A network of noncoding regulatory RNAs acts in the mammalian brain II

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. Overall design: mRNA expression profiling by RNA-seq of cerebellum and cortex from wild-type (WT), Cyrano miR-7 site mutant (CyrMut), Cyrano–/– (CyrKO), and Mir7a1–/–; Mir7b–/– (Mir7DKO) mice. This study consists of 33 polyA-selected stranded NEXTflex libraries prepared from 3-4 biological replicates for each tissue and each genotype. To minimize batch effects, libraries for wild-type tissues were prepared and sequenced for each experiment and only intra-experiment comparisons were made.

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Kleaveland B, Shi CY, Stefano J, Bartel DP