Essential Opposites

These images show mouse embryonic stem cells induced to become neurons. The cells at the top are producing a neuronal marker protein as expected (green), but the cells at the bottom lack an epigenetic regulatory factor called KAT6B and are failing to develop. Epigenetic factors are part of the machinery that assembles at genes to switch them on or off as needed. Some genes exist in a bivalent, or poised state, with both on and off signals present. While this bivalence had been recognised previously, it wasn’t known to be essential. Recent research shows, however, that KAT6B can only be recruited to its target genes and control them correctly if they exist in this poised state. This need for opposing signals at certain genes adds a layer of complexity to gene regulation that developmental biologists will have to bear in mind when manipulating cell fates for, say, regenerative therapies.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image adapted from work by Elana Bryan, Devisree Valsakumar and Nwamaka J. Idigo, and colleagues
• Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Molecular Cell, February 2025