In most HIV-1 isolates in which this PU box was not conserved , it was replaced by a binding site for the related factor Ets1 .
in most hiv-1 isolates in which this pu box was not conserved , it was replaced by a binding site for the related factor ets1 .
O O B-virus I-virus O O O B-DNA_domain_or_region I-DNA_domain_or_region O O O O O O O O O B-DNA_domain_or_region I-DNA_domain_or_region O O O O B-protein_molecule O