Past Tense

No strangers to tension, our muscles drag our bodies around, flexing their inner bundles of myofibres, each of which is a long chain of tiny stretchy sarcomeres. But how these neat, organised structures emerge during development is still a little mysterious. Here scientists grow myofibres from human induced pluripotent stem cells. Artificial colours highlight fibres pointing in similar directions – they look a little chaotic to begin with (bottom left), but over the next two weeks (left to right, bottom row followed by top row) they self-organise, grouping into similar bundles. Researchers find that even at this early stage, myofibres are getting tense – using mechanical forces as 'signals' to co-ordinate with their neighbours. Zapping tiny parts of this early muscle with laser light causes the structures to twang apart – raising questions about how much tension is involved in assembling the early musculoskeletal system.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

Website

• Image from work by Qiyan Mao and Achyuth Acharya, and colleagues
• Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in bioRxiv, January 2022 (not peer reviewed)