The nuclear orphan receptor CAR-retinoid X receptor heterodimer activates the phenobarbital-responsive enhancer module of the CYP2B gene
The nuclear orphan receptor CAR-retinoid X receptor heterodimer activates the phenobarbital-responsive enhancer module of the CYP2B gene
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DOI：
10.1128/mcb.18.10.5652
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发表时间：
1998-10-01
影响因子：
5.3
通讯作者：
Negishi, M
中科院分区：
文献类型：
--
作者：
Honkakoski, P;Zelko, I;Negishi, M
PBREM是细胞色素P-450Cyp2b10基因的苯巴比妥反应增强子模块，含有两个潜在的核受体结合位点NR1和NR2。与抗维A酸类X受体(RXR)可使NR1-核蛋白复合体超位的发现一致，DNA亲和层析与NR1寡核苷酸亲和层析从苯巴比妥处理的小鼠肝细胞核提取液中富集了核孤儿受体RXR。除了RXR，核孤儿受体CAR也存在于相同的富集组分中。在苯巴比妥处理的小鼠中，Car和RXR的结合在诱导CYP2B10mRNA之前迅速增加。在体外翻译的CAR与NR1结合，但只有在类似制备的RXR存在的情况下，当NR1位点起作用时，CAR和RXR在HepG2和HEK293细胞中的转染可以协同激活PBREM。因此，CAR-RXR异源二聚体被认为是苯巴比妥诱导的Cyp2b10基因的反式作用因子。
PBREM, the phenobarbital-responsive enhancer module of the cytochrome P-450 Cyp2b10 gene, contains two potential nuclear receptor binding sites, NR1 and NR2. Consistent with the finding that anti-retinoid X receptor (RXR) could supershift the NR1-nuclear protein complex, DNA affinity chromatography with NR1 oligonucleotides enriched the nuclear orphan receptor RXR from the hepatic nuclear extracts of phenobarbital-treated mice. In addition to RXR, the nuclear orphan receptor CAR was present in the same enriched fraction. Ln the phenobarbital-treated mice, the binding of both CAR and RXR was rapidly increased before the induction of CYP2B10 mRNA. In vitro-translated CAR bound to NR1, but only in the presence of similarly prepared RXR, PBREM was synergistically activated by transfection of CAR and RXR in HepG2 and HEK293 cells when the NR1 site was functional. A CAR-RXR heterodimer has thus been characterized as a tans-acting factor for the phenobarbital-inducible Cyp2b10 gene.