Figure 4

Long-term linage tracing shows that Sox9 expressing cells are capable of giving rise to both luminal and myoepithelial lineages (A). X-gal stained tissue section of adult virgin Sox9-CreERT2; R26R-LacZ mammary gland injected with TM and harvested after 4 weeks. Arrows point to reporter activity in myoepithelial cells. (B). GFP stained tissue section of adult virgin Sox9-CreER^T2; CAG-EGFP mammary gland injected with TM and harvested after 4 weeks. Arrows highlight the progeny of Sox9 expressing cells within the myoepithelial layer (C). Flow cytometry analysis of CD24, GFP expression of GFP positive and negative cells isolated from above adult virgin mice mammary glands. (D). Flow cytometry analysis of CD61, CD29 expression of GFP⁺ cells isolated from above adult virgin mice mammary glands.