Hydra regeneration: actin dynamics and the influence of mechanical constraints
Morphogenesis is one of the most remarkable examples of biological self-organization. We focus on the mechanical aspects of morphogenesis using Hydra, a small multicellular fresh-water polyp, as a model system. Hydra has a simple body plan with uniaxial symmetry and is famous for its regeneration properties. Using this relatively simple model system, we study how mechanics influences the development of the body plan during regeneration. I will discuss our recent results showing that structural inheritance of the actomyosin cytoskeletal organization and its dynamics direct body-axis formation during Hydra regeneration. Morphogenesis is then stabilized by dynamic cytoskeletal reorganization induced by the inherited structure. We further examine the role of mechanics in morphogenesis by embedding regenerating tissues in viscoelastic hydrogels of varying geometries and rigidities, and externally imposing an anisotropic mechanical environment. Through tracking tissue geometry and actin fiber organization during regeneration, we find that the body axis typically forms in the direction of least resistance, suggesting the importance of mechanical feedback during regeneration.
Technion, Israel Institute of Technology