Chemical and structural design of multi-capped mRNA and capped circular RNA to improve protein production

mRNA protein production was enhanced by up to tenfold in vivo using a new method called ligation-enabled mRNA-oligonucleotide assembly (LEGO).

• A branched mRNA cap effectively initiates translation on both linear and circular mRNAs without the need for internal ribosome entry sites.
• Chemical modifications, including locked nucleic acid (LNA) N-methylguanosine on the cap and additional LNA modifications on the 5' untranslated region, improve the binding of translation initiation factors and RNA stability.
• In a vaccine setting for severe acute respiratory syndrome coronavirus 2, this method resulted in 17-fold and 3.7-fold increases in antibody production after prime and boost doses, respectively.
• The LEGO platform allows for the design of non-traditional RNA structures and topologies that could be useful in both research and therapeutic contexts.

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