Seams Vital

Like the carefully stitched hem of a pleated skirt, the outer layer of the heart is fundamental to its entire shape and function. This epicardium is a regulator of development and regeneration, and supports vessel and muscle growth. To better understand the molecular mechanisms guiding its development, researchers investigated a protein called SRSF3, which helps process RNA messages (strands of genetic material). When it was removed from early mouse epicardial precursor cells, the epicardium failed to form normally (right, reduced green SRSF3 limiting outgrowth around explants cultured from embryonic hearts, compared to normal, left) so proper heart formation was prevented. Their experiments also showed cells that dodged SRSF3 deletion increased production to compensate, cautioning researchers that incomplete gene deletion can hide how important a gene really is in experiments. Understanding these growth controls could eventually help researchers tackle both congenital heart defects and the challenge of repairing broken hearts.

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

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• Image from work by Irina-Elena Lupu and Susann Bruche, and colleagues
• Institute of Developmental and Regenerative Medicine, British Heart Foundation Centre of Research Excellence, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Development, March 2026