The retinoblastoma gene product ( Rb ) is a nuclear phosphoprotein that regulates cell cycle progression .
the retinoblastoma gene product ( rb ) is a nuclear phosphoprotein that regulates cell cycle progression .
O B-protein_molecule I-protein_molecule I-protein_molecule O B-protein_molecule O O O B-protein_family_or_group I-protein_family_or_group O O B-other_name I-other_name I-other_name O