Embryonic mammary anlagen analysis using immunolabelling of whole mounts

The mouse mammary gland is a unique organ since although the mammary gland primordium forms during embryogenesis, the majority of development occurs postnatally upon hormonal stimulation at puberty and full functionality (i.e. lactation) is not achieved until after parturition. Since both the epidermis and mammary glands share the same developmental origin, many mouse models with epidermal phenotypes often also exhibit abnormal mammary gland development. However, since the most widely used methods to analyse mammary glands are laborious and time-consuming, many mouse models exist that have not been analysed for mammary phenotypes. We have developed a simplified method that allows rapid analysis of embryonic mammary anlagen using immunolabelling of whole mounts that should facilitate more comprehensive studies of mouse mammary glands.