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

• DOI: 10.1126/science.aaw1965
• Publication Date: 2020-01-24T00:09:26Z
• Authors: Mehdi Saadaoui; Didier Rocancourt; Julian Roussel; Francis Corson; Jerome Gros
• Keywords: Mesoscopic physics; Primitive streak; Germ layer; Amniote

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