DNA Methylation
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REPOSITORIES: ENA
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Project description:The Microrchidia (MORC) family of ATPases are required for transposable element (TE) silencing and heterochromatin condensation in plants and animals, and C. elegans MORC-1 has been shown to topologically entrap and condense DNA. In Arabidopsis thaliana, mutation of MORCs has been shown to reactivate silent methylated genes and transposons and to decondense heterochromatic chromocenters, despite only minor changes in the maintenance of DNA methylation. Here we provide the first evidence localizing Arabidopsis MORC proteins to specific regions of chromatin and find that MORC4 and MORC7 are closely co-localized with sites of RNA directed DNA methylation (RdDM). We further show that MORC7, when tethered to DNA by an artificial zinc finger, can facilitate the establishment of RdDM. Finally, we show that MORCs are required for the efficient RdDM mediated establishment of DNA methylation and silencing of a newly integrated FWA transgene, even though morc mutations have no effect on the maintenance of preexisting methylation at the endogenous FWA gene. We propose that MORCs function as a molecular tether in RdDM complexes to reinforce RdDM activity for methylation establishment. These findings have implications for MORC protein function in a variety of other eukaryotic organisms.
2021-07-02 | PXD026674 | Pride
Project description:DNA (cytosine-5) methyltransferase 1 (DNMT1) is essential for mammalian development and maintenance of DNA methylation following DNA replication in cells. The DNA methylation process generates S-adenosyl-L-homocysteine, a strong inhibitor of DNMT1. Here we report that S-adenosylhomocysteine hydrolase (SAHH/AHCY), the only mammalian enzyme capable of hydrolyzing S-adenosyl-L-homocysteine binds to DNMT1 during DNA replication. SAHH activates DNMT1 in vitro and its overexpression in mammalian cells leads to hypermethylation of the genome, whereas its inhibition by adenosine periodate resulted in hypomethylation of the genome. Hypermethylation was consistent in both gene bodies and repetitive DNA elements leading to both down- and up-regulation of genes. Similarly, hypomethylation led to both up- and down-regulation of genes suggesting methylated regions influence gene expression either positively or negatively. Cells overexpressing SAHH specifically up-regulated metabolic pathway genes and down-regulated PPAR and MAPK signaling pathways genes. Therefore, we suggest that alteration of SAHH level in the cell leads to aberrant DNA methylation, altered metabolite levels and gene expression.
2018-06-06 | PXD006476 | Pride
Project description:TET1 controls maintenance DNA methylation via the regulation of Dppa3
| PRJEB26374 | ENA
Project description:Accumulative studies indicate that DNA maintenance methylation by DNMT1 is initiated by binding of UHRF1 to replication fork. However, how UHRF1 gains access to chromatin in S phase is poorly understood. Here we report that LSH, a SNF2 family chromatin remodeler, facilitates DNA methylation in somatic cells primarily by promoting DNA methylation by DNMT1. We show that knockout of LSH in various somatic cells resulted in substantial reduction of DNA methylation, whereas knockout of DNMT3A and DNMT3B only moderately reduced the level of DNA methylation. Consistent with a role in maintenance methylation, genome-wide analysis of DNA methylation revealed a widespread reduction of DNA methylation in all genomic elements in LSH null cells. Mechanistically, we demonstrate that LSH interacts with UHRF1 but not DNMT1 and facilitates UHRF1 chromatin association, UHRF1-catalyzed H3 ubiquitination, and subsequent DNMT1 recruitment to replication fork. Notably, UHRF1 also enhances LSH association with replication fork. Thus, our study identifies LSH as an essential factor for maintenance methylation and provides novel insight into how LSH facilitates maintenance methylation.
2020-12-01 | GSE136931 | GEO
Project description:Our study supports a role for H3K9 methylation in promoting DNA methylation, it demonstrates for the first time that DNA maintenance methylation in mammalian cells is to large extent independent on H3K9 methylation. Examination of DNA methylation levels in UHRF1 knock in and wide type mice.
