tokens: However , viruses containing mutations in either the TAR loop sequences or stem secondary structure which were very defective for gene expression in untreated Jurkat cells , gave nearly wild-type levels of gene expression in phorbol ester -treated Jurkat cells but not in phorbol ester -treated HeLa or U937 cells .
folded_tokens: however , viruses containing mutations in either the tar loop sequences or stem secondary structure which were very defective for gene expression in untreated jurkat cells , gave nearly wild-type levels of gene expression in phorbol ester -treated jurkat cells but not in phorbol ester -treated hela or u937 cells .
labels: O O B-virus O B-other_name O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O B-DNA_substructure I-DNA_substructure I-DNA_substructure O O O O O B-other_name I-other_name O O B-cell_line I-cell_line O O O B-other_name I-other_name O B-other_name I-other_name O B-other_organic_compound I-other_organic_compound O B-cell_line I-cell_line O O O B-other_organic_compound I-other_organic_compound O O O B-cell_line I-cell_line O