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Huang Y, Liu Y, Guo X, Fan C, Yi C, Shi Q, Su H, Liu C, Yuan J, Liu D, Yang W, Han F. New insights on the evolution of nucleolar dominance in newly resynthesized hexaploid wheat Triticum zhukovskyi. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1298-1315. [PMID: 37246611 DOI: 10.1111/tpj.16320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/11/2023] [Accepted: 05/23/2023] [Indexed: 05/30/2023]
Abstract
Nucleolar dominance (ND) is a widespread epigenetic phenomenon in hybridizations where nucleolus transcription fails at the nucleolus organizer region (NOR). However, the dynamics of NORs during the formation of Triticum zhukovskyi (GGAu Au Am Am ), another evolutionary branch of allohexaploid wheat, remains poorly understood. Here, we elucidated genetic and epigenetic changes occurring at the NOR loci within the Am , G, and D subgenomes during allopolyploidization by synthesizing hexaploid wheat GGAu Au Am Am and GGAu Au DD. In T. zhukovskyi, Au genome NORs from T. timopheevii (GGAu Au ) were lost, while the second incoming NORs from T. monococcum (Am Am ) were retained. Analysis of the synthesized T. zhukovskyi revealed that rRNA genes from the Am genome were silenced in F1 hybrids (GAu Am ) and remained inactive after genome doubling and subsequent self-pollinations. We observed increased DNA methylation accompanying the inactivation of NORs in the Am genome and found that silencing of NORs in the S1 generation could be reversed by a cytidine methylase inhibitor. Our findings provide insights into the ND process during the evolutionary period of T. zhukovskyi and highlight that inactive rDNA units may serve as a 'first reserve' in the form of R-loops, contributing to the successful evolution of T. zhukovskyi.
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Affiliation(s)
- Yuhong Huang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xianrui Guo
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chaolan Fan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Congyang Yi
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qinghua Shi
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Handong Su
- Huazhong Agricultural University, Hubei, 430070, China
| | - Chang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jing Yuan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Dengcai Liu
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Wuyun Yang
- Crop Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Hidvégi N, Gulyás A, Dobránszki J. Ultrasound, as a hypomethylating agent, remodels DNA methylation and alters mRNA transcription in winter wheat (Triticum aestivum L.) seedlings. PHYSIOLOGIA PLANTARUM 2022; 174:e13777. [PMID: 36073119 PMCID: PMC9826007 DOI: 10.1111/ppl.13777] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
Any treatment that affects seed germination and seedling development is of paramount importance from an agricultural point of view since they are critical prerequisites for successful crop production. In present study, we have examined the after-effect of ultrasonication (at 30 kHz, 70 W for 5 min) of winter wheat (Triticum aestivum L. cv. SE15) seeds on the early seedling growth and development, and accompanying changes in the DNA methylation and transcriptomic pattern in 7-day-old seedlings. We used mRNA-sequencing and whole genome bisulfite sequencing (WGBS) to identify significantly differentially expressed genes (DEGs), significantly differently methylated regions (DMRs) and genes (DMGs). Ultrasonication of seeds did not alter the germination rate but increased both the length and weight of roots and shoots of 7-day-old seedlings significantly by 23%-68% and 16%-28%, respectively. Analyzing the expression intensity of 107,891 genes, significantly differentially expressed sequences related mainly to starch biosynthesis, IAA biosynthesis, photosynthesis and TCA cycle pathways. The same pathways were also affected by DNA-methylation changes. DNA hypomethylation occurred in the global methylation profile after ultrasound treatment altering the accessibility of some genes for transcription. Transcriptomic changes suggested alterations in the crosstalk between IAA and sucrose signaling, enhancement of growth processes, and increased activity of nuclear transcription factor stimulating the transcription of genes having CCAAT motif in the promoter. In the present first whole genome level study, we have identified seed ultrasonication as a priming technique that can act as a hypomethylating agent and thereby is able to modify the mRNA transcription allowing enhanced seedling growth.