2016-06-30 | E-GEOD-83884 | biostudies-arrayexpress
Project description:Non-coding transcription is an important determinant of heterochromatin formation. In Arabidopsis thaliana a specialized RNA polymerase V (Pol V) transcribes pervasively and produces long non-coding RNA. This facilitates locus-specific establishment of RNA-directed DNA methylation (RdDM). Subsequent maintenance of RdDM is associated with elevated levels of Pol V transcription, which is consistent with a mutual reinforcement of DNA methylation and non-coding transcription. However, the impact of DNA methylation on Pol V transcription remained unresolved. We found that loss of DNA methylation leads to a strong reduction of Pol V transcription. This occurs when DNA methylation is lost in all sequence contexts, which may happen not only in mutants defective in RdDM but also in mutants lacking maintenance DNA methyltransferases. Our results support a model where RdDM is maintained by a mutual reinforcement of DNA methylation and Pol V transcription with a strong crosstalk with other silencing pathways.
2021-08-27 | GSE168869 | GEO
Project description:DNA methylation in wild type bolting plants, wild type seedlings, and ddm1 seedlings. The purpose of the McrBC methylation microarray assay is to determine which regions of a genome are methylated versus those that are unmethylated in a single Arabidopsis thanliana genotype. McrBC is a methylation-sensitive enzyme that restricts DNA only at purine-Cmethyl half sites when separated between 50bp and 3kb. A designated amount of DNA from a particular genotype is sheared to a size range of 1kb-10kb using nebulization. We restrict half of the nebulized DNA with McrBC, and the methylated fraction is then removed from the unmethylated fraction through gel purification of DNA fragments greater than 1kb.* The remaining nebulized DNA is subjected to the same gel purification scheme, but with no McrBC treatment. In a single hybridization, the untreated sample is labeled with Cy5 and the McrBC-treated sample with Cy3. Thus, after labeling and microarray hybridization, the ratio of normalized Cy5 to normalized Cy3 represents the relative methylation at the sequence represented by the spot on the microarray. Dye swap analysis is carried out to take account of experimental variation by repeating the hybridization with identical samples labeled with Cy3 and Cy5, respectively. This SuperSeries is composed of the following subset Series: GSE1329: DNA methylation in wild-type bolting Arabidopsis thaliana plants GSE1330: DNA methylation in ddm1 seedling Arabidopsis thaliana plants GSE1331: VC133+137, DNA methylation in ddm1 seedling Arabidopsis thaliana plants GSE1332: VC134+136, DNA methylation in wild-type seedling Arabidopsis thaliana plants Refer to individual Series
2010-06-09 | E-GEOD-1355 | biostudies-arrayexpress
Project description:Eukaryotic DNA is wrapped around histone octamers to form nucleosomes, which are separated by linker DNA bound by histone H1. In many species, the DNA exhibits methylation of CG dinucleotides, which is epigenetically inherited via a semiconservative mechanism. How methyltransferases access DNA within nucleosomes remains mysterious. Here we show that methylation of nucleosomes requires DDM1/Lsh nucleosome remodelers in Arabidopsis thaliana and mouse. We also show that removal of histone H1, which partially restores methylation in ddm1 mutants, does so primarily in the linker DNA between nucleosomes. In h1ddm1 compound mutants, substantial portions of the genome exhibit dramatically periodic methylation that approaches wild-type levels in linker DNA but is virtually absent in nucleosomes. We also present evidence that de novo methylation supplements semiconservative maintenance of CG methylation across generations. Overall, our results demonstrate that nucleosomes and H1 are barriers to DNA methylation, which are overcome by DDM1/Lsh nucleosome remodelers.
2017-11-15 | GSE96994 | GEO
Project description:DNA N6-adenine methylation in Arabidopsis thaliana
| PRJNA322059 | ENA
Project description:A study of colorectal cancer screening using stool DNA-based SDC2 methylation test
| 2332763 | ecrin-mdr-crc