1
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Hövel I, Bader R, Louwers M, Haring M, Peek K, Gent JI, Stam M. RNA-directed DNA methylation mutants reduce histone methylation at the paramutated maize booster1 enhancer. PLANT PHYSIOLOGY 2024; 195:1161-1179. [PMID: 38366582 PMCID: PMC11142347 DOI: 10.1093/plphys/kiae072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/19/2023] [Accepted: 12/25/2023] [Indexed: 02/18/2024]
Abstract
Paramutation is the transfer of mitotically and meiotically heritable silencing information between two alleles. With paramutation at the maize (Zea mays) booster1 (b1) locus, the low-expressed B' epiallele heritably changes the high-expressed B-I epiallele into B' with 100% frequency. This requires specific tandem repeats and multiple components of the RNA-directed DNA methylation pathway, including the RNA-dependent RNA polymerase (encoded by mediator of paramutation1, mop1), the second-largest subunit of RNA polymerase IV and V (NRP(D/E)2a, encoded by mop2), and the largest subunit of RNA Polymerase IV (NRPD1, encoded by mop3). Mutations in mop genes prevent paramutation and release silencing at the B' epiallele. In this study, we investigated the effect of mutations in mop1, mop2, and mop3 on chromatin structure and DNA methylation at the B' epiallele, and especially the regulatory hepta-repeat 100 kb upstream of the b1 gene. Mutations in mop1 and mop3 resulted in decreased repressive histone modifications H3K9me2 and H3K27me2 at the hepta-repeat. Associated with this decrease were partial activation of the hepta-repeat enhancer function, formation of a multi-loop structure, and elevated b1 expression. In mop2 mutants, which do not show elevated b1 expression, H3K9me2, H3K27me2 and a single-loop structure like in wild-type B' were retained. Surprisingly, high CG and CHG methylation levels at the B' hepta-repeat remained in all three mutants, and CHH methylation was low in both wild type and mutants. Our results raise the possibility of MOP factors mediating RNA-directed histone methylation rather than RNA-directed DNA methylation at the b1 locus.
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Affiliation(s)
- Iris Hövel
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, P.O. Box 1210, 1090 GE Amsterdam, The Netherlands
| | - Rechien Bader
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, P.O. Box 1210, 1090 GE Amsterdam, The Netherlands
| | - Marieke Louwers
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, P.O. Box 1210, 1090 GE Amsterdam, The Netherlands
- argenx BV, Industriepark Zwijnaarde 7, 9052 Zwijnaarde (Ghent), Belgium
| | - Max Haring
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, P.O. Box 1210, 1090 GE Amsterdam, The Netherlands
- University Library, Universiteit van Amsterdam, P.O. Box 19185, 1000 GD Amsterdam, The Netherlands
| | - Kevin Peek
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, P.O. Box 1210, 1090 GE Amsterdam, The Netherlands
| | - Jonathan I Gent
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
| | - Maike Stam
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, P.O. Box 1210, 1090 GE Amsterdam, The Netherlands
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2
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Thieme M, Minadakis N, Himber C, Keller B, Xu W, Rutowicz K, Matteoli C, Böhrer M, Rymen B, Laudencia-Chingcuanco D, Vogel JP, Sibout R, Stritt C, Blevins T, Roulin AC. Transposition of HOPPLA in siRNA-deficient plants suggests a limited effect of the environment on retrotransposon mobility in Brachypodium distachyon. PLoS Genet 2024; 20:e1011200. [PMID: 38470914 PMCID: PMC10959353 DOI: 10.1371/journal.pgen.1011200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 03/22/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
Long terminal repeat retrotransposons (LTR-RTs) are powerful mutagens regarded as a major source of genetic novelty and important drivers of evolution. Yet, the uncontrolled and potentially selfish proliferation of LTR-RTs can lead to deleterious mutations and genome instability, with large fitness costs for their host. While population genomics data suggest that an ongoing LTR-RT mobility is common in many species, the understanding of their dual role in evolution is limited. Here, we harness the genetic diversity of 320 sequenced natural accessions of the Mediterranean grass Brachypodium distachyon to characterize how genetic and environmental factors influence plant LTR-RT dynamics in the wild. When combining a coverage-based approach to estimate global LTR-RT copy number variations with mobilome-sequencing of nine accessions exposed to eight different stresses, we find little evidence for a major role of environmental factors in LTR-RT accumulations in B. distachyon natural accessions. Instead, we show that loss of RNA polymerase IV (Pol IV), which mediates RNA-directed DNA methylation in plants, results in high transcriptional and transpositional activities of RLC_BdisC024 (HOPPLA) LTR-RT family elements, and that these effects are not stress-specific. This work supports findings indicating an ongoing mobility in B. distachyon and reveals that host RNA-directed DNA methylation rather than environmental factors controls their mobility in this wild grass model.
