Three subtypes of retinoic acid receptors ( RAR ) , termed RAR alpha , RAR beta , and RAR gamma , have been described .
three subtypes of retinoic acid receptors ( rar ) , termed rar alpha , rar beta , and rar gamma , have been described .
O O O B-other_organic_compound I-other_organic_compound O O B-protein_family_or_group O O O B-protein_molecule I-protein_molecule O B-protein_molecule I-protein_molecule O O B-protein_molecule I-protein_molecule O O O O O