Oxygenase that can act as both a histone lysine demethylase and a ribosomal histidine hydroxylase. Specifically demethylates 'Lys-4' (H3K4me) and 'Lys-36' (H3K36me) of histone H3, thereby playing a central role in histone code. Preferentially demethylates trimethylated H3 'Lys-4' (H3K4me3) and monomethylated H3 'Lys-4' (H3K4me1) residues, while it has weaker activity for dimethylated H3 'Lys-36' (H3K36me2). Also catalyzes the hydroxylation of 60S ribosomal protein L8 on 'His-216'. Acts as a regulator of osteoblast differentiation via its interaction with SP7/OSX by demethylating H3K4me and H3K36me, thereby inhibiting SP7/OSX-mediated promoter activation (By similarity). May also play a role in ribosome biogenesis and in the replication or remodeling of certain heterochromatic region. Participates in MYC-induced transcriptional activation. 2 2-oxoglutarate + N(6),N(6)-dimethyl-L-lysyl(36)-[histone H3] + 2 O2 = 2 CO2 + 2 formaldehyde + L-lysyl(36)-[histone H3] + 2 succinate 2-oxoglutarate + L-histidyl-[protein] + O2 = (3S)-3-hydroxy-L-histidyl-[protein] + CO2 + succinate Binds 1 Fe(2+) ion per subunit. Interacts with SP7/OSX; the interaction is direct (By similarity). Interacts with MYC. Interacts with PHF19; leading to its recruitment to H3K36me3 sites. Granular part of nucleoli. Nucleoplasm, nucleoplasmic foci, some of them associated with nucleoli. Widely expressed. Overexpressed in lung carcinomas. Belongs to the ROX family. NO66 subfamily.