Cries or whispers between cells during ascidian embryogenesis

During embryonic development, as cells divide, they take on increasingly precise roles in the body. In most embryos, including our own, this process is reproducible at the tissue level, with the behaviour of individual cells varying from one embryo to another.

In some embryos, however, including those of a small marine invertebrate, the sea squirt Phallusia mammillata, the reproducibility of embryonic development occurs at the cellular level: it is possible to name each cell and find a counterpart in each of the embryos of the species.

In a work published in the journal Science on July 10, an intersdiciplinary team of CNRS, INRIA, and EMBL scientists led by Patrick Lemaire, Christophe Godin and Grégoire Malandain systematically reconstructed over time the geometry and arrangement of each and every cell of living Phallusia mammillata embryos.

Analysis of this dataset shows that embryogenesis is characterized by the lack of cell movements and apoptosis and a very high reproducibity between embryos, down to the subcellular scale of the surfaces of cell contact. Furthermore, the authors were able to link this reproducibility to an unusual mode of communication, by direct cell-to-cell contact.

This work thus links the range of cellular signals and the scale, cellular or tissular, at which developmental reproducibility is observed.

A short animated video, directed by Laurence Serfaty and Isis Leterrier, explains in non-specialist terms the scientific approach and the main results of this study.