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Department of Physiology, Development and Neuroscience

 
Physical forces, not shape, identified as driving factor of cell division direction

Study by the Sanson Lab published in Developmental Cell sheds light on the driving mechanisms that determine the direction of the plane of division during development

Cells are 3D objects and it is essential that the orientation of their plane of division is tightly controlled for tissues and organs to achieve the correct shape and size. Most cells tend to divide in half splitting across the longest axis of their shape. So far, it was unclear if this was determined only by cell shape or by the forces acting on cells in a tissue: if a tissue is stretched, it is hard to tell if a cell orients its division because of the force applied to both ends, or because the forces changed its shape. 

In this study, the Sanson lab was able to determine for the first time in vivo, studying the developing Drosophila embryo, that physical forces, rather than the cell shape, are driving the direction by which cells divide. To determine this, they studied cells localized at specific boundary locations in the embryonic epithelium. Like a fence between two houses, these boundaries ensure that cells between different areas are kept separate, and they do so because they are enriched in actomyosin, that generates high forces. By cutting the boundaries with a very precise laser, the researchers were able to release the forces that anchored the cells to the boundary and determined the direction of the division. Once released, they observed that the cells, which still maintained their original shape, started dividing across a different direction, proving that the forces are the driving factor in determining cell division. 

 Image by Developmental Cell.

A correct orientation of cell divisions during development is essential to avoid conditions like microcephaly in the brain and polycystic kidney disease. This study is important because it increases our understanding of the cell division process and its potential pitfalls.

Reference: Scarpa E, Finet C, Blanchard GB, Sanson B, (2018), Actomyosin-Driven Tension at Compartmental Boundaries Orients Cell Division Independently of Cell Geometry In Vivo, Developmental Cell. http://doi.org/10.1016/j.devcel.2018.10.029

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