Description
Induction of germline-competent pluripotent stem cells from mouse fibroblasts has been achieved by the ectopic expression of four genes (Oct3/4, Sox2, c-Myc and Klf4). If this method can be applied to humans for the generation of personalized human pluripotent stem cells, it would greatly facilitate the therapeutic application of stem cells by avoiding the problem of immune rejection by the recipient associated with allograft transplants. Here we show that the ectopic expression of the same four genes in human neonatal skin derived cells is sufficient to induce pluripotent stem cells indistinguishable from human embryonic stem cells in morphology, gene expression, DNA methylation, teratoma formation and long term self-renewal ability. Extensive analysis of colonies generated by ectopic expression of these four genes indicates the presence of considerable heterogeneity in the induced colonies. These results provide a new finding to generate human induced pluripotent stem cells from postnatal somatic tissues.