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Updated: Jul 11, 2026

Indirect Immunofluorescence on Frozen Sections of Mouse Mammary Gland
Published on: December 1, 2015
The pattern of beta-catenin responsiveness within the mammary gland is regulated by progesterone receptor
Minoti Hiremath1, John P Lydon, Pamela Cowin
1Department of Cell Biology, NYU School of Medicine, MSB 618, 550 1st Avenue, New York, NY 10016, USA.
Abstract:
Experiments involving beta-catenin loss- and gain-of-function in the mammary gland have decisively demonstrated the role of this protein in normal alveologenesis. However, the relationship between hormonal and beta-catenin signaling has not been investigated. In this study, we demonstrate that activated beta-catenin rescues alveologenesis in progesterone receptor (PR; Pgr)-null mice during pregnancy. Two distinct subsets of mammary cells respond to expression of DeltaN89beta-catenin. Cells at ductal tips are inherently beta-catenin-responsive and form alveoli in the absence of PR. However, PR activity confers beta-catenin responsiveness to progenitor cells along the lateral ductal borders in the virgin gland. Once activated by beta-catenin, responding cells switch on an alveolar differentiation program that is indistinguishable from that observed in pregnancy and is curtailed by PR signaling.
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