PT - JOURNAL ARTICLE AU - Park, Mi Seul AU - Sim, GeunYoung AU - Kehling, Audrey C. AU - Nakanishi, Kotaro TI - Human Argonaute2 and Argonaute3 are catalytically activated by different lengths of guide RNA AID - 10.1101/2020.07.16.207720 DP - 2020 Jan 01 TA - bioRxiv PG - 2020.07.16.207720 4099 - http://biorxiv.org/content/early/2020/07/17/2020.07.16.207720.short 4100 - http://biorxiv.org/content/early/2020/07/17/2020.07.16.207720.full AB - RNA interfering is a eukaryote-specific gene silencing by 20∼23 nucleotide (nt) microRNAs and small interfering RNAs that recruit Argonaute proteins to complementary RNAs for degradation. In humans, Argonaute2 (AGO2) has been known as the only slicer while Argonaute3 (AGO3) barely cleaves RNAs. Therefore, the intrinsic slicing activity of AGO3 remains controversial and a long-standing question. Here, we report 14-nt 3′ end-shortened variants of let-7a, miR-27a, and specific miR-17-92 families that make AGO3 an extremely competent slicer by an ∼ 82-fold increase in target cleavage. These RNAs, named cleavage-inducing tiny guide RNAs (cityRNAs), conversely lower the activity of AGO2, demonstrating that AGO2 and AGO3 have different optimum guide lengths for target cleavage. Our study sheds light on the role of tiny guide RNAs.Competing Interest StatementThe authors have declared no competing interest.