Exit for Two

We all begin as one cell which divides into two – but for an embryo to advance further in development, a so-called jumping gene MERVL needs to be rapidly switched off. MERVL is known to be controlled by a factor called Dux, but how Dux is regulated and affects exit from the two-cell stage was unclear. Now, researchers have discovered that the cell’s nucleolus plays a role in regulating Dux. The nucleolus (pictured; DNA in cyan, nucleolus compartments in various colours) is part of our cell’s headquarters – the nucleus – and responsible for making our protein-making factories called ribosomes, and not commonly associated with gene regulation. By disrupting the nucleolus, Dux quickly re-activated, leading to increased levels of MERVL keeping the embryo stuck at the two-cell stage. Not only does embryonic exit from the two-cell stage require genes, like MERVL, to be switched off, the embryo also requires a functioning nucleolus to advance.

Read more on this research from the MRC London Institute of Medical Sciences here

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 from work by Sheila Q. Xie and colleagues
• Chromatin and Development Group, MRC London Institute of Medical Sciences, Imperial College London, London, UK
• Image copyright held by the original authors
• Research published in Genes & Development, March 2022