The gene expression program of the developing mammary gland

The developing mammary gland contains distinct microenvironments that perform specialized functions for branching and ductal invasion. These microenvironments include the terminal end buds (TEBs) at the tips of invading primary ducts and the more differentiated proximal ducts that give rise to side branches. We have devised a novel microarray approach to identify genes that are expressed in the epithelium and stroma of these distinct microenvironments. Keywords: spotted oligonucleotide Total RNA from microdissected terminal end buds and mature ducts were compared to epithelium-free distal stroma of 5 week old mammary glands. B-actin-GFP reporter mice were used to visualize the mammary glands for microdissection.