Isolation and sequencing of AGO-bound RNAs reveals characteristics of mammalian stem-loop processing in vivo

Ian M. Silverman; Sager J. Gosai; Nicholas Vrettos; Shawn W. Foley; Nathan D. Berkowitz; Zissimos Mourelatos; Brian D. Gregory

All previous examples of ac-pre-miRNAs have been shown to be cleaved within the 3p miRNA sequence and generate 5p miRNAs. To identify putative acpre-miRNAs that are processed with the opposite directionality, we performed a parallel search for pre-miRNA-seq reads that began 8-15 nucleotide from the 5' end of the 5p miRNA. From this analysis, we found 3 candidates in humans and 5 candidates in mouse including hsa-miR-140 and mmu-miR-22 (Figs. 3C-D and Table S3 ). Importantly, these 5p cleaved ac-pre-miRNAs give rise predominantly to 3p miRNAs suggesting that cleavage in this region is not a degradation byproduct and is likely a competent mechanism for generating mature miRNAs (Table S3) . These results reveal a greater collection of ac-pre-. CC-BY 4.0 International license is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It . https://doi.org/10.1101/294488 doi: bioRxiv preprint miRNAs than previously appreciated and uncover a likely novel class of 5p cleaved ac-pre-miRNAs.