Internal 6-methyladenine residues increase the in vitro translation efficiency of dihydrofolate reductase messenger RNA.

N6-Methyladenosine (m6A) is found internally in a number of mRNA molecules from higher eucaryotic cells. In these investigations, it was found that the presence of m6A residues increase the in vitro translation efficiency of capped T7 transcripts of mouse dihydrofolate reductase (DHFR) mRNA. Using an in vitro rabbit reticulocyte translation system, the formation of internal m6A residues in the DHFR transcripts resulted in a 1.5-fold increase in translated DHFR compared to transcripts void of internal m6A residues. Translation in a wheat germ system, however, resulted in no increase in translation efficiency upon m6A formation, suggesting that the mechanism may be species-specific.