GSE163387
The ZSWIM8 ubiquitin ligase mediates target-directed microRNA degradation [dataset 2]
MicroRNAs (miRNAs) associate with Argonaute (AGO) proteins to direct widespread post-transcriptional gene repression.  Although association with AGO typically protects miRNAs from nucleases, extensive pairing to some unusual target RNAs can trigger miRNA degradation.  Here we found that this target-directed miRNA degradation (TDMD) required the ZSWIM8 Cullin-RING E3 ubiquitin ligase.  This and other findings suggested and supported a mechanistic model of TDMD in which target-directed proteolysis of AGO by the ubiquitin–proteasome pathway exposes the miRNA for degradation.  Moreover, loss-of-function studies indicated that the ZSWIM8 Cullin-RING ligase accelerates degradation of numerous miRNAs in cells of mammals, flies, and nematodes, thereby specifying the half-lives of most short-lived miRNAs.  These results elucidate the mechanism of TDMD and expand the inferred role of TDMD in shaping miRNA levels in bilaterian animals. Overall design: miRNA expression profiling by small-RNA sequencing of polyclonal mammalian cell lines expressing Cas9 and either one of three control guide RNAs (gRNAs), or one of three gRNAs targeting ZSWIM8.  This study consists of libraries generated from two to three biological replicates per cell ine, with the expressied gRNA indicated.