In contrast , deletion of the upstream portion of the delta promoter led to a 10 fold decrease in expression .
in contrast , deletion of the upstream portion of the delta promoter led to a 10 fold decrease in expression .
O O O O O O B-DNA_domain_or_region I-DNA_domain_or_region O O B-DNA_domain_or_region I-DNA_domain_or_region O O O O O O O O O