Mechanical Coordination of Tissue Morphogenesis during Embryonic Development
Developing tissues of distinct cellular organizations undergo morphogenesis side by side at the same time. This constraint implies a possible role of inter-tissue forces in driving and coordinating morphogenesis. Here I will discuss our findings of such forces in the elongating avian embryonic body axis. Combining live imaging, computational modeling and microsurgery, we found that the paraxial presomitic mesoderm (PSM) compresses the axial neural tube and notochord, which adds to the intrinsic processes that drive their convergence and elongation. The resulting axial elongation then pushes the caudal progenitor domain posteriorly. Surprisingly, ablating the axial tissues greatly reduces the progenitor addition that sustains PSM growth, which can be partially rescued by restoring the pushing force with a magnetic lever. Together these results show that forces produced by collective cell dynamics couple different tissues into an engine-like positive feedback loop to drive body axis elongation.