4280
The Tax protein of human T-cell lymphotropic virus type 1 ( HTLV-1 ) is a 40-kDa transcriptional activator which is critical for HTLV-1 gene regulation and virus-induced cellular transformation .
 ( protein: Tax protein, None) , ( protein: 40-kDa transcriptional activator, 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: Tax protein, None) , ( protein: 40-kDa transcriptional activator, None) 