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Affiliation(s)
- Norbert Hidvégi
- Centre for Agricultural Genomics and Biotechnology, Faculty of the Agricultural and Food Science and Environmental ManagementUniversity of DebrecenNyíregyházaHungary
| | - Andrea Gulyás
- Centre for Agricultural Genomics and Biotechnology, Faculty of the Agricultural and Food Science and Environmental ManagementUniversity of DebrecenNyíregyházaHungary
| | - Judit Dobránszki
- Centre for Agricultural Genomics and Biotechnology, Faculty of the Agricultural and Food Science and Environmental ManagementUniversity of DebrecenNyíregyházaHungary
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Unraveling the DNA Methylation in the rDNA Foci in Mutagen-Induced Brachypodium distachyon Micronuclei. Int J Mol Sci 2022; 23:ijms23126797. [PMID: 35743241 PMCID: PMC9224279 DOI: 10.3390/ijms23126797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 02/01/2023] Open
Abstract
Many years have passed since micronuclei were first observed then accepted as an indicator of the effect of mutagens. However, the possible mechanisms of their formation and elimination from the cell are still not fully understood. Various stresses, including mutagens, can alter gene expression through changes in DNA methylation in plants. In this study we demonstrate for the first time DNA methylation in the foci of 5S and 35S rDNA sequences in individual Brachypodium distachyon micronuclei that are induced by mutagenic treatment with maleic acid hydrazide (MH). The impact of MH on global epigenetic modifications in nuclei and micronuclei has been studied in plants before; however, no in situ analyses of DNA methylation in specific DNA sequence sites are known. To address this problem, we used sequential immunodetection of 5-methylcytosine and fluorescence in situ hybridization (FISH) with 5S and 25S rDNA probes on the non-dividing cells of B. distachyon. Such investigations into the presence or absence of DNA methylation within specific DNA sequences are extremely important in plant mutagenesis in the light of altering gene expression.
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DNA Methylation-An Epigenetic Mark in Mutagen-Treated Brachypodium distachyon Cells. PLANTS 2021; 10:plants10071408. [PMID: 34371611 PMCID: PMC8309452 DOI: 10.3390/plants10071408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 07/07/2021] [Indexed: 12/15/2022]
Abstract
The chromatin structure is significantly influenced by some epigenetic modifications including DNA methylation. The nuclear organization plays an essential role in the cell response to external stresses including mutagens. We present an analysis of the correlation between epigenetic modifications and the instability of the Brachypodium distachyon genome, which are observed as micronuclei, following maleic hydrazide (MH) and nitroso-N-methylurea (MNU) treatments. We compared the level of DNA methylation in the control (untreated) and mutagen-treated B. distachyon nuclei. An immunostaining method using specific antibodies against modified DNA anti-5-methylcytosine was used for the evaluation of DNA methylation in a single nucleus and micronucleus. Interestingly, we showed an alteration of DNA methylation in cells after mutagenic treatments. The results indicate that DNA methylation might be involved in the response of the B. distachyon genome to mutagenic treatments. This demonstrates that analyses of the epigenetic modifications should be integrated into current plant genetic toxicology in order to explain the mechanisms of DNA damage and repair in plants.
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Kalinka A, Achrem M. The distribution pattern of 5-methylcytosine in rye (Secale L.) chromosomes. PLoS One 2020; 15:e0240869. [PMID: 33057421 PMCID: PMC7561101 DOI: 10.1371/journal.pone.0240869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 10/04/2020] [Indexed: 12/02/2022] Open
Abstract
The rye (Secale L.) genome is large, and it contains many classes of repetitive sequences. Secale species differ in terms of genome size, heterochromatin content, and global methylation level; however, the organization of individual types of sequences in chromosomes is relatively similar. The content of the abundant subtelomeric heterochromatin fraction in rye do not correlate with the global level of cytosine methylation, hence immunofluorescence detection of 5-methylcytosine (5-mC) distribution in metaphase chromosomes was performed. The distribution patterns of 5-methylcytosine in the chromosomes of Secale species/subspecies were generally similar. 5-methylcytosine signals were dispersed along the entire length of the chromosome arms of all chromosomes, indicating high levels of methylation, especially at retrotransposon sequences. 5-mC signals were absent in the centromeric and telomeric regions, as well as in subtelomeric blocks of constitutive heterochromatin, in each of the taxa studied. Pericentromeric domains were methylated, however, there was a certain level of polymorphism in these areas, as was the case with the nucleolus organizer region. Sequence methylation within the region of the heterochromatin intercalary bands were also demonstrated to be heterogenous. Unexpectedly, there was a lack of methylation in rye subtelomeres, indicating that heterochromatin is a very diverse fraction of chromatin, and its epigenetic regulation or potential influence on adjacent regions can be more complex than has conventionally been thought. Like telomeres and centromeres, subtelomeric heterochromatin can has a specific role, and the absence of 5-mC is required to maintain the heterochromatin state.
