Figure 5

Marker expression in keratin 6ab (K6ab)-null mammary glands. Mammary gland sections from 6-week intact animals, including terminal end buds (left column) and ducts (middle column), or from transplanted tissue after 10 weeks of outgrowth and treatment for 2 days with estrogen and progesterone (right column), were stained by immunohistochemistry for markers of mammary epithelium, including K5 (a–f), K8 (g–l), estrogen receptor α (m–r), and bromodeoxyuridine (s–x). Scale bar, 50 μm.