Developmental biology. A Me6Age for pluripotency

Cell-fate decisions are orchestrated by global changes in gene expression, some of which are driven by epigenetic alterations, often including methylation of DNA. Embryonic stem cells (ESCs) have been used to decipher many of the critical factors underlying cell-fate decisions. Mouse ESCs exist in several different pluripotent states, notably naïve or ground-state ESCs and primed epiblast stem cells (EpiSCs), which resemble pre- and post-implantation–stage embryos, respectively (1, 2). New research now reveals another role for nucleic acid methylation in stem cell–fate determination, but of RNA rather than DNA—at position six of the adenosine base (m6A). Two recent papers, by Geula et al. (3) in Science Express and Batista et al. (4), show that m6A is involved in regulating stem cell maintenance and cell-fate decisions through its modulation of RNA stability and translation.