This study examined the current changes of human ether-a-go-go-related gene （hERG） mutation derived from a LQT2 Chinese family with a highly penetrating phenotype. Mutation was identi-fied and site-directed mutagene...This study examined the current changes of human ether-a-go-go-related gene （hERG） mutation derived from a LQT2 Chinese family with a highly penetrating phenotype. Mutation was identi-fied and site-directed mutagenesis was performed to induce the mutation in wild-type （WT） hERG. WT hERG and mutated V535M were cloned and transiently expressed in HEK293 cells. At the 48th and 72nd h after transfection, membrane currents were recorded using whole cell patch-clamp procedures. An A〉G transition at 1605 resulting in replacement of V535M was identified. Compared to WT, V535M mutation significantly decreased tail currents of hERG. At test potential of-40 mV after depolarizing at ＋50 mV, tail current densities were 83.354-7.06 pA/pF in WT and 50.38-4-7.74 pA/pF in V535M respectively （n=20, P〈0.01）. Gating kinetics of bERG revealed that Vl/2 of steady-state inactivation shifted to negative potential in the mutant （V1/2,v535M： -61.814-1.7 mV vs. V1/2, wx： -43.1q-0.71 mV）. The time constant of recovery from inactivation was markedly prolonged in the mutant compared to WT among test potentials. V535M hERG mutation demonstrated markedly decreased tail current densities, which suggests that V535M is a new loss-of-function mutation of hERG channel responsible for LQT2.展开更多
Objective To identify the mutation of human ether-a-go-go-related gene(hERG)and analyze the clinical characteristics of a Chinese family with long ST syndrome(LQTS).Methods The electrocardiogram and DNA samples were o...Objective To identify the mutation of human ether-a-go-go-related gene(hERG)and analyze the clinical characteristics of a Chinese family with long ST syndrome(LQTS).Methods The electrocardiogram and DNA samples were obtained from a Chinese LQTS family of 26 members.Genotype was performed with polymorphic short tandem repeat(STR)markers at the known LQT1,LQT2,and LQT3 loci.SSCP analysis was used to find aberrant conformers.hERG mutation was confirmed by cloning and sequencing.Results Three gene carriers were linked to chromosome 7q35-36,where the potassium channel gene hERG was encoded.A 19-base pair deletion was identified.The mutation was located at nucleotide position 1 619-1 637 between transmembrane domains S4 and S5.Furthermore,A1692G polymorphism was found both in the normal control and patients.Conclusion A novel 19 bp deletion mutation of hERG is identified in a Chinese family.All gene carriers are demonstrated to be typical LQT2 ECG phenotype.展开更多
Objective： To construct a human ether-a-go-go-related gene （HERG） nonsense mutant L539fs/47-558W into the autonomously fluorescent, eukaryotic expression vector pEGFP-C2, and to verify expression of the reconstruct...Objective： To construct a human ether-a-go-go-related gene （HERG） nonsense mutant L539fs/47-558W into the autonomously fluorescent, eukaryotic expression vector pEGFP-C2, and to verify expression of the reconstruct in human embryonic kidney-293 （HEK293） cells. Methods： The mutational fragment was subcloned into pEGFP-C2-HERG by double digestion of Sbf I, Eco91 1 and rejoining of T4 ligase. After verification, the recombinant pEGFP-C2-L539fs/47-558W and pEGFP-C2-HERG were respectively transfected into HEK293 cells for 48 h by the Lipofect method to observe the expression location of the fusion protein by laser confocal imaging scanning in vivo. pcDNA3 -L539fs/47-＊558W and pcDNA3-HERG were transfected to observe the expression location of the HERG protein by immunofluoresceoce. The mutant protein size was determined by Western blotting. Results： The about 1 kb-sized mutation region cDNA fragment from pcDNA3-L539fs/47-＊558Wand the about 7.2 kb-sized target vector fragment from pcDNA3-HERG were ligated after purification and gel recovery pEGFP-C2-L539fs/47＊-558W, approximately 8.2 kb, was demonstrated successfully been constructed under agarose gel electrophoresis and further sequencing. Laser confocal imaging showed that pEGFP-C2-HERG was mainly expressed in the membrane, whereas truncated mutant-type HERG in the pEGFP-C2 vector was partially located in the cytoplasm, the others were transported to the cell membrane in living HEK293 cells. The same as the immunofluoresceoce results after transfection of pcDNA3-HERG and pcDNA3-L539fs/47-558W. Wild-type HERG-GFP fusion protein expressed 160 and 180 kDa bands. The mutant and mutant-GFP fusion proteins were 70 and 100 kDa, respectively. Conclusion： pEGFP-C2-L539fs/47-＊558W was successfully constructed by double digestion method GFP had no effect on its protein expression and trafficking in HEK293 cells, which laid a foundation for the further study on L539fs/47-＊558W展开更多
