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Waves of contractility increase in oscillation frequency with each successive cleavage of the embryo during preimplantation development

11 June 2022

Getting Into Shape

I love a Zumba class to feel the rhythm and get energised for the day. Turns out embryos do too – sort of! A fertilised egg must become a blastocyst, by repeatedly dividing in two, before it can get started on morphogenesis – the shaping of an organism. This shaping relies on the contractility of the actomyosin cortex – a thin layer of actin and myosin proteins under the cell surface that provides tension and gives the cell shape. It turns out that the actomyosin cortex needs a wake-up call to get going. Researchers found that with each round of cell division, the cell surface becomes softer allowing the rhythmic wave of contractions to ramp up in frequency, awakening the actomyosin cortex ready to help sculpt the embryo. This video shows one-, two-, four- and eight-cell embryos and the rhythmic contractions they experience (magenta arrows show upward movement, green show downward).

Written by Sophie Arthur

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BPoD stands for Biomedical Picture of the Day. Managed by the MRC Laboratory of Medical Sciences until Jul 2023, it is now run independently by a dedicated team of scientists and writers. The website aims to engage everyone, young and old, in the wonders of biology, and its influence on medicine. The ever-growing archive of more than 4000 research images documents over a decade of progress. Explore the collection and see what you discover. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.

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