Human erythropoietin gene: high level expression in stably transfected mammalian cells and chromosome localization

The glycoprotein hormone erythropoietin plays a major role in regulating erythropoiesis and deficiencies of erythropoietin result in anemia. Detailed studies of the hormone and attempts at replacement therapy have been difficult due to the scarcity of purified material. We used a cloned human erythropoietin gene to develop stably transfected mammalian cell lines that secrete large amounts of the hormone with potent biological activity. These cell lines were produced by cotransfection of mammalian cells with a plasmid containing a selectable marker and plasmid constructions containing a cloned human erythropoietin gene inserted next to a strong promoter. The protein secreted by these cells stimulated the proliferation and differentiation of erythroid progenitor cells and, with increased selection, several of these cell lines secrete up to 80 mg of the protein per liter of supernatant. Hybridization analysis of DNA from human chromosomes isolated by high resolution dual laser sorting provides evidence that the gene for human erythropoietin is located on human chromosome 7.