Fig. 3. (A) No ß-catenin is found in embryos expressing truncated ß-catenin, using an N-terminal specific antibody, until the paternal allele is activated. A monoclonal ß-catenin antibody that recognizes an epitope in the N-terminal part of the protein was used. Cre/Ø indicates embryos expressing truncated ß-catenin; +/+ indicates control embryos. ß-catenin synthesized from the paternal allele is first detected on the surface of embryos expressing truncated ß-catenin at the 4- to 8-cell stage transition (6/8-cell stage). (B) E-cadherin is absent in embryos prior to activation of the paternal allele. A polyclonal antibody against E-cadherin was used. E-cadherin is first detected on the surface of embryos lacking maternal E-cadherin at the late morula stage. Cre/Ø indicates embryos lacking maternal E-cadherin; +/+ indicates control embryos. The stage of embryonic development is indicated below the figure; fluorescent (FL) or Nomarski Differential Interference Contrast (DIC) images are indicated on the left. Scale bar: 10 µm.