Handing Over Control

One of the very first milestones in life is a reset and reboot. After fertilisation, embryonic development is under the exclusive control of the maternal genome, but at a certain stage known as the maternal to zygotic transition, the mother’s egg needs to pass control and switch on the embryonic genes. This process is called zygote genome activation (ZGA) and is essential for development to progress, yet which factors initiate this crucial step are unclear. Dppa2 (red) and Dppa4 (green) are proteins that are present throughout pre-implantation development but were found to be dispensable for ZGA but removing these maternal proteins meant embryos didn’t survive. These two-cell embryos without Dppa2 (top right), without Dppa4 (bottom left) and without both (bottom right) were shown to have gone through ZGA (shown in magenta) so Dppa2/4 may instead be bookmarking key developmental genes to activate later as a ‘guiding light from mum’.

Written by Sophie Arthur

Sophie Arthur

former Science Communications Officer MRC LMS

Formerly a stem cell biologist, Sophie has since moved into science communication working at the MRC LMS. She also writes an award winning science and education blog Soph talks science.

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• Image adapted from work by Oana Kubinyecz and colleagues
• Epigenetics Programme, Babraham Institute, Cambridge, UK
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Development, December 2021