The regulation and gating mechanism of Cav1.2 current by KCNE1 subunit / 中华急诊医学杂志

Objective To explore the regulation and mechanism of Cav1.2 current by KCNE1. Methods Transient transfection was used to transfer Cav1.2 channel plasmids separately or together with KCNE1 plasmids into HEK293 cells. The experiment was divided into 2 groups (15 cells in each group):Cav1.2 group, Cav1.2+KCNE1 group.The whole-cell patch clamp technique was used to record Cav1.2 current and gating dynamics. Results After co-transfection of KCNE1 with Cav1.2, Cav1.2 current decreased significantly. At 0 mV, peak current density of Cav1.2 was reduced from (-14.8±2.5) pA/pF to (-7.5±1.6) pA/pF (n=15, P<0.01). Based on the gate control mechanism, it is found that the regulation of Cav1.2 current by KCNE1 mainly makes the steady-state inactivation curve of the channel shifted to a more negative direction, thus accelerating the inactivation. Meanwhile, the recovery process of the channel after inactivation is slowed down and the recovery time constant was prolonged. Conclusions The KCNE1 subunit can reduce the current density of Cav1.2 by changing the channel inactivation and recovery process.

KvLQT1 and KCNE1 K+ Channel Gene Polymorphisms in Long QT Syndrome.

Long QT Syndrome (LQTS), a disorder of the cardiac repolarization process with prolongation of the QT interval (QTc ≥0.46 seconds), is an ion-channelopathy. Mutations in either KCNQ1 or KCNE1 genes are susceptible to LQTS. Hence, screening of KCNQ1 and KCNE1 genes is taken up to evaluate the genetic correlation of these genes in Long QT patients of Indian origin. A total of 33 Long QT Syndrome patients and 100 healthy subjects were enrolled for the present study. PCR-SSCP protocol was utilised for screening of KCNQ1 and KCNE1 genes followed by In-silico and statistical analysis. The clinical profile of the Long QT syndrome patients in our study revealed a higher percentage of females with the mean age also being higher in females when compared to males. The two variations (S546S and IVS13+36A>G) in KCNQ1 and the S38G polymorphism in KCNE1 gene were identified and their association with Long QT syndrome is being reported for the first time in Indian population. S546S is located in the KCNQ1 C terminus close to this domain and IVS13+36A>G is located in the intronic region in close proximity to the coding region for C-terminal domain; these may therefore affect the functional protein through non-assembly. S38G leads to a substitution of serine to glycine at 38th amino acid position (S38G) in the transmembrane domain of KCNE1. Our study reports compound heterozygosity/genetic compound ofS546S and IVS13+36A>G of KCNQ1 gene. Haplotype frequencies and linkage disequilibrium analysis revealed a significant association between the three biomarkers. Compound heterozygosity of the polymorphisms influence downstream signalling and KCNQ1- KCNE1 interactions.

Cloning of KCNE1 gene in long QT syndrome and construction of its eukaryotic expression vector / 医学研究生学报

Objective: To construct the eurokaryotic expression vector of KCNE1 gene and express recombinant KCNE1 in HEK293 cells.Methods:Human KCNE1 gene fragment was amplified from human placenta total RNA by RT-PCR and cloned into the vector of pCR2.1 TOPO by means of T-A cloning.KCNE1 cDNA was obtained from pCR2.1-KCNE1 by restriction enzyme digestion and inserted into the same restriction site of pEGFP-N1.Thus pEGFP-N1-KCNE1 was constructed and transfected into HEK293 cells with Effectene transfection reagent.Results:The eukaryotic expression vector pEGFP-N1-KCNE1 was successfully constructed by gene cloning and recombinant method and expressed in HEK293 cells.Conclusion:The cloning of KCNE1 gene and the construction and expression of its eukaryotic expression vector may shed some light on further functional study of KCNE1 gene.