Fig. 1. Partial rescue of the skeletal growth in the DKO embryo at E18.5. (A1-A5) Forelimbs of embryos of various genotypes: wild type (A1), Gli3^-/- (A2), DKO (A3), Ihh^-/-; Gli3^+/- (I^-/-; G^+/-, A4) and Ihh^-/- (A5). (A1) s, scapula; h, humerus; r, radius; u, ulna; mc, metacarpal; p, phalanges; ^*, deltoid tuberosity. (A2) Numbers 1-7 indicates polydactyly. (A3) Red arrowhead denotes bifurcation of the proximal phalange (P1). Inset shows higher magnification of boxed region. Green arrowhead indicates ectopic bone. (B1-B5) Hindlimbs from embryos of various genotypes: wild type (B1), Gli3^-/- (B2), DKO (B3), Ihh^-/-; Gli3^+/- (I^-/-; G^+/-, B4) and Ihh^-/- (A5). (B1) fe, femur; t, tibia; fi, fibula; mt, metatarsal; p, phalanges. (B2) Numbers 1-6 indicates polydactyly. (B2,B3) Big red arrowheads indicate truncation of the tibia (t^*). Small red arrowhead indicates bifurcation of the proximal phalange (P1). Inset shows higher magnification of boxed region. Green arrowhead indicates ectopic bone. (C1-C4) Rib cages from embryos of various genotypes: wild type (C1), Ihh^-/- (C2), DKO (C3) and Gli3^-/- (C4). Double-headed arrows (C1-C4) indicate the width of the rib cage. Asterisks (C3,C4) indicate the split sternum. (D1-D3) Skulls of embryos of various genotypes: wild type (D1), Ihh^-/- (D2) and DKO (D3). Asterisks (D1-D3) denote the chondrocranium. (E) Detection of Gli3 in limb cartilage proteins. Gli3^A, the full-length (190 kDa) activator form of Gli3; Gli3^R, the truncated (83 kDa) repressor form of Gli3. -cat., -catenin (102 kDa) used as normalizer. Inset shows longer exposure of the Gli3^A band. Asterisk indicates a non-specific protein (80 kDa) reacting with the antibody. (F1-H2) In situ hybridization using ³⁵S-labeled riboprobes against Gli1 (F1,F2), Gli2 (G1,G2) and Gli3 (H1,H2) on longitudinal sections through the ulna (F1,F2,H1,H2) or the humerus (G1,G2) from E14.5 wild type (F1-H1) or Ihh^-/- (F2-H2) embryos. Shown is the distal region of each element. Green arrows indicate expression in the perichondrium. Green asterisks indicate the periarticular region. P, proliferative chondrocytes; H, hypertrophic chondrocytes. r, h, u (F2,H2) indicate radius, humerus and ulna, respectively.