The Study Of The Mechanisms Of γ-globin Gene Reactivation In Non-deletion HPFH And Yunnanese(Aγδβ)～0-thalassemia In Transgenic Mice

The human P-like globin genes are a good model system for the studying of eukaryotic gene regulation, since they represent a family of genes that are expressed in a tissue-specific and developmentally stage-specific fashion. The human P-globin locus contains five functional genes in the order 5'-ε-Gγ-Aγ-δ-β-3'. During ontogeny, expression of these genes undergoes two developmental switches, from embryonic (ε) to fetal (Gγ and Aγ) during the early gestational period and from fetal to adult (δ and β) during the perinatal period. The human γ-globin genes express mainly in the fetal liver and their products become less than 1% of the total P-like globin chains in adult erythroid cells. However, naturally occurring deletion or point mutations within the β-globin gene cluster may interfere with the fetal-to-adult switching and result in the expression of the y-globin genes persisting at high levels in adults. These benign conditions are known as hereditary persistence of fetal hemoglobin (HPFH) and (δβ)°-thalassemia. The natural mutants provide the favorite molecular models for studying the mechanisms of hemoglobin switching. Furthermore, the increase of fetal hemoglobin (HbF, α₂γ₂) can ameliorate the clinical symptoms of inherited abnormalities of P-globin gene expression, such as β-thalassemia and sickle cell anemia. The investigations of these natural mutants may contribute to elucidation of the mechanisms of hemoglobin switching as well as provide certain strategies for gene therapy of β-thalassemia and sickle cell anemia.Recently, with the development of transgenic technology, producing transgenic animal model has become an important way to study the expression regulation of eukaryotic genes. Transgenic technique can not only design experiments on molecular level but also observe the involvement of almost all the factors affecting gene expression, which permits the further investigations of in vivo effect of gene regulation.In this study, we firstly construct the recombinant cosmid μLCRAγψβδβ that contains 29kb of Aγ-,δ-,β-globin genes with the natural chromosome arrangement and a 3.1kb subset with the core sequences of HS1⁴. After purification of the foreign...