The embryo-larval and adult parts of the zebrafish major alpha/beta-globin gene locus are functionally and structurally independent

We have demonstrated that, in developing Danio rerio, the embryo-larval and adult subloci of the major globin locus acquire stage-specific hyperacetylation of histone H3 and that H3 hyperacetylation profiles differ significantly between the embryo-larval sublocus (high level of acetylation within gene bodies but not in intergenic regions) and adult sublocus (extended domains of H3 acetylation covering both gene bodies and intergenic regions). The spatial organization of the two subloci is also found to be different. Whereas the adult sublocus is organized into a relatively compact contact domain, the embryo-larval sublocus has a rather low density of spatial contacts. Finally, we have demonstrated that the conserved upstream enhancer of the locus establishes spatial contacts with transcribed adult genes, but not with transcribed embryo-larval genes, and that the embryo-larval and adult subloci of the major globin gene locus are separated by an insulator colocalizing with a CTCF-binding site. 5C analysis of the major alpha/beta-globin gene domain in erythroid cells of Danio rerio