Activating mutations in the KCNJ5 gene are responsible for the significant number of aldosterone-producing adenomas. To elucidate the molecular mechanisms underlying KCNJ5 expression, we characterized the entire human KCNJ5 gene. The gene spanned approximately 29.8 kb and contained three exons and two introns. The strongest expression of KCNJ5 mRNA was observed in the adrenal gland. The promoter region contained a putative binding site for SF-1 at -1782 bp. A construct containing -2444 bp of the promoter region exhibited the strongest promoter activity in adrenal H295R cells, and the introduction of a mutation in the SF-1 binding site almost completely abolished promoter activity. Furthermore, deletion mutation, EMSA, and knockdown analyses revealed that SF-1 bound to this element and was functional. Immunochemistry showed that KCNJ5 was predominantly expressed in the zona glomerulosa, while SF-1 was ubiquitously expressed in the adrenal cortex. These results demonstrated that SF-1 mediates the expression of human KCNJ5 in the adrenal cortex.

中文翻译：

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SF-1在肾上腺皮质中对KCNJ5基因的调控：完整的基因组组织和启动子功能。

KCNJ5基因中的活化突变是导致大量醛固酮生成腺瘤的原因。为了阐明潜在的KCNJ5表达的分子机制，我们表征了整个人类KCNJ5基因。该基因跨度约为29.8 kb，包含三个外显子和两个内含子。在肾上腺中观察到KCNJ5 mRNA的最强表达。启动子区域在-1782 bp处含有一个假定的SF-1结合位点。含有-2444 bp启动子区域的构建体在肾上腺H295R细胞中表现出最强的启动子活性，并且在SF-1结合位点引入突变几乎完全消除了启动子活性。此外，删除突变，EMSA和击倒分析表明SF-1绑定到此元素，并具有功能。免疫化学表明，KCNJ5主要在肾小球带中表达，而SF-1在肾上腺皮质中普遍表达。这些结果证明SF-1介导人KCNJ5在肾上腺皮质中的表达。