MB-02 cells undergo fetal to adult globin gene switching in response to erythropoietin

The recently described MB-02 human cell line requires Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) for continuous growth and terminally differentiates into enucleate, hemoglobinized cells in response to erythropoietin. Here, analysis of globin production now demonstrates that uninduced MB-02 cells produce alpha globin and the fetal globin chains G gamma and A gamma in a ratio of 1:3. Addition of erythropoietin results in de novo synthesis of beta globin chains and a marked increase in total Hb/cell. Thus, the MB-02 cell line partially recapitulates the fetal to adult globin switch that occurs during erythroid and human fetal development and provides a new clonal human erythroid progenitor system for investigating the biochemical and molecular events involved in globin gene switching.