul, South Korea
| | - Yeonhee Choi
- Department of Biological Sciences, Seoul National University, Seoul, South Korea; Research Center for Plant Plasticity, Seoul National University, Seoul, South Korea.
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3
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Harris CJ, Zhong Z, Ichino L, Feng S, Jacobsen SE. H1 restricts euchromatin-associated methylation pathways from heterochromatic encroachment. eLife 2024; 12:RP89353. [PMID: 38814684 PMCID: PMC11139477 DOI: 10.7554/elife.89353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024] Open
Abstract
Silencing pathways prevent transposable element (TE) proliferation and help to maintain genome integrity through cell division. Silenced genomic regions can be classified as either euchromatic or heterochromatic, and are targeted by genetically separable epigenetic pathways. In plants, the RNA-directed DNA methylation (RdDM) pathway targets mostly euchromatic regions, while CMT DNA methyltransferases are mainly associated with heterochromatin. However, many epigenetic features - including DNA methylation patterning - are largely indistinguishable between these regions, so how the functional separation is maintained is unclear. The linker histone H1 is preferentially localized to heterochromatin and has been proposed to restrict RdDM from encroachment. To test this hypothesis, we followed RdDM genomic localization in an h1 mutant by performing ChIP-seq on the largest subunit, NRPE1, of the central RdDM polymerase, Pol V. Loss of H1 resulted in NRPE1 enrichment predominantly in heterochromatic TEs. Increased NRPE1 binding was associated with increased chromatin accessibility in h1, suggesting that H1 restricts NRPE1 occupancy by compacting chromatin. However, RdDM occupancy did not impact H1 localization, demonstrating that H1 hierarchically restricts RdDM positioning. H1 mutants experience major symmetric (CG and CHG) DNA methylation gains, and by generating an h1/nrpe1 double mutant, we demonstrate these gains are largely independent of RdDM. However, loss of NRPE1 occupancy from a subset of euchromatic regions in h1 corresponded to the loss of methylation in all sequence contexts, while at ectopically bound heterochromatic loci, NRPE1 deposition correlated with increased methylation specifically in the CHH context. Additionally, we found that H1 similarly restricts the occupancy of the methylation reader, SUVH1, and polycomb-mediated H3K27me3. Together, the results support a model whereby H1 helps maintain the exclusivity of heterochromatin by preventing encroachment from other competing pathways.
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Affiliation(s)
- C Jake Harris
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Zhenhui Zhong
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Lucia Ichino
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Suhua Feng
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
- Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California, Los AngelesLos AngelesUnited States
| | - Steven E Jacobsen
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
- Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California, Los AngelesLos AngelesUnited States
- Howard Hughes Medical Institute, University of California, Los AngelesLos AngelesUnited States
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Kumar BKP, Beaubiat S, Yadav CB, Eshed R, Arazi T, Sherman A, Bouché N. Genome wide inherited modifications of the tomato epigenome by trans-activated bacterial CG methyltransferase. Cell Mol Life Sci 2024; 81:222. [PMID: 38767725 PMCID: PMC11106227 DOI: 10.1007/s00018-024-05255-7] [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: 12/13/2023] [Revised: 04/16/2024] [Accepted: 04/25/2024] [Indexed: 05/22/2024]
Abstract
BACKGROUND Epigenetic variation is mediated by epigenetic marks such as DNA methylation occurring in all cytosine contexts in plants. CG methylation plays a critical role in silencing transposable elements and regulating gene expression. The establishment of CG methylation occurs via the RNA-directed DNA methylation pathway and CG methylation maintenance relies on METHYLTRANSFERASE1, the homologue of the mammalian DNMT1. PURPOSE Here, we examined the capacity to stably alter the tomato genome methylome by a bacterial CG-specific M.SssI methyltransferase expressed through the LhG4/pOP transactivation system. RESULTS Methylome analysis of M.SssI expressing plants revealed that their euchromatic genome regions are specifically hypermethylated in the CG context, and so are most of their genes. However, changes in gene expression were observed only with a set of genes exhibiting a greater susceptibility to CG hypermethylation near their transcription start site. Unlike gene rich genomic regions, our analysis revealed that heterochromatic regions are slightly hypomethylated at CGs only. Notably, some M.SssI-induced hypermethylation persisted even without the methylase or transgenes, indicating inheritable epigenetic modification. CONCLUSION Collectively our findings suggest that heterologous expression of M.SssI can create new inherited epigenetic variations and changes in the methylation profiles on a genome wide scale. This open avenues for the conception of epigenetic recombinant inbred line populations with the potential to unveil agriculturally valuable tomato epialleles.
