Regulation of alpha-like globin gene expression in murine primitive erythropoiesis (NG CaptureC)

Haemoglobin, the oxygen-carrying molecule of red blood cells, at all stages of development comprises a tetramer of two α-like and two β-like globin chains. In humans and mice the highly conserved α- and β-globin loci contain genes encoding globin chains specifically expressed only during the first trimester of gestation (termed embryonic globins) in addition to the genes encoding globin chains expressed throughout adult life. In humans the β-globin locus also encodes a β-like chain that is expressed throughout the second and third trimesters of development; this is termed γ-globin and complexes with α-globin to form fetal haemoglobin (HbF). The sequential activation and repression of the genes at each of these loci throughout development to maturity is termed haemoglobin switching and is a poorly understood process. α-thalassemia, which results from insufficient production of α-globin, is a major global health problem with several hundred thousand sufferers world-wide. The embryonically expressed ζ-globin, encoded by the gene HBZ (Hba-x in mice), can functionally substitute for α-globin in adult erythroid cells. Reactivation of this gene is consequently likely to ameliorate the symptoms of α-thalassemia in individuals with a severe phenotype. Little is currently known about the regulation of ζ-globin expression in terms of both the trans- and cis-acting regulatory elements responsible for high-levels of expression of this gene during embryonic erythropoiesis and its maintenance in a transcriptionally inactive state throughout adult life. Using ATACseq and NG Capture C and mutant mouse lines this work aims to identify and define the cis-acting regulatory network underlying zeta-globin expression, and define the contribution of each regulatory element. NG Capture-C combines 3C library preparation with oligonucleotide capture for the desired viewpoint restriction fragments. The method was applied to biological triplicates of embryonic stem cells (ESC), primitive erythroid cells (E10.5), and definitive erythroid cells (Fetal Liver: FL) capturing either promoter or enhancer elements.