Fig. 8. Alteration of the canonical Wnt pathway in the Axin2 mutants during skull morphogenesis. Sections of the Axin2^+/+ (A,C,E) and Axin2^–/– (B,D,F) sutures were immunostained with the primary antibody (brown) and counterstained with Hematoxylin (blue). Immunohistochemical staining with an antibody that recognizes only the activated form of ß-catenin (-ABC antibody) reveals stimulation of ß-catenin signaling (arrowheads) in the Axin2^–/– suture at P8 (B) and P28 (D). Expression of cyclin D1, a bona fide target of ß-catenin, is also elevated in the Axin2^–/– suture (broken lines) at P8 (F). Scale bars: 50 µm in A,B,E,F; 25 µm in C,D.