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Affiliation(s)
- Bapatla Kesava Pavan Kumar
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Derech Hamacabim 68, Rishon Lezion, Israel
- Molecular Biology, Acrannolife Genomics Private Limited, Chennai, Tamilnadu, 600035, India
| | - Sébastien Beaubiat
- INRAE, AgroParisTech, Institute Jean-Pierre Bourgin for Plant Sciences (IJPB), Université Paris-Saclay, 78000, Versailles, France
| | - Chandra Bhan Yadav
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Derech Hamacabim 68, Rishon Lezion, Israel
- Department of Genetics, Genomics, and Breeding, NIAB-EMR, East Malling, East Malling, ME19 6BJ, UK
| | - Ravit Eshed
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Derech Hamacabim 68, Rishon Lezion, Israel
| | - Tzahi Arazi
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Derech Hamacabim 68, Rishon Lezion, Israel
| | - Amir Sherman
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Derech Hamacabim 68, Rishon Lezion, Israel.
| | - Nicolas Bouché
- INRAE, AgroParisTech, Institute Jean-Pierre Bourgin for Plant Sciences (IJPB), Université Paris-Saclay, 78000, Versailles, France.
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Candela-Ferre J, Diego-Martin B, Pérez-Alemany J, Gallego-Bartolomé J. Mind the gap: Epigenetic regulation of chromatin accessibility in plants. PLANT PHYSIOLOGY 2024; 194:1998-2016. [PMID: 38236303 PMCID: PMC10980423 DOI: 10.1093/plphys/kiae024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/07/2023] [Accepted: 11/23/2023] [Indexed: 01/19/2024]
Abstract
Chromatin plays a crucial role in genome compaction and is fundamental for regulating multiple nuclear processes. Nucleosomes, the basic building blocks of chromatin, are central in regulating these processes, determining chromatin accessibility by limiting access to DNA for various proteins and acting as important signaling hubs. The association of histones with DNA in nucleosomes and the folding of chromatin into higher-order structures are strongly influenced by a variety of epigenetic marks, including DNA methylation, histone variants, and histone post-translational modifications. Additionally, a wide array of chaperones and ATP-dependent remodelers regulate various aspects of nucleosome biology, including assembly, deposition, and positioning. This review provides an overview of recent advances in our mechanistic understanding of how nucleosomes and chromatin organization are regulated by epigenetic marks and remodelers in plants. Furthermore, we present current technologies for profiling chromatin accessibility and organization.
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Affiliation(s)
- Joan Candela-Ferre
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, 46022Spain
| | - Borja Diego-Martin
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, 46022Spain
| | - Jaime Pérez-Alemany
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, 46022Spain
| | - Javier Gallego-Bartolomé
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, 46022Spain
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Vivek Hari Sundar G, Madhu A, Archana A, Shivaprasad PV. Plant histone variants at the nexus of chromatin readouts, stress and development. Biochim Biophys Acta Gen Subj 2024; 1868:130539. [PMID: 38072208 DOI: 10.1016/j.bbagen.2023.130539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 11/21/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023]
Abstract
Histones are crucial proteins that are involved in packaging the DNA as condensed chromatin inside the eukaryotic cell nucleus. Rather than being static packaging units, these molecules undergo drastic variations spatially and temporally to facilitate accessibility of DNA to replication, transcription as well as wide range of gene regulatory machineries. In addition, incorporation of paralogous variants of canonical histones in the chromatin is ascribed to specific functions. Given the peculiar requirement of plants to rapidly modulate gene expression levels on account of their sessile nature, histones and their variants serve as additional layers of gene regulation. This review summarizes the mechanisms and implications of distribution, modifications and differential incorporation of histones and their variants across plant genomes, and outlines emerging themes.
