Fig. 5. Proliferation, differentiation and apoptosis at the midline sagittal suture in Fgfr2^+/S252W mice at E18.5. (A,B) Immunohistochemical staining of Ki67 shows increased numbers and abnormal distribution of positive cells indicating abnormal proliferation in mutants (arrows). (C-H) Expression of osteogenic markers shows increased or abnormal differentiation in mutants. (C,D) Osteonectin in situ hybridization (arrows). (E,F) ALP staining (arrows). (G,H) Osteopontin in situ hybridization (arrows). (I,J) TUNEL staining does not show an obvious difference in apoptosis between mutants and controls. (A,C,E,G,I) Control littermates; (B,D,F,H,J) corresponding regions in mutant mice. s, skin; p, parietal bone; b, brain. Scale bars: A-J, 50 µm.