Abnormal proliferation and differentiation at the chondro-osseous junction and metaphysis in Fgfr2+/P253Rmice. A, B) BrdU staining shows increase in the numbers of proliferative cells in mutants at E19 (brackets). C-F) In situ hybridization of osteogenic markers shows increased expression in mutants at P0: (C, D) osteopontin; (E, F) bone sialoprotein expression. Panels A, C and E are from littermate controls. Panels B, D and F are the corresponding regions in mutant mice. (Scale bars: A-D = 50 μm).