Cleavage in Amphibians:

Blastula structure and cadherins

The organization of the blastula requires the propoer functioning the cadherin-based cell adhesion system. Janet Heasman, Chris Wylie and colleagues have used anti-sense depletion to remove various comonents of this system from the oocyte, resulting in lack of these proteins in the embryo. In the picture below, the left-hand embryo lacks an embryonically expressed cadherin (EP-cadherin). Note the loss of adhesion of the cells when the animal cap of such an embryo is removed.

(figure adapted from material courtesy of Dr. Janet Heasman, Univ. of Minnesota)