Fig. 2. Detection of Gli3 mRNA in embryos by whole-mount in situ hybridization. (A) At E11 a broad band of staining is seen between the fore- and hindlimbs in the region of the developing mammary line (arrow) and in the somites (som, arrowhead). (B) At E13.5 weak staining is seen in and around all five pairs of mammary buds but expression is strongest in bud pair number 3, inset shows bud number 3 at higher magnification. (C) Immunohistochemistry for Gli3 showed nuclear staining in the mammary bud epithelium (epi) and surrounding stroma (str) in wild type. (D) Staining was not seen in the mammary bud epithelium from a Gli3^xt/xt control embryo, although some background staining was present in the stroma.