Fig. 3.

Male cell progeny may express luminal or myoepithelial cell markers. (a) Colocalization of casein and β-galactosidase in chimeric outgrowths of lactating murine mammary glands. Arrows indicate luminal cells that express both casein and β-galactosidase. (b and c) Male cells expressing β-galactosidase and keratin 5 (K5)/keratin 14 (K14) (b) or smooth muscle actin (SMA) (c), indicating a myoepithelial fate. Arrows in b indicate cells expressing both K5/K14 and β-galactosidase; arrows in c indicate cells expressing both β-galactosidase and smooth muscle actin. (Scale bars: a and b, 20 μm; c, 10 μm.)