721
When transfected into K562 cells , which express zeta-globin , comparable amounts of activity were obtained from the -557 and -417 zeta- luciferase constructs and the alpha- luciferase constructs when no enhancers or the alpha-globin locus enhancers were used.
 ( protein: luciferase, None) , ( DNA: enhancers, None) , ( DNA: alpha-globin locus enhancers, None) , ( DNA: alpha- luciferase constructs, None) , ( cell line: K562 cells, None) , ( DNA: -557 and -417 zeta- luciferase constructs, None) , ( DNA: enhancers, None) , ( protein: luciferase, None) , ( protein: zeta-globin, 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: luciferase, None) , ( DNA: enhancers, None) , ( DNA: alpha-globin locus enhancers, None) , ( DNA: alpha- luciferase constructs, None) , ( cell line: K562 cells, None) , ( DNA: -557 and -417 zeta- luciferase constructs, None) , ( DNA: enhancers, None) , ( protein: luciferase, None) , ( protein: zeta-globin, None) 