1937
Hence, we propose that a necessary prerequisite of enhancer activity is the B-cell-specific displacement of a ZEB -like repressor by bHLH proteins .
 ( protein: bHLH proteins, None) , ( protein: ZEB -like repressor, None) , ( protein: ZEB, None) , ( DNA: enhancer, 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: bHLH proteins, None) , ( protein: ZEB -like repressor, None) , ( protein: ZEB, None) , ( DNA: enhancer, None) 