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Affiliation(s)
- G Vivek Hari Sundar
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bangalore, India
| | - Aravind Madhu
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bangalore, India; SASTRA University, Thirumalaisamudram, Thanjavur 613 401, India
| | - A Archana
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bangalore, India; SASTRA University, Thirumalaisamudram, Thanjavur 613 401, India
| | - P V Shivaprasad
- National Centre for Biological Sciences, TIFR, GKVK Campus, Bangalore, India.
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Xu G, Law JA. Loops, crosstalk, and compartmentalization: it takes many layers to regulate DNA methylation. Curr Opin Genet Dev 2024; 84:102147. [PMID: 38176333 PMCID: PMC10922829 DOI: 10.1016/j.gde.2023.102147] [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: 10/08/2023] [Revised: 12/06/2023] [Accepted: 12/06/2023] [Indexed: 01/06/2024]
Abstract
DNA methylation is a conserved epigenetic modification associated with transposon silencing and gene regulation. The stability of this modification relies on intimate connections between DNA and histone modifications that generate self-reinforcing loops wherein the presence of one mark promotes the other. However, it is becoming increasingly clear that the efficiency of these loops is affected by cross-talk between pathways and by chromatin accessibility, which is heavily influenced by histone variants. Focusing primarily on plants, this review provides an update on the aforementioned self-reinforcing loops, highlights recent advances in understanding how DNA methylation pathways are restricted to prevent encroachment on genes, and discusses the roles of histone variants in compartmentalizing epigenetic pathways within the genome. This multilayered approach facilitates two essential, yet opposing functions, the ability to maintain heritable DNA methylation patterns while retaining the flexibility to modify these patterns during development.
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Affiliation(s)
- Guanghui Xu
- Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA. https://twitter.com/@GuanghuiXu1
| | - Julie A Law
- Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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8
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Chow HT, Mosher RA. Small RNA-mediated DNA methylation during plant reproduction. THE PLANT CELL 2023; 35:1787-1800. [PMID: 36651080 DOI: 10.1093/plcell/koad010] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/11/2023] [Accepted: 01/11/2023] [Indexed: 05/30/2023]
Abstract
Reproductive tissues are a rich source of small RNAs, including several classes of short interfering (si)RNAs that are restricted to this stage of development. In addition to RNA polymerase IV-dependent 24-nt siRNAs that trigger canonical RNA-directed DNA methylation, abundant reproductive-specific siRNAs are produced from companion cells adjacent to the developing germ line or zygote and may move intercellularly before inducing methylation. In some cases, these siRNAs are produced via non-canonical biosynthesis mechanisms or from sequences with little similarity to transposons. While the precise role of these siRNAs and the methylation they trigger is unclear, they have been implicated in specifying a single megaspore mother cell, silencing transposons in the male germ line, mediating parental dosage conflict to ensure proper endosperm development, hypermethylation of mature embryos, and trans-chromosomal methylation in hybrids. In this review, we summarize the current knowledge of reproductive siRNAs, including their biosynthesis, transport, and function.
