广东汉族人群TLR2基因的多态性研究

目的:人类Toll样受体2(TLR2)是先天免疫系统中一个重要的病原微生物识别受体。本研究将建立广东汉族人群TLR2基因座位的功能性多态性图谱,为下一步疾病相关性研究打下基础。方法:收集200例健康、无亲缘关系的中国广东汉族人外周血液,随机抽取其中24例样品,对TLR2基因的启动子区、3个外显子以及它们周围的部分内含子序列进行聚合酶链式反应(PCR)扩增和直接测序,找出多态性位点,对剩余176例样品分别用序列特异性引物聚合酶链反应(PCR-SSP)及PCR技术对发现的单核苷酸多态性(SNPs)和插入/缺失(INDEL)多态性位点进行基因分型,分型结果进行Hardy-W e inberg平衡分析、中性进化分析以及连锁不平衡分析。结果:发现5个SNPs位点,其中2个位于启动子区的SNPs是首次发现,位于编码区的3个SNPs位点均为同义突变,频率最高的SNP是rs3804099,其次要等位基因频率为26.3%;在第1外显子区发现1个长度为22bp的INDEL多态位点(-196到-174),其缺失等位基因所占的频率为31.8%。所有多态性位点均符合Hardy-W e inberg平衡。中性检验显示广东汉族人群TLR2基因符合中性进化假说。连锁不平衡分析显示位于调控区的-18945 C/T和-18883 C/G 2位点之间完全连锁,而位于编码区的rs3804099和rs3804100两位点之间紧密连锁。结论:本研究首次建立了汉族正常人群TLR2基因座位的功能性多态性图谱,并研究了其分布频率,发现了一些种族特异性的多态性位点,为今后开展汉族人基因多态性与疾病相关性研究以及人群进化研究提供了重要资料。

Genetic polymorphisms of TLR2 locus in Chinese Cantonese population

AIM: Toll-like receptor 2 ( TLR2 ) was a significant pathogen recognition receptor in innate immune system. The aim of this study was to investigate the distribution of TLR2 polymorphisms in the general population of Chinese Cantonese. METHODS: Peripheral blood samples were collected from 200 unrelated healthy Chinese Cantonese individuals. The functional regions of TLR2 locus, including promoter region and all three exons with their surrounding intronic regions were amplified using PCR and sequenced in a random sample of 24 subjects. TLR2 genotyping in other 176 subjects was performed using PCR-sequence specific primer and PCR. RESULTS: A total of 5 single nucleotides polymorphisms (SNPs) were detected, the two of which were novel. SNPs located in the coding region were all synonymous substitutions. The most common SNP was rs3804099 with the minor allele frequency of 26.3%. One 22 bp insertion/deletion (INDEL) polymorphism was found in exon 1 with the deletion allele frequency of 31.8%. All polymorphic sites were consistent with Hardy-Weinberg equilibrium. Neutrality test suggested that TLR2 in Chinese Cantonese did not significantly deviate from the neutral model. Linkage disequilibrium (LD) analysis showed complete LD between SNP-18945 C/T and SNP-18 883 C/G, and strong LD between SNP rs3804099 and SNP rs3804100. CONCLUSION: This is the first report on the distribution of TLR2 polymorphisms in the general population of China. It provided some ethnic specific polymorphisms, which might help in the further studies of disease association in Chinese.