The locus activation region (LAR) of the human beta-globin-like gene cluster is characterized by a group of four DNase I hypersensitive sites, which arise specifically in erythroid tissues and are required for a normal pattern of beta-globin-like gene expression. The hypersensitive sites are found at positions 6.1, 10.9, 14.7, and 18 kilobase pairs (kbp) 5' of the epsilon-globin gene. Recently ...

High-level beta-globin gene expression is dependent on the presence of the locus control region (LCR), a powerful regulatory element physically characterized by five DNase I-hypersensitive sites (HS), designated HS1-HS5. Of these, HS3 contains seven GT motifs that are essential for its activity. One of the motifs, GT6, has been shown by in vivo footprinting to display the largest difference in ...

Correct developmental regulation of beta-like globin gene expression is achieved by preferential transcription of a gene at a given developmental stage, silencing of other beta-like gene promoters, and competition among these promoters for interaction with the locus control region (LCR). Several evolutionarily conserved DNA elements in the promoters of the beta-like genes and LCR have been stud...

Lemur beta-related globin genes have been isolated and sequenced. Orthology of prosimian and human epsilon-, gamma-, and beta-related globin genes was established by dot-matrix analysis. All of these lemur globin genes potentially encode functional beta-related globin polypeptides, though precisely when the gamma-globin gene is expressed remains unknown. The organization of the 18-kb brown lemu...

Sickle cell disease is characterized by a very heterogeneous clinical course among patients with the same mutations for sickle hemoglobin (HbS). anemia (SCA) hereditary hemoglobinopathy caused homozygosity of point mutation in beta-globin gene, which leads to substitution glutamic acid valine sixth position.

A single base substitution (A-G) at position -31 within the highly conserved proximal promoter element, the TATA box, was identified in the beta-globin gene cloned from a Japanese woman with beta +-thalassemia. It appears that she is homozygous for this specific allele, as determined by haplotype analysis using seven different polymorphic sites in the beta-globin gene cluster. Transient express...

Globin messenger RNA (mRNA) isolated from three patients homozygous for hemoglobin Lepore is shown to have a marked reduction of the amount of beta-like globin mRNA (Lepore-globin mRNA sequences) compared with alpha-globin mRNA by molecular hybridization. The relative amounts of alpha- and Lepore mRNA are similar to the amounts of alpha- and Lepore globin synthesized in intact cells and by isol...

The human beta-globin locus control region (LCR) consists of five erythroid-lineage-specific DNase I-hypersensitive sites (HSs) and is required for activation of the beta-globin locus chromatin domain and globin gene expression. Each DNase I-HS of the LCR consists of a highly conserved core element and flanking sequences. To analyze the functional role of the core elements of the HSs, we delete...

Beta-thalassemia (β-thal) is a congenital hemoglobinopathy explained by a decreased level (β+) or absence (βο) of β-globin gene expression. Microcytic hypochromic anemia and various clinical symptoms comprising severe anemia to clinically nonsymptomatic features. Treatment with an ordered blood transfusion and iron chelator agents can decrease transfusion iron overload that causes normal matura...

Transgenic mice were generated which carried the adult alpha and beta-globin genes and the major tadpole specific beta-globin gene of Xenopus laevis. The adult specific alpha and beta genes were found to express in erythroid tissues in adult mice, while the major tadpole specific beta gene (beta T1) was expressed in blood from 12.5 day embryos. The pattern of expression of the beta T1 gene duri...