Presence of nucleotide substitutions in transcriptional regulatory elements such as the erythroid cell-specific enhancer-like element and the ABO promoter in individuals with phenotypes A3 and B3, respectively
Presence of nucleotide substitutions in transcriptional regulatory elements such as the erythroid cell-specific enhancer-like element and the ABO promoter in individuals with phenotypes A3 and B3, respectively
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DOI：
10.1111/vox.12136
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发表时间：
2014-08-01
期刊：
影响因子：
2.7
通讯作者：
Uchikawa, M.
中科院分区：
文献类型：
--
作者：
Takahashi, Y.;Isa, K.;Uchikawa, M.
背景和目的在人类ABO血型基因的第一个内含子中发现了一个红细胞特异性调控元件，称为+5.8 kb位点。随后的研究表明，在表型A(m)、B-m和AB(m)中，该位点存在缺失或突变。我们研究了A(3)和B-3表型的分子机制。材料与方法从7例A(3)个体和12例B-3或AB(3)个体的外周血中制备基因组dna，采用PCR和测序方法对其核苷酸序列进行分析。K562细胞进行启动子试验。结果在A(3)个个体中发现了A等位基因+5893位点和+5909位点的两个单点突变，而启动子分析显示，每次替换导致该位点的活性降低。在两个B-3个体中，发现b等位基因上ABO启动子-77的单点突变，并且证明替代降低了启动子活性。结论+5.8 kb位点和ABO启动子等转录调控元件的核苷酸替换似乎会减少A和b等位基因的转录，导致A(3)和B-3中A和b抗原的表达分别减少。
Background and objectives An erythroid cell-specific regulatory element, referred to as the +5.8-kb site, has been identified in the first intron of the human ABO blood group gene. Subsequent studies have revealed involvement of deletion or mutation at the site in phenotypes A(m), B-m and AB(m). We investigated the molecular mechanisms involved in the A(3) and B-3 phenotypes.Materials and methods Genomic DNAs were prepared from peripheral blood of seven A(3) individuals and twelve B-3 or AB(3) individuals, and the nucleotide sequences were investigated using PCR and sequencing. Promoter assays were performed with K562 cells.Results Two single point-mutations at +5893 or +5909 in the site on the A-allele were found in A(3) individuals, while promoter assays revealed decreased activity at the site as a result of each substitution. In two B-3 individuals, a single point-mutation at -77 in the ABO promoter on the B-allele was found, and the substitution was demonstrated to reduce the promoter activity.Conclusion Nucleotide substitutions in the transcriptional regulatory elements such as the +5.8-kb site and the ABO promoter appear to decrease transcription from the A-and B-alleles, resulting in reduction in A-and B-antigen expression in A(3) and B-3, respectively.