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Affiliation(s)
- Anna Kalinka
- Institute of Biology, University of Szczecin, Szczecin, Poland
- Molecular Biology and Biotechnology Center, University of Szczecin, Szczecin, Poland
- * E-mail:
| | - Magdalena Achrem
- Institute of Biology, University of Szczecin, Szczecin, Poland
- Molecular Biology and Biotechnology Center, University of Szczecin, Szczecin, Poland
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Borowska-Zuchowska N, Robaszkiewicz E, Wolny E, Betekhtin A, Hasterok R. Ribosomal DNA loci derived from Brachypodium stacei are switched off for major parts of the life cycle of Brachypodium hybridum. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:805-815. [PMID: 30481334 PMCID: PMC6363085 DOI: 10.1093/jxb/ery425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/21/2018] [Indexed: 05/15/2023]
Abstract
Nucleolar dominance is an epigenetic phenomenon that occurs in some plant and animal allopolyploids and hybrids, whereby only one ancestral set of 35S rRNA genes retains the ability to form the nucleolus while the rDNA loci derived from the other progenitor are transcriptionally silenced. There is substantial evidence that nucleolar dominance is regulated developmentally. This study focuses upon the establishment and/or maintenance of nucleolar dominance during different stages of development in the model grass allotetraploid Brachypodium hybridum. Fluorescence in situ hybridization with a 25S rDNA probe to cells in three-dimensional cytogenetic preparations showed that nucleolar dominance is present not only in root meristematic and differentiated cells of this species, but also in male meiocytes at prophase I, tetrads of microspores, and different embryonic tissues. The inactive state of Brachypodium stacei-originated rDNA loci was confirmed by silver staining. Only B. distachyon-derived 35S rDNA loci formed nucleoli in the aforementioned tissues, whereas B. stacei-like loci remained highly condensed and thus transcriptionally suppressed. The establishment of nucleolar dominance during earlier stages of B. hybridum embryo development cannot be ruled out. However, we propose that gradual pseudogenization of B. stacei-like loci in the evolution of the allotetraploid seems to be more likely.
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Affiliation(s)
- Natalia Borowska-Zuchowska
- Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
- Correspondence:
| | - Ewa Robaszkiewicz
- Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Elzbieta Wolny
- Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Alexander Betekhtin
- Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Robert Hasterok
- Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
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Borowska-Zuchowska N, Hasterok R. Epigenetics of the preferential silencing of Brachypodium stacei-originated 35S rDNA loci in the allotetraploid grass Brachypodium hybridum. Sci Rep 2017; 7:5260. [PMID: 28706212 PMCID: PMC5509716 DOI: 10.1038/s41598-017-05413-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 05/30/2017] [Indexed: 01/16/2023] Open
Abstract
Nucleolar dominance (ND), initially described as ‘differential amphiplasty’, is a phenomenon observed in some plant and animal allopolyploids and hybrids in which the selective suppression of the activity of 35S rRNA gene loci that have been inherited from one of the two or more ancestral genomes occurs. Although more than 80 years have passed since the discovery of ND, there is still a significant lack in our understanding of the mechanisms that determine this phenomenon. Here, we aimed to investigate the epigenetic status of 35S rRNA gene loci in the monocotyledonous Brachypodium hybridum, which is an allotetraploid that has resulted from a cross between B. distachyon and B. stacei. We revealed that the repressed B. stacei-inherited rDNA loci are characterised by a high level of DNA methylation. The global hypomethylation of B. hybridum nuclear DNA induced by 5-azacytidine, however, seems to be insufficient for the transcriptional reactivation of these loci, which indicates that factors other than DNA methylation are behind the suppression of B. stacei-originated loci. We also showed that the transcriptionally active and silenced fractions of rRNA genes that had been inherited from B. distachyon occupy different domains within the chromocentres adjacent to the nucleolus, depending on their epigenetic status.
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Affiliation(s)
- Natalia Borowska-Zuchowska
- Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, 28 Jagiellonska Street, 40-032, Katowice, Poland.
