Figure 3. Failure of MR#2 invagination in Gli3^xt/xt embryos.

Analysis of the inner surface of skin whole-mounts from E18.5 wt (A, B, C) and Gli1^lzki/+ (D, E, F) and Gli3^xt/xt; Gli1^lzki/+ (G, H, I) embryos stained with X-Gal to detect Gli1-LacZ reporter expression (blue) within hair follicles and counterstained with carmine alum (pink). MRs#1 (A, D, G) and #4 (C, F, I) show comparable development at E18.5 in all three genotypes: sprouts are clearly visible (arrow). In control wt (B) and Gli1^lzki/+ (E) embryos sprout #2 has elongated and branched several times but in Gli3^xt/xt; Gli1^lzki/+ embryos (H), MR#2 shows no evidence of sprouting towards the fatpad.