10550
To further investigate the effects of E2a-Pbx1 on the B cell progenitors , we conditionally expressed E2a-Pbx1 under control of a metal response element in hematopoietic precursor cell lines in vitro.
 ( protein: E2a-Pbx1, None) , ( protein: E2a-Pbx1, None) , ( cell line: hematopoietic precursor cell lines, None) , ( cell type: B cell progenitors, 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: E2a-Pbx1, None) , ( protein: E2a-Pbx1, None) , ( cell line: hematopoietic precursor cell lines, None) , ( cell type: B cell progenitors, None) 