IPLS Seminar - Prof. Lance Davidson (University of Pittsburgh)

Title: Exposing the cryptic role of mechanics during morphogenesis

Abstract: Axis extension in vertebrates serves to convert a sphere or disk of cells in the early embryo into a long body plan that resembles that of the adult. By contrast with later morphogenetic movements that shape complex 3D structures, axis extension proceeds as a relatively simple rearrangement of cells in the plane. To shape 3D movements, tissue movements are coordinated between multiple layers of mesenchymal and epithelial cells, each undergoing independent rearrangements, and the extracellular matrices that form at their interfaces. Using the elongating dorsal tissues of the Xenopus embryo, our group has developed a complete set of experimental tools and theory for direct biomechanical analysis of these movements. In this presentation I will discuss several surprising findings as we test the coupling between the processes that generate forces needed for extension and the processes that regulate spatial and temporal mechanical properties of the embryo. Forces and material properties can be coupled in a positive fashion that preserves rates of morphogenesis or can be negatively coupled to alter rates of morphogenesis in response to changing environmental conditions. Both mechanisms highlight basic elements of robust control networks that couple mechanics and cell signaling pathways and underlie morphogenetic programs that drive self-assembly.