Sp1, Instead of AhR, Regulates the Basal Transcription of Porcine CYP1A1 at the Proximal Promoter.
Sp1, Instead of AhR, Regulates the Basal Transcription of Porcine CYP1A1 at the Proximal Promoter.
复制标题
DOI：
10.3389/fphar.2018.00927
复制
发表时间：
2018
影响因子：
5.6
通讯作者：
Wen J
中科院分区：
文献类型：
--
作者：
Xie X;Jiang J;Ye W;Chen R;Deng Y;Wen J
猪通常被用作动物模型来评估外源性化合物的毒性作用。细胞色素P450 1A1 （CYP1A1）代谢多种外源性化合物，在肝脏、肾脏和肠道中大量表达。人与猪CYP1A1氨基酸的高度相似性表明它们可能具有相同的代谢特征。因此，了解猪体内CYP1A1表达的调控机制对于预测外源化学物质的毒理学和代谢动力学尤为重要。目前，关于猪CYP1A1的转录调控的研究很少，特别是关于基础转录的研究。在这项研究中，我们首先在猪肾细胞系LLC-PK1中通过双荧光素酶测定，利用启动子截断分析，证实了猪CYP1A1基础转激活的关键调控元件位于近端启动子区域。两个重叠的顺式元件，异种反应元件（XRE）和GC盒，在这个近端区域可能在猪CYP1A1的基础转激活中起关键作用。此外，通过电泳迁移率转移试验和染色质免疫沉淀，证实GC盒结合蛋白Sp1与猪CYP1A1的近端启动子结合，而不是XRE结合蛋白AhR。在LLC-PK1细胞中，通过敲低Sp1或AhR，在mRNA水平和蛋白水平上显著下调猪CYP1A1的表达，表明这两种蛋白对猪CYP1A1的表达都很重要。然而，用AhR激动剂和拮抗剂处理的LLC-PK1细胞的启动子活性分析证实，AhR不参与猪CYP1A1近端启动子的基础调控。总之，我们的研究表明，近端启动子是猪CYP1A1基础表达的关键调控区域。虽然AhR在猪CYP1A1表达的反激活中起着重要作用，但其基础反激活的关键决定性转录因子是猪CYP1A1近端启动子上的Sp1。
Pigs are commonly used as an animal model to evaluate the toxic effects of exogenous compounds. Cytochrome P450 1A1 (CYP1A1) metabolizes numerous exogenous compounds and is abundantly expressed in the liver, kidneys, and intestines. The high amino acid similarity between human and porcine CYP1A1 indicates that they probably have the same metabolic characteristics. Therefore, understanding the regulatory mechanism of CYP1A1 expression in pigs is particularly important for predicting the toxicology and metabolic kinetics of exogenous chemicals. Currently, the transcriptional regulation of porcine CYP1A1 has rarely been studied, especially regarding basal transcription. In this study, we first confirmed that the key regulatory elements of porcine CYP1A1 basal transactivation are in the proximal promoter region using promoter truncation analysis via a dual luciferase assay in a porcine kidney cell line LLC-PK1. Two overlapping cis-elements, the xenobiotic response element (XRE) and GC box, in this proximal region potentially play key roles in the basal transactivation of porcine CYP1A1. Furthermore, using electrophoretic mobility shift assay and chromatin immunoprecipitation, the GC box binding protein Sp1 was confirmed to bind to the proximal promoter of porcine CYP1A1, instead of AhR, the XRE binding protein. In LLC-PK1 cells, by knocking down either Sp1 or AhR, the expression of porcine CYP1A1 at the mRNA level and protein level was significantly downregulated, suggesting both proteins are important for porcine CYP1A1 expression. However, promoter activity analysis in LLC-PK1 cells treated with an AhR agonist and antagonist confirmed that AhR does not participate in the basal regulation of porcine CYP1A1 at the proximal promoter. In conclusion, our study revealed that the proximal promoter is the key regulatory region for porcine CYP1A1 basal expression. Although AhR plays an important role in the transactivation of porcine CYP1A1 expression, the key determinant transcription factor for its basal transactivation is Sp1 at the proximal promoter of porcine CYP1A1.
登录
查看更多内容
影响因子：
4.8
作者：
Ma, Q;Renzelli, AJ;Antonini, JM
通讯作者：
Antonini, JM
影响因子：
3.8
作者：
Hombach-Klonisch, S;Pocar, P;Klonisch, T
通讯作者：
Klonisch, T
影响因子：
2.1
作者：
Kojima, Misaki;Degawa, Masakuni
通讯作者：
Degawa, Masakuni
DOI：
10.1006/bbrc.2001.5352
发表时间：
2001-08-10
影响因子：
3.1
作者：
Iwano, S;Saito, T;Kamataki, T
通讯作者：
Kamataki, T
影响因子：
7.3
作者：
GUENGERICH, FP;BRIAN, WR;BERNTSSON, P
通讯作者：
BERNTSSON, P