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Affiliation(s)
- Hiu Tung Chow
- The School of Plant Sciences, The University of Arizona, Tucson, Arizona 85721-0036, USA
| | - Rebecca A Mosher
- The School of Plant Sciences, The University of Arizona, Tucson, Arizona 85721-0036, USA
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9
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Sheikh AH, Nawaz K, Tabassum N, Almeida-Trapp M, Mariappan KG, Alhoraibi H, Rayapuram N, Aranda M, Groth M, Hirt H. Linker histone H1 modulates defense priming and immunity in plants. Nucleic Acids Res 2023; 51:4252-4265. [PMID: 36840717 PMCID: PMC10201415 DOI: 10.1093/nar/gkad106] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 01/17/2023] [Accepted: 02/07/2023] [Indexed: 02/26/2023] Open
Abstract
Linker H1 histones play an important role in animal and human pathogenesis, but their function in plant immunity is poorly understood. Here, we analyzed mutants of the three canonical variants of Arabidopsis H1 histones, namely H1.1, H1.2 and H1.3. We observed that double h1.1h1.2 and triple h1.1h1.2h1.3 (3h1) mutants were resistant to Pseudomonas syringae and Botrytis cinerea infections. Transcriptome analysis of 3h1 mutant plants showed H1s play a key role in regulating the expression of early and late defense genes upon pathogen challenge. Moreover, 3h1 mutant plants showed enhanced production of reactive oxygen species and activation of mitogen activated protein kinases upon pathogen-associated molecular pattern (PAMP) treatment. However, 3h1 mutant plants were insensitive to priming with flg22, a well-known bacterial PAMP which induces enhanced resistance in WT plants. The defective defense response in 3h1 upon priming was correlated with altered DNA methylation and reduced global H3K56ac levels. Our data place H1 as a molecular gatekeeper in governing dynamic changes in the chromatin landscape of defense genes during plant pathogen interaction.
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Affiliation(s)
- Arsheed H Sheikh
- King Abdullah University of Science and Technology, KAUST, 23955 Thuwal, Saudi Arabia
| | - Kashif Nawaz
- King Abdullah University of Science and Technology, KAUST, 23955 Thuwal, Saudi Arabia
| | - Naheed Tabassum
- King Abdullah University of Science and Technology, KAUST, 23955 Thuwal, Saudi Arabia
| | - Marilia Almeida-Trapp
- King Abdullah University of Science and Technology, KAUST, 23955 Thuwal, Saudi Arabia
| | - Kiruthiga G Mariappan
- King Abdullah University of Science and Technology, KAUST, 23955 Thuwal, Saudi Arabia
| | - Hanna Alhoraibi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, 21551Jeddah, Saudi Arabia
| | - Naganand Rayapuram
- King Abdullah University of Science and Technology, KAUST, 23955 Thuwal, Saudi Arabia
| | - Manuel Aranda
- King Abdullah University of Science and Technology, KAUST, 23955 Thuwal, Saudi Arabia
| | - Martin Groth
- Institute of Functional Epigenetics, Helmholtz Munich, 85764Neuherberg, Germany
| | - Heribert Hirt
- King Abdullah University of Science and Technology, KAUST, 23955 Thuwal, Saudi Arabia
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10
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Wang Y, Li Y, Zhou F, Zhang L, Gong J, Cheng C, Chen J, Lou Q. Genome-wide characterization, phylogenetic and expression analysis of Histone gene family in cucumber (Cucumis sativus L.). Int J Biol Macromol 2023; 230:123401. [PMID: 36702227 DOI: 10.1016/j.ijbiomac.2023.123401] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/14/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023]
Abstract
Histones are essential components of chromatin and play an important role in regulating gene transcription and participating in DNA replication. Here, we performed a comprehensive analysis of this gene family. In this study, we identified 37 CsHistones that were classified into five groups (H1, H2A, H2B, H3 and H4). The closely linked subfamilies exhibited more similarity in terms of motifs and intron/exon numbers. Segmental duplication (SD) is the main driving force of cucumber CsHistones expansion. Analysis of cis-regulatory elements in the promoter region of CsHistones showed that CsHistones can respond to a variety of stresses. RNA-Seq analysis indicated that the expression of most CsHistones was associated with different stresses, including downy mildew, powdery mildew, wilt, heat, cold, salt stress, and waterlogging. Expression analysis showed that several genes of H3 group were highly expressed in different reproductive organs. Notably, CsCENH3 (CsHistone30) has the characteristics of a variant histone, and we demonstrated that CsCENH3 was localized on the nucleus and its proteins were expressed in centromere region. These findings provide valuable information for the identification and potential functions of Histone genes and ideas for the cultivation of CENH3-mediated haploid induction lines in cucumber.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Yangang Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Fang Zhou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Lu Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianlei Gong
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Chunyan Cheng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Jinfeng Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Qunfeng Lou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
