To determine whether these different X1 box activities represented distinct DNA binding proteins or multimeric forms of the same factor ( s ) , protease treatment of the crude nuclear extracts followed by DNA-binding assays were carried out and demonstrated that B cell extracts contain at least two X1-specific factors .
to determine whether these different x1 box activities represented distinct dna binding proteins or multimeric forms of the same factor ( s ) , protease treatment of the crude nuclear extracts followed by dna-binding assays were carried out and demonstrated that b cell extracts contain at least two x1-specific factors .
O O O O O B-other_name I-other_name I-other_name O O B-protein_family_or_group I-protein_family_or_group I-protein_family_or_group O O O O O O O O O O O B-protein_family_or_group O O O O O O O O B-other_name I-other_name O O O O O O B-cell_component I-cell_component I-cell_component O O O O B-protein_family_or_group I-protein_family_or_group O