An endogenous cluster of target-directed microRNA degradation sites induces decay of distinct microRNA families

This is the authors' abstract. We don't add key points for this paper.

While much is known about microRNA (miRNA) biogenesis and targeting, relatively less is understood about miRNA decay. Target-directed miRNA degradation (TDMD) is a mechanism in metazoans where certain RNAs can "trigger" miRNA decay. All known TDMD triggers base pair with the miRNA seed, and extensively base pair on the miRNA 3' end, a pattern that is believed to be a requirement for miRNA turnover. Using Ago1-CLASH, we find that the Drosophila transcript Kah contains at least two triggers, a "trigger cluster," against miR-9b and the miR-279 family. One trigger contains minimal/non-canonical 3' end base-pairing but is still sufficient to induce TDMD of the miR-279 family. We find that these clustered triggers lack cooperativity, that minimal 3' pairing is required for miR-279 family turnover, and probed the in-cell structure of the Kah trigger cluster. Overall, we expand the list of endogenous TDMD triggers, which revealed unexpectedly complex regulation in miRNA turnover.