title: Hemoglobin biosynthesis in individual bursts from human adult peripheral and umbilical cord blood: analysis of the relative rates of synthesis of G gamma and A gamma globin chains.
abstract: We cultured human adult peripheral and umbilical cord blood mononuclear cells in methylcellulose and measured the synthetic rates of globin chains in individual erythropoietic bursts. Globin chains were labeled with 14C-amino acids in culture, separated by isoelectric focusing in slab gels containing 8 M urea and 3% Nonidet P-40, and quantitated by fluorographic methods. All bursts exhibited G gamma, A gamma, and beta chains in varying ratios. Cumulative frequency distributions of individual bursts differing in the ratios of G gamma/(G gamma + A gamma) and gamma/(gamma + beta) approached normal distributions. These results indicated that perinatal hemoglobin switching and the hemoglobin switching of cultured adult erythropoietic precursors do not involve population changes in the precursors. Further, a positive correlation between gamma/(gamma + beta) and G gamma/(G gamma + A gamma) ratios of individual bursts existed in all of the samples. Switching between gamma and beta chains and switching of G gamma: A gamma ratios may share common regulatory mechanisms.
mesh_terms: D002478:Cells, Cultured; D004920:Erythropoiesis; D005319:Fetal Hemoglobin / Q000096:biosynthesis; D005786:Gene Expression Regulation; D005914:Globins / Q000096:biosynthesis* / Q000235:genetics; D006441:Hemoglobin A / Q000096:biosynthesis; D006454:Hemoglobins / Q000096:biosynthesis*; D006801:Humans
chemical_list: D006454:Hemoglobins; D005914:Globins; D006441:Hemoglobin A; D005319:Fetal Hemoglobin