Fig. 3
From: Small RNA modifications: regulatory molecules and potential applications
The 2′-O-methylation (Nm) modification in piRNA. HEN1 catalyzes Nm modification of piRNA, replacing a hydrogen (–H) atom on the ribose fraction 2′-hydroxyl (–OH) with a methyl-group (–CH3). During piRNA maturation, the 3′-terminal nucleotide undergoes Nm modification, leading to formation of a stable piRNA structure that is protected from 3′-uridine degradation