Natural regulatory mutations elevate fetal globin via disruption of BCL11A or ZBTB7A binding

B-hemoglobinopathies such as Sickle Cell Disease (SCD) and b-thalassemia result from mutations in the adult b-globin gene. Reactivating the developmentally silenced fetal g-globin gene is a therapeutic goal for treating SCD and b-thalassemia1. Some forms of Hereditary Persistence of Fetal Hemoglobin (HPFH), a rare benign condition in which individuals express g‑globin throughout adulthood, are caused by point mutations in the g‑globin gene promoter at regions residing ~115 and 200 base pairs upstream of the transcription start site. Here we show that the major fetal globin repressors BCL11A and ZBTB7A/LRF directly bind to the -115 and ‑200 sites, respectively. Furthermore, introduction of naturally occurring HPFH mutations into erythroid cells by CRISPR/Cas9 disrupts repressor binding and raises g‑globin expression. These findings resolve the mystery surrounding how these HPFH mutations operate and demonstrate that BCL11A and ZBTB7A/LRF are major direct repressors of the fetal globin gene. ChIP-seq experiments were performed in two different cell lines, HUDEP-2 and K562 against BCL11A and ZBTB7A. Input samples were used as control.