Essential function of Wnt-4 in mammary gland development downstream of progesterone signaling
Abstract
Female reproductive hormones control mammary gland morphogenesis. In the absence of the progesterone receptor (PR) from the mammary epithelium, ductal side-branching fails to occur. We can overcome this defect by ectopic expression of the protooncogene Wnt-1. Transplantation of mammary epithelia fromWnt-4 −/− mice shows that Wnt-4 has an essential role in side-branching early in pregnancy. PR andWnt-4 mRNAs colocalize to the luminal compartment of the ductal epithelium. Progesterone induces Wnt-4 in mammary epithelial cells and is required for increased Wnt-4 expression during pregnancy. Thus, Wnt signaling is essential in mediating progesterone function during mammary gland morphogenesis.
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Footnotes
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↵4 Corresponding author.
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E-MAIL weinberg{at}mit.edu; FAX (617) 258-5213.
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- Received January 11, 2000.
- Accepted February 9, 2000.
- Cold Spring Harbor Laboratory Press