Exonic Mutations in the SLC12A3 Gene Cause Exon Skipping and Premature Termination in Gitelman Syndrome
Exonic Mutations in the SLC12A3 Gene Cause Exon Skipping and Premature Termination in Gitelman Syndrome
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DOI：
10.1681/asn.2013091013
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发表时间：
2015-02-01
影响因子：
13.6
通讯作者：
Abe, Takaaki
中科院分区：
文献类型：
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作者：
Takeuchi, Yoichi;Mishima, Eikan;Abe, Takaaki
多种遗传背景导致SLC12A3编码的噻嗪敏感性氯化钠协同转运蛋白功能丧失，该转运蛋白负责Gitelman综合征的表型。最近，外显子跳跃现象，其中外显子突变导致异常剪接，已经与各种疾病相关。具体地，外显子剪接增强子（ESE）序列中的突变可以促进外显子跳跃。在这里，我们使用生物信息学程序来分析SLC12A3基因中的88个错义突变，并确定可能诱导外显子跳跃的候选突变。通过微基因分析进一步研究了降低ESE评分最多的三个候选突变，其中两个（p.A356V和p.M672I）在体外引起异常剪接。此外，我们在Gitelman综合征患者中鉴定了p.M672I（c.2016G>A）突变，并发现该单核苷酸突变导致SLC12A3 mRNA转录物中外显子16的排除。功能分析显示，异常SLC12A3转录本编码的蛋白质不转运钠。这些结果表明，异常外显子跳跃是一种以前未被认识到的机制，SLC12A3的错义突变可导致Gitelman综合征。
A variety of genetic backgrounds cause the loss of function of thiazide-sensitive sodium chloride co-transporter, encoded by SLC12A3, responsible for the phenotypes in Gitelman syndrome. Recently, the phenomenon of exon skipping, in which exonic mutations result in abnormal splicing, has been associated with various diseases. Specifically, mutations in exonic splicing enhancer (ESE) sequences can promote exon skipping. Here, we used a bioinformatics program to analyze 88 missense mutations in the SLC12A3 gene and identify candidate mutations that may induce exon skipping. The three candidate mutations that reduced ESE scores the most were further investigated by minigene assay, and two (p.A356V and p.M672I) caused abnormal splicing in vitro. Furthermore, we identified the p.M672I (c.2016G>A) mutation in a patient with Gitelman syndrome and found that this single nucleotide mutation causes exclusion of exon 16 in the SLC12A3 mRNA transcript. Functional analyses revealed that the protein encoded by the aberrant SLC12A3 transcript does not transport sodium. These results suggest that aberrant exon skipping is one previously unrecognized mechanism by which missense mutations in SLC12A3 can lead to Gitelman syndrome.