13770
A cell cycle analysis showed that the constitutive activation of Stat1alpha , but not Stat3 , shortened the period of G0/G1 prolongation caused by EPO stimulation .
 ( protein: Stat1alpha, None) , ( protein: Stat3, None) , ( protein: EPO, 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: Stat1alpha, None) , ( protein: Stat3, None) , ( protein: EPO, None) 