Non-demethylase 2OG-dependent dioxygenase reactions utilizing RNA or DNA substrates. (A) Action of ALKBH8 in the synthesis of a modified tRNA. (B) Wybutosine hydroxylase catalysis by TWY5. (C) The sequential reactions of TET proteins acting on 5meC to form 5hmC, 5fC and 5caC. (D) Thymidine 7-hydroxylase activity catalyses the first step in formation of base J (a subsequent glucosyl transfer reaction is highlighted in yellow).