Interestingly F-actin was consistently oriented toward the blastopore lip in dorsal and lateral cells, but oriented parallel to the lip in ventral regions. The F-actin network is organized differently in each region with the highest percentage of alignment occurring in the lateral region. In contrast, cells lateral and ventral to the blastopore are less polarized and have tortuous cell boundaries. Cells dorsal to the blastopore, which are fated to become neural plate ectoderm, are polarized and have straight boundaries. BCR and blastopore move vegetally during epiboly, mesoderm involutes at the blastopore lip. Strain rate mapping of the dorsal, ventral and lateral epithelial cells proximal to the blastopore reveals changing patterns of strain rate throughout closure. During Xenopus gastrulation, leading edge mesendoderm (LEM). Figure 1: Mangolds dorsal lip transplant experiment in Xenopus. During this time course, the embryo also stiffens 1.5 fold. The dorsal lip of the blastopore is a structure that forms during early embryonic. We find that the embryo generates a ramping magnitude of force until it reaches a peak force on the order of 0.5 μN. While most uninjected embryos closed their blastopore by late gastrula stage. We describe the mechanics of blastopore closure at multiple scales and in different regions around the blastopore by characterizing large scale tissue deformations, cell level shape change and subcellular F-actin organization and by measuring tissue force production and structural stiffness of the blastopore during gastrulation. At the beginning of Xenopus gastrulation, the presumptive anterior. These forces are tuned to generate sustained blastopore closure throughout the course of gastrulation. The sequence can be divided into several steps: (1) As the dorsal lip of the blastopore forms, leading edge mesoderm (shown in orange here) is rotated up into. Blastopore closure in the amphibian embryo involves large scale tissue reorganization driven by physical forces. The individual blastomeres of Xenopus two- to 32-cell embryos have been fate mapped.
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