microRNAs become macro players in somatic cell reprogramming

Embryonic stem cell specific microRNAs (miRNAs) have previously been shown to enhance the efficiency of transcription-factor-based reprogramming. However, whether reprogramming could be achieved entirely by miRNAs remained unclear. A recent report shows that the expression of the miR-302/367 cluster of miRNAs can directly reprogram somatic cells without the use of any transcription factors. This new method raises interesting questions about the mechanisms of reprogramming and is likely to facilitate the generation of induced pluripotent stem cells for potential future clinical use.