This employs an Escherichia coli tester strain carrying a modified lac operon as a reporter gene , with the lac operator sequence replaced by an octamer sequence .
this employs an escherichia coli tester strain carrying a modified lac operon as a reporter gene , with the lac operator sequence replaced by an octamer sequence .
O O O B-mono_cell I-mono_cell I-mono_cell I-mono_cell O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O O B-DNA_family_or_group I-DNA_family_or_group O O O O O O O O O B-DNA_domain_or_region I-DNA_domain_or_region O