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Affiliation(s)
- Michael Thieme
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Nikolaos Minadakis
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Christophe Himber
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Université de Strasbourg, Strasbourg, France
| | - Bettina Keller
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Wenbo Xu
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Kinga Rutowicz
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Calvin Matteoli
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Université de Strasbourg, Strasbourg, France
| | - Marcel Böhrer
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Université de Strasbourg, Strasbourg, France
| | - Bart Rymen
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Université de Strasbourg, Strasbourg, France
| | - Debbie Laudencia-Chingcuanco
- United States Department of Agriculture Agricultural Research Service Western Regional Research Center, Albany, California, United States of America
| | - John P. Vogel
- United States Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Richard Sibout
- Institut National de la Recherche Agronomique Unité BIA- 1268 Biopolymères Interactions Assemblages Equipe Paroi Végétale et Polymères Pariétaux (PVPP), Nantes, France
| | - Christoph Stritt
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
| | - Todd Blevins
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Université de Strasbourg, Strasbourg, France
| | - Anne C. Roulin
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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3
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Luna-Arias JP, Castro-Muñozledo F. Participation of the TBP-associated factors (TAFs) in cell differentiation. J Cell Physiol 2024; 239:e31167. [PMID: 38126142 DOI: 10.1002/jcp.31167] [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: 09/18/2023] [Revised: 11/04/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023]
Abstract
The understanding of the mechanisms that regulate gene expression to establish differentiation programs and determine cell lineages, is one of the major challenges in Developmental Biology. Besides the participation of tissue-specific transcription factors and epigenetic processes, the role of general transcription factors has been ignored. Only in recent years, there have been scarce studies that address this issue. Here, we review the studies on the biological activity of some TATA-box binding protein (TBP)-associated factors (TAFs) during the proliferation of stem/progenitor cells and their involvement in cell differentiation. Particularly, the accumulated evidence suggests that TAF4, TAF4b, TAF7L, TAF8, TAF9, and TAF10, among others, participate in nervous system development, adipogenesis, myogenesis, and epidermal differentiation; while TAF1, TAF7, TAF15 may be involved in the regulation of stem cell proliferative abilities and cell cycle progression. On the other hand, evidence suggests that TBP variants such as TBPL1 and TBPL2 might be regulating some developmental processes such as germ cell maturation and differentiation, myogenesis, or ventral specification during development. Our analysis shows that it is necessary to study in greater depth the biological function of these factors and its participation in the assembly of specific transcription complexes that contribute to the differential gene expression that gives rise to the great diversity of cell types existing in an organism. The understanding of TAFs' regulation might lead to the development of new therapies for patients which suffer from mutations, alterations, and dysregulation of these essential elements of the transcriptional machinery.
