p53 in stem cells

Figure 4 p53 provides a barrier for the reprogramming of somatic cells to induced pluripotent stem cells. Somatic cells, such as mouse embryonic fibroblasts (MEFs), can be reprogrammed to induced pluripotent stem cells (iPSCs) after overexpression of a combination of reprogramming factors, such as Klf4, Sox2, Myc and Oct4. Klf4 and Myc induce p19^Arf expression, which prevents p53 degradation, resulting in its accumulation and expression of its target genes. Among the target genes of p53 is p21, which causes senescence, and bax, puma and noxa, which lead to apoptosis.