Fig. 1
From: Cancer-related circular RNA: diverse biological functions
Biogenesis of CircRNAs. A: Canonical splicing. A process that removes the introns of pre-mRNAs, and then exons are connected to be a liner mRNA. B, C: Backing splicing. intron pairing and RNA binding proteins (RBPs) that can promote the circularization of back splicing to generate ecircRNAs or EIcicRNA. D: Intron splicing. Lariat introns that failure to debranch at the branch point site and trimming of the lariat tail can produce ciRNAs via intron splicing