Fig. 2.

Hematoxylin and eosin staining of mammary biopsies at parturition. (A) Section from α-catenin fl/fl control tissue in which alveoli were expanded and milk and milk fat secretion were evident. (B, C) Sections from α-cat fl/fl;WC and α-cat fl/fl;MC mammary tissues, respectively. Epithelial development was sparse and many epithelial cells failed to expand to accommodate functional alveoli. (D) Section from an α-catenin control mouse (α-catenin fl/+;WC) mammary tissue at the third parturition in which alveoli were expanded and milk and milk fat secretion was evident in the lumina. (E) Section from a mouse mammary gland at the third parturition in which α-catenin was inactivated by the WAP-Cre transgene (α-cat fl/fl;WC). Epithelial development appeared comparable to the first pregnancy shown in Fig. 2B. (F), Section from a mouse mammary gland at the third parturition in which α-catenin was inactivated by the MMTV-Cre transgene (α-cat fl/fl;MC). Epithelial development appeared comparable to the first pregnancy shown in Fig. 2C. ln, lymph node.