RIOX1

Ribosomal oxygenase 1 is a protein that in humans is encoded by the RIOX1 gene (previously NO66). The protein is involved in ribosome biogenesis and replication and regulation of heterochromatic regions of the nucleus. It is a chromatin regulator, and a regulator of osteoblast differentiation. It is a Jumonji C (JmjC) domain-containing protein in the subgroup of ribosomal oxygenases (ROXs), part of the superfamily of Fe(II) and 2-oxoglutarate (2OG) dependent oxygenases. Ribosomal oxygenase 1 It is a dual-location protein found in the nucleus, nucleolus, and nucleoplasm of the cell. RIOX1 is a single-exon-gene, intronless, and is found across several species. The gene is involved in gene transcription regulation in the nucleus of the cell.Expression of RIOX1 correlates with potential of cancer. Expression levels are shown to closely correlate with the malignant potential of renal cell tumors and colorectal cancer. The gene has been shown to be an oncogenic driver (initiates cancer cell growth and proliferation) of prostate cancer. thumb|335x335px|Human RIOX1 exon structure thumb|338x338px|Domain architecture for RIOX1 and RIOX2 Both RIOX1 and RIOX2 (Previously MINA53) modify ribosome proteins through histidine hydroxylation, specifically His 216. The two proteins differ in the presence of the N-terminal extension which is absent in RIOX2. They are both part of the JmjC-domain-containing protein family, which are a part of a class of histone demethylases, which control the structure of chromatin in order to regulate gene expression. JmjC histone demethylases are linked to human diseases, many cases in cancer and neurological disorders. It enables protein demethylase and peptidyl-histidine dioxygenase activity. It also is involved in regulating DNA repair. RIOX1 has a unique N-terminal extension domain, meaning it can have unique interactions with other molecules, in addition to assistance in protein folding. Nuclear distribution of RIOX1 is localized to perichromosomal (specialized chromosome domain containing proteins for certain processes) cytoplasm in metaphase and early anaphase, localized to chromosomes in late anaphase, and localized to prenucleolar bodies in late telophase, during cellular processes of MCF-7 cells. thumb|RIOX1/NO66 hydroxylates histidine residues in the ribosomal protein RPL8 thumb|Ramachandran Plot for the RIOX1 protein, Crystal Structure of human NO66

== Phylogenetics == Analysis of RIOX1 and RIOX2 orthologous genes from different species show presence of the gene in early Cnidaria. The genomic sequence exhibited presence of both RIOX1 and RIOX2 in Hydra vugaris, an early metazoan in the phylum Cnidaria. In addition to presence in Cnidaria, RIOX1 was found in the genes of Arthropoda, Annelida, Nematoda and Mollusca, where RIOX2 was not found, with the exception of Priapulida. RIOX1's presence across species suggests that the gene is phylogenetically older, from which RIOX2 was evolved. RIOX2 is thought to have evolved in Chordata.