Critical roles of Sp1 in gene expression of human and rat H+/organic cation antiporter MATE1
Critical roles of Sp1 in gene expression of human and rat H+/organic cation antiporter MATE1
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DOI：
10.1152/ajprenal.00322.2007
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发表时间：
2007-11-01
影响因子：
4.2
通讯作者：
Inui, Ken-Ichi
中科院分区：
文献类型：
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作者：
Kajiwara, Moto;Terada, Tomohiro;Inui, Ken-Ichi
H+/有机阳离子逆向转运蛋白(多药毒素排泄1：MATE1/SLC47A1)在多种临床上重要的阳离子药物如西咪替丁的肾小管分泌中起重要作用。我们最近发现，该转运蛋白的调节极大地影响了阳离子药物在体内的药代动力学特性。目前还没有关于MATE1基因调控机制的信息。因此，在目前的研究中，我们研究了人(H)和大鼠(R)MATE1的基因调控，重点是基础表达。缺失分析表明，-65/-25和-146/-38区域分别是hMATE1和rMATE1启动子基础转录活性所必需的，并且这两个区域都含有可能的Sp1结合位点。Sp1的过度表达、Sp1结合位点的突变分析、米曲霉素A处理和电泳迁移率改变分析证实了Sp1的功能参与。此外，我们还在hMATE1(G-32A)的启动子区域发现了一个单核苷酸多态性(SNP)，属于Sp1结合位点。该rSNP的等位基因频率为3.7%，Sp1结合活性和启动子活性显著降低。本研究首次阐明了MATE1基因的转录机制，并确定了影响hMATE1启动子活性的SNP。
A H+/organic cation antiporter (multidrug and toxin extrusion 1: MATE1/SLC47A1) plays important roles in the tubular secretion of various clinically important cationic drugs such as cimetidine. We have recently found that the regulation of this transporter greatly affects the pharmacokinetic properties of cationic drugs in vivo. No information is available about the regulatory mechanisms for the MATE1 gene. In the present study, therefore, we examined the gene regulation of human (h) and rat (r) MATE1, focusing on basal expression. A deletion analysis suggested that the regions spanning -65/-25 and -146/-38 were essential for the basal transcriptional activity of the hMATE1 and rMATE1 promoter, respectively, and that both regions contained putative Sp1-binding sites. Functional involvement of Sp1 was confirmed by Sp1 overexpression, a mutational analysis of Sp1-binding sites, mithramycin A treatment, and an electrophoretic mobility shift assay. Furthermore, we found a single nucleotide polymorphism (SNP) in the promoter region of hMATE1 (G-32A), which belongs to a Sp1-binding site. The allelic frequency of this rSNP was 3.7%, and Sp1-binding and promoter activity were significantly decreased. This is the first study to clarify the transcriptional mechanisms of the MATE1 gene and to identify a SNP affecting the promoter activity of hMATE1.