12548
However, its activity becomes lower in the double-positive and a fraction of the CD4+ CD8int/- cell population , indicating that an additional enhancer, located in either the first or the third intron of the CD4 gene , is required for CD4 gene expression in this population.
 ( DNA: CD4 gene, None) , ( DNA: CD4 gene, None) , ( cell type: CD4+ CD8int/- cell population, 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: CD4 gene, None) , ( DNA: CD4 gene, None) , ( cell type: CD4+ CD8int/- cell population, None) 