EFFECTS OF TWO PROTEASE INHIBITORS ON SEA URCHIN AND AMPHIBIAN EGG DEVELOPMENT*

After a review of our present knowledge about the effects of proteases and protease inhibitors on cell growth and egg fertilization, the results of experiments where sea urchin and amphibian eggs were treated with two protease inhibitors (TPCK, TLCK) are described. Cleavage was hardly affected, but gastrulation quickly stopped or was incomplete. The morphogenetic abnormalities which follow can be explained by abnormal gastrulation and other factors: persistence of remnants of the fertilization membrane in sea urchin larvae and dissociation of the ectoderm cells in Xenopus embryos.