Hemoglobin Epsilon 1 (HBe1)

The epsilon globin gene (HBE) is normally expressed in the embryonic yolk sac: two epsilon chains together with two zeta chains (an alpha-like globin) constitute the embryonic hemoglobin Hb Gower I; two epsilon chains together with two alpha chains form the embryonic Hb Gower II. Both of these embryonic hemoglobins are normally supplanted by fetal, and later, adult hemoglobin. The five beta-like globin genes are found within a 45 kb cluster on chromosome 11 in the following order: 5"""-epsilon - G-gamma - A-gamma - delta - beta-3""". HBE gene expression in the definitive erythroblasts of the fetal liver and in the red blood cells of adult animals. The findings provided direct in vivo evidence that cis-acting silencing elements are involved in the developmental control of the HBE gene.