Methods are provided for producing cells within a lineage (lineage restricted cells) from post-mitotic differentiated cells of the same lineage ex vivo and in vivo, and for treating a subject in need of tissue regeneration therapy by employing these lineage-restricted cells. In addition, the production of lineage restricted cells from postmitotic tissues derived from patients with diseases allows for a characterization of pathways that have gone awry in these diseases and for screening of drugs that will ameliorate or correct the defects as a means of novel drug discovery. Also provided are kits for performing these methods.