Reprogramming towards pluripotency requires AID-dependent DNA demethylation

To elucidate regulatory mechanisms involved in reprogramming to generate pluripotent cells from somatic cells, this study generates interspecies heterokaryons (fused mouse ES cells and human fibroblasts) that induce reprogramming efficiently, rapidly and without cell division. SiRNA–mediated knockdown reveals that AID is required for active DNA demethylation and initiation of nuclear reprogramming towards pluripotency in human somatic cells.