A糖基转移酶基因变异导致A_(m)表型的遗传学和生物信息学分析  

Genetic and bioinformatics analysis of an individual with A_(m) phenotype due to variant of A-glycosyltransferase enzyme gene

作　　者：章旭 周助人 黄旭颖[1] 李丽春 李晓丰[1] 李剑平[1] ZHANG Xu;ZHOU Zhuren;HUANG Xuying;LI Lichun;LI Xiaofeng;LI Jianping(Institute of Transfusion Medicine,Shenyang Central Blood Station(Liaoning Blood Center),Shenyang 110044,China)

机构地区：[1]沈阳中心血站/辽宁省血液中心输血医学研究所,辽宁沈阳110044

出　　处：《中国输血杂志》2024年第10期1193-1196,共4页Chinese Journal of Blood Transfusion

基　　金：沈阳市科技创新平台建设计划项目(项目编号:21-104-0-15)。

摘　　要：目的研究1例A_(m)亚型的血清学特性和分子遗传机制。方法对1例ABO血型血清学方法鉴定正反定型不一致的标本,进行ABO基因的完整编码区和包括内含子1转录因子结合位点进行分段直接测序,对第6~7外显子的PCR产物进行克隆和测序,并对变异位点采用生物信息学软件进行预测分析。结果该标本血清学检测为A_(m)表型,在第6、7外显子存在261delG、467C/T和912C/A杂合,在内含子1中未发现碱基缺失和改变。进一步的TA克隆和测序显示该标本存在ABO*O.01.01等位基因和ABO*A1.02等位基因背景下c.912 C>A(p.S304R)变异的新等位基因。该新等位基因序列已被GenBank数据库收录,登录号为JX489776。PolyPhen2和PROVEAN算法分别预测c.912C>A变异“可能有害”和“有害”。自由能变化(ΔΔG)值预测其可能影响蛋白的稳定性。蛋白模拟模型提示p.S304R可造成α-1,3-N-乙酰半乳糖胺转移酶局部氢键网格的改变。结论α-1,3-N-乙酰半乳糖胺转移酶基因的c.912 C>A(p.S304R)变异可能造成酶蛋白结构和功能的失稳,进而导致A抗原表达减弱。Objective To investigate the serological characteristics and molecular mechanism of an individual with A_(m) phenotype.Methods The sample with ABO blood group discrepancy was confirmed by serological techniques.The full coding and flanking regions of the ABO gene including intron 1 transcription factor binding site were identified through direct sequencing of PCR-amplified products.PCR products of exon 6-through 7 were validated to isolate the ABO gene haplotypes by cloning and sequencing individual colonies.Bioinformatics software was used to analyze the structure of the mutant protein.Results The serologic characteristics of ABO blood typing showed the rare A m phenotype.The c.467C/T and c.912C/A heterozygous sites in exon 7 were identified by direct sequencing analysis.Further TA cloning and sequencing revealed that the patient carried an ABO*O.01.01 allele and a novel ABO*A allele.The new allele sequence had one nucleotide alteration(C>A)at position 912 on the background of the ABO*A1.02 allele.The new allele sequence has been included in the GenBank database with the entry number JX489776.The c.912C>A mutation was predicted to be“probably damaging”and“deleterious”by PolyPhen2 and PROVEAN algorithms,respectively.The free energy change(ΔΔG)value predicted it to have a destabilizing effect on the GTA protein.Meanwhile,modeling of the 3D structure predicted that the p.S304R amino acid substitution may alter the hydrogen bond of the GTA protein.Conclusion The p.S304R substitution ofα-1,3-N-acetylgalactosaminyltransferase gene may reduce the antigen expression owing to a greatly destabilizing effect on the structure and function of the GTA protein.

关 键 词：A_(m)亚型 A糖基转移酶基因 分子机制 生物信息学分析 

分 类 号：Q343.13[生物学—遗传学]