Hemoglobin expression in clones of K562 cell line.

The K562 cell line was cloned by dilution and the pattern of hemoglobin (Hb) production was analyzed in the clones thus obtained. The pattern of hemoglobin synthesis was different from one clone to another. According to the Hb phenotype the clones were classified in three main groups; group I no detectable Hb; group II Hb Portland; group III Hb Portland + Hb Gower I. The addition of hemin induced a better hemoglobinization and a shift in the pattern of Hb production: clones of group I were induced to produce Hb Portland and clones of group II to synthesize Hb Gower I. A constant order in the sequential expression of the different hemoglobins was observed: no Hb leads to Hb Portland + Hb Gower I. The proportion of the different globin chains varied from one clone to another, but an inverse correlation between the synthesis of G gamma and epsilon chains was observed. The alpha/non-alpha chain ratio was unbalanced in all the clones and the addition of hemin induced only a moderate increase of the synthesis of alpha chains. Recloning of three primary clones increased the homogeneity of the hemoglobin pattern, in particular after hemin induction.