Figure 1

Wip1 -knockout animals have reduced alveolar development during pregnancy. (A, B) Carmine-alum-stained whole mounts of mammary glands from virgin (nulliparous) or 3-days (3d), 7-days (7d), or 14-days (14d) pregnant wild-type (WT, blue box) or Wip1-knockout (KO, green box) mice. Images are representative of three to five animals. Scale bar, 500 μm. (C, D) Hematoxylin and eosin-stained tissue sections of mammary glands from WT (blue box) or Wip1 KO (green box) virgin and pregnant mice, as indicated earlier. Black arrows, distention of lumens present in WT alveolar lobules at 14 days of pregnancy, which are reduced in Wip1 KO sections. Insets are enlarged regions to visualize bilayered epithelium. Dotted lines, location of basement membrane. Images are representative of three animals/group. Scale bar, 100 μm.