Stabilization of Epithelial Beta-Catenin Compromises Mammary Cell Fate Acquisition and Branching Morphogenesis

The study investigates the role of the Wnt/β-catenin pathway in the development of mammary glands and hair follicles. It was found that while this pathway is crucial for the initiation of hair follicle and mammary gland development, its activity significantly decreases as the mammary bud progresses to branching. Forced activation of β-catenin compromises embryonic mammary gland branching, but a low level of Wnt/β-catenin activity is necessary for mammary cell survival. High β-catenin activity maintains the mammary bud gene signature at the expense of the outgrowth/branching gene signature and upregulates epidermal differentiation genes. Interestingly, early stabilization of β-catenin results in a partial switch to hair follicle fate, suggesting that the level of Wnt/β-catenin signaling activity may contribute to the choice between skin appendage identities.