Secondary structure RNA elements control the cleavage activity of DICER
Trung Duc Nguyen, Tam Anh Trinh, Sheng Bao, Tuan Anh Nguyen, Tuan Anh Nguyen, Tuan Anh Nguyen
Abstract
The accurate and efficient cleavage of shRNAs and pre-miRNAs by DICER is crucial for their gene-silencing activity. Here, we conduct high-throughput DICER cleavage assays for more than ~20,000 different shRNAs and show the comprehensive cleavage activities of DICER on these sequences. We discover a single-nucleotide bulge (22-bulge), which facilitates the cleavage activity of DICER on shRNAs and human pre-miRNAs. As a result, this 22-bulge enhances the gene-silencing activity of shRNAs and the accuracy of miRNA biogenesis. In addition, various single-nucleotide polymorphism-edited 22-bulges are found to govern the cleavage sites of DICER on pre-miRNAs and thereby control their functions. Finally, we identify the single cleavage of DICER and reveal its molecular mechanism. Our findings improve the understanding of the DICER cleavage mechanism, provide a foundation for the design of accurate and efficient shRNAs for gene-silencing, and indicate the function of bulges in regulating miRNA biogenesis.