Arabidopsis thaliana
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ABSTRACT:
PROVIDER: PRJNA98063 | ENA |
REPOSITORIES: ENA
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Project description:DNA methylation is an important epigenetic modification involved in many biological processes, and active DNA demethylation plays critical roles in regulating expression of genes and anti-silencing of transgenes. In this study, we isolated mutations in one arabidopsis gene, ROS5, which causes the silencing of transgenic 35S-NPTII because of DNA hypermethylation, but no effect on transgenic RD29A-LUC. ROS5 encodes an atypical small heat shock protein. ROS5 can physically interact with IDM1 and is required for preventing DNA hypermethylation of some endogenous genes that are also regualated by IDM1 and ROS1. We propose that ROS5 may regulate active DNA demethylation by interacting with IDM1, thereby creating a friendly chromatin environment that facilitates the binding of ROS1 to erase DNA methylation.
2014-08-28 | E-MTAB-4323 | biostudies-arrayexpress
Project description:Genome-wide demethylation of Arabidopsis endosperm
| PRJNA116929 | ENA
Project description:H2A.X is an H2A variant histone in eukaryotes, unique for its ability to respond to DNA damage, initiating the DNA repair pathway. H2A.X replacement within the histone octamer is mediated by the FAcilitates Chromatin Transactions (FACT) complex, a key chromatin remodeler. FACT is required for DEMETER (DME)-mediated DNA demethylation at certain loci in Arabidopsis thaliana female gametophytes during reproduction. Here, we sought to investigate whether H2A.X is involved in DME- and FACT-mediated DNA demethylation during reproduction. H2A.X is encoded by two genes in Arabidopsis genome, HTA3 and HTA5. We generated h2a.x double mutants, which displayed a normal growth profile, whereby flowering time, seed development, and root tip organization, S-phase progression and proliferation were all normal. However, h2a.x mutants were more sensitive to genotoxic stress, consistent with previous reports. H2A.X fused to Green Fluorescent Protein (GFP) under the H2A.X promoter was highly expressed especially in newly developing Arabidopsis tissues, including in male and female gametophytes, where DME is also expressed. We examined DNA methylation in h2a.x developing seeds and seedlings using whole genome bisulfite sequencing, and found that CG DNA methylation is decreased genome-wide in h2a.x mutant seeds. Hypomethylation was most striking in transposon bodies, and occurred on both parental alleles in the developing endosperm, but not the embryo or seedling. h2a.x-mediated hypomethylated sites overlapped DME targets, but also included other loci, predominately located in heterochromatic transposons and intergenic DNA. Our genome-wide methylation analyses suggest that H2A.X could function in preventing access of the DME demethylase to non-canonical sites. Alternatively, H2A.X may be involved in recruiting methyltransferases to those sites. Overall, our data show that H2A.X is required to maintain DNA methylation homeostasis in the unique chromatin environment of the Arabidopsis endosperm.
2023-08-07 | GSE233920 | GEO
Project description:To gain deeper insights into the mechanisms of DNA demethylation pathway, we conducted a genetic screen for proteins that are involved in preventing epigenetic silencing, and then the ones, which are also implicated in DNA demethylation pathway, are used for further studies. Eventually, a mutant with low luciferase luminescence (low LUC luminescence) was recovered, and named reduced LUC luminescence 6-1 (rll6-1). Map-based cloning revealed thatrll6-1 mutation is located in bacterial artificial chromosome (BAC) clone F5I10 on chromosome 4, and there are a total of 10 candidate genes were found within such a region. Analysis of genome-wide methylation patterns of rll6-1 mutant showed that rll6-1 mutation led to 3863 hyper-DMRs throughout the five Arabidopsis chromosomes, and elevated DNA methylation level of 2×35S promoter, which was similar to that found in ros1 mutant. Further analysis demonstrated that there are 1456 common hyper-DMRs shared by rll6-1 and ros1-7, which account for 2407 and 5642 hyper-DMRs, respectively, suggesting both proteins act together in a synergistic manner to remove DNA methylation. Further investigations demonstrated that rll6-1 mutation does not affect the expression of the four genes of the DNA glycosylase/lyase family. Thus, our results demonstrated that RLL6 not only participated in transcriptional anti-silencing, but is also involved in DNA demethylation pathway.
2022-07-17 | GSE208332 | GEO
Project description:The DEMETER (DME) DNA glycosylase mediates genome-wide DNA demethylation and is required for endosperm genomic imprinting and embryo viability. Targets of DME-demethylation are small, AT-rich transposons and boundaries of large heterochromatic transposons, but how DME interacts with chromatin is unclear. To investigate the interaction between DME and chromatin, we analyzed DNA methylation in Arabidopsis seeds and pollen deficient in the chromatin remodeler FAcilitates Chromatin Transactions (FACT) complex. We find that FACT co-localizes with nuclear DME, and is required for DME activity in chromatin domains with high nucleosome occupancy and histone modifications associated with heterochromatin, which comprise over half of DME target loci. We also demonstrate that heterochromatin-associated linker histone H1 mediates the requirement for FACT at a subset of DME-target loci. However, FACT is not required for DME demethylation of targets in euchromatic regions. Thus, chromatin structure determines the degree to which FACT facilitates access of DME to its targets.
