中国汉族人HIV-1辅助受体等相关基因CCR5、CCR2b、CXCR4和SDF1编码区SNP位点调查

Identification of single nucleotide polymorphisms in the coding region of CCR5,CCR2b,CXCR4 and SDF1 alleles among Chinese Han population

目的调查中国汉族人群中HIV-1感染相关基因CCR5、CCR2b、CXCR4及SDF1编码区的基因多态性特点,为我国的艾滋病防治提供基础数据。方法 CCR5用2对引物进行PCR扩增,用PCR产物做模板直接测序。CCR2b编码区经PCR扩增后,用测序引物逐段分别测序。CXCR4(cDNA编号AF147204)编码区用2对引物进行PCR扩增,然后测序。SDF1编码区用4对引物进行PCR扩增,然后分别测序。样本总数为45例,测序结果用DNAstar综合分析,寻找和鉴定SNP位点。结果 CCR5基因编码区共发现6个SNP位点,4个引起氨基酸改变,1个单碱基缺失,引起移码突变和翻译提前终止。184A→G、503G→T、668G→A、999G→T等位基因频率分别为1.1％、21.1％、8.9％和10.0％。CCR2b编码区共发现8个SNP位点,6个错义突变,即43位G→C、190位G→A、260位C→A、302位C→A、315位G→C、433位G→A,突变频率分别为:30.0％、27.8％、32.2％、5.6％、10.0％和3.3％。CXCR4编码区共发现7个SNP位点,3个错义突变即38位C→T、90位A→T、712位A→C,1个终止突变:106位G→T,基因突变频率分别为:4.4％、4.4％、10.0％和3.3％。在SDF1编码区发现1个错义SNP位点:192位G→T,突变频率为8.9％;1例单碱基缺失:100位T缺失(100△T),引起34位氨基酸移码突变。结论中国汉族人HIV-1相关基因编码区有自己的多态性特点。4个HIV-1相关基因编码区共找到22个SNP位点,17个为首次报道;2个单碱基缺失均导致移码突变和翻译提前终止,1个已经报道。它们对HIV-1感染和艾滋病病程的影响值得进一步研究。

Objective To investigate the single nucleotide polymorphism property of the coding region of CCR5, CCR2b, CXCR4 and SDF1 in Chinese Han population for AIDS prevention and therapy. Methods Totally 45 individuals were enrolled for the study. CCR5 was amplified by using 2 pairs of PCR primers. CCR2h was amplified using 1 pair of PCR primers. CXCR4(cDNA No. AF147204) was cloned by PCR amplification using 2 pairs of primers. Four exons of SDF1 were cloned by PCR amplification using 4 pairs of primers. The coding regions of each gene were sequenced by different sequencing primers. The results of the same sequencing primers were analyzed by DNAstar software to find and identify SNP sites. Results Totally six SNPs and one cytosine deletion were found in CCR5 coding region. Four SNPs, i.e. 184A→G,503G→T,668G→A,999G→T cause amino acids alteration of CCR5 protein with a mutant allelic frequen-cy of 1.1%, 21.1%, 8.9% and 10.0%, respectively, were found. The cytosine deletion results in frame shift and early termination of protein translation. Eight SNPs were found in the coding region of CCR2b, among them 6 missense, i.e. 43 G→C, 190G→A, 260C→A, 302C→A, 315G→C, 433G→A. Their mutation frequencies were 30. 9%, 27. 4%, 32.1%,5.9%,9.5% and 3.6%, respectively.Total 7 SNPs were found in the coding region of CXCR4, among them 3 missense(4.4% of 38 C→T as well as 90 A→T, 10.0% of 712 A→C) and 1 stop mutation(106 G→T with a frequency of 3.3% ). One SNP and one thymidine deletion were found in the coding region of SDFl. The SNP was G→T at 192 with a frequency of 8. 9%, resulting in a replacement of lysine by asparagine. The thymidine deletion was at 100 (100AT), causing frame shift from the 34th amino acid. Conclusions The polymorphism property of the coding region of HIV-1 related genes in Chinese Han population is different from that of other nationalities. Altogether 22 SNPs were identified in CCR5, CCR2b, CXCR4 and SDFl alleles, 17 of which were reported for the first time. Two deletions were discovered in CCR5 and SDF1. Their influences on HIV- 1 infection and AIDS progression needs to be further studied.