Since expression of the viruses is in large part regulated by the sequence elements in their long terminal repeats ( LTRs ) , this study was directed to an analysis of the regulatory elements in the HIV-2 LTR .
since expression of the viruses is in large part regulated by the sequence elements in their long terminal repeats ( ltrs ) , this study was directed to an analysis of the regulatory elements in the hiv-2 ltr .
O O O O O O 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 I-DNA_domain_or_region O B-DNA_domain_or_region O O O O O O O O O O O B-DNA_family_or_group I-DNA_family_or_group O O B-virus O O