RNA decay via 3′ uridylation

► Post-transcriptional 3′ uridylation can target eukaryotic RNAs for degradation. ► mRNAs, pre-miRNAs and various small RNAs can be modified in this way. ► In some cases RNA 3′ uridylation is antagonised by 2′-O-methylation. ► Uridylation may be a widespread mechanism by which RNA stability is regulated.