4070
A critical role of Sp1- and Ets- related transcription factors in maintaining CTL-specific expression of the mouse perforin gene .
 ( DNA: mouse perforin gene, 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:
 ( DNA: mouse perforin gene, None) 