1600
A unique region containing four or five near-perfect direct repeats ( DR ) of 21 bp with one 12-bp insert was proven to be the main transcription-activation element , with enhancer-like characteristics .
 ( DNA: direct repeats, None) , ( DNA: DR, None) , ( DNA: 12-bp insert, None) , ( DNA: transcription-activation element, 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: direct repeats, None) , ( DNA: DR, None) , ( DNA: 12-bp insert, None) , ( DNA: transcription-activation element, None) 