Mi2β-mediated silencing of the fetal γ-globin gene in adult erythroid cells

M Amaya, M Desai… - Blood, The Journal …, 2013 - ashpublications.org
M Amaya, M Desai, MN Gnanapragasam, SZ Wang, S Zu Zhu, DC Williams Jr, GD Ginder
Blood, The Journal of the American Society of Hematology, 2013ashpublications.org
An understanding of the human fetal to adult hemoglobin switch offers the potential to
ameliorate β-type globin gene disorders such as sickle cell anemia and β-thalassemia
through activation of the fetal γ-globin gene. Chromatin modifying complexes, including
MBD2-NuRD and GATA-1/FOG-1/NuRD, play a role in γ-globin gene silencing, and Mi2β
(CHD4) is a critical component of NuRD complexes. We observed that knockdown of Mi2β
relieves γ-globin gene silencing in β-YAC transgenic murine chemical inducer of …
Abstract
An understanding of the human fetal to adult hemoglobin switch offers the potential to ameliorate β-type globin gene disorders such as sickle cell anemia and β-thalassemia through activation of the fetal γ-globin gene. Chromatin modifying complexes, including MBD2-NuRD and GATA-1/FOG-1/NuRD, play a role in γ-globin gene silencing, and Mi2β (CHD4) is a critical component of NuRD complexes. We observed that knockdown of Mi2β relieves γ-globin gene silencing in β-YAC transgenic murine chemical inducer of dimerization hematopoietic cells and in CD34+ progenitor-derived human primary adult erythroid cells. We show that independent of MBD2-NuRD and GATA-1/FOG-1/NuRD, Mi2β binds directly to and positively regulates both the KLF1 and BCL11A genes, which encode transcription factors critical for γ-globin gene silencing during β-type globin gene switching. Remarkably, <50% knockdown of Mi2β is sufficient to significantly induce γ-globin gene expression without disrupting erythroid differentiation of primary human CD34+ progenitors. These results indicate that Mi2β is a potential target for therapeutic induction of fetal hemoglobin.
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