UBC Math Bio Seminar: Francis Corson

Mechanical forces play an essential role in development, most evidently as the drivers of morphogenesis, but also potentially as long-range signals contributing to embryonic self-organization. Regulative development is particularly evident in experiments in which the avian embryonic disk is bisected: each half can give rise to a fully-formed embryo, implying a dramatic redirection of force generation and gene expression. Having identified a contractile ring, at the boundary between the embryonic and extraembryonic territories, as the engine of early avian morphogenesis, we wondered whether tension along the embryo margin might underlie embryonic regulation. Indeed, a mechanical analog of a Turing model, in which contractility plays the role of activator, and tension the role of inhibitor, recapitulates the steady pattern of tissue motion in intact embryos and its redirection upon bisection. We further show that mechanical feedback also impinges on gene expression, driving the emergence of ectopic embryos and the accompanying rescaling of embryonic territories. Our findings demonstrate a central role for mechanical forces in embryonic self-organization and cell fate allocation.