151
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Xie L, Lin L, Huang S, Yang T, Shi D, Li X. Inhibition of Suv39H1 enhances transgenic IFNα-2b gene expression in Bcap-37 cells. Anim Biotechnol 2018; 30:358-365. [PMID: 30179066 DOI: 10.1080/10495398.2018.1500373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The low expression of exogenous transferred gene limited the application of transgenic animal technology. Suppressor of variegation 3 ∼ 9 homolog 1(SUV39H1) gene plays a prominent role on repressive heterochromatin and transcription. To understand if exogenous transgenic gene expression was affected by SUV39H1 epigenetic modification, in this paper, the effective shRNA fragments targeting SUV39H1 gene were first screened, their roles on expression of exogenous transgenic genes were determined by using Bcap-37 cell line with stable expressing IFNα-2b gene as a model, the preliminary regulation mechanism of SUV39H1 gene was investigated. The results showed that the designed shRNA1/2 fragments of SUV39H1 gene had an obvious inhibition effect on the expression of SUV39H1 gene, reached 53.07 and 31.28%, respectively by qRT-PCR analysis. Compared with the control group, the expression of IFNα-2b gene in transgenic Bcap-37 cells infected with shRNA1 and 2 viruses significantly increased by 96.25 and 121.08%, respectively (p < 0.05). In addition, the expression of DNMT1, HDAC1 and G9a gene in the shRNA infected cells reduced significantly, and the expression of the HAT1 gene increased significantly (p < 0.05). The above results indicated that the expression of exogenous transgenic gene could be promoted by suppressing SUV39H1 gene at the cell level.
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Affiliation(s)
- Liangliang Xie
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University , Guangxi , China
| | - Lang Lin
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University , Guangxi , China
| | - Shihai Huang
- College of Life Science and Technology, Guangxi University , Guangxi , China
| | - Ting Yang
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University , Guangxi , China
| | - Deshun Shi
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University , Guangxi , China
| | - Xiangping Li
- State Key Laboratory of Subtropical Bioresource Conservation and Utilization at Guangxi University , Guangxi , China
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152
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Meller B, Kuźnicki D, Arasimowicz-Jelonek M, Deckert J, Floryszak-Wieczorek J. BABA-Primed Histone Modifications in Potato for Intergenerational Resistance to Phytophthora infestans. FRONTIERS IN PLANT SCIENCE 2018; 9:1228. [PMID: 30233606 PMCID: PMC6135045 DOI: 10.3389/fpls.2018.01228] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/02/2018] [Indexed: 05/23/2023]
Abstract
In this paper we analyzed β-aminobutyric acid (BABA)-primed epigenetic adjustment of potato cv. "Sarpo Mira" to Phytophthora infestans. The first stress-free generation of the potato genotype obtained from BABA-primed parent plants via tubers and seeds showed pronounced resistance to the pathogen, which was tuned with the transcriptional memory of SA-responsive genes. During the early priming phase before the triggering stress, we found robust bistable deposition of histone marks (H3K4me2 and H3K27me3) on the NPR1 (Non-expressor of PR genes) and the SNI1 gene (Suppressor of NPR1, Inducible), in which transcription antagonized silencing. Switchable chromatin states of these adverse systemic acquired resistance (SAR) regulators probably reprogrammed responsiveness of the PR1 and PR2 genes and contributed to stress imprinting. The elevated levels of heritable H3K4me2 tag in the absence of transcription on SA-dependent genes in BABA-primed (F0) and its vegetative and generative progeny (F1) before pathogen challenge provided evidence for the epigenetic mark for intergenerational memory in potato. Moreover, our study revealed that histone acetylation was not critical for maintaining BABA-primed defense information until the plants were triggered with the virulent pathogen when rapid and boosted PRs gene expression probably required histone acetyltransferase (HAT) activity both in F0 and F1 progeny.
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Affiliation(s)
- Barbara Meller
- Department of Plant Physiology, Poznań University of Life Sciences, Poznań, Poland
| | - Daniel Kuźnicki
- Department of Plant Physiology, Poznań University of Life Sciences, Poznań, Poland
| | | | - Joanna Deckert
- Department of Plant Ecophysiology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań, Poland
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153
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Mechanistic insights into plant SUVH family H3K9 methyltransferases and their binding to context-biased non-CG DNA methylation. Proc Natl Acad Sci U S A 2018; 115:E8793-E8802. [PMID: 30150382 DOI: 10.1073/pnas.1809841115] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
DNA methylation functions in gene silencing and the maintenance of genome integrity. In plants, non-CG DNA methylation is linked through a self-reinforcing loop with histone 3 lysine 9 dimethylation (H3K9me2). The plant-specific SUPPRESSOR OF VARIEGATION 3-9 HOMOLOG (SUVH) family H3K9 methyltransferases (MTases) bind to DNA methylation marks and catalyze H3K9 methylation. Here, we analyzed the structure and function of Arabidopsis thaliana SUVH6 to understand how this class of enzyme maintains methylation patterns in the genome. We reveal that SUVH6 has a distinct 5-methyl-dC (5mC) base-flipping mechanism involving a thumb loop element. Autoinhibition of H3 substrate entry is regulated by a SET domain loop, and a conformational transition in the post-SET domain upon cofactor binding may control catalysis. In vitro DNA binding and in vivo ChIP-seq data reveal that the different SUVH family H3K9 MTases have distinct DNA binding preferences, targeting H3K9 methylation to sites with different methylated DNA sequences, explaining the context biased non-CG DNA methylation in plants.
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154
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Relationship between epigenetic marks and the behavior of 45S rDNA sites in chromosomes and interphase nuclei of Lolium-Festuca complex. Mol Biol Rep 2018; 45:1663-1679. [PMID: 30121822 DOI: 10.1007/s11033-018-4310-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/14/2018] [Indexed: 10/28/2022]
Abstract
The grasses of the Lolium-Festuca complex show a prominent role in world agricultural scenario. Several studies have demonstrated that the plasticity of 45S rDNA sites has been recently associated with the possible fragility of the loci. Often, these fragile sites were observed as extended sites and gaps in metaphases. This organization can be evaluated in relation to their transcriptional activity/accessibility through epigenetic changes. Thus, this study aimed to investigate the relationship of the 5-methylcytosine and histone H3 lysine-9 dimethylation in different conformations of 45S rDNA sites in interphase nuclei and in metaphase chromosomes of L. perenne, L. multiflorum and F. arundinacea. The FISH technique using 45S rDNA probes was performed sequentially after the immunolocalization. The sites showed predominantly the following characteristics in the interphase nuclei: intra- and perinucleolar position, decondensed or partially condensed and hypomethylated and hyper/hypomethylated status. Extranucleolar sites were mainly hypermethylated for both epigenetic marks. The 45S rDNA sites with gaps identified in metaphases were always hypomethylated, which justifies it decondensed and transcriptional state. The frequency of sites with hypermethylated gaps was very low. The structural differences observed in these sites are directly related to the assessed epigenetic marks, justifying the different conformations throughout the cell cycle.
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155
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Wang H, Jiang D, Axelsson E, Lorković ZJ, Montgomery S, Holec S, Pieters BJGE, Al Temimi AHK, Mecinović J, Berger F. LHP1 Interacts with ATRX through Plant-Specific Domains at Specific Loci Targeted by PRC2. MOLECULAR PLANT 2018; 11:1038-1052. [PMID: 29793052 DOI: 10.1016/j.molp.2018.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 04/10/2018] [Accepted: 05/11/2018] [Indexed: 06/08/2023]
Abstract
Heterochromatin Protein 1 (HP1) is a major regulator of chromatin structure and function. In animals, the network of proteins interacting with HP1 is mainly associated with constitutive heterochromatin marked by H3K9me3. HP1 physically interacts with the putative ortholog of the SNF2 chromatin remodeler ATRX, which controls deposition of histone variant H3.3 in mammals. In this study, we show that the Arabidopsis thaliana ortholog of ATRX participates in H3.3 deposition and possesses specific conserved domains in plants. We found that plant Like HP1 (LHP1) protein interacts with ATRX through domains that evolved specifically in land plant ancestors. Loss of ATRX function in Arabidopsis affects the expression of a limited subset of genes controlled by PRC2 (POLYCOMB REPRESSIVE COMPLEX 2), including the flowering time regulator FLC. The function of ATRX in regulation of flowering time requires novel LHP1-interacting domain and ATPase activity of the ATRX SNF2 helicase domain. Taken together, these results suggest that distinct evolutionary pathways led to the interaction between ATRX and HP1 in mammals and its counterpart LHP1 in plants, resulting in distinct modes of transcriptional regulation.
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Affiliation(s)
- Haifeng Wang
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, 117604 Singapore, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543 Singapore, Singapore
| | - Danhua Jiang
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, 117604 Singapore, Singapore
| | - Elin Axelsson
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Zdravko J Lorković
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Sean Montgomery
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Sarah Holec
- Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, 117604 Singapore, Singapore
| | - Bas J G E Pieters
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Abbas H K Al Temimi
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Jasmin Mecinović
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, 117604 Singapore, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543 Singapore, Singapore.
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156
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Abstract
Heterochromatin is a key architectural feature of eukaryotic chromosomes, which endows particular genomic domains with specific functional properties. The capacity of heterochromatin to restrain the activity of mobile elements, isolate DNA repair in repetitive regions and ensure accurate chromosome segregation is crucial for maintaining genomic stability. Nucleosomes at heterochromatin regions display histone post-translational modifications that contribute to developmental regulation by restricting lineage-specific gene expression. The mechanisms of heterochromatin establishment and of heterochromatin maintenance are separable and involve the ability of sequence-specific factors bound to nascent transcripts to recruit chromatin-modifying enzymes. Heterochromatin can spread along the chromatin from nucleation sites. The propensity of heterochromatin to promote its own spreading and inheritance is counteracted by inhibitory factors. Because of its importance for chromosome function, heterochromatin has key roles in the pathogenesis of various human diseases. In this Review, we discuss conserved principles of heterochromatin formation and function using selected examples from studies of a range of eukaryotes, from yeast to human, with an emphasis on insights obtained from unicellular model organisms.
