Abstract
Protease inhibitors were injected into Xenopus embryos to determine the involvement of proteases in development. Injection of inhibitors of endopeptidase into the dorsal region of Xenopus embryos resulted in abnormal gastrulation with incomplete invagination and development of the embryos into defective tadpoles. In contrast, injection of protease inhibitors into the ventral region resulted in normal development. The frequency of abnormal gastrulation was significantly less on injection of an endopeptidase inhibitor in which the functional aldehyde group has been reduced with NaBH4. These results suggest that during early development of Xenopus embryos, the protease activity in the dorsal region is necessary for gastrulation.