Fig. 7. Impaired IHH signaling in Bmpr1a^CKO mice. (A) Expression of Ihh, and Ptc1 by in situ hybridization. Expression of Ihh and its target, Ptc, is reduced in mutants. (B) No differences in expression levels of the PTHrP receptor Pthr1 are observed in mutants. (C) Ihh may be a direct target of BMP pathways in chondrocytes. p994 luc consists of a 994 bp fragment of the mouse Ihh promoter (-889/+105) (Yoshida et al., 2004). 2HC8 consists of a 429 bp fragment of the mouse Ihh promoter (-423/+1) (Seki and Hata, 2004). These were transiently transfected into RCS chondrocytes in the presence or absence of BMP2 (60 ng/ml) and a SMAD1 expression construct. ^*P<0.05; ^**P<0.005.