Microarray expression profiling of distinct subsets of mouse mammary epithelial cells

The purpose of this microarray experiment was to obtain reference gene expression patterns of a number of epithelial cell populations [mammary stem cells (MASC), luminal progenitors (LP), alveolar luminal stem/progenitor cells (WC virgin-these are mammary epithelial cells genetically marked by Wap-Cre in virgin females), mature luminal cells (ML, mainly represent ductal luminal cells in virgin females), and alveolar luminal cells (WC preg – these are alveolar cells genetically marked by Wap-Cre during mid-gestation)] present in the mammary gland of wildtype adult mice on a C57BL6 genetic background. For the isolation of RNA from mammary stem cells (MASC, Lin-CD24+CD29hi), luminal progenitors (LP, Lin-CD24hiCD29+CD61+), and mature luminal cells (ML, lin-CD24hiCD29+CD61-), the thoracic and inguinal mammary glands from 3 adult virgin female mice were harvested, minced and digested into a single cell suspension. Form each of these 3 single cell suspensions, the above populations were sorted by FACS. For alveolar luminal stem/progenitor cells and alveolar luminal cells, Lin-YFP+ mammary epithelial cells were isolated from virgin or midgestation mice genetically marked by Wap-Cre;R26Y. R26Y is a conditional YFP reporter that would be turned on upon Cre-mediated recombination.