Disabling de novo DNA methylation in embryonic stem cells allows an illegitimate fate trajectory

Kinoshita, Masaki; Li, Meng Amy; Barber, Michael; Mansfield, William; Dietmann, Sabine; Smith, Austin

Abstract

Genome remethylation is essential for mammalian development but specific reasons are unclear. Here we examined embryonic stem (ES) cell fate in the absence of de novo DNA methyltransferases. We observed that ES cells deficient for both Dnmt3a and Dnmt3b are rapidly eliminated from chimeras. On further investigation we found that in vivo and in vitro the formative pluripotency transition is derailed toward production of trophoblast. This aberrant trajectory is associated with failure to suppress activation of Ascl2. Ascl2 encodes a bHLH transcription factor expressed in the placenta. Misexpression of Ascl2 in ES cells provokes transdifferentiation to trophoblast-like cells. Conversely, Ascl2 deletion rescues formative transition of Dnmt3a/b mutants and improves contribution to chimeric epiblast. Thus, de novo DNA methylation safeguards against ectopic activation of Ascl2. However, Dnmt3a/b-deficient cells remain defective in ongoing embryogenesis. We surmise that multiple developmental transitions may be secured by DNA methylation silencing potentially disruptive genes.

Citation

Kinoshita, M., Li, M. A., Barber, M., Mansfield, W., Dietmann, S., & Smith, A. (2021). Disabling de novo DNA methylation in embryonic stem cells allows an illegitimate fate trajectory. Proceedings of the National Academy of Sciences, 118(38), Article e2109475118. https://doi.org/10.1073/pnas.2109475118

• Journal Article Type: Article
• Acceptance Date: Jul 18, 2021
• Online Publication Date: Sep 13, 2021
• Publication Date: Sep 21, 2021
• Deposit Date: Mar 5, 2025
• Publicly Available Date: Mar 6, 2025
• Journal: Proceedings of the National Academy of Sciences
• Print ISSN: 0027-8424
• Electronic ISSN: 1091-6490
• Publisher: National Academy of Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 118
• Issue: 38
• Article Number: e2109475118
• DOI: https://doi.org/10.1073/pnas.2109475118
• Keywords: DNA methylation, embryonic stem cells, pluripotency
• Public URL: https://nottingham-repository.worktribe.com/output/46190286
• Publisher URL: https://www.pnas.org/doi/full/10.1073/pnas.2109475118
• Additional Information: Accepted: 2021-07-18; Published: 2021-09-13