Lewis W, Lee JD, Dodgson JB. Adult chicken alpha-globin gene expression in transfected QT6 quail cells: evidence for a negative regulatory element in the alpha D gene region.
Nucleic Acids Res 1991;
19:5321-9. [PMID:
1656392 PMCID:
PMC328894 DOI:
10.1093/nar/19.19.5321]
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Abstract
The chicken adult alpha-globin genes, alpha A and alpha D, are closely linked in chromosomal DNA and are coordinately expressed in vivo in an approximate 3:1 ratio, respectively. When subcloned DNAs containing one or the other gene are stably transfected into QT6 quail fibroblasts, the alpha A-globin gene is expressed at measurable RNA levels, but the alpha D gene is not. The alpha A gene expression can be considerably increased by the presence of a linked Rous sarcoma virus long terminal repeat enhancer, but that of the alpha D gene remains undetectable. Transfection with subclones containing both genes, either in cis or in trans, leads to considerably reduced alpha A RNA levels and still no observable alpha D gene expression. Transfection with deleted subclones suggests that maximal expression levels in this system require the alpha A-globin gene promoter, as opposed to that of the alpha D gene, but that such expression is greatly reduced by one or more DNA sequences which lie approximately 2,000 base pairs upstream of the alpha A gene, within the body of the alpha D gene.
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