5154
We demonstrate that loss of p16 causes upregulation of this DNA precursor pathway enzyme via activation of E2F by a mechanism involving retinoblastoma protein .
 ( protein: enzyme, None) , ( protein: p16, None) , ( protein: E2F, None) , ( protein: retinoblastoma protein, 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: enzyme, None) , ( protein: p16, None) , ( protein: E2F, None) , ( protein: retinoblastoma protein, None) 