A natural regulatory mutation in the proximal promoter elevates fetal globin expression by creating a de novo GATA1 site
A natural regulatory mutation in the proximal promoter elevates fetal globin expression by creating a de novo GATA1 site
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DOI：
10.1182/blood-2018-07-863951
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发表时间：
2019-02-21
期刊：
影响因子：
20.3
通讯作者：
Crossley, Merlin
中科院分区：
文献类型：
--
作者：
Martyn, Gabriella E.;Wienert, Beeke;Crossley, Merlin
β-血红蛋白病如镰状细胞病和β-地中海贫血是由成人β-珠蛋白基因突变引起的。重新激活发育沉默的胎儿γ-珠蛋白基因可提高胎儿血红蛋白水平并改善β-血红蛋白病的症状。胎儿γ-珠蛋白持续表达到成年期是在称为胎儿血红蛋白遗传持续性（HPFH）的遗传条件下自然发生的。胎儿γ-珠蛋白近端启动子的点突变可引起HPFH。-113 A>G HPFH突变福尔斯属于HPFH突变的2115簇，其为胎儿球蛋白阻遏物BCL 11 A的结合位点。我们证明，-113 A>G HPFH突变，不像簇中的其他突变，不破坏BCL 11 A结合，而是创建一个从头结合位点的转录激活因子GATA 1。使用成簇的规则间隔短回文重复序列（CRISPR）-CRISPR相关蛋白9（Cas9）系统将-113 A>G HPFH突变引入红系细胞增加了GATA 1结合并提高了胎儿球蛋白水平。这些结果揭示了-113 A>G HPFH突变提高胎儿珠蛋白的机制，并证明了胎儿珠蛋白启动子对点突变的敏感性，点突变通常破坏阻遏物结合位点，但在此产生了红细胞激活物的从头位点。
beta-hemoglobinopathies, such as sickle cell disease and beta-thalassemia, result from mutations in the adult beta-globin gene. Reactivating the developmentally silenced fetal gamma-globin gene elevates fetal hemoglobin levels and ameliorates symptoms of beta-hemoglobinopathies. The continued expression of fetal gamma-globin into adulthood occurs naturally in a genetic condition termed hereditary persistence of fetal hemoglobin (HPFH). Point mutations in the fetal gamma-globin proximal promoter can cause HPFH. The -113A>G HPFH mutation falls within the 2115 cluster of HPFH mutations, a binding site for the fetal globin repressor BCL11A. We demonstrate that the -113A>G HPFH mutation, unlike other mutations in the cluster, does not disrupt BCL11A binding but rather creates a de novo binding site for the transcriptional activator GATA1. Introduction of the -113A>G HPFH mutation into erythroid cells using the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) system increases GATA1 binding and elevates fetal globin levels. These results reveal the mechanism by which the -113A>G HPFH mutation elevates fetal globin and demonstrate the sensitivity of the fetal globin promoter to point mutations that often disrupt repressor binding sites but here create a de novo site for an erythroid activator.