BCL11A-deficient human erythropoiesis is impaired in vitro and after xenotransplantation into mice

• BCL11A disruption impairs erythroid precursor expansion in vitro and after xenotransplantation into immunodeficient mice

• BCL11A regulates at least 25 genes directly and numerous others indirectly in erythroid precursors

Genetic depletion of the transcriptional repressor BCL11A in red blood cell precursors alleviates b-hemoglobinopathies by inducing the fetal g-globin genes. However, additional erythroid genes are regulated by BCL11A and the effects of its deficiency on erythropoiesis are insufficiently described. We discovered that Cas9 disruption of the BCL11A intron 2 erythroid enhancer in CD34+ hematopoietic stem and progenitor cells using a clinically approved strategy caused impaired expansion and apoptosis of erythroid precursors in vitro and reduced repopulation of the erythroid compartment after xenotransplantation into immunodeficient mice. Mutant colony-forming unit erythroid cells, proerythroblasts and basophilic erythroblasts exhibited dysregulation of 94 genes (> 2-fold change, FDR < 0.05), 25 of which are likely direct targets of BCL11A. Differentially expressed genes were associated with a range of biological pathways that impact cell expansion and survival. Our findings show that BCL11A regulates additional aspects of erythropoiesis beyond g-globin gene repression, with unknown clinical consequences.