Fig. 1
From: New insight into circRNAs: characterization, strategies, and biomedical applications
Characterization of circRNAs. a Biogenesis of circRNAs. circRNAs are produced from back-splicing or intron self-splicing of precursor RNAs. Exons, introns, 5′untranslated regions (UTR), 3′UTR or antisense sequences, can generate circRNAs, which include ciRNAs, EIciRNAs, ecircRNAs, and others. CircRNAs regulate biological process via various regulation mechanism, including circRNA-miRNA sponge (b), circRNA-protein interaction (c), circRNA immunity (d), circR-loop (e), guiding A-to-I editing (f), and translation (g). h, i Degradation mechanism of circRNA. h RNase H1 degrades a subgroup of ciRNAs in R-loops. i circRNAs are degraded by RNase L in PKR activated innate immunity. j Recruitment of endonucleases by m6A marks to degrade circRNAs