Embryonic stem cell–specific microRNAs promote induced pluripotency

Judson et al . show that microRNAs specific to mouse embryonic stem cells can substitute for the reprogramming factor cMyc in the generation of induced pluripotent stem cells. The development of reprogramming methods that do not rely on transgenes may facilitate clinical translation of this technology. This report demonstrates that introduction of microRNAs (miRNAs) specific to embryonic stem cells enhances the production of mouse induced pluripotent stem (iPS) cells. The miRNAs miR-291-3p, miR-294 and miR-295 increase the efficiency of reprogramming by Oct4 , Sox2 and Klf4 , but not by these factors plus cMyc . cMyc binds the promoter of the miRNAs, suggesting that they are downstream effectors of cMyc during reprogramming. However, unlike cMyc, the miRNAs induce a homogeneous population of iPS cell colonies.