Microsurgery: making an organotypic Keller Sandwich explant from Xenopus laevis embryos.
Channel: Lance Davidson
Date: 2021-09-30

This video details microsurgical manipulations to isolate and visualize morphogenesis of the Keller Sandwich, a planar preparation of multiple germ-layers in the Xenopus embyro. The Keller Sandwich is assembled from two early gastrula stage dorsal marginal zone (DMZ) explants from the Xenopus laevis embryo. DMZ explants isolated before involution maintain planar patterning processes and block radial signals that might be exchanged between pre- and post-involution tissues.The Keller Sandwich can be used to study tissue-, cell-, and subcellular-processes relevant to the tissue movement of convergent extension, from patterning to cell behaviors, and their collective biomechanics. Convergent extension is a common large scale collective movement that shapes the body and organs in animals. This explant has been used to study chemical signaling and biomechanics of convergent extension. 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.