PIWI-interacting RNAs (piRNAs) of between approximately 24 and 31 nucleotides in length guide PIWI proteins to silence transposons in animal gonads, thereby ensuring fertility(1). In the biogenesis of piRNAs, PIWI proteins are first loaded with 5 '
-O-methylation. Regardless of the endonucleolytic mechanism, pre-piRNAs are matured by Trimmer and Hen1. Our findings highlight multiplexed processing of piRNA precursors that supports robust and flexible piRNA biogenesis.
A silkworm model recapitulates key steps of Zucchini-mediated cleavage of pre-pre-piRNA and provides insights into Zucchini-mediated and -independent pathways that generate pre-piRNAs, which converge to a common piRNA maturation step.
