Microsurgery: making an organotypic mesendoderm explant from gastrula stage Xenopus laevis.
Channel: Lance Davidson
Date: 2021-09-30

This video details microsurgical manipulations to isolate and visualize morphogenesis of the mesendoderm, a key germ-layer from the Xenopus embryo. Mesendoderm contribute to the heart, liver, and other ventral organs in vertebrates. Movements of mesendoderm mantle closure complete the gastrulation movements of the Xenopus laevis embryo. Cells exposed in this explant expose collective cell behaviors within a mesenchymal tissue. Free-edge sheet-like collective movements of these tissues contrast to movements of epithelial tissues in that mesendodermal cells are not constrained by tight junctions or adherens junctions, yet migrate in a coherent and persistent mode over several hours. Mesendoderm cells are largest motile cells in the Xenopus embryo and complete a 500 µm migratory path. Note: this video was made to accompany a more detailed protocol to be published by Cold Spring Harbor Laboratory Protocols in 2022. Copyright: Lance Davidson.