Figure 8.

Ribozyme methods for circRNA synthesis. The group I intron self-splicing system comprises RNA fragments of exons and introns of the foreign organism flanking the antigen sequence. The group I intron self-splicing system requires guanosine triphosphate (GTP) and Mg2+ in the reaction as co-factors for the formation of circRNA from a linear RNA molecule. The principle of the group II intron self-splicing method resembles the principle of the group I intron self-splicing method, but it can use foreign introns without exons. However, the self-splicing of group II introns is known to form 2’, 5’-phosphodiester bonds at the ligation site.