RRC ID 53896
Author Gamou T, Habano W, Terashima J, Ozawa S.
Title A CAR-responsive enhancer element locating approximately 31 kb upstream in the 5'-flanking region of rat cytochrome P450 (CYP) 3A1 gene.
Journal Drug Metab Pharmacokinet
Abstract Constitutive androstane receptor (CAR) is one of the principal regulators of hepatic cytochrome P450s (CYPs) 3A (CYP3A). cDNA-mediated expression of a mature rat CAR (rCAR) into rat hepatoma cells induced CYP3A1 and CYP2B mRNAs. Aberrant rCAR failed in these inductions. Three important human CYP3A4 regulatory elements (REs), proximal ER6 (proER6), xenobiotic responsive enhancer module (XREM) and constitutive liver enhancer module (CLEM), support constitutive and inducible expression of CYP3As mediated by CAR and pregnane X receptor (PXR). NHR-scan software predicted proER6, XREM and CLEM at -255 b, -8 kb and -11.5 kb, respectively of CYP3A4, but neither XREM nor CLEM was predicted in rat CYP3A. A luciferase reporter construct carrying a 5'-flanking sequence of CYP3A1 (-31,739 to -31,585 from its transcription initiation site) revealed important for the rCAR-dependent transactivation of CYP3A1. This region includes two putative binding motifs of nuclear receptors (DR4 and DR2), a putative hepatocyte nuclear factor-1 binding motif (HNF1), nuclear factor-kappa B binding motif (NFκB), activator protein 1 binding motif (AP-1), and ecotropic viral integration site 1 binding motif (Evi1). We hereby conclude DR4 and/or DR2 motifs being primarily responsible and HNF1 being synergistically functioning elements for the rCAR-mediated transcription of CYP3A1.
Volume 30(2)
Pages 188-97
Published 2015-4-1
DOI 10.1016/j.dmpk.2014.12.008
PII S1347-4367(14)00029-9
PMID 25989892
MeSH 5' Flanking Region* Animals Binding Sites Carcinoma, Hepatocellular / enzymology Carcinoma, Hepatocellular / genetics Cell Line, Tumor Constitutive Androstane Receptor Cytochrome P-450 CYP3A / genetics* Cytochrome P-450 CYP3A / metabolism Dexamethasone / pharmacology Gene Expression Regulation, Enzymologic Genes, Reporter Hepatocyte Nuclear Factor 1 / metabolism Hepatocytes / drug effects Hepatocytes / enzymology* Liver Neoplasms / enzymology Liver Neoplasms / genetics Male Protein Binding RNA, Messenger / metabolism Rats, Inbred F344 Receptors, Cytoplasmic and Nuclear / genetics* Receptors, Cytoplasmic and Nuclear / metabolism Response Elements* Transcription, Genetic Transcriptional Activation Transfection Tricarboxylic Acids / pharmacology
IF 2.772
Times Cited 1
DNA material Rat BAC RNB1 (RDB06273) RNB1-193K14