In lymphoid cells , only the upstream sequences are required for transactivation by the Z/R combination , and the AP-1 site is dispensable .
in lymphoid cells , only the upstream sequences are required for transactivation by the z/r combination , and the ap-1 site is dispensable .
O B-cell_type I-cell_type O O O B-DNA_domain_or_region I-DNA_domain_or_region O O O O O O B-protein_molecule O O O O B-protein_domain_or_region I-protein_domain_or_region O O O