Fig. 6. Ihh signaling is disrupted in the long bones of prx1cre;Ift88^fl/n conditional mutants. (A-D) Radioactive in situ hybridization analysis of Ihh expression in the fibula of wild-type (C) and conditional mutant (D) mice at E18.5. Strong expression of Ihh is seen in the prehypertrophic chondrocytes in the wild-type sample (C). Ihh expression is also evident in the prehypertrophic chondrocytes of conditional mutants (D) although at reduced levels. (E-L) Analysis of Ptch1 (E-H) and Gli1 (I-L) expression in wild-type (G,K) and conditional mutant (H,L) tibiae. In wild-type samples, Ptch1 and Gli1 expression is increased in the proliferating and prehypertrophic regions (asterisks) in addition to the perichondrium (arrowhead). By contrast, no significant expression of Ptch1 or Gli1 is seen in conditional mutant samples. (M-P) Expression of PTHrP in wild-type (M,O) and conditional mutant (N,P) radii at E14.5. PTHrP is expressed in both wild-type (O) and conditional mutant (P) radii at E14.5. Bright field images of each section (A,B,E,F,I,J,M,N) show histology.