Human Globin Gene Regulation During Development

描述(申请人提供)：人类从胎儿到成人的血红蛋白转换是由转录因子调节的，这些转录因子增强或抑制伽马或β-珠蛋白基因与强大的基因位点控制区的相互作用。我们最近证实，在人类和小鼠的成年红系祖细胞中，KLF1基因的敲除降低了BCL11A水平，并增加了人类伽马和β-珠蛋白基因的表达比率。这些结果表明，KLF1通过直接激活β-珠蛋白和间接抑制γ-珠蛋白基因表达来控制珠蛋白基因的切换。此外，我们最近还分离到一种蛋白(FOKLF1；KLF1的朋友)，它与KLF1形成络合物并激活β-珠蛋白基因的表达。有趣的是，FOKLF1基因的敲除显著增加了人类伽马和β-珠蛋白基因的比例。这些结果提示，对成人红系祖细胞进行FOKLF1的可控性基因敲除或药物抑制，可能为β-地中海贫血和镰状细胞病患者提供了一种激活胎儿血红蛋白的方法。我们建议的具体目标如下：(1)定义对伽马到β-珠蛋白基因至关重要的FOKLF1结构域(2)定义FOKLF1和KLF1基因调控元件，这些基因调控元件负责这些基因在发育过程中的上调。(3)鉴定具有FOKLF1基因突变/变异的遗传性胎儿血红蛋白持续性(HPFH)个体。 公共卫生相关性：我们最近分离出一种蛋白(FOKLF1；KLF1的朋友)，它在成年最终祖细胞中与KLF1相互作用，并激活β-珠蛋白基因的表达。有趣的是，FOKLF1基因的敲除显著增加了人类伽马和β-珠蛋白基因的比例。这些结果提示，在成人红系祖细胞中对FOKLF1进行受控敲除或药物抑制，可能为β-地中海贫血和镰状细胞病患者提供了一种激活胎儿血红蛋白的方法。

DESCRIPTION (provided by applicant): The switch from fetal to adult hemoglobin in humans is regulated by transcription factors that enhance or inhibit interactions of the gamma- or beta-globin gene with the powerful Locus Control Region. We recently demonstrated that knockdowns of KLF1 in human and mouse adult erythroid progenitors reduce BCL11A levels and increase human gamma- to beta-globin gene expression ratios. These results suggest that KLF1 controls globin gene switching by directly activating beta-globin and indirectly repressing gamma-globin gene expression. In addition, we have recently isolated a protein (FOKLF1; Friend of KLF1) that complexes with KLF1 and activates beta-globin gene expression. Interestingly, knockdowns of FOKLF1 dramatically increase human gamma- to beta-globin gene ratios. These results suggest that controlled knockdown or pharmacological inhibition of FOKLF1 in adult erythroid progenitors may provide a method for activating fetal hemoglobin in patients with beta-thalassemia and sickle cell disease. The Specific Aims of our proposal are as follows: (1) To define FOKLF1 domains essential for gamma- to beta-globin genes witching (2) To define FOKLF1 and KLF1 gene regulatory elements responsible for the up-regulation of these genes during development. (3) To identify HPFH (Hereditary Persistence of Fetal Hemoglobin) individuals who have mutations/variations in the FOKLF1 gene. PUBLIC HEALTH RELEVANCE: We have recently isolated a protein (FOKLF1; Friend of KLF1) that interacts with KLF1 in adult definitive progenitors and activates beta-globin gene expression. Interestingly, knockdowns of FOKLF1 dramatically increase human gamma- to beta-globin gene ratios. These results suggest that controlled knockdown or pharmacological inhibition of FOKLF1 in adult erythroid progenitors may provide a method for activating fetal hemoglobin in individuals with beta-thalassemia and sickle cell disease.