Molecular genetic analysis of Mi(a)-positive hybrid glycophorins revealed two novel alleles of GP.Vw and multiple variant transcripts of GYPB existing in both the homozygous GP.Mur and wild-type GPB individuals
Molecular genetic analysis of Mi(a)-positive hybrid glycophorins revealed two novel alleles of GP.Vw and multiple variant transcripts of GYPB existing in both the homozygous GP.Mur and wild-type GPB individuals
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Mi(a) 阳性杂交血型糖蛋白的分子遗传学分析揭示了纯合 GP.Mur 和野生型 GPB 个体中存在 GP.Vw 的两个新等位基因和 GYPB 的多个变异转录本
作者：
Wei Ling;Sun Ainong;Wen Jizhi;Wang Zhen;Li Qiao;Liao Yanting;Luo Guangping;Ji Yanli
研究背景MNS血型系统的杂合血型糖蛋白表达一系列包括Mia在内的低发生率抗原，这些抗原在东南亚人群中普遍存在。本研究首次在中国南方汉族人群中阐明了Mia阳性杂合血型糖蛋白的分子基础。研究设计和方法从111例Mia阳性献血者的全血中提取DNA，分析GYPB基因在GP.Mur纯合子个体中的RNA转录。采用高分辨率熔解曲线（HRM）分析GYP（B-A-B）基因型。对熔解曲线变异的标本进行GYPB假外显子3的测序。采用HRM法对GYPB/GYPB基因型正常的Mia阳性样本进行GYPA外显子2-4的TA克隆和测序。GYPB的转录本分析在纯合子GP.Mur和野生型血型糖蛋白B（GPB）个体中进行，使用从培养的红细胞提取的RNA。结果杂合GYP *Mur/GYPB（n= 101），纯合GYP *Mur/GYP*Mur（n= 7），包括一个新的GYP * Mur等位基因，其具有额外的GYPA/GYPE特异性核苷酸取代（c.229+ 110 A>T）、异型性GYP *Bun/GYPB（n= 1）和GYP *Vw/GYPA（n= 2），并有两个新的GYP *Vwalleles。RNA转录本分析显示，GYPB在GP、Mur纯合子和正常GPB个体中均存在多个转录本。此外，对GYPB转录本的成功分析表明，培养的成红细胞是一个很好的RNA转录本分析的来源，因为该蛋白只在红细胞上表达。
BackgroundThe hybrid glycophorins of MNS blood group system express a series of low incidence antigens including Mia, which are commonly found in Southeast Asian populations. In this study, the molecular basis of Mia‐positive hybrid glycophorins was firstly clarified in the Chinese Southern Han population. RNA transcripts ofGYPBgene in the homozygous GP.Mur individuals were also analyzed.Study design and methodsDNAs were extracted from the whole blood samples of 111 Mia‐positive donors. Then, high‐resolution melting (HRM) analysis forGYP(B‐A‐B) was used to analyze the genotypes. Sequencing ofGYPBpseudoexon 3 was conducted in the samples with variant melting curves. TA‐cloning and subsequent sequencing ofGYPAexons 2–4 were performed in the Mia‐positive samples with normalGYPB/GYPBgenotype by HRM. The transcript analysis ofGYPBwas conducted in homozygous GP.Mur and wild‐type glycophorin B (GPB) individuals using RNA extracted from the cultured erythroblast.ResultsThe heterozygousGYP*Mur/GYPB(n= 101), homozygousGYP*Mur/GYP*Mur(n= 7) including one novelGYP*Murallele with an extraGYPA/GYPEspecific nucleotide substitution (c.229+110A>T), heterozygousGYP*Bun/GYPB(n= 1) andGYP*Vw/GYPA(n= 2) with two novelGYP*Vwalleles were identified. RNA transcript analysis revealed multiple transcripts ofGYPBexisting in both homozygous GP.Mur and normal GPB individuals.ConclusionThe results showed the genetic diversity of hybrid glycophorins in the Chinese population. Besides, the successful analysis ofGYPBtranscripts indicates that the cultured erythroblast is a good source for RNA transcript analysis for the protein only expressed on the red blood cells.