Ribosomal oxygenase 1 (RIOX1)

Ribosomal oxygenase 1 (RIOX1) is a nucleolar enzyme best known for its roles as a histone lysine demethylase and as a ribosomal protein histidine hydroxylase. It specifically demethylates lysines on histone H3, particularly H3K4me3 and H3K4me1, with weaker activity on H3K36me2, thus playing a role in epigenetic regulation of gene expression. In addition to chromatin targets, RIOX1 hydroxylates histidine residues in ribosomal protein L8, implicating it in ribosome biogenesis. RIOX1 also demethylates non-histone proteins, such as cyclic GMP-AMP synthase (cGAS), and regulates DNA repair pathways, particularly by modulating homologous recombination after ionizing radiation via cGAS demethylation. It participates in MYC-induced transcriptional activation and is involved in the regulation of osteoblast differentiation. RIOX1 is associated with several disease contexts, including cancer (notably lung cancer) and Sotos syndrome 3. It is broadly considered a potential therapeutic enzyme target due to its central role in chromatin and DNA-damage response pathways.

Other names

Ribosomal oxygenase 1RIOX1NO66MAPJDJMJD9C14orf169Myc-associated protein with JmjC domainNucleolar protein 66Bifunctional lysine-specific demethylase and histidyl-hydroxylase NO66Ribosomal oxygenase NO6660S ribosomal protein L8 histidine hydroxylasehsNO66ROXURLC2

Lysine demethylation on histones (e.g., H3K4me3, H3K36me2); Histidine hydroxylation of ribosomal proteins; Demethylation of non-histone proteins such as cyclic GMP-AMP synthase (cGAS); Regulation of homologous recombination (HR) DNA repair