Biochemical and physical basis of morphogenesis

One of the most intriguing questions in biology is how, starting with a single cell, organisms develop the complex structures that we observe across the animal kingdom. Cells coordinate and differentiate at the right time and location, and apply forces to each other to generate diverse organ shapes.

This raises several fundamental questions:

• How do cells exchange information to coordinate their differentiation?
• How is biological shape encoded in the genome?
• What is the physical basis of organ morphogenesis?

The main experimental system that we use to address these question is the zebrafish notochord. This organ constitutes the structural axis of the embryo, providing mechanical support and promoting the elongation of the embryo. During notochord development, initially coin-shaped cells exchange information through gene regulatory networks to generate patterns of gene expression, determine cell fate and control organ shape. However, the physical and molecular basis of notochord development remains largely unexplored.

To investigate the interplay between biochemical signals and mechanics we make use of the unique properties of the zebrafish model. We develop complex zebrafish transgenic that allow us to visualize in vivo the dynamics of gene expression and perturb the different components of the gene regulatory networks. To understand the role of mechanics in notochord development, we combine live imaging with the study of the physics driving changes in cell shape. Physical measurements and gene expression dynamics are integrated into mathematical models that will help us to identify general principles underlying organ morphogenesis.