Identification and functional analysis of two novel connexin 50 mutations associated with autosome dominant congenital cataracts.
Identification and functional analysis of two novel connexin 50 mutations associated with autosome dominant congenital cataracts.
复制标题
与常染色体显性先天性白内障相关的两种新型连接蛋白 50 突变的鉴定和功能分析
DOI：
10.1038/srep26551
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发表时间：
2016-05-24
影响因子：
4.6
通讯作者：
Yao K
中科院分区：
文献类型：
--
作者：
Yu Y;Wu M;Chen X;Zhu Y;Gong X;Yao K
常染色体显性遗传性先天性白内障（ADCC）是一种临床和遗传异质性疾病。本研究招募了两个具有双侧核性白内障或悬韧带粉化表型的中国家系。候选基因的直接测序鉴定了Cx50的两个新的错义突变，Cx50P59A（c.175C > G）和Cx50R76H（c.227G > A），两者与所有受影响的个体共分离良好。生物信息学分析预测这两种突变都是有害的。通过稳定转染重组系统检测野生型和突变型Cx50的功能和细胞行为，显示出相似的蛋白表达水平。荧光显微镜下的蛋白质分布模式显示，Cx50R76 H定位在并置膜形成巨大的细胞质蛋白质积累的间隙连接，而Cx50P59A突变被发现在形成可检测的斑块效率低下。MTT法检测细胞生长，结果显示Cx50P59A的诱导作用降低了细胞活力。本研究首次报道了Cx50 P59 A和Cx50 R76 H突变与ADCC相关，并扩展了Cx50与先天性白内障相关的突变谱。遗传、细胞和功能数据表明，由突变的Cx50蛋白控制的细胞间通讯的改变可能是ADCC的分子机制，这进一步证实了Cx50在维持人类透镜透明度中的作用。
Autosomal dominant congenital cataracts (ADCC) are clinically and genetically heterogeneous diseases. The present study recruited two Chinese families with bilateral nuclear cataract or zonular pulverulent phenotype. Direct sequencing of candidate genes identified two novel missense mutations of Cx50, Cx50P59A (c.175C > G) and Cx50R76H (c.227G > A), both co-segregated well with all affected individuals. Bioinformatics analysis predicted deleterious for both mutations. Functional and cellular behaviors of wild type and mutant Cx50 examined by stably transfecting recombinant systems revealed similar protein expression levels. Protein distribution pattern by fluorescence microscopy showed that Cx50R76H localized at appositional membranes forming gap junctions with enormous cytoplasmic protein accumulation, whereas the Cx50P59A mutation was found inefficient at forming detectable plaques. Cell growth test by MTT assay showed that induction of Cx50P59A decreased cell viability. Our study constitutes the first report that the Cx50P59A and Cx50R76H mutations are associated with ADCC and expands the mutation spectrum of Cx50 in association with congenital cataracts. The genetic, cellular, and functional data suggest that the altered intercellular communication governed by mutated Cx50 proteins may act as the molecular mechanism underlying ADCC, which further confirms the role of Cx50 in the maintenance of human lens transparency.