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157
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Underwood CJ, Choi K, Lambing C, Zhao X, Serra H, Borges F, Simorowski J, Ernst E, Jacob Y, Henderson IR, Martienssen RA. Epigenetic activation of meiotic recombination near Arabidopsis thaliana centromeres via loss of H3K9me2 and non-CG DNA methylation. Genome Res 2018; 28:519-531. [PMID: 29530927 PMCID: PMC5880242 DOI: 10.1101/gr.227116.117] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 01/15/2018] [Indexed: 02/02/2023]
Abstract
Eukaryotic centromeres contain the kinetochore, which connects chromosomes to the spindle allowing segregation. During meiosis, centromeres are suppressed for inter-homolog crossover, as recombination in these regions can cause chromosome missegregation and aneuploidy. Plant centromeres are surrounded by transposon-dense pericentromeric heterochromatin that is epigenetically silenced by histone 3 lysine 9 dimethylation (H3K9me2), and DNA methylation in CG and non-CG sequence contexts. However, the role of these chromatin modifications in control of meiotic recombination in the pericentromeres is not fully understood. Here, we show that disruption of Arabidopsis thaliana H3K9me2 and non-CG DNA methylation pathways, for example, via mutation of the H3K9 methyltransferase genes KYP/SUVH4 SUVH5 SUVH6, or the CHG DNA methyltransferase gene CMT3, increases meiotic recombination in proximity to the centromeres. Using immunocytological detection of MLH1 foci and genotyping by sequencing of recombinant plants, we observe that H3K9me2 and non-CG DNA methylation pathway mutants show increased pericentromeric crossovers. Increased pericentromeric recombination in H3K9me2/non-CG mutants occurs in hybrid and inbred backgrounds and likely involves contributions from both the interfering and noninterfering crossover repair pathways. We also show that meiotic DNA double-strand breaks (DSBs) increase in H3K9me2/non-CG mutants within the pericentromeres, via purification and sequencing of SPO11-1-oligonucleotides. Therefore, H3K9me2 and non-CG DNA methylation exert a repressive effect on both meiotic DSB and crossover formation in plant pericentromeric heterochromatin. Our results may account for selection of enhancer trap Dissociation (Ds) transposons into the CMT3 gene by recombination with proximal transposon launch-pads.
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Affiliation(s)
- Charles J. Underwood
- Howard Hughes Medical Institute, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA;,Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Kyuha Choi
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Christophe Lambing
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Xiaohui Zhao
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Heïdi Serra
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Filipe Borges
- Howard Hughes Medical Institute, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Joe Simorowski
- Howard Hughes Medical Institute, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Evan Ernst
- Howard Hughes Medical Institute, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Yannick Jacob
- Howard Hughes Medical Institute, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ian R. Henderson
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Robert A. Martienssen
- Howard Hughes Medical Institute, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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158
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Wendte JM, Schmitz RJ. Specifications of Targeting Heterochromatin Modifications in Plants. MOLECULAR PLANT 2018; 11:381-387. [PMID: 29032247 DOI: 10.1016/j.molp.2017.10.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/06/2017] [Accepted: 10/08/2017] [Indexed: 05/19/2023]
Abstract
Plants encode a diverse repertoire of DNA methyltransferases that have specialized to target cytosines for methylation in specific sequence contexts. These include the de novo methyltransferase, DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2), which methylates cytosines in all sequence contexts through an RNA-guided process, the CHROMOMETHYLASES (CMTs), which methylate CHH and CHG cytosines (where H is A, T, or C), and METHYLTRANSFERASE 1 (MET1), which maintains methylation of symmetrical CG contexts. In this review, we discuss the sequence specificities and targeting of each of these pathways. In particular, we highlight recent studies that indicate CMTs preferentially target CWG or CWA/CAW motifs (where W is A or T), and discuss how self-reinforcing feedback loops between DNA methyltransferases and histone modifications characteristic of heterochromatin specify targeting. Finally, the initiating events that lead to gene body methylation are discussed as a model illustrating how interdependent targeting of different silencing pathways can potentiate the establishment of off-target epialleles.
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Affiliation(s)
- Jered M Wendte
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA 30602, USA.
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159
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Brocklehurst S, Watson M, Carr IM, Out S, Heidmann I, Meyer P. Induction of epigenetic variation in Arabidopsis by over-expression of DNA METHYLTRANSFERASE1 (MET1). PLoS One 2018; 13:e0192170. [PMID: 29466369 PMCID: PMC5821449 DOI: 10.1371/journal.pone.0192170] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/17/2018] [Indexed: 11/18/2022] Open
Abstract
Epigenetic marks such as DNA methylation and histone modification can vary among plant accessions creating epi-alleles with different levels of expression competence. Mutations in epigenetic pathway functions are powerful tools to induce epigenetic variation. As an alternative approach, we investigated the potential of over-expressing an epigenetic function, using DNA METHYLTRANSFERASE1 (MET1) for proof-of-concept. In Arabidopsis thaliana, MET1 controls maintenance of cytosine methylation at symmetrical CG positions. At some loci, which contain dense DNA methylation in CG- and non-CG context, loss of MET1 causes joint loss of all cytosines methylation marks. We find that over-expression of both catalytically active and inactive versions of MET1 stochastically generates new epi-alleles at loci encoding transposable elements, non-coding RNAs and proteins, which results for most loci in an increase in expression. Individual transformants share some common phenotypes and genes with altered gene expression. Altered expression states can be transmitted to the next generation, which does not require the continuous presence of the MET1 transgene. Long-term stability and epigenetic features differ for individual loci. Our data show that over-expression of MET1, and potentially of other genes encoding epigenetic factors, offers an alternative strategy to identify epigenetic target genes and to create novel epi-alleles.
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Affiliation(s)
| | - Michael Watson
- Center for Plant Sciences, University of Leeds, Leeds, United Kingdom
| | - Ian M. Carr
- School of Medicine Institute of Biomed. & Clin. Sciences (LIBACS), University of Leeds, Leeds, United Kingdom
| | - Suzan Out
- Enza Zaden Research and Development B.V., Enkhuizen, NL
| | - Iris Heidmann
- Enza Zaden Research and Development B.V., Enkhuizen, NL
| | - Peter Meyer
- Center for Plant Sciences, University of Leeds, Leeds, United Kingdom
- * E-mail:
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160
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Yolcu S, Li X, Li S, Kim YJ. Beyond the genetic code in leaf senescence. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:801-810. [PMID: 29253191 DOI: 10.1093/jxb/erx401] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 05/10/2017] [Indexed: 06/07/2023]
Abstract
Leaf senescence is not only genetically programmed but also induced by exogenous stress to ensure completion of the plant life cycle, successful reproduction and environmental adaptability. Genetic reprogramming is a major aspect of leaf senescence, and the senescence signaling that follows is controlled by a complex regulatory network. Recent studies suggest that the activity of transcription factors together with epigenetic mechanisms ensures the robustness of this network, with the latter including chromatin remodeling, DNA modification, and RNA-mediated control of transcription factors and other senescence-associated genes. In this review, we provide an overview of the relevant epigenetic mechanisms and summarize recent findings of epigenetic regulators of plant leaf senescence involved in DNA methylation and histone modification along with the functions of small RNAs in this process.
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Affiliation(s)
- Seher Yolcu
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, Republic of Korea
| | - Xiaojie Li
- Agricultural Genomics Institute, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Shengben Li
- Agricultural Genomics Institute, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yun Ju Kim
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, Republic of Korea
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161
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Xu J, Zhou S, Gong X, Song Y, van Nocker S, Ma F, Guan Q. Single-base methylome analysis reveals dynamic epigenomic differences associated with water deficit in apple. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:672-687. [PMID: 28796917 PMCID: PMC5787839 DOI: 10.1111/pbi.12820] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/12/2017] [Accepted: 08/07/2017] [Indexed: 05/11/2023]
Abstract
Cytosine methylation is an essential feature of epigenetic regulation and is involved in various biological processes. Although cytosine methylation has been analysed at the genomic scale for several plant species, there is a general lack of understanding of the dynamics of global and genic DNA methylation in plants growing in environments challenged with biotic and abiotic stresses. In this study, we mapped cytosine methylation at single-base resolution in the genome of commercial apple (Malus x domestica), and analysed changes in methylation patterns associated with water deficit in representative drought-sensitive and drought-tolerant cultivars. We found that the apple genome exhibits ~54%, ~38% and ~8.5% methylation at CG, CHG and CHH sequence contexts, respectively. We additionally documented changes in gene expression associated with water deficit in an attempt to link methylation and gene expression changes. Global methylation and transcription analysis revealed that promoter-unmethylated genes showed higher expression levels than promoter-methylated genes. Gene body methylation appears to be positively correlated with gene expression. Water deficit stress was associated with changes in methylation at a multitude of genes, including those encoding transcription factors (TFs) and transposable elements (TEs). These results present a methylome map of the apple genome and reveal widespread DNA methylation alterations in response to water deficit stress. These data will be helpful for understanding potential linkages between DNA methylation and gene expression in plants growing in natural environments and challenged with abiotic and biotic stresses.
