fig2

Figure 2. Biogenesis and molecular characteristics of circRNAs. circRNAs are formed through post-transcriptional splicing, in which complementary intronic sequences bind to RBPs, including QKI, FUS, and NF90/NF110, that promote exon ligation and circRNA formation. The resulting covalently closed circular structures lack a 5' cap and a 3' poly(A) tail, contributing to their stability and regulatory functions.