Zhuang Xiaotong, Wang Lianqing, Song Zixun, Xiao Wei
Department of Ophthalmology, Shengjing Hospital, China Medical University, Shenyang, China; Department of Ophthalmology, The Fourth People's Hospital of Shenyang, Shenyang, China.
Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China; Central Laboratory, Central Hospital of Zibo, Zibo, China.
PLoS One. 2015 Jul 6;10(7):e0131471. doi: 10.1371/journal.pone.0131471. eCollection 2015.
To investigate a novel insertion variant of CRYGD identified in a Chinese family with nuclear congenital cataract.
A Chinese family with congenital nuclear cataract was recruited for the mutational screening of candidate genes by direct sequencing. Recombinant N-terminal Myc tagged wildtype or mutant CRYGD was expressed in HEK293T cells. The expression pattern, protein solubility and subcellular distribution were analyzed by western blotting and immunofluorescence.
A novel insertion variant, c.451_452insGACT, in CRYGD was identified in the patients. It causes a frameshift and a premature termination of the polypeptide to become Y151*. A significantly reduced solubility was observed for this mutant. Unlike wildtype CRYGD, which existed mainly in the cytoplasm, Y151* was mis-located in the nucleus.
We have identified a novel mutation, c.451_452insGACT, in CRYGD, which is associated with nuclear cataract. This is the first insertion mutation of CRYGD found to cause autosomal dominant congenital cataract. The mutant protein, with loss of solubility and localization to the nucleus, is hypothesized to be the major cause of cataract in these patients.
研究在中国一个患有核性先天性白内障的家族中鉴定出的CRYGD基因的一种新型插入变异。
招募一个患有先天性核性白内障的中国家族，通过直接测序对候选基因进行突变筛查。将重组N端Myc标记的野生型或突变型CRYGD在HEK293T细胞中表达。通过蛋白质印迹和免疫荧光分析其表达模式、蛋白质溶解性和亚细胞分布。
在患者中鉴定出CRYGD基因的一种新型插入变异，即c.451_452insGACT。它导致移码突变，使多肽提前终止为Y151*。观察到该突变体的溶解性显著降低。与主要存在于细胞质中的野生型CRYGD不同，Y151*错误定位于细胞核。
我们在CRYGD基因中鉴定出一种新型突变c.451_452insGACT，其与核性白内障相关。这是首次发现CRYGD基因的插入突变导致常染色体显性先天性白内障。推测突变蛋白溶解性丧失且定位于细胞核是这些患者患白内障的主要原因。
