Novel single nucleotide polymorphisms in the promoter and intron 1 of human pregnane X receptor/NR1l2 and their association with CYP3A4 expression
Novel single nucleotide polymorphisms in the promoter and intron 1 of human pregnane X receptor/NR1l2 and their association with CYP3A4 expression
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DOI：
10.1124/dmd.107.016600
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发表时间：
2008-01-01
影响因子：
3.9
通讯作者：
Schuetz, Erin
中科院分区：
文献类型：
--
作者：
Lamba, Jatinder;Lamba, Vishal;Schuetz, Erin
这一假设得到了验证，即妊娠X受体（PXR）顺式调控区域的序列多样性是诱导型和构成型CYP3A4表达变异的重要决定因素。采用比较基因组学和计算算法相结合的方法，选择人类PXR启动子和内含子1的区域，在多态性发现资源24 DNA子集中进行重测序。然后在供体人肝脏中对PXR单核苷酸多态性（SNP）进行基因分型，对CYP3A4和多药耐药蛋白1 mRNA进行表型分析，并对原代人肝细胞进行基础和利福平诱导的CYP3A4活性表型分析。人类PXR启动子[16.9千碱基（kb）]明显大于啮齿动物（2.9 kb）。在PXR的启动子和内含子1中鉴定出89个snp。与CYP3A4表型测量最一致的SNP是44477T b> C（-1359）启动子SNP（与内含子1a中6个碱基对缺失的SNP 463970和内含子1b中C核苷酸插入的SNP 46551存在连锁不平衡）；内含子1中的SNP 63396C> T(与SNP 63704A> G、63813（CAAA)（CA）可变重复和SNP 65104T> C存在连锁不平衡）；以及SNP 56348C> A、SNP 69789A> G和SNP 66034T> c。与携带PXR野生型等位基因的肝脏相比，携带变异PXR等位基因的供体肝脏中PXR靶点的表达发生了改变。这些结果在供体肝脏和培养的肝细胞中发现了与PXR靶基因（CYP3A4）表达相关的PXR启动子和内含子1 snp，并且大量相关的内含子1 snp将影响与PXR表达相关的转录因子肝核因子3 β (FOXA2)的假定结合位点。
The hypothesis was tested that sequence diversity in pregnane X receptor (PXR) cis-regulatory regions is a significant determinant of variation in inducible and constitutive CYP3A4 expression. A combination of comparative genomics and computational algorithms was used to select regions of the human PXR promoter and intron 1 that were resequenced in the polymorphism discovery resource 24 DNA subset. PXR single nucleotide polymorphisms (SNP) were then genotyped in donor human livers phenotyped for CYP3A4 and multidrug resistance protein 1 mRNA and primary human hepatocytes phenotyped for basal and rifampin-inducible CYP3A4 activity. The human PXR promoter [16.9 kilobase (kb)] was significantly larger than in rodents (2.9 kb). Eighty-nine SNPs were identified in the promoter and intron 1 of PXR. The SNPs most consistently associated with CYP3A4 phenotypic measures were a 44477T> C (-1359) promoter SNP (in linkage disequilibrium with SNP 463970, a 6-base pair deletion in intron 1a, and SNP 46551, a C nucleotide insertion in intron 1b); SNP 63396C> T in intron 1 (in linkage disequilibrium with SNP 63704A> G, a 63813(CAAA)(CA) variable repeat, and SNP 65104T> C); and SNP 56348C> A, SNP 69789A> G, and SNP 66034T> C. Donor livers with the variant PXR alleles had altered hepatic expression of PXR targets compared with livers with PXR wild-type alleles. These results identified PXR promoter and intron 1 SNPs associated with PXR target gene expression (CYP3A4) in donor livers and cultured hepatocytes and that a striking number of the linked intron 1 SNPs will affect putative binding sites for hepatic nuclear factor 3 beta (FOXA2), a transcription factor linked with PXR expression.