Identification of sequences and factors required for HbF repression

 描述（由申请方提供）：胎儿血红蛋白（HbF）水平是β-血红蛋白疾病镰状细胞病和β-地中海贫血临床严重程度的关键调节因子。的 该提案的目的是确定调节HbF水平的机制，并可作为重新诱导HbF治疗β-血红蛋白疾病的合理目标。全基因组关联研究（GWAS）已经将BCL 11 A鉴定为关键的HbF相关基因座。功能研究表明BCL 11 A是一个真正的γ-珠蛋白转录抑制因子。天然存在的常见遗传变异调节BCL 11 A的红细胞特异性增强子。我们先前的研究确定了GWAS标记的BCL 11 A红系增强子作为与HbF水平相关的常见遗传变异的底物。基因组编辑已经揭示了该增强子内的关键序列，该增强子是成年阶段HbF抑制所需的。我假设这些序列募集关键的反式作用因子，这些因子本身是抑制HbF水平所必需的。此外，我推测，在BCL 11 A和HBS 1 L-MYB基因座的其他关键序列所需的抑制HbF在成人阶段。为了验证这些假设，我将：（1）利用高分辨率，高通量的基因组编辑方法来识别与HbF水平相关的BCL 11 A和HBS 1 L-MYB非编码序列;（2）定义与BCL 11 A和HBS 1 L-MYB关键非编码序列物理和功能相互作用的反式作用因子。我希望这些目标的实现不仅将加深我们目前对珠蛋白基因表达发育调控的顺式和反式作用决定因素的理解，而且还将产生新的见解来指导HbF再诱导的治疗工作。

 DESCRIPTION (provided by applicant): The level of fetal hemoglobin (HbF) is a key modifier of the clinical severity of the β-hemoglobin disorders sickle cell disease and β-thalassemia. The goal of this proposal is to identify mechanisms that regulate HbF level and could serve as rational targets for efforts to re-induce HbF for the β-hemoglobin disorders. Genome- wide association studies (GWASs) have identified BCL11A as a critical HbF-associated locus. Functional studies have demonstrated that BCL11A is a bona fide repressor of γ-globin transcription. Naturally occurring common genetic variation modulates an erythroid-specific enhancer of BCL11A. Our prior studies identified the GWAS-marked erythroid enhancer of BCL11A as the substrate for common genetic variation associated with HbF level. Genome editing has revealed critical sequences within this enhancer required for HbF repression in the adult stage. I hypothesize that these sequences recruit critical trans-acting factors, which themselves are required for suppressing HbF levels. In addition, I hypothesize that other critical sequences at the BCL11A and HBS1L-MYB loci are required to repress HbF in the adult-stage. To test these hypotheses, I will: (1) utilize a high-resolution, high-throughput genome editing approach to identify non-coding sequences at BCL11A and HBS1L-MYB associated with HbF level; and (2) define trans-acting factors that physically and functionally interact with critical on-coding sequences at BCL11A and HBS1L-MYB. I expect that accomplishment of these aims will not only deepen our current understanding of cis- and trans-acting determinants of developmental regulation of globin gene expression but also yield novel insights to guide therapeutic efforts for HbF re-induction.