Characterization of Human OATP2B1 (SLCO2B1) Gene Promoter Regulation
Characterization of Human OATP2B1 (SLCO2B1) Gene Promoter Regulation
复制标题
DOI：
10.1007/s11095-006-9572-6
复制
发表时间：
2006-02
影响因子：
3.7
通讯作者：
Tomoji Maeda;M. Hirayama;Ryunosuke Higashi;Masanobu Sato;I. Tamai
中科院分区：
文献类型：
--
作者：
Tomoji Maeda;M. Hirayama;Ryunosuke Higashi;Masanobu Sato;I. Tamai
目的研究有机阴离子转运蛋白OATP2B1(SLCO2B1)在肝脏、小肠等多种组织中的转录调控，并与肝脏特异性转运蛋白进行比较。方法用荧光素酶活性测定法检测其启动子活性。结果OATP2B1启动子区域的缺失突变研究表明，含有Sp1结合位点的−59区域具有基本的启动子活性，而其上游区域的启动子活性在肠源性细胞和肝源性细胞中有所不同。凝胶漂移实验和培养细胞中Sp1的过表达证实了Sp1与启动子区域的结合。虽然OATP2B1的启动子有一个可能的HNF1α结合位点，但HNF1α的过表达并未诱导OATP2B1的表达。结论肝脏和小肠中OATP2B1的组成性表达需要转录因子Sp1，而参与肝脏特异性OATP表达的HNF1α似乎不参与OATP2B1的表达。因此，我们认为OATP2B1的组织表达谱不同于其他肝脏特异的OATP。
PurposeWe investigated transcriptional regulation of organic anion transporter OATP2B1 (SLCO2B1) that is expressed in multiple tissues such as liver, small intestine, and others and compared it with that of liver-specific OATPs.MethodsThe promoter activity was examined by luciferase assay. Specific bindings of transcription factors to the promoter region were examined by gel mobility shift assay using native and mutated nucleotides of the promoter region of OATP2B1.ResultsDeletion–mutation study of the promoter region of OATP2B1 showed that the −59 region that included the Sp1 binding site had basal promoter activity, whereas promoter activities of the further upper region were different between intestine-derived Caco-2 cells and liver-derived HepG2 cells. The association of Sp1 to the promoter region was confirmed by gel shift assay and overexpression of Sp1 in cultured cells. Although the promoter of OATP2B1 has a putative HNF1α binding site, overexpression of HNF1α did not induce the expression of OATP2B1.ConclusionSp1, a transcription factor, was required for constitutive expression of OATP2B1 in liver and small intestine, whereas HNF1α, which is involved in the expression of liver-specific OATPs, did not seem to play a role in OATP2B1 expression. Accordingly, it was suggested that the tissue expression profile of OATP2B1 was different from that of other liver-specific OATPs.