Promoter competition in globin gene control

In this issue of Blood, in an elegant blending of natural history and modern directed genome editing, Topfer et al provide strong evidence for a simple but compelling model of the role of promoter competition in the switching of hemoglobin production during development.1 Controlling this switch to reactivate production of fetal hemoglobin (HbF) in adult erythroid cells offers promising therapeutic avenues for inherited hemoglobinopathies such as sickle cell disease and 13-thalassemia. The study by Topfer et al resolves some issues that have been under investigation for more than half a century and culminates in a unifying model for the impact of deletions within the HBB gene cluster (encoding all the 13-like globins) on expression of fetal HBG genes (HBG1 and HBG2 encoding the Ag- and Gg-globins, respectively).

Automated summary

In this study, Topfer et al use a combination of natural history and modern genome editing techniques to provide evidence for the role of promoter competition in the switching of hemoglobin production. Their findings offer promising therapeutic approaches for inherited hemoglobin disorders and resolve a long-standing issue, proposing a unifying model.