975
We also examined the function of the IL-3 CK-1/CK-2 elements that are present in many cytokine genes and found that they acted as a repressor of basal level expression when cloned upstream of a heterologous promoter but were also inducible by PMA /PHA .
 ( protein: /PHA, None) , ( DNA: IL-3 CK-1/CK-2 elements, None) , ( DNA: cytokine genes, None) , ( DNA: heterologous promoter, 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: /PHA, None) , ( DNA: IL-3 CK-1/CK-2 elements, None) , ( DNA: cytokine genes, None) , ( DNA: heterologous promoter, None) 