EMS supershift analyses have demonstrated that Sp1 is involved in U1A formation while Sp3 is involved in U1B and U2 formation .
ems supershift analyses have demonstrated that sp1 is involved in u1a formation while sp3 is involved in u1b and u2 formation .
B-other_name I-other_name I-other_name O O O B-protein_molecule O O O B-other_name I-other_name O B-protein_molecule O O O O O O O O