Switched Off

Hidden within our genome are sequences of DNA called transposable elements (TEs) that can move between locations, and potentially disrupt key genes. Our germ cells – precursors of eggs and sperm – have evolved a defence in the form of piwi-interacting RNAs (piRNAs), which silence TEs. But whether piRNAs also silence genes involved in producing germ cells was unclear. Using the nematode worm as a model, researchers found that piRNAs silenced genes involved in sperm formation. In worms with mutated non-functioning piRNAs (bottom), there were more germ cells expressing genes linked to creating sperm (red) compared to a ‘normal’ worm (top). As these worms are hermaphrodites, they need this ‘switch off’ of sperm production to be able to start making egg cells (yellow). This study shows that piRNAs could have wider roles in humans beyond simply silencing TEs.

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 Eric Cornes and colleagues
• Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, Institut Pasteur, UMR 3738, CNRS, Paris, France
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Developmental Cell, January 2022