Mouse primordial germ cells (PGCs) erase global DNA methylation (5mC) as part of the comprehensive epigenetic reprogramming that occurs during PGC development. 5mC plays an important role in maintaining stable gene silencing and repression of transposable elements (TE) but it is not clear how the extensive loss of DNA methylation impacts on gene expression and TE repression in developing PGCs. Using a novel epigenetic disruption and recovery screen and genetic analyses, we identified a core set of germline-specific genes that are dependent exclusively on promoter DNA methylation for initiation and maintenance of developmental silencing. These gene promoters appear to possess a specialised chromatin environment that does not acquire any of the repressive H3K27me3, H3K9me2, H3K9me3 or H4K20me3 histone modifications when silenced by DNA methylation. Intriguingly, this methylation-dependent subset is highly enriched in genes with roles in suppressing TE activity in germ cells. We show that the mechanism for developmental regulation of the germline genome-defence genes involves DNMT3B-dependent de novo DNA methylation. These genes are then activated by lineage-specific promoter demethylation during distinct global epigenetic reprogramming events in migratory (~E8.5) and post-migratory (E10.5-11.5) PGCs. We propose that genes involved in genome defence are developmentally regulated primarily by promoter DNA methylation as a sensory mechanism that is coupled to the potential for TE activation during global 5mC erasure, thereby acting as a failsafe to ensure TE suppression and maintain genomic integrity in the germline.
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http://dx.doi.org/10.1242/dev.081661 | DOI Listing |
Mol Biol Rep
January 2025
Department of Pathology and Laboratory Medicine, Baylor Scott and White Medical Center, Baylor College of Medicine, Temple, TX, USA.
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Proc Natl Acad Sci U S A
January 2025
Department of Chemical Engineering, Stanford University, Stanford, CA 94305.
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CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia.
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View Article and Find Full Text PDFLab Chip
January 2025
Department of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta 4259, Midori-ku, Yokohama 226-8501, Japan.
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View Article and Find Full Text PDFAppl Environ Microbiol
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Department of Biological Sciences, Minnesota State University Mankato, Mankato, Minnesota, USA.
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