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Affiliation(s)
- Jidi Xu
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Shasha Zhou
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Xiaoqing Gong
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Yi Song
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Steve van Nocker
- Department of HorticultureMichigan State UniversityEast LansingMIUSA
| | - Fengwang Ma
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Qingmei Guan
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
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162
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LaBonte NR, Zhao P, Woeste K. Signatures of Selection in the Genomes of Chinese Chestnut ( Castanea mollissima Blume): The Roots of Nut Tree Domestication. FRONTIERS IN PLANT SCIENCE 2018; 9:810. [PMID: 29988533 PMCID: PMC6026767 DOI: 10.3389/fpls.2018.00810] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/25/2018] [Indexed: 05/18/2023]
Abstract
Chestnuts (Castanea) are major nut crops in East Asia and southern Europe, and are unique among temperate nut crops in that the harvested seeds are starchy rather than oily. Chestnut species have been cultivated for three millennia or more in China, so it is likely that artificial selection has affected the genome of orchard-grown chestnuts. The genetics of Chinese chestnut (Castanea mollissima Blume) domestication are also of interest to breeders of hybrid American chestnut, especially if the low-growing, branching habit of Chinese chestnut, an impediment to American chestnut restoration, is partly the result of artificial selection. We resequenced genomes of wild and orchard-derived Chinese chestnuts and identified selective sweeps based on pooled whole-genome SNP datasets. We present candidate gene loci for chestnut domestication and discuss the potential phenotypic effects of candidate loci, some of which may be useful genes for chestnut improvement in Asia and North America. Selective sweeps included predicted genes potentially related to flower phenology and development, fruit maturation, and secondary metabolism, and included some genes homologous to domestication candidates in other woody plants.
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Affiliation(s)
- Nicholas R. LaBonte
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Nicholas R. LaBonte
| | - Peng Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
| | - Keith Woeste
- Hardwood Tree Improvement and Regeneration Center, Northern Research Station, USDA Forest Service, West Lafayette, IN, United States
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163
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Jacob Y, Voigt P. In Vitro Assays to Measure Histone Methyltransferase Activity Using Different Chromatin Substrates. Methods Mol Biol 2018; 1675:345-360. [PMID: 29052201 DOI: 10.1007/978-1-4939-7318-7_20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In vitro histone modification (HM) assays are used to characterize the activity of chromatin-modifying enzymes. These assays provide information regarding the modification sites on histones, the product specificity, and the impact of other histone or nucleotide modifications on enzyme activity. In particular, histone methyltransferase (HMT) assays have been instrumental in elucidating the activity and site specificity of many plant HMT enzymes. In this chapter, we describe a general protocol that can be used to perform HMT assays using different chromatin substrates, detection methods, and enzymes directly purified from plant material or heterologous sources.
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Affiliation(s)
- Yannick Jacob
- Department of Molecular, Cellular and Developmental Biology, Yale University, 165 Prospect St., New Haven, CT, 06511-2106, USA
| | - Philipp Voigt
- Wellcome Trust Centre for Cell Biology, The University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF, UK.
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164
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Ramirez-Prado JS, Piquerez SJM, Bendahmane A, Hirt H, Raynaud C, Benhamed M. Modify the Histone to Win the Battle: Chromatin Dynamics in Plant-Pathogen Interactions. FRONTIERS IN PLANT SCIENCE 2018; 9:355. [PMID: 29616066 PMCID: PMC5868138 DOI: 10.3389/fpls.2018.00355] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/02/2018] [Indexed: 05/02/2023]
Abstract
Relying on an immune system comes with a high energetic cost for plants. Defense responses in these organisms are therefore highly regulated and fine-tuned, permitting them to respond pertinently to the attack of a microbial pathogen. In recent years, the importance of the physical modification of chromatin, a highly organized structure composed of genomic DNA and its interacting proteins, has become evident in the research field of plant-pathogen interactions. Several processes, including DNA methylation, changes in histone density and variants, and various histone modifications, have been described as regulators of various developmental and defense responses. Herein, we review the state of the art in the epigenomic aspects of plant immunity, focusing on chromatin modifications, chromatin modifiers, and their physiological consequences. In addition, we explore the exciting field of understanding how plant pathogens have adapted to manipulate the plant epigenomic regulation in order to weaken their immune system and thrive in their host, as well as how histone modifications in eukaryotic pathogens are involved in the regulation of their virulence.
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Affiliation(s)
- Juan S. Ramirez-Prado
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, University Paris-Sud, University of Évry Val d’Essonne, University Paris Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, UMR9213 Institut des Sciences des Plantes de Paris Saclay, Essonne, France
| | - Sophie J. M. Piquerez
- Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, University Paris-Sud, University of Évry Val d’Essonne, University Paris Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, UMR9213 Institut des Sciences des Plantes de Paris Saclay, Essonne, France
| | - Abdelhafid Bendahmane
- Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, University Paris-Sud, University of Évry Val d’Essonne, University Paris Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, UMR9213 Institut des Sciences des Plantes de Paris Saclay, Essonne, France
| | - Heribert Hirt
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, University Paris-Sud, University of Évry Val d’Essonne, University Paris Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, UMR9213 Institut des Sciences des Plantes de Paris Saclay, Essonne, France
| | - Cécile Raynaud
- Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, University Paris-Sud, University of Évry Val d’Essonne, University Paris Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, UMR9213 Institut des Sciences des Plantes de Paris Saclay, Essonne, France
| | - Moussa Benhamed
- Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, University Paris-Sud, University of Évry Val d’Essonne, University Paris Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, UMR9213 Institut des Sciences des Plantes de Paris Saclay, Essonne, France
- *Correspondence: Moussa Benhamed,
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Itabashi E, Osabe K, Fujimoto R, Kakizaki T. Epigenetic regulation of agronomical traits in Brassicaceae. PLANT CELL REPORTS 2018; 37:87-101. [PMID: 29058037 DOI: 10.1007/s00299-017-2223-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/05/2017] [Indexed: 05/08/2023]
Abstract
Epigenetic regulation, covalent modification of DNA and changes in histone proteins are closely linked to plant development and stress response through flexibly altering the chromatin structure to regulate gene expression. In this review, we will illustrate the importance of epigenetic influences by discussing three agriculturally important traits of Brassicaceae. (1) Vernalization, an acceleration of flowering by prolonged cold exposure regulated through epigenetic silencing of a central floral repressor, FLOWERING LOCUS C. This is associated with cold-dependent repressive histone mark accumulation, which confers competency of consequence vegetative-to-reproductive phase transition. (2) Hybrid vigor, in which an F1 hybrid shows superior performance to the parental lines. Combination of distinct epigenomes with different DNA methylation states between parental lines is important for increase in growth rate in a hybrid progeny. This is independent of siRNA-directed DNA methylation but dependent on the chromatin remodeler DDM1. (3) Self-incompatibility, a reproductive mating system to prevent self-fertilization. This is controlled by the S-locus consisting of SP11 and SRK which are responsible for self/non-self recognition. Because self-incompatibility in Brassicaceae is sporophytically controlled, there are dominance relationships between S haplotypes in the stigma and pollen. The dominance relationships in the pollen rely on de novo DNA methylation at the promoter region of a recessive allele, which is triggered by siRNA production from a flanking region of a dominant allele.
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Affiliation(s)
- Etsuko Itabashi
- Institute of Vegetable and Floriculture Science, NARO, Kusawa, Ano, Tsu, Mie, 514-2392, Japan.
| | - Kenji Osabe
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Kunigami, Okinawa, 904-0495, Japan
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Tomohiro Kakizaki
- Institute of Vegetable and Floriculture Science, NARO, Kusawa, Ano, Tsu, Mie, 514-2392, Japan
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166
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Sarma S, Lodha M. Phylogenetic relationship and domain organisation of SET domain proteins of Archaeplastida. BMC PLANT BIOLOGY 2017; 17:238. [PMID: 29228906 PMCID: PMC5725981 DOI: 10.1186/s12870-017-1177-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND SET is a conserved protein domain with methyltransferase activity. Several genome and transcriptome data in plant lineage (Archaeplastida) are available but status of SET domain proteins in most of the plant lineage is not comprehensively analysed. RESULTS In this study phylogeny and domain organisation of 506 computationally identified SET domain proteins from 16 members of plant lineage (Archaeplastida) are presented. SET domain proteins of rice and Arabidopsis are used as references. This analysis revealed conserved as well as unique features of SET domain proteins in Archaeplastida. SET domain proteins of plant lineage can be categorised into five classes- E(z), Ash, Trx, Su(var) and Orphan. Orphan class of SET proteins contain unique domains predominantly in early Archaeplastida. Contrary to previous study, this study shows first appearance of several domains like SRA on SET domain proteins in chlorophyta instead of bryophyta. CONCLUSION The present study is a framework to experimentally characterize SET domain proteins in plant lineage.
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Affiliation(s)
- Supriya Sarma
- Centre for Cellular and Molecular Biology (CSIR), Uppal Road, Habsiguda, Hyderabad, 500007, India.
| | - Mukesh Lodha
- Centre for Cellular and Molecular Biology (CSIR), Uppal Road, Habsiguda, Hyderabad, 500007, India.
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Huang SSC, Ecker JR. Piecing together cis-regulatory networks: insights from epigenomics studies in plants. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 10:e1411. [PMID: 29194997 DOI: 10.1002/wsbm.1411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/11/2017] [Accepted: 10/12/2017] [Indexed: 12/20/2022]
Abstract
5-Methylcytosine, a chemical modification of DNA, is a covalent modification found in the genomes of both plants and animals. Epigenetic inheritance of phenotypes mediated by DNA methylation is well established in plants. Most of the known mechanisms of establishing, maintaining and modifying DNA methylation have been worked out in the reference plant Arabidopsis thaliana. Major functions of DNA methylation in plants include regulation of gene expression and silencing of transposable elements (TEs) and repetitive sequences, both of which have parallels in mammalian biology, involve interaction with the transcriptional machinery, and may have profound effects on the regulatory networks in the cell. Methylome and transcriptome dynamics have been investigated in development and environmental responses in Arabidopsis and agriculturally and ecologically important plants, revealing the interdependent relationship among genomic context, methylation patterns, and expression of TE and protein coding genes. Analyses of methylome variation among plant natural populations and species have begun to quantify the extent of genetic control of methylome variation vs. true epimutation, and model the evolutionary forces driving methylome evolution in both short and long time scales. The ability of DNA methylation to positively or negatively modulate binding affinity of transcription factors (TFs) provides a natural link from genome sequence and methylation changes to transcription. Technologies that allow systematic determination of methylation sensitivities of TFs, in native genomic and methylation context without confounding factors such as histone modifications, will provide baseline datasets for building cell-type- and individual-specific regulatory networks that underlie the establishment and inheritance of complex traits. This article is categorized under: Laboratory Methods and Technologies > Genetic/Genomic Methods Biological Mechanisms > Regulatory Biology.
