However , these cells have been impossible to generate given the requirement of GATA-1 for Epo receptor expression and red cell viability ( C . Simon and S . Orkin , unpublished observations ) .
however , these cells have been impossible to generate given the requirement of gata-1 for epo receptor expression and red cell viability ( c . simon and s . orkin , unpublished observations ) .
O O O O O O O O O O O O O B-protein_molecule O B-protein_family_or_group I-protein_family_or_group O O B-cell_type I-cell_type O O O O O O O O O O O O O O