USF2介导β珠蛋白基因簇LCR远端调节γ-珠蛋白表达的分子机制

胎儿血红蛋白（HbF）的代偿性表达是缓解β地贫患者临床表型的重要因素。因此，调控HbF的顺式元件LCR天然变异的功能研究方兴未艾。本课题组前期利用1142例β地贫患者高通量靶向测序数据，通过关联分析，在LCR上鉴定了1个显著加重地贫患者临床表型的SNP。我们通过数据挖掘和预实验，筛选出转录因子USF2是介导LCR远端调控β类珠蛋白基因的新成员。本课题应用基因编辑，ATAC-seq，ChIP-seq和3C等技术，以2株代表不同红系发育时期的细胞为对象，研究USF2及其LCR靶序列在调节β类珠蛋白基因转换中的作用机制，研究内容包括：1. 功能性SNP对USF2介导LCR远端调节γ-珠蛋白基因的作用；2. USF2在β类珠蛋白基因转换中的工作原理； 3. USF2与已知红系转录因子的调控网络。该研究可增加血红蛋白转换机制的新内容，同时为β地贫靶向治疗提供理论基础。

The compensatory expression of HbF (fetal hemoglobin) is one of key factors in ameliorating the clinical severity of β-thalassemia patients. However, relationship between HbF and the variants in LCR, a fundamental cis-element upstream of β-globin cluster remains largely unclear. In this study, we identified a novel SNP using association studies on capture-based deep sequencing data of 1142 β-thalassemia patients. Further data mining led us to identifying transcription factor USF2 to be a new member of inducing long-range interaction of LCR to β-like globin cluster. We plan to carry out gene-editing, ATAC-seq and 3C to investigate the mechanism of USF2-mediated long-range interaction between LCR and β-like globin genes with two cell lines representing different erythroid developmental stages. The objectives of this study include: 1. The impact of functional SNP on USF2-mediated long-range interaction; 2. Underlying mechanisms of β-like globin switch induced by USF2; 3. The regulating network between USF2 and known erythroid transcription factors. This study can add to our understandings towards mechanism of globin switch and provide theoretical basis of gene-targeted therapy of β-thalassemia.