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Affiliation(s)
- Shao-Shan C Huang
- Genomic Analysis Laboratory and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Joseph R Ecker
- Genomic Analysis Laboratory and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.,Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA, USA
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Wang PH, Wittmeyer KT, Lee TF, Meyers BC, Chopra S. Overlapping RdDM and non-RdDM mechanisms work together to maintain somatic repression of a paramutagenic epiallele of maize pericarp color1. PLoS One 2017; 12:e0187157. [PMID: 29112965 PMCID: PMC5675401 DOI: 10.1371/journal.pone.0187157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 10/14/2017] [Indexed: 11/18/2022] Open
Abstract
Allelic variation at the Zea mays (maize) pericarp color1 (p1) gene has been attributed to epigenetic gene regulation. A p1 distal enhancer, 5.2 kb upstream of the transcriptional start site, has demonstrated variation in DNA methylation in different p1 alleles/epialleles. In addition, DNA methylation of sequences within the 3’ end of intron 2 also plays a role in tissue-specific expression of p1 alleles. We show here a direct evidence for small RNAs’ involvement in regulating p1 that has not been demonstrated previously. The role of mediator of paramutation1 (mop1) was tested in the maintenance of somatic silencing at distinct p1 alleles: the non-paramutagenic P1-wr allele and paramutagenic P1-rr’ epiallele. The mop1-1 mutation gradually relieves the silenced phenotype after multiple generations of exposure; P1-wr;mop1-1 plants display a loss of 24-nt small RNAs and DNA methylation in the 3’ end of the intron 2, a region close to a Stowaway transposon. In addition, a MULE sequence within the proximal promoter of P1-wr shows depletion of 24nt siRNAs in mop1-1 plants. Release of silencing was not correlated with small RNAs at the distal enhancer region of the P1-wr allele. We found that the somatic silencing of the paramutagenic P1-rr’ is correlated with significantly reduced H3K9me2 in the distal enhancer of P1-rr’; mop1-1 plants, while symmetric DNA methylation is not significantly different. This study highlights that the epigenetic regulation of p1 alleles is controlled both via RdDM as well as non-RdDM mechanisms.
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Affiliation(s)
- Po-Hao Wang
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Kameron T. Wittmeyer
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Plant Biology Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Tzuu-fen Lee
- Department of Plant & Soil Sciences and Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
| | - Blake C. Meyers
- Department of Plant & Soil Sciences and Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
| | - Surinder Chopra
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Plant Biology Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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169
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Satish M, Nivya MA, Abhishek S, Nakarakanti NK, Shivani D, Vani MV, Rajakumara E. Computational characterization of substrate and product specificities, and functionality of S-adenosylmethionine binding pocket in histone lysine methyltransferases from Arabidopsis, rice and maize. Proteins 2017; 86:21-34. [PMID: 29024026 DOI: 10.1002/prot.25399] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/21/2017] [Accepted: 10/08/2017] [Indexed: 12/15/2022]
Abstract
Histone lysine methylation by histone lysine methyltransferases (HKMTs) has been implicated in regulation of gene expression. While significant progress has been made to understand the roles and mechanisms of animal HKMT functions, only a few plant HKMTs are functionally characterized. To unravel histone substrate specificity, degree of methylation and catalytic activity, we analyzed Arabidopsis Trithorax-like protein (ATX), Su(var)3-9 homologs protein (SUVH), Su(var)3-9 related protein (SUVR), ATXR5, ATXR6, and E(Z) HKMTs of Arabidopsis, maize and rice through sequence and structure comparison. We show that ATXs may exhibit methyltransferase specificity toward histone 3 lysine 4 (H3K4) and might catalyse the trimethylation. Our analyses also indicate that most SUVH proteins of Arabidopsis may bind histone H3 lysine 9 (H3K9). We also predict that SUVH7, SUVH8, SUVR1, SUVR3, ZmSET20 and ZmSET22 catalyse monomethylation or dimethylation of H3K9. Except for SDG728, which may trimethylate H3K9, all SUVH paralogs in rice may catalyse monomethylation or dimethylation. ZmSET11, ZmSET31, SDG713, SDG715, and SDG726 proteins are predicted to be catalytically inactive because of an incomplete S-adenosylmethionine (SAM) binding pocket and a post-SET domain. E(Z) homologs can trimethylate H3K27 substrate, which is similar to the Enhancer of Zeste homolog 2 of humans. Our comparative sequence analyses reveal that ATXR5 and ATXR6 lack motifs/domains required for protein-protein interaction and polycomb repressive complex 2 complex formation. We propose that subtle variations of key residues at substrate or SAM binding pocket, around the catalytic pocket, or presence of pre-SET and post-SET domains in HKMTs of the aforementioned plant species lead to variations in class-specific HKMT functions and further determine their substrate specificity, the degree of methylation and catalytic activity.
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Affiliation(s)
- Mutyala Satish
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India
| | - M Angel Nivya
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India
| | - Suman Abhishek
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India
| | - Naveen Kumar Nakarakanti
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India
| | - Dixit Shivani
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India
| | - Madishetti Vinuthna Vani
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India
| | - Eerappa Rajakumara
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India
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170
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Analysis of the meiotic transcriptome reveals the genes related to the regulation of pollen abortion in cytoplasmic male-sterile pepper (Capsicum annuum L.). Gene 2017; 641:8-17. [PMID: 29031775 DOI: 10.1016/j.gene.2017.10.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 10/04/2017] [Accepted: 10/10/2017] [Indexed: 01/23/2023]
Abstract
CMS, which refers to the inability to generate functional pollen grains while still producing a normal gynoecium, has been widely used for pepper hybrid seed production. Pepper line 8214A is an excellent CMS line exhibiting 100% male sterility and superior economic characteristics. A TUNEL assay revealed the nuclear DNA is damaged in 8214A PMCs during meiosis. TEM images indicated that the 8214A PMCs exhibited asynchronous meiosis after prophase I, and some PMCs degraded prematurely with morphological features typical of PCD. Additionally, at the end of meiosis, the 8214A PMCs formed abnormal non-tetrahedral tetrads that degraded in situ. To identify the genes involved in the pollen abortion of line 8214A, the transcriptional profiles of the 8214A and the 8214B anthers (i.e., from the fertile maintainer line) during meiosis were analyzed using an RNA-seq approach. A total of 1355 genes were determined to be differentially expressed, including 424 and 931 up- and down- regulated genes, respectively, in the 8214A anthers during meiosis relative to the expression levels in the 8214B. The expression levels of ubiquitin ligase and cell cycle-related genes were apparently down-regulated, while the expression of methyltransferase genes was up-regulated in the 8214A anthers during meiosis, which likely contributed to the PCD of these PMCs during meiosis. Thus, our results may be useful for revealing the molecular mechanism regulating the pollen abortion of CMS pepper.
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171
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Zogli P, Libault M. Plant response to biotic stress: Is there a common epigenetic response during plant-pathogenic and symbiotic interactions? PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 263:89-93. [PMID: 28818387 DOI: 10.1016/j.plantsci.2017.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 07/04/2017] [Accepted: 07/07/2017] [Indexed: 05/26/2023]
Abstract
Plants constantly interact with pathogenic and symbiotic microorganisms. Recent studies have revealed several regulatory mechanisms controlling these interactions. Among them, the plant defense system is activated not only in response to pathogenic, but also in response to symbiotic microbes. Interestingly, shortly after symbiotic microbial recognition, the plant defense system is suppressed to promote plant infection by symbionts. Research studies have demonstrated the influence of the plant epigenome in modulating both pathogenic and symbiotic plant-microbe interactions, thereby influencing plant survival, adaptation and evolution of the plant response to microbial infections. It is however unclear if plant pathogenic and symbiotic responses share similar epigenomic profiles or if epigenomic changes differentially regulate plant-microbe symbiosis and pathogenesis. In this mini-review, we provide an update of the current knowledge of epigenomic control on plant immune responses and symbiosis, with a special attention being paid to knowledge gap and potential strategies to fill-in the missing links.
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Affiliation(s)
- Prince Zogli
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Marc Libault
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA.
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172
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Affiliation(s)
- Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331
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173
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Abstract
Information encoded in DNA is interpreted, modified, and propagated as chromatin. The diversity of inputs encountered by eukaryotic genomes demands a matching capacity for transcriptional outcomes provided by the combinatorial and dynamic nature of epigenetic processes. Advances in genome editing, visualization technology, and genome-wide analyses have revealed unprecedented complexity of chromatin pathways, offering explanations to long-standing questions and presenting new challenges. Here, we review recent findings, exemplified by the emerging understanding of crossregulatory interactions within chromatin, and emphasize the pathologic outcomes of epigenetic misregulation in cancer.
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174
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Oberlin S, Sarazin A, Chevalier C, Voinnet O, Marí-Ordóñez A. A genome-wide transcriptome and translatome analysis of Arabidopsis transposons identifies a unique and conserved genome expression strategy for Ty1/Copia retroelements. Genome Res 2017; 27:1549-1562. [PMID: 28784835 PMCID: PMC5580714 DOI: 10.1101/gr.220723.117] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 07/18/2017] [Indexed: 01/17/2023]
Abstract
Retroelements, the prevalent class of plant transposons, have major impacts on host genome integrity and evolution. They produce multiple proteins from highly compact genomes and, similar to viruses, must have evolved original strategies to optimize gene expression, although this aspect has been seldom investigated thus far. Here, we have established a high-resolution transcriptome/translatome map for the near-entirety of Arabidopsis thaliana transposons, using two distinct DNA methylation mutants in which transposon expression is broadly de-repressed. The value of this map to study potentially intact and transcriptionally active transposons in A. thaliana is illustrated by our comprehensive analysis of the cotranscriptional and translational features of Ty1/Copia elements, a family of young and active retroelements in plant genomes, and how such features impact their biology. Genome-wide transcript profiling revealed a unique and widely conserved alternative splicing event coupled to premature termination that allows for the synthesis of a short subgenomic RNA solely dedicated to production of the GAG structural protein and that preferentially associates with polysomes for efficient translation. Mutations engineered in a transgenic version of the Arabidopsis EVD Ty1/Copia element further show how alternative splicing is crucial for the appropriate coordination of full-length and subgenomic RNA transcription. We propose that this hitherto undescribed genome expression strategy, conserved among plant Ty1/Copia elements, enables an excess of structural versus catalytic components, mandatory for mobilization.
