Epo caused an increase in the proportion of cells expressing cell surface glycophorin A ( GPA ) and up-regulated beta- and gamma- globin by several fold .
epo caused an increase in the proportion of cells expressing cell surface glycophorin a ( gpa ) and up-regulated beta- and gamma- globin by several fold .
B-protein_family_or_group O O O O O O O O O O O B-protein_molecule I-protein_molecule O B-protein_molecule O O O O O O O O O O O