To test these hypotheses , we studied several tat mutants , including two stop codon mutants and one deletion mutant using replication-competent HIV-1 constructs carrying wild-type or mutant LTRs with modifications in the NF-kappa B and/or Sp1 binding sites .
to test these hypotheses , we studied several tat mutants , including two stop codon mutants and one deletion mutant using replication-competent hiv-1 constructs carrying wild-type or mutant ltrs with modifications in the nf-kappa b and/or sp1 binding sites .
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