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Affiliation(s)
- Stefan Oberlin
- Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Alexis Sarazin
- Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
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175
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Zhang Y, Jia RX, Pan MH, Lu Y, Cui XS, Kim NH, Sun SC. HT-2 toxin affects development of porcine parthenotes by altering DNA and histone methylation in oocytes matured in vitro. Theriogenology 2017; 103:110-116. [PMID: 28780481 DOI: 10.1016/j.theriogenology.2017.07.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/25/2017] [Accepted: 07/29/2017] [Indexed: 12/17/2022]
Abstract
T-2 toxin is a type A mycotoxin produced by various Fusarium species, while HT-2 toxin is a major metabolite of T-2 toxin. Both T-2 toxin and HT-2 toxin are known to have deleterious effects on animals. Our previous work showed that HT-2 treatment caused the failure of porcine oocyte maturation. In this study, we reported that HT-2 also affected porcine embryo development. In HT-2 toxin treated group, all the percentages of embryos in 2-cell, 4-cell and blastocyst stage were significantly lower compared with those in control groups. We then explored the causes from the epigenetic modification aspect of the oocytes. The analysis of fluorescence intensity showed that 5-methyl cytosine (5 mC) level was increased after exposure to HT-2 toxin in porcine oocytes, indicating that the general DNA methylation level increased in the treated porcine oocytes. In addition, histone modifications were also affected, since our results showed that H3K4me2 and H3K9me2 levels were increased in the oocytes from HT-2-treated group. Therefore, our results indicated that HT-2 toxin decreased porcine embryo developmental competence through altering the epigenetic modifications of oocytes.
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Affiliation(s)
- Yue Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Ru-Xia Jia
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Meng-Hao Pan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yujie Lu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiang-Shun Cui
- Department of Animal Sciences, Chungbuk National University, Cheongju 361-763, Republic of Korea
| | - Nam-Hyung Kim
- Department of Animal Sciences, Chungbuk National University, Cheongju 361-763, Republic of Korea
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
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177
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Du J. Structure and Mechanism of Plant DNA Methyltransferases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 945:173-192. [PMID: 27826839 DOI: 10.1007/978-3-319-43624-1_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
DNA methylation is an important epigenetic mark that functions in eukaryotes from fungi to animals and plants, where it plays a crucial role in the regulation of epigenetic silencing. Once the methylation mark is established by the de novo DNA methyltransferase (MTase), it requires specific regulatory mechanisms to maintain the methylation state during chromatin replication, both during meiosis and mitosis. Plants have distinct DNA methylation patterns that are both established and maintained by unique DNA MTases and are regulated by plant-specific pathways. This chapter focuses on the exceptional structural and functional features of plant DNA MTases that provide insights into these regulatory mechanisms.
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Affiliation(s)
- Jiamu Du
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 201602, China.
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178
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Qu XL, Ming-Zhang, Yuan-Fang, Wang H, Zhang YZ. Effect of 2,3',4,4',5-Pentachlorobiphenyl Exposure on Endometrial Receptivity and the Methylation of HOXA10. Reprod Sci 2017. [PMID: 28631552 DOI: 10.1177/1933719117711258] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Polychlorinated biphenyls (PCBs) are one of the most common endocrine-disrupting chemicals and have obvious toxicity on human reproductive development. The aim of our study was to investigate the toxicity of chronic 2,3',4,4',5-pentachlorobiphenyl (PCB 118) exposure on embryo implantation and endometrial receptivity, with the possible mechanism of DNA methylation involved. Virgin CD-1 female mice (3 weeks old) were housed and orally treated with PCB 118 (0, 1, 10, 100 μg/kg) for a month. After mating with fertile males, the pregnant mice were killed on gestation day 4.5. Compared with the control group, implantation failures were observed in 1 μg/kg PCB 118- and 100 μg/kg PCB 118-treated groups. Abnormal endometrial morphology with open uterine lumens and densely compact stromal cells and poorly developed pinopodes were substantially in response to PCB 118 doses above, as well as the significant downregulation of implantation-associated genes (estrogen receptor 1, homeobox A10 [HOXA10], integrin subunit beta 3) and hypermethylation in the promoter region of HOXA10 further. It was confirmed that chronic exposure to PCB 118 produced an increased number of implantation failures in association with a defective uterine morphology during the implantation period. Alterations in methylation of HOXA10 could explain, at least in part, the mechanism of effects of PCB 118 exposure on the implantation process.
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Affiliation(s)
- Xin-Lan Qu
- 1 The Reproductive Medicine Center, Zhongnan Hospital of Wuhan University, Wuhan, China.,2 Department of Obstetrics and Gynecology, Zhongnan Hospital of Wuhan University, Wuhan, China.,3 Hubei Provincial Key Laboratory of Developmentally Originated Diseases, Wuhan, China
| | - Ming-Zhang
- 1 The Reproductive Medicine Center, Zhongnan Hospital of Wuhan University, Wuhan, China.,2 Department of Obstetrics and Gynecology, Zhongnan Hospital of Wuhan University, Wuhan, China.,3 Hubei Provincial Key Laboratory of Developmentally Originated Diseases, Wuhan, China
| | - Yuan-Fang
- 4 Department of Oncology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Hui Wang
- 3 Hubei Provincial Key Laboratory of Developmentally Originated Diseases, Wuhan, China.,5 Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan, China
| | - Yuan-Zhen Zhang
- 1 The Reproductive Medicine Center, Zhongnan Hospital of Wuhan University, Wuhan, China.,2 Department of Obstetrics and Gynecology, Zhongnan Hospital of Wuhan University, Wuhan, China.,3 Hubei Provincial Key Laboratory of Developmentally Originated Diseases, Wuhan, China
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Jiang H, Moreno-Romero J, Santos-González J, De Jaeger G, Gevaert K, Van De Slijke E, Köhler C. Ectopic application of the repressive histone modification H3K9me2 establishes post-zygotic reproductive isolation in Arabidopsis thaliana. Genes Dev 2017; 31:1272-1287. [PMID: 28743695 PMCID: PMC5558928 DOI: 10.1101/gad.299347.117] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/27/2017] [Indexed: 11/24/2022]
Abstract
Hybrid seed lethality as a consequence of interspecies or interploidy hybridizations is a major mechanism of reproductive isolation in plants. This mechanism is manifested in the endosperm, a dosage-sensitive tissue supporting embryo growth. Deregulated expression of imprinted genes such as ADMETOS (ADM) underpin the interploidy hybridization barrier in Arabidopsis thaliana; however, the mechanisms of their action remained unknown. In this study, we show that ADM interacts with the AT hook domain protein AHL10 and the SET domain-containing SU(VAR)3-9 homolog SUVH9 and ectopically recruits the heterochromatic mark H3K9me2 to AT-rich transposable elements (TEs), causing deregulated expression of neighboring genes. Several hybrid incompatibility genes identified in Drosophila encode for dosage-sensitive heterochromatin-interacting proteins, which has led to the suggestion that hybrid incompatibilities evolve as a consequence of interspecies divergence of selfish DNA elements and their regulation. Our data show that imbalance of dosage-sensitive chromatin regulators underpins the barrier to interploidy hybridization in Arabidopsis, suggesting that reproductive isolation as a consequence of epigenetic regulation of TEs is a conserved feature in animals and plants.
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Affiliation(s)
- Hua Jiang
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala 75007, Sweden
| | - Jordi Moreno-Romero
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala 75007, Sweden
| | - Juan Santos-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala 75007, Sweden
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Kris Gevaert
- Department of Biochemistry, Ghent University, Ghent 9052, Belgium
- VIB Center for Medical Biotechnology, Ghent 9052, Belgium
| | - Eveline Van De Slijke
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala 75007, Sweden
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180
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Paces J, Nic M, Novotny T, Svoboda P. Literature review of baseline information to support the risk assessment of RNAi‐based GM plants. ACTA ACUST UNITED AC 2017. [PMCID: PMC7163844 DOI: 10.2903/sp.efsa.2017.en-1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jan Paces
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
| | | | | | - Petr Svoboda
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
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181
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Bewick AJ, Niederhuth CE, Ji L, Rohr NA, Griffin PT, Leebens-Mack J, Schmitz RJ. The evolution of CHROMOMETHYLASES and gene body DNA methylation in plants. Genome Biol 2017; 18:65. [PMID: 28457232 PMCID: PMC5410703 DOI: 10.1186/s13059-017-1195-1] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/17/2017] [Indexed: 12/11/2022] Open
Abstract
Background The evolution of gene body methylation (gbM), its origins, and its functional consequences are poorly understood. By pairing the largest collection of transcriptomes (>1000) and methylomes (77) across Viridiplantae, we provide novel insights into the evolution of gbM and its relationship to CHROMOMETHYLASE (CMT) proteins. Results CMTs are evolutionary conserved DNA methyltransferases in Viridiplantae. Duplication events gave rise to what are now referred to as CMT1, 2 and 3. Independent losses of CMT1, 2, and 3 in eudicots, CMT2 and ZMET in monocots and monocots/commelinids, variation in copy number, and non-neutral evolution suggests overlapping or fluid functional evolution of this gene family. DNA methylation within genes is widespread and is found in all major taxonomic groups of Viridiplantae investigated. Genes enriched with methylated CGs (mCG) were also identified in species sister to angiosperms. The proportion of genes and DNA methylation patterns associated with gbM are restricted to angiosperms with a functional CMT3 or ortholog. However, mCG-enriched genes in the gymnosperm Pinus taeda shared some similarities with gbM genes in Amborella trichopoda. Additionally, gymnosperms and ferns share a CMT homolog closely related to CMT2 and 3. Hence, the dependency of gbM on a CMT most likely extends to all angiosperms and possibly gymnosperms and ferns. Conclusions The resulting gene family phylogeny of CMT transcripts from the most diverse sampling of plants to date redefines our understanding of CMT evolution and its evolutionary consequences on DNA methylation. Future, functional tests of homologous and paralogous CMTs will uncover novel roles and consequences to the epigenome. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1195-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam J Bewick
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Chad E Niederhuth
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Lexiang Ji
- Institute of Bioinformatics, University of Georgia, Athens, GA, 30602, USA
| | - Nicholas A Rohr
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Patrick T Griffin
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Jim Leebens-Mack
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA.
