The Research Progression and Clinical Significance of Circular RNAs in Head and Neck Cancers

Figure 1

Models for the biogenesis of circRNAs. circRNAs are produced from special linear pre-mRNAs by back splicing circularization. (a) Introns which have complementary base pairs can contribute to the formation of circRNAs by bringing the adjacent two exons to close together. The exons and introns are then cut away by spliceosome to form circRNAs. (b) Both RNA binding proteins (RBP) and specific sequences in introns can serve as a bridge and stimulate back splicing circularization because they can dimerize and bring exons in close proximity. (c) That pair intron make exon skipping through back splicing produce a lariat precursor. Lariat precursors may also contribute to the formation of circRNAs.