A Network of Noncoding Regulatory RNAs Acts in the Mammalian Brain
Noncoding RNAs (ncRNAs) play increasingly appreciated gene-regulatory roles. Here, we describe a regulatory network centered on four ncRNAs--a long ncRNA, a circular RNA, and two microRNAs--using gene editing in mice to probe the molecular consequences of disrupting key components of this network. The long ncRNA Cyrano uses an extensively paired site to miR-7 to trigger destruction of this microRNA. Cyrano-directed miR-7 degradation is much more efficient than previously described examples of target-directed microRNA degradation, which come from studies of artificial and viral RNAs. By reducing miR-7 levels, Cyrano prevents repression of miR-7-targeted mRNAs and enables the accumulation of Cdr1as, a circular RNA known to regulate neuronal activity. Without Cyrano, excess miR-7 causes cytoplasmic destruction of Cdr1as, in part through enhanced slicing of Cdr1as by a second miRNA, miR-671. Thus, several types of ncRNAs can collaborate to establish a sophisticated regulatory network.\n\nHIGHLIGHTSA long noncoding RNA, a circular RNA, and two microRNAs form a regulatory network\n\nThe Cyrano long noncoding RNA directs potent, multiple-turnover destruction of miR-7\n\nUnchecked miR-7 prevents accumulation of Cdr1as circular RNA in cytoplasm of neurons miR-7 prevents this accumulation by enhancing the miR-671-directed slicing of Cdr1as