1309
The major GC-box binding activity A1 was purified and identified as the transcription factor Sp1 .
 ( DNA: GC-box, None) , ( protein: transcription factor Sp1, None) , ( protein: Sp1, None) , ( protein: A1, 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: GC-box, None) , ( protein: transcription factor Sp1, None) , ( protein: Sp1, None) , ( protein: A1, None) 