摘要
目的研究HERG基因Y475C突变的致病机制。方法利用DNA定点突变技术构建Y475C表达载体,脂质体介导法转染人胚胎肾细胞进行表达。转染后48h用膜片钳技术记录KCNH2(亦称HERG)通道电流变化情况,明确Y475C突变导致2型长QT综合征的机制。结果电生理学研究显示与野生型通道电流相比,Y475C突变单独或与等量野生型质粒共转染时电流密度均显著降低,并且通道激活特征,包括V1/2(半激活电压)和K斜率因子也有显著改变。Y475C对通道失活特征无显著影响。结论Y475C突变通过负显性抑制效应以及通道门控特性的改变导致该基因编码的快速激活延迟整流钾电流显著降低是引起患者QT间期延长的机制。
Objective To investigate the molecular pathogenesis for a novel mutation Y475C found in Chinese patients. Methods The Y475C mutant construct was generated by site-directed mutagenesis using human wild-type（WT） pcD-NA3-HERG cDNA as a template. WT and mutant construct were transiently transfected into human embryonic kidney 293 cells using an effective method. After transfection, the recording of HERG current was performed using the patch clamp technique. Results Electrophysiological recordings showed that when the Y475C mutation was transfected or co-transfected with WT, the HERG current density was significantly reduced . Moreover, HERG channel activation characteristics for WT, Y475C ,Y475C-WT were significantly different. Y475C mutation had no effect on HERG channel inactivation. Conclusions The Y475C mutation results in significantly reduced HERG current through dominant negative suppression and changes of channel gating characteristics.
出处
《中国心脏起搏与心电生理杂志》
2007年第4期300-303,共4页
Chinese Journal of Cardiac Pacing and Electrophysiology
基金
国家自然科学基金资助项目(项目编号:30170381)
北京市科技新星计划资助项目(项目编号:2004-BG-01)
国家985工程资助项目(项目编号:985-2-034-24)
