title: The in vivo expression of the globin genes of the beta cistron in gamma-, delta-, and delta beta-thalassemia heterozygotes.
abstract: There is considerable evidence suggesting that the switch from gamma to delta and beta chain production after birth is due, in part, to silencing of the gamma genes by stage-specific factors which bind to their promoters and to the competition from the adult (delta and beta) genes for a common enhancer element located in the locus control region. As a consequence one can expect that the increased Hb F production in adults with hereditary persistence of fetal hemoglobin or delta beta-thalassemia is directed mainly by gamma-globin genes in cis to the deletion(s) responsible for these conditions. Here we review data on heterozygotes with gamma-, delta- or delta beta-thalassemia, who also had an A gamma T mutation, in cis or in trans, which was used as a marker of gamma gene expression. The results show that a deletion affecting adult beta genes favors the expression of gamma genes in cis, while the deletion of a single gamma gene does not affect the expression of the beta gene in cis but leads to a faster gamma-->beta switch postnatally.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912-2100.
authors.forename: A J
authors.initials: AJ
authors.lastname: Dimovski
authors.forename: A D
authors.initials: AD
authors.lastname: Adekile
authors.forename: T H
authors.initials: TH
authors.lastname: Huisman
mesh_terms: D017353:Gene Deletion; D005796:Genes; D005914:Globins / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D005810:Multigene Family; D013789:Thalassemia / Q000235:genetics*; D017086:beta-Thalassemia / Q000235:genetics
chemical_list: D005914:Globins