Further detail of early embryonic development uncovered

Published on 19 April 2023

Latest research from the Universities of Dundee and Bristol has determined key details on the formation of large-scale functional structures during early embryonic development.

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From left: Dr Rastko Skepnek and Professor Kees Weijer

The study, published in eLife, introduces and analyses a model for cell intercalations, a key cellular mechanism driving large scale tissue shape changes required to develop complex functional structures.

During primitive streak formation in the chick embryo, cell intercalations facilitate coordinated movements of hundreds of thousands of cells in two counter-rotating millimetre scale cell flows that drive the formation of the primitive streak at the site where the flows meet. During intercalation, cells pull against each other in order to exchange their neighbours. This is a complex, active process that requires a carefully coordinated shrinking and subsequent expansion of cell-cell interfaces, known as the T1 transition.

Dr Rastko Sknepnek and Prof Cornelis Weijer lead and co-corresponding author, respectively of the study said, “In this study we have introduced a mechanochemical model that describes the dynamics of active T1 transforms, i.e. cell intercalation events that occur perpendicular to the externally applied mechanical stress. This includes an explicit positive feedback loop between mechanical stresses and the kinetics of force-generating, junctional myosin motors. The results provide a key cellular mechanism for convergence-extension flows observed during primitive streak formation in avian embryos.”

Prof Weijer said “Our findings show that active intercalations can generate stress that activates T1 events in neighbouring cells resulting in tension dependent tissue reorganisation. Errors in these processes can lead to significant congenital defects. Therefore, understanding the coordination of critical cell behaviours during early development is necessary to be able to diagnose, treat and prevent problems that could lead to birth defects”.

The research was supported by funding from the Biotechnology and Biological Sciences Research Council (BBSRC).

Read the paper “Generating active T1 transitions through mechanochemical feedback” by Rastko Sknepnek, Ilyas Djafer-Cherif, Manli Chuai, Cornelis Weijer, and Silke Henkes accepted for publication in eLife (

Story category Academic collaboration