利用PCR-SSCP及克隆分析对HERG基因突变的新发现(英文)

Identification of a Novel HERG Gene Mutation by PCR SSCP and Cloning Analyses

为研究ＱＴ延长综合征（ＬＱＴＳ）致病的分子遗传学基础。我们在ＰＣＲ基础上建立ＳＳＣＰ方法对ＬＱＴ患者和正常对照者ＨＥＲＧ基因的突变进行研究。并且利用克隆技术对突变进行确证。通过ＳＳＣＰ分析，在１例正常对照者中发现异常条带，该突变无法用直接测序确证，因此我们将其转入质粒，克隆后再进行测序。结果提示在ＨＥＲＧ基因７５２位点（５′→３′）异常插入９个碱基。突变型为杂合子。突变导致蛋白通道氨基酸序列中插入ＧｌｙＡｌａＧｌｙ。与其他已报道的突变不同，本文所发现的３个氨基酸的插入突变不是ＬＱＴＳ发生的遗传基础。

To investigate genetic risk factor of Long QT Syndrome(LQTS), mutations of HERG gene were screened in individuals susceptible to LQT and health controls by PCR based SSCP analysis. A PCR based cloning assay was also developed and used to identify the mutation. An abnormal conformer was found in one healthy control by SSCP screening. This mutation was not able to be identified by direct sequencing. To separate the mutated allele, we transformed it into plasmid and the final sequencing suggested it is a heterozygous 9 base pairs insertion at position 752 of HERG cDNA sequence (5′→3′). This mutation results in a Gly Ala Gly insertion in amino acid sequence. Unlike other mutations previously reported, the nine base pairs insertion is not a genetic risk factor of LQTS.