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182
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Liu Y, El-Kassaby YA. Regulatory crosstalk between microRNAs and hormone signalling cascades controls the variation on seed dormancy phenotype at Arabidopsis thaliana seed set. PLANT CELL REPORTS 2017; 36:705-717. [PMID: 28197719 DOI: 10.1007/s00299-017-2111-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/26/2017] [Indexed: 05/05/2023]
Abstract
We employed an Illumina sequencing approach to identify candidate microRNA cohorts that may greatly contribute to seed dormancy modulation and to construct a microRNA-gene regulatory network in hormone signalling cascades. MicroRNAs (miRNAs) are important signalling molecules and regulate many developmental programs of plants. Some miRNAs have been integrated into gene regulatory networks (GRNs) and coordinate developmental plasticity, but few study systematically investigated how phenotypical variations are regulated through differential expression of miRNA tags in GRNs during seed set. Using 'top-down' analyses (i.e., identify miRNAs associated with known phenotypical variations), we chose two Arabidopsis ecotypes (Cvi-0 and Col-0) with contrasting seed dormancy and sequenced miRNA reads in the first ten phases at seed set. We computationally predicted target genes of miRNAs and implemented statistical analyses for normalized relative expression of top abundant miRNA cohorts between the two ecotypes. We especially focused on miRNA cohorts targeting mRNAs encoding transcription factors in hormone signalling cascades. We report, with high confidence hits, that a cohort of 14 miRNAs (miR-156b, -159b, -160, -161*, -319a, -390a, -396, -773a, -779, -842, -852, -859, -1886*, and a novel sequence in miR8172 family) may greatly contribute to seed dormancy modulation, of which seven are involved in hormone signalling cascades. Moreover, their expression patterns indicated that 5 ± 1 days after flowering (at embryogenesis-to-maturation transition) is a critical phase at seed set. This study reinforces the notion that miRNAs that regulate seed dormancy modulation and provides a novel paradigm of studying the correlation between genotypes (miRNAs) and phenotypes.
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Affiliation(s)
- Yang Liu
- Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Yousry A El-Kassaby
- Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
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183
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Yan A, Chen Z. The pivotal role of abscisic acid signaling during transition from seed maturation to germination. PLANT CELL REPORTS 2017; 36:689-703. [PMID: 27882409 DOI: 10.1007/s00299-016-2082-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 11/15/2016] [Indexed: 05/22/2023]
Abstract
Seed maturation and germination are two continuous developmental processes that link two distinct generations in spermatophytes; the precise genetic control of these two processes is, therefore, crucially important for the survival of the next generation. Pieces of experimental evidence accumulated so far indicate that a concerted action of endogenous signals and environmental cues is required to govern these processes. Plant hormone abscisic acid (ABA) has been suggested to play a predominant role in directing seed maturation and maintaining seed dormancy under unfavorable environmental conditions until antagonized by gibberellins (GA) and certain environmental cues to allow the commencement of seed germination when environmental conditions are favorable; therefore, the balance of ABA and GA is a major determinant of the timing of seed germination. Due to the advent of new technologies and system biology approaches, molecular studies are beginning to draw a picture of the sophisticated genetic network that drives seed maturation during the past decade, though the picture is still incomplete and many details are missing. In this review, we summarize recent advances in ABA signaling pathway in the regulation of seed maturation as well as the transition from seed maturation to germination, and highlight the importance of system biology approaches in the study of seed maturation.
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Affiliation(s)
- An Yan
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore, 637616, Singapore
| | - Zhong Chen
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore, 637616, Singapore.
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184
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Giovannoni J, Nguyen C, Ampofo B, Zhong S, Fei Z. The Epigenome and Transcriptional Dynamics of Fruit Ripening. ANNUAL REVIEW OF PLANT BIOLOGY 2017; 68:61-84. [PMID: 28226232 DOI: 10.1146/annurev-arplant-042916-040906] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Fruit has evolved myriad forms that facilitate seed dispersal in varied environmental and ecological contexts. Because fleshy fruits become attractive and nutritious to seed-dispersing animals, the transition from unripe to ripe fruit represents a dramatic shift in survival strategy-from protecting unripe fruit against damaging animals to making it appealing to those same animals once ripened. For optimal fitness, ripening therefore must be tightly controlled and coordinated with seed development. Fruits, like many vegetative tissues of plants that contribute to human diets, are also subject to decay, which is enhanced as a consequence of the ripening transition. As such, ripening control has enormous relevance for both plant biology and food security. Here, we review the complex interactions of hormones and transcription factors during fleshy-fruit ripening, with an emphasis on the recent discovery that epigenome dynamics are a critical and early regulator of the cascade of molecular events that ultimately contribute to fruit maturation and ripening.
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Affiliation(s)
- James Giovannoni
- Robert W. Holley Center, US Department of Agriculture-Agricultural Research Service, Ithaca, New York 14853;
- Boyce Thompson Institute, Ithaca, New York 14853;
- School of Integrated Plant Sciences, Cornell University, Ithaca, New York 14853; ,
| | - Cuong Nguyen
- School of Integrated Plant Sciences, Cornell University, Ithaca, New York 14853; ,
| | - Betsy Ampofo
- School of Integrated Plant Sciences, Cornell University, Ithaca, New York 14853; ,
| | - Silin Zhong
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China;
| | - Zhangjun Fei
- Boyce Thompson Institute, Ithaca, New York 14853;
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185
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Bewick AJ, Schmitz RJ. Gene body DNA methylation in plants. CURRENT OPINION IN PLANT BIOLOGY 2017; 36:103-110. [PMID: 28258985 PMCID: PMC5413422 DOI: 10.1016/j.pbi.2016.12.007] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/29/2016] [Indexed: 05/19/2023]
Abstract
The type, amount, and location of DNA methylation within a gene provides pivotal information on the enzymatic pathway by which it was achieved and its functional consequences. In plants (angiosperms specifically), gene body methylation (gbM) refers to genes with an enrichment of CG DNA methylation within the transcribed regions and depletion at the transcriptional start and termination sites. GbM genes often compose the bulk of methylated genes within angiosperm genomes and are enriched for housekeeping functions. Contrary to the transcriptionally repressive effects of other chromatin modifications within gene bodies, gbM genes are constitutively expressed. GbM has intrigued researchers since its discovery, and much effort has been placed on identifying its functional role. Here, we highlight the recent findings on the evolutionary origin and molecular mechanism of gbM and synthesize studies describing the possible roles for this enigmatic epigenetic phenotype.
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Affiliation(s)
- Adam J Bewick
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA 30602, USA.
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186
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AtMBD6, a methyl CpG binding domain protein, maintains gene silencing in Arabidopsis by interacting with RNA binding proteins. J Biosci 2017; 42:57-68. [PMID: 28229965 DOI: 10.1007/s12038-016-9658-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
DNA methylation, mediated by double-stranded RNA, is a conserved epigenetic phenomenon that protects a genome from transposons, silences unwanted genes and has a paramount function in plant or animal development. Methyl CpG binding domain proteins are members of a class of proteins that bind to methylated DNA. The Arabidopsis thaliana genome encodes 13 methyl CpG binding domain (MBD) proteins, but the molecular/biological functions of most of these proteins are still not clear. In the present study, we identified four proteins that interact with AtMBD6. Interestingly, three of them contain RNA binding domains and are co-localized with AtMBD6 in the nucleus. The interacting partners includes AtRPS2C (a 40S ribosomal protein), AtNTF2 (nuclear transport factor 2) and AtAGO4 (Argonoute 4). The fourth protein that physically interacts with AtMBD6 is a histone-modifying enzyme, histone deacetylase 6 (AtHDA6), which is a known component of the RNA-mediated gene silencing system. Analysis of genomic DNA methylation in the atmbd6, atrps2c and atntf2 mutants, using methylation-sensitive PCR detected decreased DNA methylation at miRNA/siRNA producing loci, pseudogenes and other targets of RNA-directed DNA methylation. Our results indicate that AtMBD6 is involved in RNA-mediated gene silencing and it binds to RNA binding proteins like AtRPS2C, AtAGO4 and AtNTF2. AtMBD6 also interacts with histone deacetylase AtHDA6 that might have a role in chromatin condensation at the targets of RdDM.
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187
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Abstract
Recent studies from a number of model organisms have indicated chromatin structure and its remodeling as a major contributory agent for aging. Few recent experiments also demonstrate that modulation in the chromatin modifying agents also affect the life span of an organism and even in some cases the change is inherited epigenetically to subsequent generations. Hence, in the present report we discuss the chromatin organization and its changes during aging.