2018-04-17 | GSE105000 | GEO
Project description:Ecotype-specific differences in genome methylation were assayed in Arabidopsis Col and Ler variations using genomic tiling microarrays. Comparative genome hybridization was also performed so that the contribution of ecotype-specific amplifications and deletions could be estimated and integrated into the analysis of differential DNA methylation. Keywords: methylation analysis and comparative genome hybridization
2007-05-09 | GSE7580 | GEO
Project description:Parent-of-origin-specific (imprinted) gene expression is regulated in Arabidopsis thaliana endosperm by cytosine demethylation of the maternal genome mediated by the DNA glycosylase DEMETER, but the extent of the methylation changes is not known. Here we show that virtually the entire endosperm genome is demethylated, coupled with extensive local non-CG hypermethylation of siRNA-targeted sequences. Mutation of DEMETER partially restores endosperm CG methylation to levels found in other tissues, indicating that CG demethylation is specific to maternal sequences. Endosperm demethylation is accompanied by CHH hypermethylation of embryo transposable elements. Our findings demonstrate extensive reconfiguration of the endosperm methylation landscape that likely reinforces transposon silencing in the embryo. Keywords: Epigenetics; bisulfite sequencing Examination of DNA methylation in four Arabidopsis tissues Description of processed data and raw data file contents can be found in the attached README.txt file
2009-06-16 | E-GEOD-15922 | biostudies-arrayexpress
Project description:Arabidopsis Messenger RNA N6-methyladenosine Demethylation Regulates Plant Development
| PRJNA316096 | ENA
Project description:Cytosine DNA methylation is considered to be a stable epigenetic mark, but active demethylation has been observed in both plants and animals. In Arabidopsis thaliana, DNA glycosylases of the DEMETER (DME) family remove methylcytosines from DNA. Demethylation by DME is necessary for genomic imprinting and demethylation by a related protein, REPRESSOR OF SILENCING1, which prevents gene silencing in a transgenic background. However, the extent and function of demethylation by DEMETER-LIKE (DML) proteins in WT plants is not known. Using genome-tiling microarrays, we mapped DNA methylation in mutant and WT plants and identified 179 loci actively demethylated by DML enzymes. Mutations in DML genes lead to locus-specific DNA hypermethylation. Reintroducing WT DML genes restores most loci to the normal pattern of methylation, although at some loci, hypermethylated epialleles persist. Of loci demethylated by DML enzymes, >80% are near or overlap genes. Genic demethylation by DML enzymes primarily occurs at the 5' and 3' ends, a pattern opposite to the overall distribution of WT DNA methylation. Our results show that demethylation by DML DNA glycosylases edits the patterns of DNA methylation within the Arabidopsis genome to protect genes from potentially deleterious methylation. Keywords: whole genome profiling, DNA methylation, demethylase
2007-04-02 | GSE7336 | GEO
Project description:The eukaryotic genome is divided into regions of heterochromatin and euchromatin. The histone variant H2A.Z specifically localizes at euchromatin and displays a genome-wide anti-correlation with DNA methylation. DNA methylation plays a central role in the epigenetic regulation of many eukaryotic genomes. Active DNA demethylation is critical for controlling the epigenome in plants and mammals. Yet, little is known about how DNA demethylases are recruited to target loci. Here we report that SWR1, a conserved histone H2A.Z deposition complex, regulates DNA demethylation in Arabidopsis thaliana by recruiting the plant DNA demethylase ROS1. A forward genetic screen for anti-silencing mutants identified two SWR1 components, PIE1 and ARP6, as cellular factors required for ROS1-mediated DNA demethylation. We further discovered two bromodomain-containing proteins, the methyl-DNA-binding protein AtMBD9, and NPX1, a plant homolog of ScBDF1 in yeast, as components of the SWR1 complex in Arabidopsis. AtMBD9 and NPX1 function redundantly in preventing DNA hypermethylation and transcriptional gene silencing by recognizing histone acetylation marks established by IDM1, a known regulator of DNA demethylation. We show that IDM1 is required for H2A.Z deposition in many genomic regions targeted for active DNA demethylation. We found that H2A.Z interacts with ROS1 and is required for locus-specific DNA demethylation and antisilencing. Our results reveal a role of H2A.Z in active DNA demethylation, and a mechanism through which DNA demethylases can be recruited to target regions by specific histone acetylation marks.
2019-08-01 | GSE115170 | GEO