Fig. 7. Schematic representation of the phenotypes obtained for embryos either expressing truncated ß-catenin, lacking maternal E-cadherin, or expressing truncated ß-catenin as well as lacking maternal E-cadherin. (A) A control early/late 2-cell stage embryo (E/L2C) where interaction of ß-catenin (yellow and blue rectangles) and E-cadherin (blue zig-zag lines) ensures adhesion of the two blastomeres. (B) In early 2-cell stage embryos (E2C) lacking maternal E-cadherin, the adhesion complex cannot form, resulting in blastomeres that are not able to adhere. Consequently larger amounts of ß-catenin translocate to the nucleus. (C) In early 2-cell embryos expressing truncated ß-catenin (yellow squares), the blastomeres fail to adhere, even though E-cadherin is present on the blastomere surface. (D) In late 2-cell embryos expressing truncated ß-catenin, the wild-type paternal ß-catenin allele is activated. Protein translated from this allele is sequestered by E-cadherin to form the adhesion complex (yellow and blue rectangles with blue zig-zag lines attached), and a lesser amount is translocated to the nucleus. (E) By contrast, in late 2-cell stage embryos expressing truncated ß-catenin and also lacking maternal E-cadherin, all newly synthesized ß-catenin is able to translocate to the nucleus because no E-cadherin is present to sequester it to the adhesion complex.