Table 2 Common linear mRNA sequence modifications53.
From: Breaking the mold with RNA—a “RNAissance” of life science
Region | Modification | Impact on function |
|---|---|---|
5’ cap | Methylation | Reduce immunogenicity and enhance translation |
5’ UTR | Incorporation of IRES viral sequences | Initiate translation at lower initiation factor expression levels to improve efficacy |
ORF | Codon optimization | Several modifications (such as using more frequent codons, using codon pairs that work better together, using the same proportion of each codon found in highly expressed proteins, or reducing UU and UA dinucleotides) can increase rate and efficiency of translation but may impact function or alter conformation |
3’ UTR | Incorporation of specific α- or β-globin mRNA sequences | Addition of α-globin sequence improves stability while β-globin sequence extends duration of protein expression |
Poly(A) tail | Increased length | A long poly(A) tail can increase stability and efficiency of protein translation but should be optimized for each target cell type |
Incorporation of adenosine analogs | Protect mRNA from 3’-exonuclease activity | |
Any | Modification of nucleosides | Optimize protein expression through uridine depletion Lower innate immune responses induced by Toll-like receptor by incorporating 5-methylcytidine, N6-methyladenosine, or 5-methyluridine |
