Cloning of rat cytochrome P450RAI (CYP26) cDNA and regulation of its gene expression by all-trans-retinoic acid in vivo
Cloning of rat cytochrome P450RAI (CYP26) cDNA and regulation of its gene expression by all-trans-retinoic acid in vivo
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DOI：
10.1016/s0003-9861(02)00043-7
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发表时间：
2002-05-15
影响因子：
3.9
通讯作者：
Ross, AC
中科院分区：
文献类型：
--
作者：
Wang, YP;Zolfaghari, R;Ross, AC
从人、斑马鱼和小鼠中克隆的维甲酸(RA)诱导的细胞色素P450(P450 RAI或CyP26)在全反式维甲酸代谢为4-羟基-维甲酸和4-氧代维甲酸的过程中起作用。为了进一步研究细胞色素P26在大鼠模型中的作用，我们首先克隆了大鼠的细胞色素P26基因。该核苷酸序列预测了一个由497个氨基酸组成的蛋白质，其序列与小鼠有95%的同源性，与人的CYP26有91%的同源性。动物研究表明，与配对喂养的维生素A充足的大鼠(定义为0.008)相比，缺乏维生素A的大鼠的CYP26mRNA的表达非常低(0.0%+/-0.05%；P<；0.05)。在动力学研究中，维生素A缺乏的大鼠给予全反式维甲酸(All-tran-RA)的∼100μg治疗，3-72 h后取肝脏，用实时定量聚合酶链式反应(Real-time PCR法)分析其基因表达。肝脏细胞色素P26mRNA在3h后增加到对照组的近10倍(P<；0.001)，在10h左右达到峰值，约为对照组的2000倍(P<；0.01)，然后迅速下降。细胞色素P26对RA的剂量响应接近线性(R2=0.9638)。此外，在维生素A缺乏、对照和RA处理的条件下，在肺、睾丸和小肠中观察到明显的CYP26基因表达的调节。我们的结论是，在体内，肝脏和肝外组织中细胞色素P26基因的表达受饮食和维甲酸的动态调节。在维甲酸缺乏的情况下，CYP26的长期下调可能是保存RA的关键，而CYP26的急剧上调可能对于防止饮食或外源性来源的RA有害过度可能是重要的。(C)2002年埃尔塞维尔科学公司(美国)。版权所有。
A novel retinoic acid (RA)-inducible cytochrome P450 (P450 RAI or CYP26), previously cloned from human, zebra fish, and mouse, functions in the metabolism of all-trans-RA to polar metabolites including 4-hydroxy-RA and 4-oxo-RA. To further study CYP26 in the rat model, we first cloned rat CYP26 cDNA. The nucleotide sequence predicts a 497-amino-acid protein whose sequence is 95% identical to mouse and 91% homologous to human CYP26. Animal studies showed that CYP26 mRNA expression is very low (0.0 +/- 0.008; P < 0.05) in vitamin-A-deficient rats compared to pair-fed vitamin-A-sufficient rats (defined as 1.0). In a kinetic study, vitamin-A-deficient rats were treated with ∼ 100 μg of all-trans-RA and liver was collected after 3-72 h for analysis of CYP26 mRNA by quantitative real-time PCR. Liver CYP26 mRNA increased to nearly 10-fold above control after 3 h (P < 0.0 1), reaching a peak of about 2000-fold greater around 10 h (P < 0.001) and then decreased rapidly. The CYP26 dose response to RA was nearly linear (R-2 = 0.9638). Additionally, significant regulation of CYP26 gene expression was observed in the vitamin-A-deficient, control, and RA-treated condition in lung, testis, and small intestine. We conclude that CYP26 mRNA expression is dynamically regulated in vivo by diet and RA in hepatic and extrahepatic tissues. The long-term down-regulation of CYP26 in retinoid deficiency may be critical for conserving RA, while the acute up-regulation of CYP26 may be important for preventing a deleterious overshoot of RA derived from either dietary or exogenous sources. (C) 2002 Elsevier Science (USA). All rights reserved.