HEN1 Methyltransferase Homolog 1 (HENMT1)

The Drosophila hpRNA pathway is a hybrid mechanism that combines canonical RNA interference factors Dicer-2, Hen1 (C1ORF59), and Argonaute-2 with the canonical microRNA factor Loquacious (TARBP2) to generate approximately 21-nucleotide siRNAs. These novel regulatory RNAs reveal unexpected complexity in the sorting of small RNAs and open a window onto the biologic usage of endogenous RNA interference in Drosophila.extensive complementarity between a target RNA and an Argonaute-1-bound miRNA triggers miRNA tailing and 3-prime-to 5-prime trimming. In flies, Argonaute-2-bound small RNAs, but not those bound to Argonaute-1, bear a 2-prime-O-methyl group at their 3-prime ends. This modification blocks target-directed small RNA remodeling: in flies lacking Hen1, the enzyme that adds the 2-prime-O-methyl group,