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11
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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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12
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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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13
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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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14
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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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Guo J, Li P, Yu A, Chapman MA, Liu A. Genome-wide characterization and evolutionary analysis of linker histones in castor bean ( Ricinus communis). FRONTIERS IN PLANT SCIENCE 2022; 13:1014418. [PMID: 36340363 PMCID: PMC9635857 DOI: 10.3389/fpls.2022.1014418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
H1s, or linker histones, are ubiquitous proteins in eukaryotic cells, consisting of a globular GH1 domain flanked by two unstructured tails. Whilst it is known that numerous non-allelic variants exist within the same species, the degree of interspecific and intraspecific variation and divergence of linker histones remain unknown. The conserved basic binding sites in GH1 and evenly distributed strong positive charges on the C-terminal domain (CTD) are key structural characters for linker histones to bind chromatin. Based on these features, we identified five linker histones from 13 GH1-containing proteins in castor bean (Ricinus communis), which were named as RcH1.1, RcH1.2a, RcH1.2b, RcH1.3, and RcH1.4 based on their phylogenetic relationships with the H1s from five other economically important Euphorbiaceae species (Hevea brasiliensis Jatropha curcas, Manihot esculenta Mercurialis annua, and Vernicia fordii) and Arabidopsis thaliana. The expression profiles of RcH1 genes in a variety of tissues and stresses were determined from RNA-seq data. We found three RcH1 genes (RcH1.1, RcH1.2a, and RcH1.3) were broadly expressed in all tissues, suggesting a conserved role in stabilizing and organizing the nuclear DNA. RcH1.2a and RcH1.4 was preferentially expressed in floral tissues, indicating potential involvement in floral development in castor bean. Lack of non-coding region and no expression detected in any tissue tested suggest that RcH1.2b is a pseudogene. RcH1.3 was salt stress inducible, but not induced by cold, heat and drought in our investigation. Structural comparison confirmed that GH1 domain was highly evolutionarily conserved and revealed that N- and C-terminal domains of linker histones are divergent between variants, but highly conserved between species for a given variant. Although the number of H1 genes varies between species, the number of H1 variants is relatively conserved in more closely related species (such as within the same family). Through comparison of nucleotide diversity of linker histone genes and oil-related genes, we found similar mutation rate of these two groups of genes. Using Tajima's D and ML-HKA tests, we found RcH1.1 and RcH1.3 may be under balancing selection.
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Affiliation(s)
- Jiayu Guo
- Key Laboratory for Forest Resource Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, China
| | - Ping Li
- Key Laboratory for Forest Resource Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, China
| | - Anmin Yu
- Key Laboratory for Forest Resource Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, China
| | - Mark A. Chapman
- Biological Sciences and Centre for Underutilised Crops, University of Southampton, Southampton, United Kingdom
| | - Aizhong Liu
- Key Laboratory for Forest Resource Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, China
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Liu ZW, Simmons CH, Zhong X. Linking transcriptional silencing with chromatin remodeling, folding, and positioning in the nucleus. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102261. [PMID: 35841650 PMCID: PMC10014033 DOI: 10.1016/j.pbi.2022.102261] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/03/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
Chromatin organization is important for many DNA-templated processes in eukaryotic cells such as replication and transcription. Recent studies have uncovered the capacity of epigenetic modifications, phase separation, and nuclear architecture and spatial positioning to regulate chromatin organization in both plants and animals. Here, we provide an overview of the recent progress made in understanding how chromatin is organized within the nucleus at both the local and global levels with respect to the regulation of transcriptional silencing in plants. To be concise while covering important mechanisms across a range of scales, we focus on how epigenetic modifications and chromatin remodelers alter local chromatin structure, how liquid-liquid phase separation physically separates broader chromatin domains into distinct droplets, and how nuclear positioning affects global chromatin organization.
