14909
In this study we identified a sequence element present in the most proximal region located between bases -214 and -201, TTCTTCTAATTAA , which is important in the high constitutive expression of CD20 in mature B cells and the induction of CD20 in pre-B cells .
 ( cell type: pre-B cells, None) , ( protein: CD20, None) , ( protein: CD20, None) , ( DNA: sequence 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:
 ( cell type: pre-B cells, None) , ( protein: CD20, None) , ( protein: CD20, None) , ( DNA: sequence element, None) 