Figure 2.

The biogenesis (a) and potential function (b–d) of circular RNAs. (a) Four types of circRNAs created via back splicing—ecircRNA, intergenic circRNA, elcircRNA, and ciRNA. (b) circRNAs can serve as sponges for binding miRNAs or RBPs. (c), exosome-derived circRNAs. )(d) aelcircRNA and ciRNA can regulate gene expression by binding with the RNA Pol II and U1 snRNP complex. RBP: RNA binding proteins; miRNA: microRNA; U1 snRNP: small nuclear ribonucleoprotein; and RNA pol II: RNA polymerase II.