Cytochrome b Reductase 1 (CYBRD1)

DCYTB encodes a protein with 6 predicted transmembrane domains and 4 conserved histidine residues which are proposed heme ligands. DCYTB shares 45 to 50% similarity with the cytochrome b561 family of plasma membrane reductases, is highly expressed in the brush-border membrane of duodenal enterocytes, and induces ferric reductase activity when expressed in Xenopus oocytes and cultured cells. Duodenal expression levels of DCYTB mRNA and protein were regulated by changes in physiologic modulators of iron absorption, including chronic anemia, iron deficiency, and hypoxia. Three major transcripts of 1, 4, and greater than 5 kb were detectable by Northern blot analysis, indicative of alternative splicing or the presence of unprocessed pre-mRNA species.