Control of RNA lifespan is vital for the proper functioning of our cells. Marc Bühler’s group at the Friedrich Miescher Institute for Biomedical Research (FMI) has discovered a novel mechanism determining the fate of RNA in mammalian cells: two proteins involved in RNA interference – Dgcr8 and Drosha – together with a methyltransferase, Mettl3, mark nascent RNAs for degradation as they are transcribed. This mechanism allows RNA transcripts to “remember” the conditions under which they were synthesized.