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Affiliation(s)
- Juan Pedro Luna-Arias
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México City, Mexico
| | - Federico Castro-Muñozledo
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México City, Mexico
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4
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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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5
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Felgines L, Rymen B, Martins LM, Xu G, Matteoli C, Himber C, Zhou M, Eis J, Coruh C, Böhrer M, Kuhn L, Chicher J, Pandey V, Hammann P, Wohlschlegel J, Waltz F, Law JA, Blevins T. CLSY docking to Pol IV requires a conserved domain critical for small RNA biogenesis and transposon silencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.26.573199. [PMID: 38234754 PMCID: PMC10793415 DOI: 10.1101/2023.12.26.573199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Eukaryotes must balance the need for gene transcription by RNA polymerase II (Pol II) against the danger of mutations caused by transposable element (TE) proliferation. In plants, these gene expression and TE silencing activities are divided between different RNA polymerases. Specifically, RNA polymerase IV (Pol IV), which evolved from Pol II, transcribes TEs to generate small interfering RNAs (siRNAs) that guide DNA methylation and block TE transcription by Pol II. While the Pol IV complex is recruited to TEs via SNF2-like CLASSY (CLSY) proteins, how Pol IV partners with the CLSYs remains unknown. Here we identified a conserved CYC-YPMF motif that is specific to Pol IV and is positioned on the complex exterior. Furthermore, we found that this motif is essential for the co-purification of all four CLSYs with Pol IV, but that only one CLSY is present in any given Pol IV complex. These findings support a "one CLSY per Pol IV" model where the CYC-YPMF motif acts as a CLSY-docking site. Indeed, mutations in and around this motif phenocopy pol iv null mutants. Together, these findings provide structural and functional insights into a critical protein feature that distinguishes Pol IV from other RNA polymerases, allowing it to promote genome stability by targeting TEs for silencing.
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6
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Martins LM, Law JA. Moving targets: Mechanisms regulating siRNA production and DNA methylation during plant development. CURRENT OPINION IN PLANT BIOLOGY 2023; 75:102435. [PMID: 37598540 PMCID: PMC10581331 DOI: 10.1016/j.pbi.2023.102435] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/29/2023] [Accepted: 07/10/2023] [Indexed: 08/22/2023]
Abstract
DNA methylation is a conserved modification that must be precisely regulated during development to facilitate its roles in silencing transposable elements and regulating gene expression. In plants, DNA methylation changes during reproduction are widely documented and, in many cases, the underlying mechanisms are well understood. In somatic tissues, the diversity of methylation patterns are only recently emerging but they are often associated with the RNA-directed DNA methylation (RdDM) pathway. Here, we discuss advances in our understanding of how the locus-specific targeting and tissue-specific expression of RdDM proteins regulate methylation patterns, how the targeting of methylation at loci with imperfect homology expands the purview of RdDM, and how natural variation within RdDM factors impacts DNA methylation patterns.
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Affiliation(s)
- Laura M Martins
- Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - 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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7
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Zhang HW, Huang K, Gu ZX, Wu XX, Wang JW, Zhang Y. A cryo-EM structure of KTF1-bound polymerase V transcription elongation complex. Nat Commun 2023; 14:3118. [PMID: 37253723 DOI: 10.1038/s41467-023-38619-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/10/2023] [Indexed: 06/01/2023] Open
Abstract
De novo DNA methylation in plants relies on transcription of RNA polymerase V (Pol V) along with KTF1, which produce long non-coding RNAs for recruitment and assembly of the DNA methylation machinery. Here, we report a cryo-EM structure of the Pol V transcription elongation complex bound to KTF1. The structure reveals the conformation of the structural motifs in the active site of Pol V that accounts for its inferior RNA-extension ability. The structure also reveals structural features of Pol V that prevent it from interacting with the transcription factors of Pol II and Pol IV. The KOW5 domain of KTF1 binds near the RNA exit channel of Pol V providing a scaffold for the proposed recruitment of Argonaute proteins to initiate the assembly of the DNA methylation machinery. The structure provides insight into the Pol V transcription elongation process and the role of KTF1 during Pol V transcription-coupled DNA methylation.
