title: Site-directed mutagenesis of neonatal convulsions associated KCNQ2 gene and its protein expression.
abstract: OBJECTIVE
  To study the protocol of construction of a KCNQ2-c.812G>T mutant and its eukaryotic expression vector, the c.812G>T (p.G271V) mutation, which was detected in a Chinese pedigree of benign familial infantile convulsions (BFIC), and to examine the expression of mutant protein in human embyonic kidney (HEK) 293 cells.
  
  
  METHODS
  A KCNQ2 mutation c.812G>T was engineered on KCNQ2 cDNAs cloned into pcDNA3.0 by sequence overlap extension PCR and restriction enzymes. HEK293 cells were co-transfected with pRK5-GFP and KCNQ2 plasmid (the wild type or mutant) using lipofectamine and then subjected to confocal microscopy. The transfected cells were immunostained to visualize the intracellular expression of the mutant molecules.
  
  
  RESULTS
  Direct sequence analysis revealed a G to T transition at position 812. The c.812G>T mutation was correctly combined to eukaryotic expressive vector pcDNA3.0 and expressed in HEK293 cells. Immunostaining of transfected cells showed the expression of both the wild type and mutant molecules on the plasma membrane, which suggested that the c.812G>T mutation at the pore forming region of KCNQ2 channel did not impair normal protein expression in HEK293 cells.
  
  
  CONCLUSIONS
  Successful construction of mutant KCNQ2 eukaryotic expression vector and expression of KCNQ2 protein in HEK293 cells provide a basis for further study on the functional effects of convulsion-causing KCNQ2 mutations and for understanding the molecular pathogenesis of epilepsy.
authors.affiliation: Department of Neonatology, First Affiliated Hospital, Medical College of Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Xi-Hui
authors.initials: XH
authors.lastname: Zhou
authors.affiliation: Department of Neonatology, First Affiliated Hospital, Medical College of Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Zhi-Yan
authors.initials: ZY
authors.lastname: Hui
authors.affiliation: Department of Neonatology, First Affiliated Hospital, Medical College of Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Rui-Ming
authors.initials: RM
authors.lastname: Shi
authors.affiliation: Department of Neonatology, First Affiliated Hospital, Medical College of Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Song
authors.affiliation: Department of Neonatology, First Affiliated Hospital, Medical College of Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Neonatology, First Affiliated Hospital, Medical College of Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
keywords: KCNQ2 gene; eukaryotic expression vector; site-directed mutagenesis
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