| | - Robert Hasterok
- Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, 28 Jagiellonska Street, 40-032, Katowice, Poland
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Susek K, Braszewska-Zalewska A, Bewick AJ, Hasterok R, Schmitz RJ, Naganowska B. Epigenomic diversification within the genus Lupinus. PLoS One 2017; 12:e0179821. [PMID: 28640886 PMCID: PMC5480990 DOI: 10.1371/journal.pone.0179821] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 06/05/2017] [Indexed: 12/23/2022] Open
Abstract
Deciphering the various chemical modifications of both DNA and the histone compound of chromatin not only leads to a better understanding of the genome-wide organisation of epigenetic landmarks and their impact on gene expression but may also provide some insights into the evolutionary processes. Although both histone modifications and DNA methylation have been widely investigated in various plant genomes, here we present the first study for the genus Lupinus. Lupins, which are members of grain legumes (pulses), are beneficial for food security, nutrition, health and the environment. In order to gain a better understanding of the epigenetic organisation of genomes in lupins we applied the immunostaining of methylated histone H3 and DNA methylation as well as whole-genome bisulfite sequencing. We revealed variations in the patterns of chromatin modifications at the chromosomal level among three crop lupins, i.e. L. angustifolius (2n = 40), L. albus (2n = 50) and L. luteus (2n = 52), and the legume model plant Medicago truncatula (2n = 16). Different chromosomal patterns were found depending on the specific modification, e.g. H3K4me2 was localised in the terminal parts of L. angustifolius and M. truncatula chromosomes, which is in agreement with the results that have been obtained for other species. Interestingly, in L. albus and L. luteus this modification was limited to one arm in the case of all of the chromosomes in the complement. Additionally, H3K9me2 was detected in all of the analysed species except L. luteus. DNA methylation sequencing (CG, CHG and CHH contexts) of aforementioned crop but also wild lupins such as L. cosentinii (2n = 32), L. digitatus (2n = 36), L. micranthus (2n = 52) and L. pilosus (2n = 42) supported the range of interspecific diversity. The examples of epigenetic modifications illustrate the diversity of lupin genomes and could be helpful for elucidating further epigenetic changes in the evolution of the lupin genome.
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Affiliation(s)
- Karolina Susek
- Department of Genomics, Institute of Plant Genetics, Polish Academy of Sciences, Poznan, Poland
| | | | - Adam J. Bewick
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Robert Hasterok
- Department of Plant Anatomy and Cytology, University of Silesia in Katowice, Katowice, Poland
| | - Robert J. Schmitz
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Barbara Naganowska
- Department of Genomics, Institute of Plant Genetics, Polish Academy of Sciences, Poznan, Poland
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Eichten SR, Stuart T, Srivastava A, Lister R, Borevitz JO. DNA methylation profiles of diverse Brachypodium distachyon align with underlying genetic diversity. Genome Res 2016; 26:1520-1531. [PMID: 27613611 PMCID: PMC5088594 DOI: 10.1101/gr.205468.116] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 08/25/2016] [Indexed: 12/13/2022]
Abstract
DNA methylation, a common modification of genomic DNA, is known to influence the expression of transposable elements as well as some genes. Although commonly viewed as an epigenetic mark, evidence has shown that underlying genetic variation, such as transposable element polymorphisms, often associate with differential DNA methylation states. To investigate the role of DNA methylation variation, transposable element polymorphism, and genomic diversity, whole-genome bisulfite sequencing was performed on genetically diverse lines of the model cereal Brachypodium distachyon. Although DNA methylation profiles are broadly similar, thousands of differentially methylated regions are observed between lines. An analysis of novel transposable element indel variation highlighted hundreds of new polymorphisms not seen in the reference sequence. DNA methylation and transposable element variation is correlated with the genome-wide amount of genetic variation present between samples. However, there was minimal evidence that novel transposon insertions or deletions are associated with nearby differential methylation. This study highlights unique relationships between genetic variation and DNA methylation variation within Brachypodium and provides a valuable map of DNA methylation across diverse resequenced accessions of this model cereal species.
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Affiliation(s)
- Steven R Eichten
- ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australia, 2601
| | - Tim Stuart
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia, 6009
| | - Akanksha Srivastava
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia, 6009
| | - Ryan Lister
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia, 6009
| | - Justin O Borevitz
- ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australia, 2601
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Yaish MW, Peng M, Rothstein SJ. Global DNA methylation analysis using methyl-sensitive amplification polymorphism (MSAP). Methods Mol Biol 2014; 1062:285-98. [PMID: 24057373 DOI: 10.1007/978-1-62703-580-4_16] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA methylation is a crucial epigenetic process which helps control gene transcription activity in eukaryotes. Information regarding the methylation status of a regulatory sequence of a particular gene provides important knowledge of this transcriptional control. DNA methylation can be detected using several methods, including sodium bisulfite sequencing and restriction digestion using methylation-sensitive endonucleases. Methyl-Sensitive Amplification Polymorphism (MSAP) is a technique used to study the global DNA methylation status of an organism and hence to distinguish between two individuals based on the DNA methylation status determined by the differential digestion pattern. Therefore, this technique is a useful method for DNA methylation mapping and positional cloning of differentially methylated genes. In this technique, genomic DNA is first digested with a methylation-sensitive restriction enzyme such as HpaII, and then the DNA fragments are ligated to adaptors in order to facilitate their amplification. Digestion using a methylation-insensitive isoschizomer of HpaII, MspI is used in a parallel digestion reaction as a loading control in the experiment. Subsequently, these fragments are selectively amplified by fluorescently labeled primers. PCR products from different individuals are compared, and once an interesting polymorphic locus is recognized, the desired DNA fragment can be isolated from a denaturing polyacrylamide gel, sequenced and identified based on DNA sequence similarity to other sequences available in the database. We will use analysis of met1, ddm1, and atmbd9 mutants and wild-type plants treated with a cytidine analogue, 5-azaC, or zebularine to demonstrate how to assess the genetic modulation of DNA methylation in Arabidopsis. It should be noted that despite the fact that MSAP is a reliable technique used to fish for polymorphic methylated loci, its power is limited to the restriction recognition sites of the enzymes used in the genomic DNA digestion.
