CHANGING RATES OF GLOBIN CHAIN SYNTHESIS DURING ERYTHROID CELL MATURATION IN THALASSEMIA

The rates of synthesis of the α-, β- and γ-chains of hemoglobin by reticulocytes of patients with β-thalassemia major were compared to those in nucleated erythroid precursors from the same individuals. Nucleated erythroid precursors were freed from reticulocyte contamination by Dextran sedimentation. Cells were incubated with radioactive amino acids, solubilized in cold acid-acetone and their globin chains separated by carboxymethyl cellulose chromatography in 8 m-urea. β-Chain synthesis was 1.5-fold greater in thalassemic nucleated erythroid precursors than in reticulocytes. This decrease in the relative rate of β-chain synthesis with cell development is compatible with an increased rate of decay of the β-chain synthesizing capacity, which may be unique to thalassemic erythroid cells. γ-Chain synthesis in thalassemic nucleated erythroid precursors appeared to occur at only one-half the rate of reticulocyte γ-chain synthesis. This difference may reflect selective survival of thalassemic cells with higher rates of γ-chain synthesis. © 1969.