NR1I3（nuclear receptor subfamily 1 group I member 3），癌症关联基因，基因ID：9970，该基因编码核受体超家族的一个成员，是外源和内源代谢的关键调控因子。该蛋白以单体或异二聚体的形式与DNA结合，并与视黄醇X受体结合，调节参与药物代谢和胆红素清除的靶基因的转录，如细胞色素P450家族成员与大多数核受体不同，这种转录调节因子在缺乏配体的情况下具有组成性活性，但同时受激动剂和反激动剂的调节配体结合导致这种蛋白质转移到细胞核，在那里它激活或抑制靶基因转录这些配体包括胆红素、各种外来化合物、类固醇激素和处方药。已发现该基因编码不同亚型的多个转录变体。[由RefSeq提供，2008年7月]This gene encodes a member of the nuclear receptor superfamily， and is a key regulator of xenobiotic and endobiotic metabolism. The protein binds to DNA as a monomer or a heterodimer with the retinoid X receptor and regulates the transcription of target genes involved in drug metabolism and bilirubin clearance， such as cytochrome P450 family members. Unlike most nuclear receptors， this transcriptional regulator is constitutively active in the absence of ligand but is regulated by both agonists and inverse agonists. Ligand binding results in translocation of this protein to the nucleus， where it activates or represses targe。