Cell culture experiments demonstrated that the natural variant with four Sp1 sites had a slightly higher promoter activity and viral replication rate than the isogenic control LTR with three Sp1 sites .
cell culture experiments demonstrated that the natural variant with four sp1 sites had a slightly higher promoter activity and viral replication rate than the isogenic control ltr with three sp1 sites .
B-other_name I-other_name I-other_name O O O O O O O B-protein_N/A O O O O O O O O O O O O O B-DNA_domain_or_region I-DNA_domain_or_region I-DNA_domain_or_region O O B-protein_N/A O O