Prospective identification and purification of hair cell and supporting cell progenitors from the embryonic cochlea

Expression of the cyclin-dependent kinase inhibitor p27^Kip1 defines a post-mitotic population of cells in the embryonic mammalian cochlea that constitutes the nascent organ of Corti. Here, we describe techniques to purify these precursors using a transgenic p27/GFP reporter and fluorescence activated cell sorting (FACS). We demonstrate that these cells express other markers of the sensory lineage, such as Sox2, and when placed in dissociated cell culture differentiate as hair cells and supporting cells. The purified sensory progenitors thus obtained provide a means of studying the process of hair cell and supporting cell differentiation in vitro, as well as providing a means of analyzing the molecular and physiological properties of this unique population of cells.