In addition , in vivo footprint analysis showed the putative X and Y boxes to be occupied by transcription factors in wild-type B cells , but not in RFX -deficient B cells .
in addition , in vivo footprint analysis showed the putative x and y boxes to be occupied by transcription factors in wild-type b cells , but not in rfx -deficient b cells .
O O O O O O O O O O O O O O O O O O B-protein_family_or_group I-protein_family_or_group O B-cell_type B-cell_type I-cell_type O O O O B-protein_family_or_group O O O O