HBG1 gene promoter and HBG2 gene promoter (HBG1 and HBG2 promoters)

The HBG1 and HBG2 gene promoters are cis-regulatory regions located just upstream of the gamma-globin genes on chromosome 11. These promoters play a crucial role in regulating the expression of fetal hemoglobin (Hb F), which consists of two alpha and two gamma chains. Variation or targeted editing of these promoters can reactivate gamma-globin expression in adults, offering a therapeutic approach to treating hemoglobinopathies like sickle cell disease and β-thalassemia. Natural mutations in the promoters, such as those seen in hereditary persistence of fetal hemoglobin (HPFH), elevate Hb F and ameliorate disease phenotypes. Genome editing strategies targeting these promoter elements aim to disrupt the binding of repressors (e.g., BCL11A), safely increasing Hb F levels without adverse effects on red blood cell development. These regulatory sequences are not proteins, receptors, or enzymes but are established gene therapy targets due to their central role in hemoglobin switching and disease modulation.

Other names

Gamma-globin gene promoterHBG1 promoterHBG2 promoterHPFH (hereditary persistence of fetal hemoglobin) regulatory elementAgamma promoter (HBG1)Ggamma promoter (HBG2)

Disruption/blocking of repressor binding (e.g., BCL11A repressor element); Activation of gamma-globin gene transcription; Induction of fetal hemoglobin synthesis through promoter editing