良性家族性婴儿惊厥KCNQ2基因G271V突变体钾通道的功能研究  

The Function of Potassium Channel in KCNQ2 G271V Mutants of Benign Familial Neonatal Convulsions

作　　者：惠智艳[1] 张旭 孙红梅[1] 周熙惠 HUI Zhi-yan;ZHANG Xu;SUN Hong-mei;ZHOU Xi-hui(Department of Critical Care Medicine,Yan＇an University Affiliated Hospital,Yan＇an 716000,China;Department of Neonatology,First Affiliated Hospital of Xi＇an Jiaotong University,Xi＇an 710061,China)

机构地区：[1]延安大学附属医院重症医学科,延安716000 [2]西安交通大学第一附属医院新生儿科,西安710061

出　　处：《四川大学学报（医学版）》2018年第6期876-880,共5页Journal of Sichuan University(Medical Sciences)

摘　　要：目的观察良性家族性婴儿惊厥相关基因KCNQ2突变体G271V的钾通道的功能,进一步探讨KCNQ2基因G271V突变的致病机理。方法将前期成功构建的突变体G271V或和Kv7.2及Kv7.3的真核表达载体转染进真核表达细胞(HEK293细胞),利用全细胞膜片钳技术检测G271V突变体的钾通道功能。结果转染HEK293细胞后,G271V突变体无电流产生,与野生型相比,激活电流明显下降,诱导电压门控去极化改变。G271V的最大激活电流密度为(2.47±0.41)pA/pF(n=12),Kv7.2的最大激活电流密度为(20.53±2.51)pA/pF(n=10),差异有统计学意义(P<0.001)。同时,突变体可以消除同源通道的电流改变,Kv7.2/Kv7.3的最大激活电流密度为(123.68±15.21)pA/pF(n=15),Kv7.2/G271V/Kv7.3的最大激活电流密度为(42.71±6.27)pA/pF(n=10),而G271V/Kv7.3的最大激活电流密度为(3.74±0.76)pA/pF(n=10),差异有统计学意义(P<0.05),突变体引起Kv7.2/G271V/Kv7.3异源通道电流减少约50%。结论 G271V突变体不能使钾通道开放去极化钾电流,突变体引起钾通道功能缺陷。Objective To determine the function of potassium channel in KCNQ2 G271V mutants of benign familial neonatal convulsions. Methods HEK293 cells were transfected with pcDNA3-WT-KCNQ2 and / or pcDNA3-G271V-KCNQ2 and pcDNA3-WT-KCNQ3. The potassium channel function of G271V mutants was assessed using the whole cell patch clamp technique. Results G271V mutants did not show currents in the transfected HEK cells, inducing large depolarizing shift of the conductance voltage relationship and slowing down the current activation kinetics. The required current density was （2.47±0.41） pA/pF （n=12） for the expression of G271V, and whereas （20.53±2.51） pA/pF （n=10,P〈0.001） for Kv7.2. G271V mutants abolished currents in the homomeric channel. Kv7.2/Kv7.3 induced robust current was （123.68±15.21） pA/pF （n=15） and Kv7.2/G271V/Kv7.3 （42.71±6.27） pA/pF （n=10）, G271V/Kv7.3 induced almost no current （3.74±0.76） pA/pF （n=10,P〈0.05）, resulting in about 50% reduction of currents in Kv7.2/G271V/Kv7.3 in the heteromultimeric condition. Conclusion The G271V channel fails to open potassium currents in response to depolarization, indicating a more severe functional defect of the Kv7 potassium channel.

关 键 词：癫痫 KCNQ2 Kv7.2 电压门控钾通道 膜片钳电生理技术 

分 类 号：R720.597[医药卫生—急诊医学]