What is it about?

In developing embryos, cells receive signals telling them to switch on gene expression and to adopt specific identities. During this process, signals can be graded and variable so while a group of cells will all “see” the signal, only a few will respond. Looking at the first step of brain induction in ascidian embryos, we tried to understand why only two cells out of a group of eight competent cells all seeing the brain inducing signal will respond and start to express brain specific genes. We constructed a computational model of this process based on our experimental data to help us to understand how cells can interpret the signal and why some cells react to the signal and others ignore it.

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Why is it important?

The computational model was able to reproduce experimental measurements and shows that the geometry, or shape, of the embryo is important during the selection of which cells will become brain cells. Because of the shape of the embryo, some cells see more signal than others and above a certain threshold level of signal, the cells will switch on genes that promote brain formation.


The computational model helps us to understand how the geometry of the embryo creates different levels of positive and negative inputs and how these different imputs are integrated and interpreted so that specific cells go on to adopt a different identity from their neighbours.

Clare Hudson
Sorbonne University and CNRS

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This page is a summary of: Model of neural induction in the ascidian embryo, PLoS Computational Biology, February 2023, PLOS, DOI: 10.1371/journal.pcbi.1010335.
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