Fig. 5. Epidermal differentiation fails in activated β-catenin mutants. (A-N) Expression of KRT14 (A,B), DSC1 (I,J) and DSG1 (K,L) is decreased, and expression of KRT10, filaggrin and loricrin (C-H) is absent in stabilized β-catenin mutants, but laminin 5 expression (M,N) indicates that the basement membrane remains intact. Scale bar in N applies to A-N. Arrows indicate expression. (O-S) TEM of E16.5 control (O,R) and mutant (P,Q,S) dorsal epidermis (O-Q) or epidermal-dermal junction region (R,S) reveals the presence of basal (Ba), spinous (Sp) and granular (Gr) layers in control epidermis (O), and their absence in the mutant (P). Pigment granules are present in mutant ectoderm (red arrows in Q). The basement membrane (BM) is intact in the mutant, but hemidesmosomes (red arrows in R) are reduced in number (S).