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Affiliation(s)
- Pramod C. Rath
- School of Life Sciences, Molecular Biology Laboratory, Jawaharlal Nehru University, New Delhi, Delhi India
| | - Ramesh Sharma
- Department of Biochemistry, North Eastern Hill University, Shillong, Megalaya India
| | - S. Prasad
- Biochemistry & Molecular Biology Lab, Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh India
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188
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Zakrzewski F, Schmidt T. Epigenetic Characterization of Satellite DNA in Sugar Beet (Beta vulgaris). PLANT EPIGENETICS 2017. [DOI: 10.1007/978-3-319-55520-1_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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189
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Su SY, Chen SH, Lu IH, Chiang YS, Wang YB, Chen PY, Lin CY. TEA: the epigenome platform for Arabidopsis methylome study. BMC Genomics 2016; 17:1027. [PMID: 28155665 PMCID: PMC5260138 DOI: 10.1186/s12864-016-3326-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background Bisulfite sequencing (BS-seq) has become a standard technology to profile genome-wide DNA methylation at single-base resolution. It allows researchers to conduct genome-wise cytosine methylation analyses on issues about genomic imprinting, transcriptional regulation, cellular development and differentiation. One single data from a BS-Seq experiment is resolved into many features according to the sequence contexts, making methylome data analysis and data visualization a complex task. Results We developed a streamlined platform, TEA, for analyzing and visualizing data from whole-genome BS-Seq (WGBS) experiments conducted in the model plant Arabidopsis thaliana. To capture the essence of the genome methylation level and to meet the efficiency for running online, we introduce a straightforward method for measuring genome methylation in each sequence context by gene. The method is scripted in Java to process BS-Seq mapping results. Through a simple data uploading process, the TEA server deploys a web-based platform for deep analysis by linking data to an updated Arabidopsis annotation database and toolkits. Conclusions TEA is an intuitive and efficient online platform for analyzing the Arabidopsis genomic DNA methylation landscape. It provides several ways to help users exploit WGBS data. TEA is freely accessible for academic users at: http://tea.iis.sinica.edu.tw.
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Affiliation(s)
- Sheng-Yao Su
- Bioinformatics Program, Taiwan International Graduate Program, Institute of Information Science, Academia Sinica, Taipei, Taiwan.,Institute of Information Science, Academia Sinica, Taipei, Taiwan.,Institute of Biomedical Informatics, National Yang-Ming University, Taipei, Taiwan
| | - Shu-Hwa Chen
- Institute of Information Science, Academia Sinica, Taipei, Taiwan
| | - I-Hsuan Lu
- Institute of Information Science, Academia Sinica, Taipei, Taiwan
| | - Yih-Shien Chiang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Bin Wang
- Institute of Information Science, Academia Sinica, Taipei, Taiwan
| | - Pao-Yang Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
| | - Chung-Yen Lin
- Institute of Information Science, Academia Sinica, Taipei, Taiwan. .,Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli, Taiwan. .,Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan.
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190
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Gouil Q, Baulcombe DC. DNA Methylation Signatures of the Plant Chromomethyltransferases. PLoS Genet 2016; 12:e1006526. [PMID: 27997534 PMCID: PMC5221884 DOI: 10.1371/journal.pgen.1006526] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/09/2017] [Accepted: 12/07/2016] [Indexed: 12/22/2022] Open
Abstract
DNA methylation in plants is traditionally partitioned into CG, CHG and CHH contexts (with H any nucleotide but G). By investigating DNA methylation patterns in trinucleotide contexts in four angiosperm species, we show that such a representation hides spatial and functional partitioning of different methylation pathways and is incomplete. CG methylation (mCG) is largely context-independent whereas, at CHG motifs, there is under-representation of mCCG in pericentric regions of A. thaliana and tomato and throughout the chromosomes of maize and rice. In A. thaliana the biased representation of mCCG in heterochromatin is related to specificities of H3K9 methyltransferase SUVH family members. At CHH motifs there is an over-representation of different variant forms of mCHH that, similarly to mCCG hypomethylation, is partitioned into the pericentric regions of the two dicots but dispersed in the monocot chromosomes. The over-represented mCHH motifs in A. thaliana associate with specific types of transposon including both class I and II elements. At mCHH the contextual bias is due to the involvement of various chromomethyltransferases whereas the context-independent CHH methylation in A. thaliana and tomato is mediated by the RNA-directed DNA methylation process that is most active in the gene-rich euchromatin. This analysis therefore reveals that the sequence context of the methylome of plant genomes is informative about the mechanisms associated with maintenance of methylation and the overlying chromatin structure. Dense cytosine DNA methylation (mC) in eukaryotes is associated with closed chromatin and gene silencing. In plants it is well known that the sequence context of the mC (either mCG, mCHG or mCHH) provides a clue as to which of several mechanisms is involved but now, based on detailed analyses of the DNA methylome in wild type and mutants of four plant species, we reveal that there is additional information in the mC sequence context. Low mCCG and over-representation of mCAA and mCTA or mCAT in A. thaliana and tomato differentiates regions of the chromosomes near the centromere where methylation is dominated by chromomethyltransferases from the chromosome arms in which mCHH is context-independent and predominantly RNA-directed. Rice and maize have similar sequence context-dependent DNA methylation but the corresponding chromosome domains are not spatially separate as in the dicots. The discovery of the subcomponents of plant methylomes based on sequence context will allow greater resolution in past and future analyses of plant methylomes.
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Affiliation(s)
- Quentin Gouil
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - David C. Baulcombe
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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191
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Galbraith DA, Yi SV, Grozinger CM. Evaluation of Possible Proximate Mechanisms Underlying the Kinship Theory of Intragenomic Conflict in Social Insects. Integr Comp Biol 2016; 56:1206-1214. [DOI: 10.1093/icb/icw111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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192
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Feng SJ, Liu XS, Tao H, Tan SK, Chu SS, Oono Y, Zhang XD, Chen J, Yang ZM. Variation of DNA methylation patterns associated with gene expression in rice (Oryza sativa) exposed to cadmium. PLANT, CELL & ENVIRONMENT 2016; 39:2629-2649. [PMID: 27412910 DOI: 10.1111/pce.12793] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 06/23/2016] [Accepted: 07/05/2016] [Indexed: 05/17/2023]
Abstract
We report genome-wide single-base resolution maps of methylated cytosines and transcriptome change in Cd-exposed rice. Widespread differences were identified in CG and non-CG methylation marks between Cd-exposed and Cd-free rice genomes. There are 2320 non-redundant differentially methylated regions detected in the genome. RNA sequencing revealed 2092 DNA methylation-modified genes differentially expressed under Cd exposure. More genes were found hypermethylated than those hypomethylated in CG, CHH and CHG (where H is A, C or T) contexts in upstream, gene body and downstream regions. Many of the genes were involved in stress response, metal transport and transcription factors. Most of the DNA methylation-modified genes were transcriptionally altered under Cd stress. A subset of loss of function mutants defective in DNA methylation and histone modification activities was used to identify transcript abundance of selected genes. Compared with wide type, mutation of MET1 and DRM2 resulted in general lower transcript levels of the genes under Cd stress. Transcripts of OsIRO2, OsPR1b and Os09g02214 in drm2 were significantly reduced. A commonly used DNA methylation inhibitor 5-azacytidine was employed to investigate whether DNA demethylation affected physiological consequences. 5-azacytidine provision decreased general DNA methylation levels of selected genes, but promoted growth of rice seedlings and Cd accumulation in rice plant.
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Affiliation(s)
- Sheng Jun Feng
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xue Song Liu
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hua Tao
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shang Kun Tan
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shan Shan Chu
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Youko Oono
- Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | - Xian Duo Zhang
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jian Chen
- Institute of Food Safety and Quality, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Zhi Min Yang
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, 210095, China
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193
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Wang Y, Xue X, Zhu JK, Dong J. Demethylation of ERECTA receptor genes by IBM1 histone demethylase affects stomatal development. Development 2016; 143:4452-4461. [PMID: 27697902 PMCID: PMC5201038 DOI: 10.1242/dev.129932] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/19/2016] [Indexed: 12/21/2022]
Abstract
DNA methylation and histone modifications interact to modulate gene expression in biological organisms. The histone demethylase IBM1 suppresses DNA methylation and gene silencing, primarily by targeting genic regions in the Arabidopsis genome. The chromatin regulator EDM2 is also required for prevention of genic DNA methylation because it maintains IBM1 expression by promoting IBM1 mRNA distal polyadenylation. Loss-of-function ibm1 and edm2 mutant plants display a wide range of developmental defects, but little is known about which developmentally important genes are regulated by IBM1 and EDM2. Here, we show that both ibm1 and edm2 mutants display defects in production of stomatal lineage cells, which is linked to DNA hypermethylation of the ERECTA family genes, including ER, ERL1 and ERL2 Stomatal phenotypes and DNA methylation levels of ER genes in ibm1 and edm2 mutants are restored by mutations in the genes encoding the histone methyltransferase KYP and DNA methyltransferase CMT3. Our data demonstrate that a specific plant developmental context is influenced by IBM1-regulated histone modification and DNA methylation on the gene body region of the ERECTA receptors.
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Affiliation(s)
- Yuhua Wang
- Shanghai Center for Plant Stress Biology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Xueyi Xue
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47906, USA
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
- Department of Plant Biology and Pathology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901, USA
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194
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Wang Z, Chen F, Li X, Cao H, Ding M, Zhang C, Zuo J, Xu C, Xu J, Deng X, Xiang Y, Soppe WJJ, Liu Y. Arabidopsis seed germination speed is controlled by SNL histone deacetylase-binding factor-mediated regulation of AUX1. Nat Commun 2016; 7:13412. [PMID: 27834370 PMCID: PMC5114640 DOI: 10.1038/ncomms13412] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 09/30/2016] [Indexed: 12/22/2022] Open
Abstract
Histone acetylation is known to affect the speed of seed germination, but the molecular regulatory basis of this remains ambiguous. Here we report that loss of function of two histone deacetylase-binding factors, SWI-INDEPENDENT3 (SIN3)-LIKE1 (SNL1) and SNL2, results in accelerated radicle protrusion and growth during seed germination. AUXIN RESISTANT 1 (AUX1) is identified as a key factor in this process, enhancing germination speed downstream of SNL1 and SNL2. AUX1 expression and histone H3 acetylation at lysines 9 and 18 is regulated by SNL1 and SNL2. The D-type cyclins encoding genes CYCD1;1 and CYCD4;1 display increased expression in AUX1 over-expression lines and the snl1snl2 double mutant. Accordingly, knockout of CYCD4;1 reduces seed germination speed of AUX1 over-expression lines and snl1snl2 suggesting the importance of cell cycling for radicle protrusion during seed germination. Together, our work identifies AUX1 as a link between histone acetylation mediated by SNL1 and SNL2, and radicle growth promoted by CYCD1;1 and CYCD4;1 during seed germination. Histone acetylation influences the speed of seed germination. Here, Wang et al. show that loss of the SNL1/SNL2 histone deacetylase binding factors accelerates seed germination and provide evidence that they act by regulating the expression of AUX1 which in turn influences cell division.
