Hemoglobin Synthesis in 7-Day and 14-Day-Old Erythroid Colonies from the Bone Marrow of Normal Individuals

Abstract

Bone marrow cells from hematologically normal subjects were obtained by aspiration in 19 cases and by surgery in two cases; erythroid colonies were subsequently cultured from these cells in plasma clots. The hemoglobins synthesized in culture were studied either by incubation of the cells at the 6th-7th day of culture, or at the 13th-l4th day of culture with ³H-leucine, in order to determine whether the reactivation of fetal hemoglobin (Hb F) in vitro was related to the stage of differentiation of the erythroid precursors. Hemoglobins synthesized in culture were specifically purified from other proteins by affinity chromatography on Sepharose-haptoglobin and were analyzed by separation of globin chain on carboxy-methyl-cellulose in urea. In 14-day-old cultures, reactivation of Hb F synthesis was observed in all cases but one (mean value 8.2%, range 2.3% to 17.7%). In the 7-day-old cultures, a lower proportion of Hb F synthesis was observed (mean value 4.2%, range 1.6% to 7.6%).

These results indicate that the reactivation of Hb F synthesis is related to the stage of differentiation of the erythroid precursors.