The life of an embryo starts as a ball of undifferentiated cells. Gradually, biochemical signals, in concert with mechanical cues, pattern the embryonic tissues from which organs emerge. Understanding the role of mechanics in shaping a tissue is one of the challenges in modern developmental biology. We are interested in a process specific to vertebrate embryos called somitogenesis, which leads to the formation of our musculoskeletal structure. Somites are produced from the mesodermal tissue situated at the two sides of the central axis, known as the presomitic mesoderm (PSM). During the axial growth of the embryo, the presomitic mesoderm expands posteriorly, while at the anterior, cells undergo mesenchymal to epithelial transition and the tissue compacts into epithelial structures known as the somites. The somites eventually detach from the rest of the mesoderm through mechanisms that are not yet well understood. Our objective is to understand how force-generating parameters!

  such as cytoskeletal elements and intercellular adhesion could induce a mechanical instability in the PSM that leads to somite production. In this talk, we will present our findings on the cellular mechanisms implied in the posterior growth of the PSM, as well as the modifications in the mechanical response of the mesoderm as it differentiates along the axis, evidenced by changes in its liquid behavior.