Figure 5. Mammary mesenchyme specification in E14.5 Gli3^xt/xt embryos.

(A, B) Analysis of sections of MR#2 stained with X-Gal (blue) for expression of Conductin-LacZ reporter and counterstained with NFR. Control Conductin^lz/+ embryos (A) show Wnt/β-catenin signaling pathway activity in the mammary mesenchyme and central epithelial cells whereas Gli3^xt/xt; Conductin^lz/+ embryos (B) show activation only within the mesenchymal compartment. Immunohistochemical analysis of serial sections from control E13 Gli1^lzki/+ (C, E, G) and mutant Gli3^xt/xt;Gli1^lzki/+ (D, F, H) embryos for expression of (C, D) p63, (E, F) ER and (G, H)AR. Note the epithelium of Gli3^xt/xt;Gli1^lzki/+ mutant embryos fails to invaginate (D), the mammary mesenchyme shows no histological evidence of condensation and few cells express ER (F) and AR (H).