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Affiliation(s)
- Zhi Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Fengying Chen
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaoying Li
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Cao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Meng Ding
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cun Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinghong Zuo
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaonan Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jimei Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Deng
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yong Xiang
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Wim J J Soppe
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.,Institute of Molecular Physiology and Biotechnology of Plants (IMBIO), University of Bonn, 53115 Bonn, Germany
| | - Yongxiu Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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195
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Cuerda-Gil D, Slotkin RK. Non-canonical RNA-directed DNA methylation. NATURE PLANTS 2016; 2:16163. [PMID: 27808230 DOI: 10.1038/nplants.2016.163] [Citation(s) in RCA: 152] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/26/2016] [Indexed: 05/18/2023]
Abstract
Small RNA-directed DNA methylation (RdDM) has been extensively studied in plants, resulting in a deep understanding of a major 'canonical RdDM' mechanism. However, current models of canonical RdDM cannot explain how this self-perpetuating mechanism is initiated. Recent investigations into the initiation of epigenetic silencing have determined that there are several alternative 'non-canonical RdDM' pathways that function through distinct mechanisms to modify chromatin. This Review aims to illustrate the diversity of non-canonical RdDM mechanisms described to date, recognize common themes within this dizzying array of interconnected pathways, and identify the key unanswered questions remaining in this field.
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Affiliation(s)
- Diego Cuerda-Gil
- Department of Molecular Genetics, The Ohio State University, 500 Aronoff Laboratory, 318 West Twelfth Avenue, Columbus, Ohio 43210, USA
| | - R Keith Slotkin
- Department of Molecular Genetics, The Ohio State University, 500 Aronoff Laboratory, 318 West Twelfth Avenue, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, 105 Biological Sciences Building, 484 West Twelfth Avenue, Columbus, Ohio 43210, USA
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196
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Yao X, Xing M, Ooi WF, Tan P, Teh BT. Epigenomic Consequences of Coding and Noncoding Driver Mutations. Trends Cancer 2016; 2:585-605. [PMID: 28741489 DOI: 10.1016/j.trecan.2016.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/30/2016] [Accepted: 09/02/2016] [Indexed: 12/27/2022]
Abstract
Chromatin alterations are integral to the pathogenic process of cancer, as demonstrated by recent discoveries of frequent mutations in chromatin-modifier genes and aberrant DNA methylation states in different cancer types. Progress is being made on elucidating how chromatin alterations, and how proteins catalyzing these alterations, mechanistically contribute to tissue-specific tumorigenesis. In parallel, technologies enabling the genome-wide profiling of histone modifications have revealed the existence of noncoding driver genetic alterations in cancer. In this review, we survey the current knowledge of coding and noncoding cancer drivers, and discuss their impact on the chromatin landscape. Translational implications of these findings for novel cancer therapies are also presented.
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Affiliation(s)
- Xiaosai Yao
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Manjie Xing
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 5 Lower Kent Ridge Road, Singapore 119074, Singapore; Cancer and Stem Cell Biology Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Wen Fong Ooi
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Patrick Tan
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore; Cancer and Stem Cell Biology Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore; National Cancer Centre, 11 Hospital Drive, Singapore 169610, Singapore; Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore 117599, Singapore; SingHealth/Duke-NUS Precision Medicine Institute, Singapore 168752, Singapore.
| | - Bin Tean Teh
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore; National Cancer Centre, 11 Hospital Drive, Singapore 169610, Singapore; Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore 117599, Singapore; SingHealth/Duke-NUS Precision Medicine Institute, Singapore 168752, Singapore; Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673.
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197
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Feng W, Michaels SD. Accessing the Inaccessible: The Organization, Transcription, Replication, and Repair of Heterochromatin in Plants. Annu Rev Genet 2016; 49:439-59. [PMID: 26631514 DOI: 10.1146/annurev-genet-112414-055048] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Eukaryotic genomes often contain large quantities of potentially deleterious sequences, such as transposons. One strategy for mitigating this risk is to package such sequences into so-called constitutive heterochromatin, where the dense chromatin environment is thought to inhibit transcription by excluding transcription factors and RNA polymerase. This type of model makes it tempting to think of heterochromatin as an inert region that is isolated from the rest of the nucleus. Recent work on heterochromatin, however, reveals that it is a dynamic environment. Despite its dense packaging, heterochromatin must remain accessible for a host of processes, including DNA replication and repair, and, paradoxically, transcription. In plants, transcripts produced by specialized RNA polymerases are used to target regions of the genome for silencing via DNA methylation. Thus, the maintenance of heterochromatin requires a careful balancing act of access and exclusion, which is achieved through the action of a host of interrelated pathways.
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Affiliation(s)
- Wei Feng
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305;
| | - Scott D Michaels
- Department of Biology, Indiana University, Bloomington, Indiana 47405;
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198
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A Comparative Analysis of 5-Azacytidine- and Zebularine-Induced DNA Demethylation. G3-GENES GENOMES GENETICS 2016; 6:2773-80. [PMID: 27402357 PMCID: PMC5015934 DOI: 10.1534/g3.116.030262] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The nonmethylable cytosine analogs, 5-azacytidine and zebularine, are widely used to inhibit DNA methyltransferase activity and reduce genomic DNA methylation. In this study, whole-genome bisulfite sequencing is used to construct maps of DNA methylation with single base pair resolution in Arabidopsis thaliana seedlings treated with each demethylating agent. We find that both inhibitor treatments result in nearly indistinguishable patterns of genome-wide DNA methylation and that 5-azacytidine had a slightly greater demethylating effect at higher concentrations across the genome. Transcriptome analyses revealed a substantial number of upregulated genes, with an overrepresentation of transposable element genes, in particular CACTA-like elements. This demonstrates that chemical demethylating agents have a disproportionately large effect on loci that are otherwise silenced by DNA methylation.
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199
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Niederhuth CE, Schmitz RJ. Putting DNA methylation in context: from genomes to gene expression in plants. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:149-156. [PMID: 27590871 DOI: 10.1016/j.bbagrm.2016.08.009] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 08/20/2016] [Accepted: 08/23/2016] [Indexed: 12/26/2022]
Abstract
Plant DNA methylation is its own language, interpreted by the cell to maintain silencing of transposons, facilitate chromatin structure, and to ensure proper expression of some genes. Just as in any language, context is important. Rather than being a simple "on-off switch", DNA methylation has a range of "meanings" dependent upon the underlying sequence and its location in the genome. Differences in the sequence context of individual sites are established, maintained, and interpreted by differing molecular pathways. Varying patterns of methylation within genes and surrounding sequences are associated with a continuous range of expression differences, from silencing to constitutive expression. These often-subtle differences have been pieced together from years of effort, but have taken off with the advent of methods for assessing methylation across entire genomes. Recognizing these patterns and identifying underlying causes is essential for understanding the function of DNA methylation and its systems-wide contribution to a range of processes in plant genomes. This article is part of a Special Issue entitled: Plant Gene Regulatory Mechanisms and Networks, edited by Dr. Erich Grotewold and Dr. Nathan Springer.
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Affiliation(s)
- Chad E Niederhuth
- Department of Genetics, The University of Georgia, Athens, GA, 30602, USA
| | - Robert J Schmitz
- Department of Genetics, The University of Georgia, Athens, GA, 30602, USA.
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200
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Zhao Q, Zhang J, Chen R, Wang L, Li B, Cheng H, Duan X, Zhu H, Wei W, Li J, Wu Q, Han JDJ, Yu W, Gao S, Li G, Wong J. Dissecting the precise role of H3K9 methylation in crosstalk with DNA maintenance methylation in mammals. Nat Commun 2016; 7:12464. [PMID: 27554592 PMCID: PMC5426519 DOI: 10.1038/ncomms12464] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 07/05/2016] [Indexed: 12/21/2022] Open
Abstract
In mammals it is unclear if UHRF1-mediated DNA maintenance methylation by DNMT1 is strictly dependent on histone H3K9 methylation. Here we have generated an Uhrf1 knockin (KI) mouse model that specifically abolishes the H3K9me2/3-binding activity of Uhrf1. The homozygous Uhrf1 KI mice are viable and fertile, and exhibit ∼10% reduction of DNA methylation in various tissues. The reduced DNA methylation occurs globally in the genome and does not restrict only to the H3K9me2/3 enriched repetitive sequences. In vitro UHRF1 binds with higher affinity to reconstituted nucleosome with hemi-methylated CpGs than that with H3K9me2/3, although it binds cooperatively to nucleosome with both modifications. We also show that the nucleosome positioning affects the binding of methylated DNA by UHRF1. Thus, while our study supports a role for H3K9 methylation in promoting DNA methylation, it demonstrates for the first time that DNA maintenance methylation in mammals is largely independent of H3K9 methylation.
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Affiliation(s)
- Qian Zhao
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jiqin Zhang
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Ruoyu Chen
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Lina Wang
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Bo Li
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Hao Cheng
- Key Laboratory of Computational Biology, CAS Center for Excellence in Molecular Cell Science, Collaborative Innovation Center for Genetics and Developmental Biology, Chinese Academy of Sciences-Max Planck Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Xiaoya Duan
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Haijun Zhu
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Wei Wei
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jiwen Li
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Qihan Wu
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jing-Dong J. Han
- Key Laboratory of Computational Biology, CAS Center for Excellence in Molecular Cell Science, Collaborative Innovation Center for Genetics and Developmental Biology, Chinese Academy of Sciences-Max Planck Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Wenqiang Yu
- Department of Biochemistry and Molecular Biology, Laboratory of RNA Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 130 Dong-An Road, Shanghai 200032, China
| | - Shaorong Gao
- Clinical and Translational Research Center of Shanghai First Maternity, Infant Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Guohong Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jiemin Wong
- Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
- Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China
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