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Affiliation(s)
- Hong-Wei Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kun Huang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhan-Xi Gu
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao-Xian Wu
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jia-Wei Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
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8
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Xu W, Sato H, Bente H, Santos-González J, Köhler C. Endosperm cellularization failure induces a dehydration-stress response leading to embryo arrest. THE PLANT CELL 2023; 35:874-888. [PMID: 36427255 PMCID: PMC9940880 DOI: 10.1093/plcell/koac337] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 11/22/2022] [Indexed: 06/16/2023]
Abstract
The endosperm is a nutritive tissue supporting embryo growth in flowering plants. Most commonly, the endosperm initially develops as a coenocyte (multinucleate cell) and then cellularizes. This process of cellularization is frequently disrupted in hybrid seeds generated by crosses between different flowering plant species or plants that differ in ploidy, resulting in embryo arrest and seed lethality. The reason for embryo arrest upon cellularization failure remains unclear. In this study, we show that triploid Arabidopsis thaliana embryos surrounded by uncellularized endosperm mount an osmotic stress response that is connected to increased levels of abscisic acid (ABA) and enhanced ABA responses. Impairing ABA biosynthesis and signaling aggravated triploid seed abortion, while increasing endogenous ABA levels as well as the exogenous application of ABA-induced endosperm cellularization and suppressed embryo growth arrest. Taking these results together, we propose that endosperm cellularization is required to establish dehydration tolerance in the developing embryo, ensuring its survival during seed maturation.
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Affiliation(s)
- Wenjia Xu
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
| | - Hikaru Sato
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
| | - Heinrich Bente
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Juan Santos-González
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
| | - Claudia Köhler
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
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9
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Shi M, Wang C, Wang P, Zhang M, Liao W. Methylation in DNA, histone, and RNA during flowering under stress condition: A review. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 324:111431. [PMID: 36028071 DOI: 10.1016/j.plantsci.2022.111431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/07/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
Flowering is the most critical transition period in the whole lifecycle of plants, and it is a highly sensitive period to stress. New combinations of temperature, drought stress, carbon dioxide and other abiotic/biotic conditions resulting from contemporary climate change affect the flowering process. Plants have evolved several strategies to deal with environmental stresses, including epigenetic modifications. Numerous studies show that environmental stresses trigger methylation/demethylation during flowering to preserve/accelerate plant lifecycle. What's more, histone and DNA methylation can be induced to respond to stresses, resulting in changes of flowering gene expression and enhancing stress tolerance in plants. Furthermore, RNA methylation may influence stress-regulated flowering by regulating mRNA stability and antioxidant mechanism. Our review presents the involvement of methylation in stress-repressed and stress-induced flowering. The crosstalk between methylation and small RNAs, phytohormones and exogenous substances (such as salicylic acid, nitric oxide) during flowering under different stresses were discussed. The latest regulatory evidence of RNA methylation in stress-regulated flowering was collected for the first time. Meanwhile, the limited evidences of methylation in biotic stress-induced flowering were summarized. Thus, the review provides insights into understanding of methylation mechanism in stress-regulated flowering and makes use for the development of regulating plant flowering at epigenetic level in the future.
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Affiliation(s)
- Meimei Shi
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China
| | - Chunlei Wang
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China
| | - Peng Wang
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China
| | - Meiling Zhang
- College of Science, Gansu Agricultural University, Lanzhou 730070, China
| | - Weibiao Liao
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China.
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10
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Tang Y, Yan X, Gu C, Yuan X. Biogenesis, Trafficking, and Function of Small RNAs in Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:825477. [PMID: 35251095 PMCID: PMC8891129 DOI: 10.3389/fpls.2022.825477] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/19/2022] [Indexed: 05/03/2023]
Abstract
Small RNAs (sRNAs) encoded by plant genomes have received widespread attention because they can affect multiple biological processes. Different sRNAs that are synthesized in plant cells can move throughout the plants, transport to plant pathogens via extracellular vesicles (EVs), and transfer to mammals via food. Small RNAs function at the target sites through DNA methylation, RNA interference, and translational repression. In this article, we reviewed the systematic processes of sRNA biogenesis, trafficking, and the underlying mechanisms of its functions.
