Developmental stage specific chromosome architecture in human erythroid cells (Capture-C)

Chromatin structure is tightly intertwined with transcription regulation. Here we compared the chromosomal architectures of fetal and adult human erythroblasts and find that globally, chromatin structures and compartments A/B are highly similar at both developmental stages. At a finer scale, we detect distinct folding patterns at the developmentally controlled b-globin locus. Specifically, new fetal stage-specific contacts are uncovered between a region separating the fetal (g-) and adult (b-) globin genes (encompassing the HBBP1 and BGLT3 non-coding genes) and two distal chromosomal sites (HS5 and 3'HS1) that flank the locus. In contrast, in adult cells the HBBP1-BGLT3 region contacts the embryonic e-globin gene, physically separating the fetal globin genes from the enhancer (LCR). Removal of the HBBP1 gene strongly reactivates g-globin expression, accompanied by increased LCR-g-globin and decreased BGLT3-e-globin interactions, mimicking the effects of deleting the fetal globin repressor BCL11A. Our results uncover a new critical regulatory region as a potential target for therapeutic genome editing for hemoglobinopathies and highlight the power of chromosome conformation analysis in discovering new cis control elements. We compared the chromatin structures of the developmentally controlled β-globin locus by Capture-C.