Fig. 1

Prototypical RNA species and their modifications. All types of RNA are modified; structures for three of more than 120 modifications are shown in the lower panel. RNA secondary structures were adapted from the following sources: XIST long non-coding RNA (lncRNA) [82]; 5S and 5.8S rRNA, tRNA, microRNA (miRNA), small nuclear RNA (snRNA), transfer-messenger RNA (tmRNA), 16-18S, 23-28S rRNA [83]. Abbreviations: ac⁴C N4-acetylcytidine, ac⁴Cm N4-acetyl-2’-O-methylcytidine, Am 2’-O-methyladenosine, Cm 2’-O-methylcytidine, Gm 2’-O-methylguanosine, I inosine, i⁶A N6-isopentenyladenosine, mcm⁵U 5-methoxycarbonylmethyluridine, m⁵C 5-methylcytidine, m⁵U 5-methyluridine, m⁶A N⁶-methyladenosine, nt nucleotide, 3′-U/A 3′-uridylation/adenylation, 2’-O-Me 2’-O-methylation, Um 2’-O-methyluridine, Y pseudouridine