13477
Site-directed mutagenesis of binding sites for the repressor proteins BP1 and BP2 in the upstream portion of the beta globin gene flanking region led to a 4-6 fold increase in promoter activity .
 ( DNA: beta globin gene flanking region, None) , ( DNA: upstream portion, 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: beta globin gene flanking region, None) , ( DNA: upstream portion, None) 