Zygotic epigenetic reprogramming entails genome-wide DNA demethylation that is accompanied by Tet methylcytosine dioxygenase 3 (Tet3)-driven oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC; refs 1-4). Here we demonstrate using detailed immunofluorescence analysis and ultrasensitive LC-MS-based quantitative measurements that the initial loss of paternal 5mC does not require 5hmC formation. Small-molecule inhibition of Tet3 activity, as well as genetic ablation, impedes 5hmC accumulation in zygotes without affecting the early loss of paternal 5mC. Instead, 5hmC accumulation is dependent on the activity of zygotic Dnmt3a and Dnmt1, documenting a role for Tet3-driven hydroxylation in targeting de novo methylation activities present in the early embryo. Our data thus provide further insights into the dynamics of zygotic reprogramming, revealing an intricate interplay between DNA demethylation, de novo methylation and Tet3-driven hydroxylation.
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http://dx.doi.org/10.1038/ncb3296 | DOI Listing |
PLoS One
October 2024
Group «Mechanisms of DNA Repair and Carcinogenesis», CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, Villejuif Cedex, France.
Human thymine-DNA glycosylase (TDG) excises T mispaired with G in a CpG context to initiate the base excision repair (BER) pathway. TDG is also involved in epigenetic regulation of gene expression by participating in active DNA demethylation. Here we demonstrate that under extended incubation time the full-length TDG (TDGFL), but neither its isolated catalytic domain (TDGcat) nor methyl-CpG binding domain-containing protein 4 (MBD4) DNA glycosylase, exhibits significant excision activity towards T and C in regular non-damaged DNA duplex in TpG/CpA and CpG/CpG contexts.
View Article and Find Full Text PDFNeurosci Bull
November 2024
Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200030, China.
Biochem Soc Trans
October 2024
Institute of Longevity and Aging Research, Zhongshan Hospital, Fudan University, Shanghai, China.
Nat Commun
July 2024
Laboratory of Genetics and Genomics, National Institute on Aging, NIH, Baltimore, MD, USA.
DNA hydroxymethylation (5hmC), the most abundant oxidative derivative of DNA methylation, is typically enriched at enhancers and gene bodies of transcriptionally active and tissue-specific genes. Although aberrant genomic 5hmC has been implicated in age-related diseases, its functional role in aging remains unknown. Here, using mouse liver and cerebellum as model organs, we show that 5hmC accumulates in gene bodies associated with tissue-specific function and restricts the magnitude of gene expression changes with age.
View Article and Find Full Text PDFEpigenetics
December 2024
Department of Cell and Developmental Biology, Perelman School of Medicine, Smilow Center for Translational Research, Philadelphia, PA, USA.
TET1/2/3 dioxygenases iteratively demethylate 5-methylcytosine, beginning with the formation of 5-hydroxymethylcytosine (5hmC). The post-mitotic brain maintains higher levels of 5hmC than most peripheral tissues, and TET1 ablation studies have underscored the critical role of TET1 in brain physiology. However, deletion of precludes the disentangling of the catalytic and non-catalytic functions of TET1.
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