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Affiliation(s)
- Yunjia Tang
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiaoning Yan
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Chenxian Gu
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiaofeng Yuan
- College of Life Science, Zhejiang Chinese Medical University, Hangzhou, China
- Academy of Chinese Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
- *Correspondence: Xiaofeng Yuan,
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11
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The Dynamism of Transposon Methylation for Plant Development and Stress Adaptation. Int J Mol Sci 2021; 22:ijms222111387. [PMID: 34768817 PMCID: PMC8583499 DOI: 10.3390/ijms222111387] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 02/06/2023] Open
Abstract
Plant development processes are regulated by epigenetic alterations that shape nuclear structure, gene expression, and phenotypic plasticity; these alterations can provide the plant with protection from environmental stresses. During plant growth and development, these processes play a significant role in regulating gene expression to remodel chromatin structure. These epigenetic alterations are mainly regulated by transposable elements (TEs) whose abundance in plant genomes results in their interaction with genomes. Thus, TEs are the main source of epigenetic changes and form a substantial part of the plant genome. Furthermore, TEs can be activated under stress conditions, and activated elements cause mutagenic effects and substantial genetic variability. This introduces novel gene functions and structural variation in the insertion sites and primarily contributes to epigenetic modifications. Altogether, these modifications indirectly or directly provide the ability to withstand environmental stresses. In recent years, many studies have shown that TE methylation plays a major role in the evolution of the plant genome through epigenetic process that regulate gene imprinting, thereby upholding genome stability. The induced genetic rearrangements and insertions of mobile genetic elements in regions of active euchromatin contribute to genome alteration, leading to genomic stress. These TE-mediated epigenetic modifications lead to phenotypic diversity, genetic variation, and environmental stress tolerance. Thus, TE methylation is essential for plant evolution and stress adaptation, and TEs hold a relevant military position in the plant genome. High-throughput techniques have greatly advanced the understanding of TE-mediated gene expression and its associations with genome methylation and suggest that controlled mobilization of TEs could be used for crop breeding. However, development application in this area has been limited, and an integrated view of TE function and subsequent processes is lacking. In this review, we explore the enormous diversity and likely functions of the TE repertoire in adaptive evolution and discuss some recent examples of how TEs impact gene expression in plant development and stress adaptation.
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12
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The effect of RNA polymerase V on 24-nt siRNA accumulation depends on DNA methylation contexts and histone modifications in rice. Proc Natl Acad Sci U S A 2021; 118:2100709118. [PMID: 34290143 DOI: 10.1073/pnas.2100709118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
RNA-directed DNA methylation (RdDM) functions in de novo methylation in CG, CHG, and CHH contexts. Here, we performed map-based cloning of OsNRPE1, which encodes the largest subunit of RNA polymerase V (Pol V), a key regulator of gene silencing and reproductive development in rice. We found that rice Pol V is required for CHH methylation on RdDM loci by transcribing long noncoding RNAs. Pol V influences the accumulation of 24-nucleotide small interfering RNAs (24-nt siRNAs) in a locus-specific manner. Biosynthesis of 24-nt siRNAs on loci with high CHH methylation levels and low CG and CHG methylation levels tends to depend on Pol V. In contrast, low methylation levels in the CHH context and high methylation levels in CG and CHG contexts predisposes 24-nt siRNA accumulation to be independent of Pol V. H3K9me1 and H3K9me2 tend to be enriched on Pol V-independent 24-nt siRNA loci, whereas various active histone modifications are enriched on Pol V-dependent 24-nt siRNA loci. DNA methylation is required for 24-nt siRNAs biosynthesis on Pol V-dependent loci but not on Pol V-independent loci. Our results reveal the function of rice Pol V for long noncoding RNA production, DNA methylation, 24-nt siRNA accumulation, and reproductive development.
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13
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Crespi M. Plant transcription links environmental cues and phenotypic plasticity. Transcription 2020; 11:97-99. [PMID: 33252015 DOI: 10.1080/21541264.2020.1837498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- M Crespi
- Institute of Plant Sciences Paris-Saclay IPS2, Universities of Paris-Saclay and Evry, CNRS, INRAE , Gif sur Yvette, France.,Institute of Plant Sciences Paris-Saclay IPS2, University of Paris, CNRS, INRAE , Gif sur Yvette, France
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