Pregnane X Receptor

Pregnane X Receptor

Identifiers Symbols NR1I2; BXR; ONR1; PAR; PAR1; PAR2; PARq; PRR; PXR; SAR; SXR External IDs OMIM: 603065 MGI: 1337040 HomoloGene: 40757 IUPHAR: NR1I2 ChEMBL: 3401 GeneCards: NR1I2 Gene

Gene Ontology
Molecular function	• steroid hormone receptor activity • transcription coactivator activity • ligand-activated sequence-specific DNA binding RNA polymerase II transcription factor activity • protein binding • drug binding • zinc ion binding • sequence-specific DNA binding
Cellular component	• nucleoplasm
Biological process	• transcription initiation from RNA polymerase II promoter • xenobiotic metabolic process • signal transduction • steroid metabolic process • gene expression • intracellular receptor signaling pathway • exogenous drug catabolic process • xenobiotic transport • negative regulation of transcription, DNA-dependent • positive regulation of transcription, DNA-dependent • drug export
Sources: Amigo / QuickGO

RNA expression pattern More reference expression data Orthologs Species Human Mouse Entrez 8856 18171 Ensembl ENSG00000144852 ENSMUSG00000022809 UniProt O75469 O54915 RefSeq (mRNA) NM_003889 NM_001098404 RefSeq (protein) NP_003880 NP_001091874 Location (UCSC) Chr 3:
119.5 – 119.54 Mb Chr 16:
38.25 – 38.29 Mb PubMed search

In the field of molecular biology, the pregnane X receptor (PXR), also known as the steroid and xenobiotic sensing nuclear receptor (SXR) or nuclear receptor subfamily 1, group I, member 2 (NR1I2) is a protein that in humans is encoded by the NR1I2 gene.

PXR is a nuclear receptor whose primary function is to sense the presence of foreign toxic substances and in response up regulate the expression of proteins involved in the detoxification and clearance of these substances from the body. PXR belongs to the nuclear receptor superfamily, members of which are transcription factors characterized by a ligand-binding domain and a DNA-binding domain. The encoded protein is a transcriptional regulator of the cytochrome P450 gene CYP3A4, binding to the response element of the CYP3A4 promoter as a heterodimer with the 9-cis retinoic acid receptor RXR. It is activated by a range of compounds that induce CYP3A4, including dexamethasone and rifampicin. Several alternatively spliced transcripts encoding different isoforms, some of which use non-AUG (CUG) translation initiation codon, have been described for this gene. Additional transcript variants exist, however, they have not been fully characterized.