title: Retinoid X receptor RXR alpha binds to and trans-activates the hepatitis B virus enhancer.
abstract: A retinoid X receptor (RXR) response element was located within the functionally defined hepatitis B virus (HBV) enhancer element. A short segment of the enhancer that contains this region has been shown with genetic analysis to play a key role in the regulation of enhancer function and to represent a major determinant of liver-specific activity. Both the full-length protein and the DNA-binding domain of the liver-specific receptor RXR alpha bound to the putative retinoic acid response element in the HBV enhancer. In vivo, an HBV enhancer-reporter gene construct responds to induction with retinoic acid when cotransfected with an RXR alpha expression vector. A single-base transition (G----A) in the HBV retinoic acid response element leads to a dramatic reduction both in the in vitro binding activity of RXR alpha and the in vivo activity of the HBV enhancer. Thus, retinoic acid and the RXR alpha are implicated as being significant determinants in the liver-specific regulation of HBV gene expression and the resultant disease pathogenesis.
authors.affiliation: Department of Microbiology and Immunology, University of Colorado Medical School, Denver 80262.
authors.forename: B
authors.initials: B
authors.lastname: Huan
authors.forename: A
authors.initials: A
authors.lastname: Siddiqui
mesh_terms: D001483:Base Sequence; D006528:Carcinoma, Hepatocellular; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000187:drug effects; D005814:Genes, Viral; D006514:Hepatitis B Surface Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008113:Liver Neoplasms; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D015533:Transcriptional Activation; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D004268:DNA-Binding Proteins; D006514:Hepatitis B Surface Antigens; D009687:Nuclear Proteins; D011956:Receptors, Cell Surface; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D015534:Trans-Activators; D014157:Transcription Factors; D014212:Tretinoin