Description
In the murine system, Oct4, Sox2, c-Myc and Klf4 are sufficient to convert fibroblasts to induced pluripotent stem (iPS) cells that exhibit many characteristics of embryonic stem (ES) cells. Herein, we show that the orphan nuclear receptor Esrrb works in conjunction with Oct4 and Sox2 to mediate reprogramming of mouse embryonic fibroblasts (MEFs) to iPS cells. Esrrb reprogrammed cells share similar expression and epigenetic signatures as ES cells. These cells are also pluripotent and can differentiate in vitro and in vivo into the three major embryonic cell lineages. Furthermore, these cells contribute to mouse chimeras and are germline transmissible. In ES cells, Esrrb targets many genes involved in selfrenewal and pluripotency. This suggests that Esrrb may mediate reprogramming through the up-regulation of ES cell-specific genes. Our findings also indicate that it is possible to reprogram MEFs without exogenous Klf transcription factors and link a nuclear receptor to somatic cell reprogramming.