【摘要】 目的分析一例罕见B放散型的ABO基因分子遗传背景。方法对一例血型血清学正反定型不符的无偿捐血者样本进行了包括吸收放散、血型物质检测等系列血清学实验后,采用PCR-SSP方法、第6、7外显子PCR产物直接测序,进行ABO基因定型;并对第6、7外显子及第6内含子进行基因克隆序列分析,以及采用PCR扩增样本的ABO基因5端调控(CBF/NF-Y增强子)区域,扩增产物经胶回收后进行直接序列测定。结果经过吸收放散等血型血清学实验鉴定为Bel表现型,在此样本中发现了一个ABO*B变异等位基因,它是在ABO基因的第7外显子695核苷酸位出现T>C突变,导致232位氨基酸由Leu转变为Pro。ABO基因微卫星增强区域序列测定为4个43个碱基长度的重复,第1个重复中nt41为C/G杂合,其余3个重复序列中nt41均为G,定为G/C型(B101/O01等位基因型)。结论在中国人群中再次报道nt695位突变的ABO新等位基因,表明ABO基因的第232位氨基酸对决定ABH糖基转移酶活性是至关重要的。更多还原

【Abstract】 Objective To analyze the molecular genetic background of Bel subtype in a Chinese individual. Methods Blood sample from a female donor,identified with discrepancies,was further diagnosed by series serological tests including absorption-elution and saliva substrate test. Genomic DNAs were genotyped by PCR-SSP and direct DNA sequencing at the exon 6 and 7 of ABO gene. The exon 6,exon 7 and the intervening intron 6 of ABO gene were analyzed by cloning and haplotype-sequencing. And the sample was detected for nucleotide sequencing of the 5’regulatory region containing the CBF/NF-Y enhancer at ABO gene locus. Results The individual was phenotyped as Bel subgroup through absorption-elution test. A variant Bel allele identified differs from the B101 by single 695T> C missense mutation in exon7,which results in an amino acid change from Leu to Pro at 232 amino acid position. The sample had four 43-bp minisatellite repeats within the CBF/NF-Y enhancer region of ABO gene. It were genotyped as G/C type ( B101/O01 genotype) as a nucleotide showed heterozygosity (G/C) at nt.41 of the first repeat while other repeats showed homozygous. Conclusion A novel B allele with nt695 missense mutation was identified again in Chinese population. It indicates that the alteration of amino acid at the position of 232 is critical to the activity of ABO glycosyltransferases.更多还原