cis基因交换形成RHD-CE(2～9)-D等位基因  

Generation of RHD-CE(2～9)-D Allele by Gene Conversion in cis

作　　者：邵超鹏[1] 李桢[1] 熊文[1] 周一炎[1] 李雪梅[1] 

机构地区：[1]深圳市血液中心和深圳市输血医学研究所,深圳518035

出　　处：《遗传》2005年第4期561-565,共5页Hereditas（Beijing)

基　　金：广东省医学科研项目(编号:A2003712);深圳市医药卫生科研计划项目(编号:200304283)~~

摘　　要：以往通过基因组DNA分析,分别在高加索人和中国人中观察到少数Rh阴性个体存在RHD基因第1和第10外显子,但是该等位基因形成的具体分子机制尚有争论。分别针对RHD基因mRNA的5′和3′非编码区设计一对特异性引物,通过逆转录PCR(RTPCR)和cDNA测序,分析2例RHD基因阳性(拥有第1和第10外显子)、D抗原表型阴性个体的全长mRNA/cDNA序列,同时以1例正常Rh阳性个体(CcDDee)作对照。结果正常Rh阳性个体拥有正常RHD基因mRNA,2名携带RHD基因的Rh阴性个体则均检出存在与正常RHD基因或RHCE基因转录产物相同长度、以及相同外显子构成的mRNA,但该转录子的第1和第10外显子及3′非编码区序列与RHD基因一致,而第2～9外显子全部序列与RHCE(e)基因mRNA相同,表明2名个体均存在RHDCE(2～9)D融合RHD等位基因,即其RHD基因的第2～9外显子被同源RHCE(e)基因替换,导致不能编码正常RhD蛋白,形成个体D抗原阴性表型。Previously a few Rh-negative individuals in Caucasian and Chinese were found existing exons 1 and 10 of RHD through genomic DNA testing. The molecular mechanisms, however, remain disputed. In this study, 2 individuals carrying RHD positive, D antigen negative allele （with exon 1 and 10 of RHD） and their mRNA were investigated by using reverse transcriptase PCR （RT-PCR） and sequencing through one pair of specific primers for 5＇- and 3＇-non-coding region of RHD,taking a Rh-positive （Ccee） sample as control. As a result, the control sample had a normal RHD mRNA, whereas other transcripts were detected in both RHD-positive, D antigen negative individuals, which have same length and exons as the normal FtHD or RHCE mRNA.Those transcripts had the same sequences with RHD in exon 1 and exon 10, while the sequences in exons 2-9 were in concordance with RHCE（e） mRNA. It indicated that a hybrid RHD allele,RHD-CE（2-9）-D, was existed in the 2 individuals, in which the exons 2-9 of RHD were substituted by homologous RHCE（e）. Thus, this allele could not code normal RhD protein and therefore resulted in Rh-negative phenotype.

关 键 词：RH血型 MRNA 只HD基因 RHCE基因 基因交换 

分 类 号：R394[医药卫生—医学遗传学]