Cellular commitment and differentiation in the cochlea: potential advances using gene transfer

The development of individual cells as hair cells and supporting cells is a key step during the embryonic formation of the auditory system. However, at present the factors that play a role in the commitment and differentiation of cells as hair cells and supporting cells have not been identified. Recent advances in molecular biological techniques have led to the identification of candidate genes that may be involved in hair cell and supporting cell development, however it has been difficult to determine the specific effects of these genes. The development of new methods for gene transfer into post-mitotic cells should provide powerful new techniques for examining the specific effects of candidate genes. Virally mediated vectors, such as adenovirus and herpes simplex virus, and non-virally mediated vectors, such as lipofectins and biolistics, have been shown to efficiently transfer candidate genes into many different cell types, including hair cells, supporting cells, and spiral ganglion neurons. In addition, studies in other developing systems have demonstrated that these techniques can be used to determine the effects of expression of candidate genes during the specification of individual cell phenotypes. These results suggest that these vectors can be used effectively to study the role of specific genes during the development of the auditory system.