Structural and Functional Insights on an Uncharacterized Aγ-Globin-Gene Polymorphism Present in Four β0-Thalassemia Families with High Fetal Hemoglobin Levels
Structural and Functional Insights on an Uncharacterized Aγ-Globin-Gene Polymorphism Present in Four β0-Thalassemia Families with High Fetal Hemoglobin Levels
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DOI：
10.1007/s40291-016-0187-2
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发表时间：
2016-04-01
影响因子：
4
通讯作者：
Paciaroni, Katia
中科院分区：
文献类型：
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作者：
Bianchi, Nicoletta;Cosenza, Lucia Carmela;Paciaroni, Katia
一些DNA多态与胎儿血红蛋白(HBF)的高产量有关，尽管其分子基础还不完全清楚。为了确定和表征新的HBF相关因素，我们集中研究了五个先证者及其四个家庭(来自埃及、伊拉克和伊朗)，他们患有严重的地中海贫血(β(0)-IVSII-1或β(0)-IVSI-1)和异常的HBF升高(>；患者招募，基因组DNA测序，Western blotting，凝胶迁移率改变分析，表面等离子共振(SPR)生物特异性相互作用分析，基于对接实验的生物信息学分析。本研究研究了四个患有β(0)-地中海贫血(β(0)-IVSII-1和β(0)-IVSI-1)并表达异常高HBF水平的家系，先天性或骨髓移植排斥反应后获得的。这种(G->；A)多态存在于A伽马珠蛋白基因的+25位，对应于A伽马珠蛋白基因的5‘非编码区，当存在时，它与所有与XmnI多态和β(0)-地中海贫血突变相关的熟悉成员的第11号染色体上存在物理联系。Aγ-珠蛋白基因+25(G->；A)多态对应的区域属于DNA结合蛋白复合体识别的序列，包括LYAR(Ly-1抗体反应克隆)，这是一个锌指转录因子，先前被认为参与下调红系细胞中γ-珠蛋白基因的表达。我们在四个β(0)地中海贫血和HBF高表达的家系中发现了一个新的Aγ-珠蛋白基因多态性。此外，我们报告的证据表明，A伽马珠蛋白基因+25(G->；A)多态降低了该序列与特定DNA结合蛋白复合体之间相互作用的效率。
Several DNA polymorphisms have been associated with high production of fetal hemoglobin (HbF), although the molecular basis is not completely understood. In order to identify and characterize novel HbF-associated elements, we focused on five probands and their four families (from Egypt, Iraq and Iran) with thalassemia major (either beta(0)-IVSII-1 or beta(0)-IVSI-1) and unusual HbF elevation (> 98 %), congenital or acquired after rejection of bone marrow transplantation, suggesting an anticipated favorable genetic background to high HbF expression.Patient recruitment, genomic DNA sequencing, western blotting, electrophoretic mobility shift assays, surface plasmon resonance (SPR) biospecific interaction analysis, bioinformatics analyses based on docking experiments.A polymorphism of the A gamma-globin gene is here studied in four families with beta(0)-thalassemia (beta(0)-IVSII-1 and beta(0)-IVSI-1) and expressing unusual high HbF levels, congenital or acquired after rejection of bone marrow transplantation. This (G -> A) polymorphism is present at position +25 of the A gamma-globin genes, corresponding to a 5'-UTR region of the A gamma-globin mRNA and, when present, is physically linked in chromosomes 11 of all the familiar members studied to the XmnI polymorphism and to the beta(0)-thalassemia mutations. The region corresponding to the +25(G -> A) polymorphism of the A gamma-globin gene belongs to a sequence recognized by DNA-binding protein complexes, including LYAR (Ly-1 antibody reactive clone), a zinc-finger transcription factor previously proposed to be involved in down-regulation of the expression of gamma-globin genes in erythroid cells.We found a novel polymorphism of the A gamma-globin gene in four families with beta(0)-thalassemia and high levels of HbF expression. Additionally, we report evidence suggesting that the A gamma-globin gene +25(G -> A) polymorphism decreases the efficiency of the interaction between this sequence and specific DNA binding protein complexes.