Hydra morphogenesis: actin dynamics and the role of topological defects


  Kinneret Keren  
Physics Department, Technion- Israel Institute of Technology

Morphogenesis, the emergence of form and function in a developing organism, is one of the most remarkable examples of pattern formation in nature. Despite substantial progress in the field, we still do not understand the organizational principles responsible for the convergence of this process, across scales, to form viable organisms under variable conditions. 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 and is famous for its regeneration properties which allow us to explore how mechanical forces and feedback contribute to the formation and stabilization of the body plan during morphogenesis. I will present our recent results showing that structural inheritance of the supra-cellular actomyosin fibers directs body-axis formation in regenerating Hydra. I will further discuss our efforts to develop a framework for describing and quantifying the actomyosin fiber organization in regenerating Hydra as an active nematic material, and to relate the nematic dynamics during regeneration with the development of the body plan.