Structural basis for piRNA targeting.

ABSTRACT: PIWI proteins use PIWI-interacting RNAs (piRNAs) to identify and silence transposable elements and thereby maintain genome integrity between metazoan generations¹. The targeting of transposable elements by PIWI has been compared to mRNA target recognition by Argonaute proteins^2,3, which use microRNA (miRNA) guides, but the extent to which piRNAs resemble miRNAs is not known. Here we present cryo-electron microscopy structures of a PIWI-piRNA complex from the sponge Ephydatia fluviatilis with and without target RNAs, and a biochemical analysis of target recognition. Mirroring Argonaute, PIWI identifies targets using the piRNA seed region. However, PIWI creates a much weaker seed so that stable target association requires further piRNA-target pairing, making piRNAs less

SUBMITTER: Anzelon TA 

PROVIDER: S-EPMC9302021 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature