2669
This shift is apparently not caused by a recruitment phenomenon, because in FCS+ culture , the total number of colonies is not significantly modified by RA addition.
 ( cell line: FCS+ culture, 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:
 ( cell line: FCS+ culture, None) 