目的探究ether-a-go-go相关基因(ether-a-go-go related gene,ERG)通道在胰岛β-细胞中的作用。方法提取野生型(wild type,WT)与ERG基因敲除型(knockout,KO)小鼠胰岛β-细胞,利用全细胞膜片钳技术记录钾离子电流与动作电位,分析敲除ERG...目的探究ether-a-go-go相关基因(ether-a-go-go related gene,ERG)通道在胰岛β-细胞中的作用。方法提取野生型(wild type,WT)与ERG基因敲除型(knockout,KO)小鼠胰岛β-细胞,利用全细胞膜片钳技术记录钾离子电流与动作电位,分析敲除ERG基因后钾电流与动作电位的变化。对两组小鼠进行腹腔注射葡萄糖耐量实验,分析基因敲除后小鼠糖耐量的变化,探究ERG基因是否对体内血糖浓度有影响。结果在两组小鼠胰岛β-细胞中记录到的钾离子电流均呈现内向整流趋势,KO组钾离子电流明显减小,动作电位时程明显延长。动物实验中,KO组小鼠糖刺激2 h后血糖浓度较WT组显著降低。结论 ERG通道电流是胰岛β-细胞中钾离子电流的重要组成部分,可显著影响动作电位时程,进而影响体内血糖浓度。展开更多
文摘This study examined the current changes of human ether-a-go-go-related gene （hERG） mutation derived from a LQT2 Chinese family with a highly penetrating phenotype. Mutation was identi-fied and site-directed mutagenesis was performed to induce the mutation in wild-type （WT） hERG. WT hERG and mutated V535M were cloned and transiently expressed in HEK293 cells. At the 48th and 72nd h after transfection, membrane currents were recorded using whole cell patch-clamp procedures. An A〉G transition at 1605 resulting in replacement of V535M was identified. Compared to WT, V535M mutation significantly decreased tail currents of hERG. At test potential of-40 mV after depolarizing at ＋50 mV, tail current densities were 83.354-7.06 pA/pF in WT and 50.38-4-7.74 pA/pF in V535M respectively （n=20, P〈0.01）. Gating kinetics of bERG revealed that Vl/2 of steady-state inactivation shifted to negative potential in the mutant （V1/2,v535M： -61.814-1.7 mV vs. V1/2, wx： -43.1q-0.71 mV）. The time constant of recovery from inactivation was markedly prolonged in the mutant compared to WT among test potentials. V535M hERG mutation demonstrated markedly decreased tail current densities, which suggests that V535M is a new loss-of-function mutation of hERG channel responsible for LQT2.
基金supported by the National Natural Science Foundation of China(No.30772155)the Natural Science Foundation of Zhejiang Province(No.Y206608)+3 种基金the Scientific and Technological Project of Zhejiang Province(No.2006C33038)Youth and Doctor Foundation of Ningbo(No.2005A610016)the Key Project of Ningbo City(No.2005C100004)the Zhejiang Provincial Program for the Cultivation of High-level Innovative Health Talents,and the Ningbo Program for the Health Technology Talents
文摘Objective To identify the mutation of human ether-a-go-go-related gene(hERG)and analyze the clinical characteristics of a Chinese family with long ST syndrome(LQTS).Methods The electrocardiogram and DNA samples were obtained from a Chinese LQTS family of 26 members.Genotype was performed with polymorphic short tandem repeat(STR)markers at the known LQT1,LQT2,and LQT3 loci.SSCP analysis was used to find aberrant conformers.hERG mutation was confirmed by cloning and sequencing.Results Three gene carriers were linked to chromosome 7q35-36,where the potassium channel gene hERG was encoded.A 19-base pair deletion was identified.The mutation was located at nucleotide position 1 619-1 637 between transmembrane domains S4 and S5.Furthermore,A1692G polymorphism was found both in the normal control and patients.Conclusion A novel 19 bp deletion mutation of hERG is identified in a Chinese family.All gene carriers are demonstrated to be typical LQT2 ECG phenotype.
基金Supported by the National Natural Science Foundation of China(No.30800473)
文摘Objective： To construct a human ether-a-go-go-related gene （HERG） nonsense mutant L539fs/47-558W into the autonomously fluorescent, eukaryotic expression vector pEGFP-C2, and to verify expression of the reconstruct in human embryonic kidney-293 （HEK293） cells. Methods： The mutational fragment was subcloned into pEGFP-C2-HERG by double digestion of Sbf I, Eco91 1 and rejoining of T4 ligase. After verification, the recombinant pEGFP-C2-L539fs/47-558W and pEGFP-C2-HERG were respectively transfected into HEK293 cells for 48 h by the Lipofect method to observe the expression location of the fusion protein by laser confocal imaging scanning in vivo. pcDNA3 -L539fs/47-＊558W and pcDNA3-HERG were transfected to observe the expression location of the HERG protein by immunofluoresceoce. The mutant protein size was determined by Western blotting. Results： The about 1 kb-sized mutation region cDNA fragment from pcDNA3-L539fs/47-＊558Wand the about 7.2 kb-sized target vector fragment from pcDNA3-HERG were ligated after purification and gel recovery pEGFP-C2-L539fs/47＊-558W, approximately 8.2 kb, was demonstrated successfully been constructed under agarose gel electrophoresis and further sequencing. Laser confocal imaging showed that pEGFP-C2-HERG was mainly expressed in the membrane, whereas truncated mutant-type HERG in the pEGFP-C2 vector was partially located in the cytoplasm, the others were transported to the cell membrane in living HEK293 cells. The same as the immunofluoresceoce results after transfection of pcDNA3-HERG and pcDNA3-L539fs/47-558W. Wild-type HERG-GFP fusion protein expressed 160 and 180 kDa bands. The mutant and mutant-GFP fusion proteins were 70 and 100 kDa, respectively. Conclusion： pEGFP-C2-L539fs/47-＊558W was successfully constructed by double digestion method GFP had no effect on its protein expression and trafficking in HEK293 cells, which laid a foundation for the further study on L539fs/47-＊558W
