A tensile ring drives tissue flows to shape the gastrulating amniote embryo

Mehdi Saadaoui (1) , Didier Rocancourt (1) , Julian Roussel (1) , Francis Corson (2) , Jerome Gros (1)

1 Régulation Dynamique de la Morphogénèse - Dynamic Regulation of Morphogenesis
2 Biophysique et Neuroscience Théoriques

Tissue morphogenesis is driven by local cellular deformations that are powered by contractile actomyosin networks. How localized forces are transmitted across tissues to shape them at a mesoscopic scale is still unclear. Analyzing gastrulation in entire avian embryos, we show that it is driven by the graded contraction of a large-scale supracellular actomyosin ring at the margin between the embryonic and extraembryonic territories. The propagation of these forces is enabled by a fluid-like response of the epithelial embryonic disk, which depends on cell division. A simple model of fluid motion entrained by a tensile ring quantitatively captures the vortex-like "polonaise" movements that accompany the formation of the primitive streak. The geometry of the early embryo thus arises from the transmission of active forces generated along its boundary.

Domains: Life Sciences [q-bio]; Development Biology; Morphogenesis

Mehdi Saadaoui, Didier Rocancourt, Julian Roussel, Francis Corson, Jerome Gros. A tensile ring drives tissue flows to shape the gastrulating amniote embryo. Science, 2020, 367 (6476), pp.453-458. ⟨10.1126/science.aaw1965⟩. ⟨pasteur-02905796⟩