中国北方汉族人群KIR2DL4等位基因水平多态性的研究

Polymorphism of KIR2DL4 gene among northern Chinese Han population

目的了解中国北方汉族人群KIR2DL4等位基因水平的分子遗传多态性。方法采用磁珠法从327人份北方汉族无关个体标本中提取基因组DNA,采用本实验室建立的KIR2DL4测序分型专利技术对KIR2DL4基因的全部编码区(CDS)序列分为4段做特异性PCR扩增后,采用Sanger测序法对扩增产物所涵盖的每个外显子做双向测序。所获得的序列用Assign 4.7分析软件分析每个标本的基因型。结果共检出8种KIR2DL4等位基因,基因频率由高到低分别为KIR2DL4^(+)00102[77.1%(252/327)]、^(+)00501[35.8%(117/327)]、^(+)011[20.2%(66/327)]、^(+)00602[12.5%(41/327)]、^(+)00801[8.6%(28/327)]、^(+)00103[4.9%(16/327)]、^(+)00503[1.5%(5/327)]、^(+)00504[0.9%(3/327)]。能正常膜表达的10A型等位基因(KIR2DL4^(+)00102、^(+)00103、^(+)00501、^(+)00503、^(+)00504、^(+)00602)及存在CDS nt811位置腺嘌呤缺失而不能正常膜表达的9A型等位基因(KIR2DL4^(+)00801、^(+)011)的检出比例分别为97.6%(319/327)及27.8%(91/327),约为3.5∶1。与南方汉族人群相比较,中国北方汉族人群KIR2DL4各等位基因的检出频率无明显差异(P>0.05)。结论所获得的KIR2DL4分子遗传多态性数据可为疾病关联、人类进化等研究提供重要参考。

Objective To investigate the polymorphism of KIR2DL4 gene in northern Chinese Han population.Methods A total of 327 DNA samples were isolated by magnetic beads from unrelated individuals of northern Chinese Han population.The coding sequence(CDS)of KIR2DL4 were amplified using four pairs of KIR2DL4-specific PCR primers developed by our own KIR sequencing-based typing patent,and each exon of KIR2DL4 carried by the four PCR amplicons was then subjected to DNA Sanger sequencing in both directions.The genotype of each sample was assigned using the Assign 4.7 software.Results Among 327 individuals,8 different kinds of KIR2DL4 alleles were detected,with observed frequencies ranked as KIR2DL4^(+)00102[77.1%(252/327)],^(+)00501[35.8%(117/327)],^(+)011[20.2%(66/327)],^(+)00602[12.5%(41/327)],^(+)00801[8.6%(28/327)],^(+)00103[4.9%(16/327)],^(+)00503[1.5%(5/327)]and^(+)00504[0.9%(3/327)].In this study,the 10A type alleles which can encode a full membrane-bound receptor include 2DL4^(+)00102,^(+)00103,^(+)00501,^(+)00503,^(+)00504 and^(+)00602,whereas the 9A type alleles which produce truncated forms of receptor include 2DL4^(+)00801 and^(+)011.The observed frequencies for 10A and 9A type KIR2DL4 alleles were 97.6%(319/327)and 27.8%(91/327),respectively.The ratio of 10A to 9A type was 3.5:1.The observed frequencies of KIR2DL4 alleles in northern Chinese Han population showed no significant difference compared with southern Chinese Han population(P>0.05).Conclusion The allelic diversity of KIR2DL4 elucidated in the present study can provide valuable data for KIR-associated disease studies and human evolution.