Fig. 6. Gli3 expression in postnatal mammary gland. (A) Gli3 mRNA was detected by northern blot analysis of mRNA isolated from mammary glands of both 7-week-old virgin (7wV) and mid-pregnant (13.5dP) mice. Keratin 18 (K18) was used as a control for mRNA integrity and loading. (B) Gli3 mRNA was detected by in situ hybridization in mammary epithelium (arrowhead) of 4-week-old virgin (4wV) mice. (D) Expression continues during pregnancy within both the luminal and myoepithelial cells (arrowhead). Sense control hybridization showed no signal in glands from 4-week-old virgins (C) or 13-day pregnant mice (E). Immunohistochemistry for Gli3 showed nuclear staining in both luminal and myoepithelial cells (arrowheads) of 4-week-old virgins (F) and 13-day pregnant mice (G). Staining was also seen in stromal cells at both stages (arrows).