766
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 .
 ( protein: deletion mutant, None) , ( DNA: replication-competent HIV-1 constructs, None) , ( protein: stop codon mutants, None) , ( protein: tat mutants, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: deletion mutant, None) , ( DNA: replication-competent HIV-1 constructs, None) , ( protein: stop codon mutants, None) , ( protein: tat mutants, None) 