6478
Furthermore, introduction of exogenous GATA-1 in both MEL cells and Xenopus embryos and explants relieves the block to erythroid differentiation imposed by PU.1 .
 ( protein: PU.1, None) , ( cell line: MEL cells, None) , ( protein: GATA-1, 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: PU.1, None) , ( cell line: MEL cells, None) , ( protein: GATA-1, None) 