2704
Electrophoretic mobility shift assays indicate that MS-2beta and MS-2gamma interact with nuclear factors that are induced during U937 differentiation .
 ( protein: MS-2gamma, None) , ( cell line: U937, None) , ( protein: MS-2beta, None) , ( protein: nuclear factors, 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: MS-2gamma, None) , ( cell line: U937, None) , ( protein: MS-2beta, None) , ( protein: nuclear factors, None) 