9916
In previous work, we identified an essential site in the c-sis/PDGF-B promoter , Tax-responsive element 1 ( TRE1 ), necessary for transactivation by Tax .
 ( DNA: Tax-responsive element 1, None) , ( DNA: TRE1, None) , ( DNA: c-sis/PDGF-B promoter, None) , ( protein: Tax, None) , ( protein: c-sis/PDGF-B, 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:
 ( DNA: Tax-responsive element 1, None) , ( DNA: TRE1, None) , ( DNA: c-sis/PDGF-B promoter, None) , ( protein: Tax, None) , ( protein: c-sis/PDGF-B, None) 