新等位基因MICA＊065的鉴定及其序列分析

Identification and Sequence Analysis of Novel MICA ＊ 065 Allele

目的 鉴定中国深圳地区人群中新发现的1个主要组织相容复合物Ⅰ类相关基因A位点（MICA）等位基因,并对该新MICA基因的突变情况进行分析.方法 选择2012年1～12月,于深圳市血液中心行组织配型的供、患者中,1例MICA基因分型异常的健康供者作为研究对象.采用自主建立的基于聚合酶链反应-碱基序列直接测序（PCR-SBT）法对本例供者MICA基因第2～5外显子进行测序分型,利用分子克隆和单倍体测序的方法,鉴定出该个体MICA等位基因的序列.利用序列比对方法,对该MICA等位基因的突变情况进行分析.结果 于本例供者血液样品中,检出了1个新变异的MICA等位基因,其序列与MICA＊ 010∶01最为相近,但存在基因组DNA nt 637位点的碱基由胞嘧啶（C）突变为胸腺嘧啶（T）,MICA基因第4外显子中的第1 91位密码子由CGC变异为TGC,导致氨基酸由精氨酸变异为半胱氨酸,该序列提交国际GenBank数据库（序列号：JN043370）和国际免疫遗传学信息系统/人类白细胞抗原（IMGT/HLA）数据库（序列号：HWS10013775）,已被命名为MICA＊ 065.结论 新等位基因MICA＊ 065的变异碱基T,是1个全新的随机突变位点,未在MICA其他等位基因中发现.

Objective To identify a novel MICA allele in Chinese population in Shenzhen and analyze the mutation feature for this novel allele.Methods From January to December 2012,a healthy donor with inconclusive MICA genotyping result was selected from patients and donors who registered to do human leukocyte antiges （HLA） genotyping in Shenzhen Blood Center as study object.Self established sequence typing-based method was used to genotype exon 2-5 of MICA gene for this sample.Then the sequence of the MICA allele was identified by cloning and haplotype sequencing.The type of mutation of this MICA allele was characterized by sequence alignment.Results A novel MICA allele was identified in this study.It differed from the closest allele MICA ＊ 010：01 by single nucleotide change at genomic DNA nt637 cytosine （C） to thymine （T） （codon191 CGC to TGC） in exon 4,which resulted in the change of an amino acid （arginine to cysteine）.The sequence of this novel allele was submitted to GenBank Database under the accession number JN043370 and the international ImMunoGeneTics project/human leukocyte antigen （IMGT/HLA） Database with number HWS10013775,and the name of MICA ＊ 065 had been officially assigned.Conclusions The mutation of T in novel allele MICA ＊ 065 is a new random mutation,which is not found in any other MICA allele.