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Affiliation(s)
- Zhang-Wei Liu
- Laboratory of Genetics & Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Carl H Simmons
- Laboratory of Genetics & Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Xuehua Zhong
- Laboratory of Genetics & Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53706, USA.
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NODULIN HOMEOBOX is required for heterochromatin homeostasis in Arabidopsis. Nat Commun 2022; 13:5058. [PMID: 36030240 PMCID: PMC9420119 DOI: 10.1038/s41467-022-32709-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 08/11/2022] [Indexed: 11/11/2022] Open
Abstract
Arabidopsis NODULIN HOMEOBOX (NDX) is a nuclear protein described as a regulator of specific euchromatic genes within transcriptionally active chromosome arms. Here we show that NDX is primarily a heterochromatin regulator that functions in pericentromeric regions to control siRNA production and non-CG methylation. Most NDX binding sites coincide with pericentromeric het-siRNA loci that mediate transposon silencing, and are antagonistic with R-loop structures that are prevalent in euchromatic chromosomal arms. Inactivation of NDX leads to differential siRNA accumulation and DNA methylation, of which CHH/CHG hypomethylation colocalizes with NDX binding sites. Hi-C analysis shows significant chromatin structural changes in the ndx mutant, with decreased intrachromosomal interactions at pericentromeres where NDX is enriched in wild-type plants, and increased interchromosomal contacts between KNOT-forming regions, similar to those observed in DNA methylation mutants. We conclude that NDX is a key regulator of heterochromatin that is functionally coupled to het-siRNA loci and non-CG DNA methylation pathways. Arabidopsis NDX was previously reported as a regulator of euchromatic gene expression. Here the authors show that NDX functions at pericentromeric regions and regulates heterochromatin homeostasis by controlling siRNA production and non-CG methylation.
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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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Multi-omics data integration reveals link between epigenetic modifications and gene expression in sugar beet (Beta vulgaris subsp. vulgaris) in response to cold. BMC Genomics 2022; 23:144. [PMID: 35176993 PMCID: PMC8855596 DOI: 10.1186/s12864-022-08312-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/13/2022] [Indexed: 12/19/2022] Open
Abstract
Background DNA methylation is thought to influence the expression of genes, especially in response to changing environmental conditions and developmental changes. Sugar beet (Beta vulgaris ssp. vulgaris), and other biennial or perennial plants are inevitably exposed to fluctuating temperatures throughout their lifecycle and might even require such stimulus to acquire floral competence. Therefore, plants such as beets, need to fine-tune their epigenetic makeup to ensure phenotypic plasticity towards changing environmental conditions while at the same time steering essential developmental processes. Different crop species may show opposing reactions towards the same abiotic stress, or, vice versa, identical species may respond differently depending on the specific kind of stress. Results In this study, we investigated common effects of cold treatment on genome-wide DNA methylation and gene expression of two Beta vulgaris accessions via multi-omics data analysis. Cold exposure resulted in a pronounced reduction of DNA methylation levels, which particularly affected methylation in CHH context (and to a lesser extent CHG) and was accompanied by transcriptional downregulation of the chromomethyltransferase CMT2 and strong upregulation of several genes mediating active DNA demethylation. Conclusion Integration of methylomic and transcriptomic data revealed that, rather than methylation having directly influenced expression, epigenetic modifications correlated with changes in expression of known players involved in DNA (de)methylation. In particular, cold triggered upregulation of genes putatively contributing to DNA demethylation via the ROS1 pathway. Our observations suggest that these transcriptional responses precede the cold-induced global DNA-hypomethylation in non-CpG, preparing beets for additional transcriptional alterations necessary for adapting to upcoming environmental changes. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08312-2.
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