Section: New Results

Morphogenesis of the sea urchin embryo

Participants : Angie Moullet, Grégoire Malandain.

This work is made in collaboration with Barthélḿy Delorme and Matteo Rauzi (iBV, Nice).

The goal of the project is to understand how biophysical forces are generated and how they work to produce exquisitely precise and controlled tissue shape changes in embryo development. Tissue morphogenesis is a process by which the embryo is reshaped into the final form of a developed animal. Tissues are constituted by cells that are interconnected one another: local changes of cell mechanical properties and shape drive consequent tissue shape change. Nevertheless, the knowledge per se of the mechanisms and mechanics at the cell level which drive cell shape changes is insufficient to explain how tissues change their shape. Emerging properties arise at higher scales resulting from the interaction of cells within tissues and of tissues coordinating and interacting with one another.

To study the embryo evolution at a cellular scale, temporal series will be acquired by a multi-view light-sheet microscope. We will use the Mediterranean sea urchin embryo species Paracentrotus lividus as a model system and focus on the process of tissue folding, that will process that is vital since folding defects can impair neurulation in vertebrates and gastrulation in all animals which are organized into the three germ layers. From the technological perspective, new tools are needed to be able to visualize cells and to provide quantifiable data at high temporal and spatial resolution over large regions and across the entire embryo.

The goal of A. Moullet's internship (that begins dec. the 1st) is to measure and study the archenteron length evolution over a population of sea urchin embryos.