Fig. 1: Synthesis of circRNA from linear RNA precursor.
From: Recent advances and perspectives on the development of circular RNA cancer vaccines
a Chemical synthesis by the treatment of T4 polynucleotide kinase (T4 PNK) and calf intestinal alkaline phosphatase (CIAP) followed by the conjugation of 5’-end phosphate with 3’-end hydroxyl catalyzed by the treatment of condensing agents (BrCN or EDC). b Enzymatic synthesis catalyzed by T4 RNA ligases using a DNA splint in a complementary base-paring manner to facilitate site-specific ligation. c Ribozymatic synthesis by Group I intron-based permuted intron‒exon (PIE) system. Permutation of a native group I intron and insertion of a custom sequence (C-S) into the exonic region (E2 and E1). And then this PIE system spontaneously ligates in the presence of free guanosine to form circRNA and release the two half-intron fragments.
