N 6-methyladenine in DNA antagonizes SATB1 in early development
© 2020, The Author(s), under exclusive licence to Springer Nature Limited. The recent discovery of N6-methyladenine (N6-mA) in mammalian genomes suggests that it may serve as an epigenetic regulatory mechanism1. However, the biological role of N6-mA and the molecular pathways that exert its function remain unclear. Here we show that N6-mA has a key role in changing the epigenetic landscape during cell fate transitions in early development. We found that N6-mA is upregulated during the development of mouse trophoblast stem cells, specifically at regions of stress-induced DNA double helix destabilization (SIDD)2–4. Regions of SIDD are conducive to topological stress-induced unpairing of the double helix and have critical roles in organizing large-scale chromatin structures3,5,6. We show that the presence of N6-mA reduces the in vitro interactions by more than 500-fold between SIDD and SATB1, a crucial chromatin organizer that interacts with SIDD regions. Deposition of N6-mA also antagonizes SATB1 function in vivo by preventing its binding to chromatin. Concordantly, N6-mA functions at the boundaries between euchromatin and heterochromatin to restrict the spread of euchromatin. Repression of SIDD–SATB1 interactions mediated by N6-mA is essential for gene regulation during trophoblast development in cell culture models and in vivo. Overall, our findings demonstrate an unexpected molecular mechanism for N6-mA function via SATB1, and reveal connections between DNA modification, DNA secondary structures and large chromatin domains in early embryonic development.
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Li, Z., Zhao, S., Nelakanti, R., Lin, K., Wu, T., Alderman, M., Guo, C., Wang, P., Zhang, M., Min, W., Jiang, Z., Wang, Y., Li, H., & Xiao, A. (2020). N 6-methyladenine in DNA antagonizes SATB1 in early development. Nature, 583 (7817), 625-630. https://doi.org/10.1038/s41586-020-2500-9