During development, human beta-globin locus regulation undergoes two critical switches, the embryonic-to-fetal and fetal-to-adult hemoglobin switches. To define the role of the fetal (A)gamma-globin promoter in switching, human beta-globin-YAC transgenic mice were produced with the (A)gamma-globin promoter replaced by the erythroid porphobilinogen deaminase (PBGD) promoter (PBGD(A)gamma-YAC). A...

Mammals have 2 distinct erythroid lineages. The primitive erythroid lineage originates in the yolk sac and generates a cohort of large erythroblasts that terminally differentiate in the bloodstream. The definitive erythroid lineage generates smaller enucleated erythrocytes that become the predominant cell in fetal and postnatal circulation. These lineages also have distinct globin expression pa...

BACKGROUND Human globin gene expression is precisely regulated by a complicated network of transcription factors and chromatin modifying activities during development and erythropoiesis. Eos (Ikaros family zinc finger 4, IKZF4), a member of the zinc finger transcription factor Ikaros family, plays a pivotal role as a repressor of gene expression. The aim of this study was to examine the role of...

Purified human globin injected into rats forms aggregates which are identifiable by their characteristic appearance in thin sections in the electron microscope and by their positive autoradiographs when the globin is tritiated before injection. Globin is taken up by endothelial cells of glomerular capillaries and is transported across the cell within the limits of a surrounding membrane. Globin...

The human leukemia cell line, K562, produces embryonic and fetal hemoglobins and glycophorin A, proteins normally associated only with erythroid cells. Hemoglobin accumulation is enhanced by exposure of the cells to 0.05 mM hemin. We have examined K562 cells before and after exposure to hemin to determine whether expression of these erythroid proteins was shared by all cells or confined to spec...

A variant of hereditary persistence of fetal hemoglobin (HPFH), first described in a patient from Seattle, was studied by structural analysis of the gamma-globin genes. A family study suggested that the determinant for this form of HPFH, in which the HbF contains both G gamma- and A gamma-globin chains, segregated with the beta S gene. No deletions or other abnormalities were detected in the fe...

DNA sequence-specific binding proteins eluted from chicken erythrocyte and thymus nuclei, and fractionated as described by Emerson and Felsenfeld (19), have been investigated by filter binding and footprint analyses. The erythrocyte nuclear protein fraction specifically binds to at least two sites within the 5' flanking chromatin hypersensitive site of the chicken beta A-globin gene, and to a s...

In an effort to activate the globin genes of non-erythroid cells, tetraploid murine erythroleukaemia cells (Friend cells) were fused with diploid human amniotic fibroblasts. When the Friend cells were pretreated with dimethylsulphoxide, an average of 27% heterokaryons was observed. These cells stained with benzidine, an indication that they contained haemoglobin. The cells incorporated radioact...

RNA interference (RNAi), a process by which target messenger RNA (mRNA) is cleaved by small interfering complementary RNA (siRNA), is widely used for investigations of regulation of gene expression in various cells. In this study, siRNA complementary to 5' region of exon II of alpha-globin mRNA was examined for its role in erythroid colony forming cells (ECFCs) isolated from normal peripheral b...

Objectives. Check with hematological data that the diagnosis and clinical grade of β-thalassemia intermedia can be established when a triplication genes alpha (αααanti 3.7) heterozygous are coherent. Methods. Retrospective study in which 73 patients Caucasian origin participated, who simultaneously showed tripling or quadrupling α β-thalassemia. Screening for most frequent α-thalassemia mutatio...