1例Alagille综合征患儿JAG1基因筛查及突变功能分析  

JAG1 gene screening and mutation function analysis for an Alagille syndrome patient

作　　者：张尔格 徐月娟[1] 陈笋[1] 徐让[2] 孙锟[1] 

机构地区：[1]上海交通大学医学院附属新华医院小儿心血管科,上海200092 [2]上海交通大学医学院附属新华医院科研中心,上海200092

出　　处：《上海交通大学学报（医学版）》2016年第11期1599-1604,共6页Journal of Shanghai Jiao tong University:Medical Science

基　　金：国家重点基础研究发展计划(2010CB529501);国家自然科学基金(81300068;81270233);上海市科委重点基础研究项目(13JC1401705)~~

摘　　要：目的·对1例Alagille综合征患儿进行JAG1基因筛查及突变功能分析。方法·收集患儿及其父母的临床资料及辅助检查结果,抽提DNA进行JAG1基因突变筛查。构建JAG1野生型及突变型表达质粒,转染NIH-3T3细胞,通过real-time RT-PCR、Western blotting分析突变体mRNA和蛋白的表达量;糖苷内切酶H消化实验分析蛋白糖基化结构;RBP-Jκ荧光素酶报告基因检测突变体蛋白对Notch信号通路转录因子RBP-Jκ的激活作用。结果·在患儿及其父亲中发现1个未报道过的JAG1错义突变c.1655C>T(p.Pro552Leu),该突变在患儿母亲及对照健康儿童中未发现。与野生型相比,突变型JAG1在mRNA、蛋白表达量上无明显改变,翻译后糖苷化修饰正常,但突变蛋白对Notch信号通路转录因子RBP-Jκ的激活作用减弱。结论·该患儿携带的JAG1错义突变使JAG1蛋白功能受损,可能是Alagille综合征的致病原因。Objective · To perform JAG1 gene screening and mutation function analysis for an Alagille syndrome patient. Methods · Clinical data and auxiliary examination results of the patient and his parents were collected. Genomic DNA was extracted for JAG1 mutation screening. Vectors with wild-type and mutant JAG1 expressions were constructed and transfected into NIH-3T3 cells. mRNA and protein expression levels were analyzed with real-time RT-PCR and Western blotting. Endoglycosidase H digestion experiment was performed to analyze the glycosylational structure. The effect of JAG1 protein on activating the transcription factor RBP-Jκ in Notch signaling pathway was detected with RBP-Jκ luciferase reporter gene assay. Results · A novel missense mutation c.1655C〉T （p.Pro552Leu） was detected in the patient and his father, but was not found in his mother or healthy controls. Wild-type and mutant JAG1 had no difference in mRNA or protein expression levels. Post-translational glycosylational structure of the mutant JAG1 was the same as wild-type JAG1. However, the effect of activating the transcription factor RBP-Jκ in Notch signaling pathway was reduced in mutant JAG1 than in wild-type JAG1. Conclusion · The JAG1 missense mutation carried by the patient results in impaired function of JAG1, which may be the cause of Alagille syndrome.

关 键 词：ALAGILLE综合征 JAG1 错义突变 NOTCH信号通路 

分 类 号：R725.9[医药卫生—儿科]