Fig. 5: A class of napRNAs embedded in miRNA spacer regions (misRNAs).

a Statistics of the number of pre-miRNAs that intersected with the napRNAs. b Genome Browser view of the full-length misRNAs (RPM, reads per million) in an extended region of misRNA hsa-misRNA-4. The highly stable secondary structures of misRNAs hsa-misRNA-4 (c) and mmu-misRNA-18 (d). e, f The dynamic changes in misRNAs under different conditions or in different stages. Heatmaps showing the differentially expressed misRNAs in HepG2 cells under four stress-response conditions (e) and in C2C12 cells at four developmental stages (f). Each row represents a differentially expressed misRNA, and each column represents a treatment type. The color, ranging from blue to red, represents the relative expression value from low to high, respectively. g Genome Browser view of the processing of misRNAs in the miRNA-17-92 cluster. Genome Browser view of 5’-start, 3’-end and coverage signals (RPM, reads per million) in an extended region of the miRNA-17-92 cluster. h Diagram of miRNA processing from the miRNA cluster. The miRNA cluster pri-miR-17-92 simultaneously yielded five miRNA spacers. These miRNA spacers are shown in various colors based on the spacer type, which are the same as those for the TGS reads in (g). i The proposed model of misRNA biogenesis. During the miRNA maturation process in humans and mice, the spacer region between the two pre-miRNAs is separated and is then folded into a structural misRNA and bound by a microprocessor complex to prevent further degradation.