血浆载脂蛋白B基因3'端可变数目串联重复序列的结构研究

目的研究载脂蛋白B（apollpoprotein B，apoB）基因apoB 3’端可变数目串联重复序列（variable number of tandem repeats，VNTR）多态性与序列结构。方法应用聚合酶链反应结合琼脂糖凝胶电泳技术检测了522名随机抽取的体检人员apoB基因3’VNTR多态性，选取26个样本的PCR产物进行DNA序列测定。结果分离出16个等位基因即高变单元（hypervariable element，HVE），其中杂合子多于纯合子，最大的等位基因是HVE58，最小的是HVE24；HVE34频率最高40．4％，其次是HVE32，占34．7％。对26名60个等位基因进行的DNA核苷酸测序中，发现一个等位基因异构体（Y-A=ATAATTAAATATTT），4个结构模式。结论中国人与欧美人群在apoB基因3’VNTR等位基因频率分布上存在明显差异，在等位基因异构体与结构模式上也存在不同。

Structure analysis of apolipoprotein B 3' variable number of tandem repeats

OBJECTIVE: To study the distribution, frequency and structure of variable number of tandem repeats (VNTR) in 3o region of apoB gene in Chinese population. METHODS: Genomic DNA was extracted from peripheral blood obtained under consent from randomly-chosen 522 individuals who came to the hospital for physical examination, and used to screen for polymorphisms of 3o VNTR of the apoB gene by employing polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), gradient polyacrylamide gel electrophoresis, cloning and sequencing. RESULTS: Sixteen types of alleles of apoB 3oVNTR were identified, among which heterozygotes were more than homozygotes. The biggest allele is HVE58, and the smallest one is HVE22. HVE34 had the highest frequency (40.4%), followed by HVE32 (34.7%). This showed significant difference from the allelic distribution of other populations (Caucasian and Swedish). Through sequencing of 60 alleles, a new isomer (Y-A=ATAATTAAATATTT) and four new types of alleles were found. CONCLUSION: The Chinese population we studied had a higher frequency of small alleles and showed a difference in allelic structure and frequency distribution from European and American in this populations.