Figure 2.

Chemical structures of mRNA modifications. Chemical structures in eukaryotic mRNA, including m⁶A, m¹A, m⁵C, hm⁵C, Ψ, I, U, and 2′-O-Me. m⁶A is mostly found in the 3′UTRs as well as the 5′UTRs; m¹A-containing mRNA is 10 times less common than m⁶A-containing mRNA, but it is found in all segments of mRNA; m⁵C is found in both coding and non-coding regions, especially in GC-rich regions, where it regulates transcription differently; Ψ appears in many locations; 2′-O-Me is concentrated in the mRNA region that encodes amino acids.