Characterization of the human SLC30A8 promoter and intronic enhancer.
Characterization of the human SLC30A8 promoter and intronic enhancer.
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DOI：
10.1530/jme-11-0055
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发表时间：
2011-12
影响因子：
3.5
通讯作者：
O'Brien RM
中科院分区：
文献类型：
--
作者：
Pound LD;Sarkar SA;Cauchi S;Wang Y;Oeser JK;Lee CE;Froguel P;Hutton JC;O'Brien RM
全基因组关联（GWA）研究表明，编码锌转运蛋白-8（ZnT-8）的SLC 30 A8的多态性变体与2型糖尿病（T2 D）易感性的改变相关。这种关联与从Slc 30 a8敲除小鼠分离的胰岛中葡萄糖刺激的胰岛素分泌减少的观察结果一致。在本研究中，首次使用免疫组织化学染色来显示SLC 30 A8在胰岛中特异性表达。融合基因的研究，然后用于检查的SLC 30 A8的胰岛特异性表达的分子基础。对βTC-3细胞中SLC 30 A8荧光素酶表达的分析显示，相对于翻译起始位点，位于−6154和−1之间的近端启动子区域仅在稳定转染中有活性，而在瞬时转染中没有活性。VISTA分析鉴定了SLC 30 A8启动子中的三个区域和SLC 30 A8内含子2中的一个区域，其在小鼠Slc 30 a8基因中是保守的。另外的融合基因实验表明，当与异源启动子连接时，这些Slc 30 a8启动子区域均未表现出增强子活性，而SLC 30 A8内含子2中的保守区域选择性地在βTC-3而不是αTC-6细胞中赋予升高的报告基因表达。最后，单核苷酸多态性（SNP），rs62510556，在这个保守的内含子2增强子的功能影响进行了研究。凝胶阻滞研究表明，rs62510556影响一个未知的转录因子的结合和融合基因的分析表明，它调节增强子的活性。然而，遗传分析表明，这种SNP不是导致SLC 30 A8和T2 D之间关联的因果变异，至少在欧洲人中是这样。
Genome-wide association (GWA) studies have shown that a polymorphic variant in SLC30A8, which encodes zinc transporter-8 (ZnT-8), is associated with altered susceptibility to type 2 diabetes (T2D). This association is consistent with the observation that glucose-stimulated insulin secretion is decreased in islets isolated from Slc30a8 knockout mice. In the present study immunohistochemical staining was first used to show that SLC30A8 is expressed specifically in pancreatic islets. Fusion gene studies were then used to examine the molecular basis for the islet-specific expression of SLC30A8. The analysis of SLC30A8-luciferase expression in βTC-3 cells revealed that the proximal promoter region, located between −6154 and −1, relative to the translation start site, was only active in stable but not transient transfections. VISTA analyses identified three regions in the SLC30A8 promoter and a region in SLC30A8 intron 2 that are conserved in the mouse Slc30a8 gene. Additional fusion gene experiments demonstrated that none of these Slc30a8 promoter regions exhibited enhancer activity when ligated to a heterologous promoter whereas the conserved region in SLC30A8 intron 2 conferred elevated reporter gene expression selectively in βTC-3 but not αTC-6 cells. Finally, the functional effects of a single nucleotide polymorphism (SNP), rs62510556, in this conserved intron 2 enhancer were investigated. Gel retardation studies showed that rs62510556 affects the binding of an unknown transcription factor and fusion gene analyses showed that it modulates enhancer activity. However genetic analyses suggest that this SNP is not a causal variant that contributes to the association between SLC30A8 and T2D, at least in Europeans.