FUT2基因座4个新变异等位基因的分析

Analysis of four new variant alleles at FUT2 locus

目的 探讨FUT2基因座新变异等位基因的结构、检测方法与表达状态。方法 应用PCR、RFLPs、基因重组、DNA序列检测及基因表达技术,对4种FUT2基因座新变异等位基因进行分析。结果在新几内亚人个体中,发现了3种新的FUT2等位基因,分别由错义突变C664T、G868A和G760A所致。经基因表达证实:3种基因编码的α2-FUT酶蛋白缺乏相应的糖基转移酶活性;在中国汉族个体中,发现1例同义突变A660T。C664T和A660T改变了限制性内切酶Sac Ⅰ的识别序列,可以用RFLPs方法进行检测。在应用DNA序列分析技术检测杂合子时,可能会漏检显示弱峰的变异,RFLPs技术不能确定内切酶识别序列内部的具体变异点。结论 C664T、G868A和G760A突变所形成的FUT2基因为非分泌型基因,序列多态性的检测应使用2种以上的方法相互验证。

Objective To investigate the molecular structure, gene expression and detecting methods of some new variant alleles at FUT2 locus. Method We examined four new variant alleles at FUT2 locus using PCR, RFLPs, gene recombination, DNA sequencing and techniques related to gene expression. Results Three missense gene mutations which were C664T, G868A and G760A respectively were found in three New Guinea individuals. Absence of the glycosyltransferase activity in all three enzymes coded by above three missense gene mutations were confirmed by gene expression techniques. Nonsense mutation A660T was found in one Chinese Han individuals. Changing of sequence of endonuclease SacI resulted from C664T and A660T can be detected by RFLP method. Weak peaks of variats might be missed if DNA sequencing was used to detect heterozygotes. RFLP method can't be used to determine specific site of variation within identified sequence of endonuclease. Conclusion All three FUT2 genes resulted from three mutations C664T, G868A, and G760A were non-secretor genes. More than two methods must be used for checking results each other when detect DNA sequence polymorphisms.