PMID- 11264453 OWN - NLM STAT- MEDLINE DCOM- 20010614 LR - 20131121 IS - 0362-1642 (Print) IS - 0362-1642 (Linking) VI - 41 DP - 2001 TI - Phenobarbital response elements of cytochrome P450 genes and nuclear receptors. PG - 123-43 AB - Phenobarbital (PB) response elements are composed of various nuclear receptor (NR)-binding sites. A 51-bp distal element PB-responsive enhancer module (PBREM) conserved in the PB-inducible CYP2B genes contains two NR-binding direct repeat (DR)-4 motifs. Responding to PB exposure in liver, the NR constitutive active receptor (CAR) translocates to the nucleus, forms a dimer with the retinoid X receptor (RXR), and activates PBREM via binding to DR-4 motifs. For CYP3A genes, a common NR site [DR-3 or everted repeat (ER)-6] is present in proximal promoter regions. In addition, the distal element called the xenobiotic responsive module (XREM) is found in human CYP3A4 genes, which contain both DR-3 and ER-6 motifs. Pregnane X receptor (PXR) could bind to all of these sites and, upon PB induction, a PXR:RXR heterodimer could transactivate XREM. These response elements and NRs are functionally versatile, and capable of responding to distinct but overlapping groups of xenochemicals. FAU - Sueyoshi, T AU - Sueyoshi T AD - Pharmacogenetics Section, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA. FAU - Negishi, M AU - Negishi M LA - eng PT - Journal Article PT - Review PL - United States TA - Annu Rev Pharmacol Toxicol JT - Annual review of pharmacology and toxicology JID - 7607088 RN - 0 (Hypnotics and Sedatives) RN - 0 (Receptors, Cytoplasmic and Nuclear) RN - 9035-51-2 (Cytochrome P-450 Enzyme System) RN - YQE403BP4D (Phenobarbital) SB - IM MH - Animals MH - Cytochrome P-450 Enzyme System/drug effects/*genetics MH - Gene Expression Regulation, Enzymologic/drug effects MH - Humans MH - Hypnotics and Sedatives/*pharmacology MH - Phenobarbital/*pharmacology MH - Receptors, Cytoplasmic and Nuclear/*drug effects MH - Response Elements/*drug effects RF - 100 EDAT- 2001/03/27 10:00 MHDA- 2001/06/23 10:01 CRDT- 2001/03/27 10:00 PHST- 2001/03/27 10:00 [pubmed] PHST- 2001/06/23 10:01 [medline] PHST- 2001/03/27 10:00 [entrez] AID - 41/1/123 [pii] AID - 10.1146/annurev.pharmtox.41.1.123 [doi] PST - ppublish SO - Annu Rev Pharmacol Toxicol. 2001;41:123-43. doi: 10.1146/annurev.pharmtox.41.1.123.