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Affiliation(s)
- Mahmoud W Yaish
- Department of Biology, College of Science, Sultan Qaboos University, Muscat, Oman
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Gong Z, Xue C, Zhang M, Guo R, Zhou Y, Shi G. Physical localization and DNA methylation of 45S rRNA gene loci in Jatropha curcas L. PLoS One 2013; 8:e84284. [PMID: 24386362 PMCID: PMC3875529 DOI: 10.1371/journal.pone.0084284] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 11/20/2013] [Indexed: 11/18/2022] Open
Abstract
In eukaryotes, 45S rRNA genes are arranged in tandem arrays of repeat units, and not all copies are transcribed during mitosis. DNA methylation is considered to be an epigenetic marker for rDNA activation. Here, we established a clear and accurate karyogram for Jatropha curcas L. The chromosomal formula was found to be 2n=2x=22=12m+10 sm. We found that the 45S rDNA loci were located at the termini of chromosomes 7 and 9 in J. curcas. The distribution of 45S rDNA has no significant difference in J. curcas from different sources. Based on the hybridization signal patterns, there were two forms of rDNA - dispersed and condensed. The dispersed type of signals appeared during interphase and prophase, while the condensed types appeared during different stages of mitosis. DNA methylation analysis showed that when 45S rDNA stronger signals were dispersed and connected to the nucleolus, DNA methylation levels were lower at interphase and prophase. However, when the 45S rDNA loci were condensed, especially during metaphase, they showed different forms of DNA methylation.
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Affiliation(s)
- Zhiyun Gong
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, Jiangsu, China
- * E-mail:
| | - Chao Xue
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, Jiangsu, China
| | - Mingliang Zhang
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, Jiangsu, China
| | - Rui Guo
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, Jiangsu, China
| | - Yong Zhou
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, Jiangsu, China
| | - Guoxin Shi
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, Jiangsu, China
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Testillano PS, Solís MT, Risueño MC. The 5-methyl-deoxy-cytidine (5mdC) localization to reveal in situ the dynamics of DNA methylation chromatin pattern in a variety of plant organ and tissue cells during development. PHYSIOLOGIA PLANTARUM 2013; 149:104-13. [PMID: 23193951 DOI: 10.1111/ppl.12015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 11/07/2012] [Accepted: 11/18/2012] [Indexed: 12/16/2023]
Abstract
DNA methylation of cytosine residues constitutes a prominent epigenetic modification of the chromatin fiber which is locked in a transcriptionally inactive conformation leading to gene silencing. Plant developmental processes, as differentiation and proliferation, are accompanied by chromatin remodeling and epigenetic reprogramming. Despite the increasing knowledge gained on the epigenetic mechanisms controlling plant developmental processes, the knowledge of the DNA methylation regulation during relevant developmental programs in flowering plants, such as gametogenesis or embryogenesis, is very limited. The analysis of global DNA methylation levels has been frequently conducted by high performance capillary electrophoresis, and more recently also by ELISA-based assays, which provided quantitative data of whole organs and tissues. Nevertheless, to investigate the DNA methylation dynamics during plant development in different cell types of the same organ, the analysis of spatial and temporal pattern of nuclear distribution of 5-methyl-deoxy-cytidine (5mdC) constitutes a potent approach. In this work, immunolocalization of 5mdC on sections and subsequent confocal laser microscopy analysis have been applied for in situ cellular analysis of a variety of plant cells, tissues and organs with different characteristics, e.g. hardness, heterogeneity, cell accessibility, tissue compactness, etc.; the results demonstrated the versatility and feasibility of the approach for different plant samples, and revealed defined DNA methylation nuclear patterns associated with differentiation and proliferation events of various plant cell types and developmental programs. Quantification of 5mdC immunofluorescence intensity by image analysis software also permitted to estimate differences in global DNA methylation levels among different cells types of the same organ during development.
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Affiliation(s)
- Pilar S Testillano
- Plant Development and Nuclear Architecture, Biological Research Centre, CIB-CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
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