8516
The regulatory regions of several genes specifically expressed in B cells contain functional binding sites for Oct2 .
 ( protein: Oct2, None) , ( DNA: regulatory regions, None) , ( DNA: functional binding sites, None) , ( cell type: B cells, 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: Oct2, None) , ( DNA: regulatory regions, None) , ( DNA: functional binding sites, None) , ( cell type: B cells, None) 