Fig. 1. Abnormal skin development and Wnt/β-catenin pathway activation in stabilized β-catenin mutant embryos. (A-H) Control littermate and KRT14-Cre Ctnnb1^(Ex3)fl/+ (Act β-catenin) embryos at the stages indicated. Arrows indicate keratinized plaques in mutant embryos. (I,J) Higher magnification views of dorsal skin from G and H, respectively. Pigment (arrows) accumulates in mutant skin. (K,L) Immunohistochemistry for β-catenin at E15.5 showing elevated β-catenin levels in control placodes (K), and cytoplasmic and nuclear β-catenin throughout mutant ectoderm (L, arrows). (M-P) X-gal-stained control BATgal (M,O) and KRT14-Cre Ctnnb1^(Ex3)fl/+ BATgal (Act β-catenin BATgal) (N,P) littermates at E13.5 (M,N) and E16.5 (O,P), showing increased BATgal expression and its irregular pattern in the mutant. Scale bar in L applies to K and L.