Ablation of COUP-TFII reveals its function in the control of bone and cartilage development. (A and B) von Kossa staining (A) and micro-CT scans (B) of distal femora of wild-type and COUP-TFII+/− mice. (C and D) Histomorphometric analysis of vertebrae from 6-wk-old mice (C) and quantification of changes in bone volume/tissue volume (BV/TV) in COUP-TFII+/− mice (D) (n = 7–9 mice). (Scale bar, 100 μm.) (E) Immunostaining of COUP-TFII and β-galactosidase antibodies in E13.5 limb bud. (F and G) Nonradioactive in situ hybridization on E13.5 mice femora showing expression of Ihh (F) and ColX (G). (Scale bars, 50 μm.) (H and I) Wild-type and COUP-TFII mutant femurs at E14.5. (H) Alcian blue staining. (I) In situ hybridization with ColX probe. (Scale bars, 100 μm.) Double-headed arrows in F, G, and I indicate positive staining by in situ hybridization. *P < 0.05.