Fig. 5. Inhibition of canonical Wnt signaling by sclerostin in Bmpr1a cKO mice. (A) QRT-PCR analysis for Sost, Dkk1, Dkk2 and Lrp5 using calvariae at E16.5, E17.5 and E18.5. Values are expressed relative to wild type at E16.5. Student's t-test; ^*P<0.05. (B) QRT-PCR analysis for Wnt target gene Axin2 and Ctgf using E18.5 calvariae. Expression levels of Axin2 and Ctgf were significantly increased in cKO calvariae. Student's t-test; ^*P<0.05. (C) Immunohistochemical staining of sclerostin (brown) counterstained with Hematoxylin (blue) using E17.5 calvariae. Broken line, osteoblasts. Scale bars: 50 µm, left panel; 10 µm, right panel. (D) Detection of BMPR1A (green), canonical Wnt signaling (blue) and sclerostin (red) using E17.5 calvariae. Canonical Wnt signaling was assessed by β-gal staining using TOPGAL mice. Nuclei were stained with DAPI (blue). Broken line, osteoblasts. Scale bars: 20 µm. (E) Immunohistochemical staining for sclerostin (red) in primary osteoblasts from Bmpr1a cKO and wild-type control. Nuclei were stained with DAPI (blue). Scale bars: 20 µm.