scholarly journals Chromatin remodeling in replication‐uncoupled maintenance DNA methylation and chromosome stability: Insights from ICF syndrome studies

2021 ◽  
Author(s):  
Motoko Unoki
Keyword(s):  
Dna Methylation ◽  
Chromatin Remodeling ◽  
Chromosome Stability ◽  
Icf Syndrome

scholarly journals Persistent epigenetic memory impedes rescue of the telomeric phenotype in human ICF iPSCs following DNMT3B correction

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Shir Toubiana ◽  
Miriam Gagliardi ◽  
Mariarosaria Papa ◽  
Roberta Manco ◽  
Maty Tzukerman ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Dna Methyltransferase ◽  
De Novo ◽  
Pharmacological Intervention ◽  
Icf Syndrome ◽  
Genome Wide ◽  
Mammalian Genomes ◽  
Induced Pluripotent ◽  
Methylation Patterns

DNA methyltransferase 3B (DNMT3B) is the major DNMT that methylates mammalian genomes during early development. Mutations in human DNMT3B disrupt genome-wide DNA methylation patterns and result in ICF syndrome type 1 (ICF1). To study whether normal DNA methylation patterns may be restored in ICF1 cells, we corrected DNMT3B mutations in induced pluripotent stem cells from ICF1 patients. Focusing on repetitive regions, we show that in contrast to pericentromeric repeats, which reacquire normal methylation, the majority of subtelomeres acquire only partial DNA methylation and, accordingly, the ICF1 telomeric phenotype persists. Subtelomeres resistant to de novo methylation were characterized by abnormally high H3K4 trimethylation (H3K4me3), and short-term reduction of H3K4me3 by pharmacological intervention partially restored subtelomeric DNA methylation. These findings demonstrate that the abnormal epigenetic landscape established in ICF1 cells restricts the recruitment of DNMT3B, and suggest that rescue of epigenetic diseases with genome-wide disruptions will demand further manipulation beyond mutation correction.

100 ASSESSMENT OF LOCUS-SPECIFIC DNA METHYLATION: OPTIMIZATION FOR BOVINE EMBRYOS

2009 ◽  
Vol 21 (1) ◽  
pp. 150
Author(s):  
E. Wroclawska ◽  
J. O. Brant ◽  
T. P. Yang ◽  
K. Moore
Keyword(s):  
Dna Methylation ◽  
Somatic Cell ◽  
Chromatin Remodeling ◽  
Plasmid Dna ◽  
Dna Amplification ◽  
Early Embryo ◽  
Small Samples ◽  
Small Scale ◽  
Research Education

Assessment of chromatin remodeling in early embryos is a major focus of studies today, and evaluation of DNA methylation at specific loci is one approach to study these epigenetic modifications. Our objective was to optimize the bisulfite sequencing methodology for use with very small cell numbers originating from pre-implantation embryos, making the process more time- and cost-efficient. The optimized steps include bisulfite conversion of small samples, bisulfite primer design, high-throughput plasmid DNA amplification, and preparation for sequencing. Methylation at 2 loci, Satellite I and Oct4, was investigated in bovine in vitro-produced (IVP) embryos collected at the 2-cell, 8-cell, and blastocyst stages. Bovine skin fibroblasts were first used to optimize the particular steps of the process. All reactions were run in duplicate and no-template negative and somatic cell-positive controls were treated alongside samples. Incorporating the use of Methyl Primer Express (Applied Biosystems, Foster City, CA), MacVector (Oxford Molecular Ltd., Campbell, CA), and Mfold software (Mathews DH et al. 1999 J. Mol. Biol. 288, 911–940; Zuker M 2003 Nucleic Acids Res. 31, 3406–3415) improved the specificity of bisulfite primers by exclusion of secondary or tertiary structures. The DNA from bisulfite treatment for 15 to 16 h was of better quality than DNA treated for 18 h. After initial PCR optimization, different cell concentrations were used to establish that detectable PCR products and subsequent methylation data could be obtained from DNA isolated from as few as 8 cells. Treating single blastocysts and pools of ten 8-cell and forty 2-cell embryos was sufficient for the entire scope of the experiment, allowing use of the same samples across all loci. After molecular cloning, plasmid DNA was amplified by 3 different methods and evaluated for efficiency: miniprep, TempliPhi (GE Healthcare, Piscataway, NJ), or 96-well glycerol stocks and automated TempliPhi format. Although TempliPhi alone was better than miniprep for small-scale experiments, it was the 96-well format that saved weeks of time and was most cost-effective. Sequencing was performed on a minimum of 8 clones/sample using ABI Prism sequencers (Applied Biosystems), and results were analyzed using Chromas Pro software (Technelysium Pty. Ltd., Helensvale, Australia). Percentage methylation of bovine IVP 2-cell, 8-cell, and blastocyst stage embryos for Satellite I was 25, 10, and 22%, respectively, and for Oct4 was 88, 88, and 79%, respectively. However, somatic cell methylation was 74% for Satellite I and 88% for Oct4, implying that Satellite I is demethylated during early embryo development, whereas Oct4 remains hypermethylated. In conclusion, these improved methods will benefit further studies of chromatin remodeling in early bovine pre-implantation embryos. This project was supported by National Research Initiative Competitive Grant no. 2006-35203-16620 from the USDA Cooperative State Research, Education, and Extension Service.

scholarly journals Histone acetylation recruits the SWR1 complex to regulate active DNA demethylation in Arabidopsis

2019 ◽  
Vol 116 (33) ◽  
pp. 16641-16650 ◽  
Author(s):  
Wen-Feng Nie ◽  
Mingguang Lei ◽  
Mingxuan Zhang ◽  
Kai Tang ◽  
Huan Huang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Conceptual Framework ◽  
Histone Acetylation ◽  
Chromatin Remodeling ◽  
Nuclear Protein ◽  
Dna Demethylation ◽  
Specific Target ◽  
Active Dna Demethylation ◽  
Chromatin Remodeling Complex ◽  
Genomic Regions

Active DNA demethylation is critical for controlling the DNA methylomes in plants and mammals. However, little is known about how DNA demethylases are recruited to target loci, and the involvement of chromatin marks in this process. Here, we identify 2 components of the SWR1 chromatin-remodeling complex, PIE1 and ARP6, as required for ROS1-mediated DNA demethylation, and discover 2 SWR1-associated bromodomain-containing proteins, AtMBD9 and nuclear protein X1 (NPX1). AtMBD9 and NPX1 recognize histone acetylation marks established by increased DNA methylation 1 (IDM1), a known regulator of DNA demethylation, redundantly facilitating H2A.Z deposition at IDM1 target loci. We show that at some genomic regions, H2A.Z and DNA methylation marks coexist, and H2A.Z physically interacts with ROS1 to regulate DNA demethylation and antisilencing. Our results unveil a mechanism through which DNA demethylases can be recruited to specific target loci exhibiting particular histone marks, providing a conceptual framework to understand how chromatin marks regulate DNA demethylation.

scholarly journals Involvement of Putative SNF2 Chromatin Remodeling Protein DRD1 in RNA-Directed DNA Methylation

2004 ◽  
Vol 14 (9) ◽  
pp. 801-805 ◽  
Author(s):  
Tatsuo Kanno ◽  
M.Florian Mette ◽  
David P Kreil ◽  
Werner Aufsatz ◽  
Marjori Matzke ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Chromatin Remodeling
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