Whereas c-Fos /c-Jun heterodimers do not exist in B cells , they form and bind to the X2-box in class II nonexpressing cells .
whereas c-fos /c-jun heterodimers do not exist in b cells , they form and bind to the x2-box in class ii nonexpressing cells .
O B-protein_molecule B-protein_molecule O O O O O B-cell_line I-cell_line O O O O O O O B-DNA_domain_or_region O B-cell_line I-cell_line I-cell_line I-cell_line O