Chloramphenicol acetyltransferase ( CAT ) activities directed by 5' upstream promoter were detected preferentially in perforin-expressing cell lines .
chloramphenicol acetyltransferase ( cat ) activities directed by 5' upstream promoter were detected preferentially in perforin-expressing cell lines .
B-protein_family_or_group I-protein_family_or_group O B-protein_molecule O O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O O O O B-cell_line I-cell_line I-cell_line O