11042
Chloramphenicol acetyltransferase expression constructs containing regions of the human collagenase-1 promoter were stably or transiently transfected into U937 cells , and reporter activity was assessed at various times after the onset of phorbol 12-myristate 13-acetate (PMA)-mediated differentiation .
 ( protein: Chloramphenicol acetyltransferase, None) , ( protein: collagenase-1, None) , ( DNA: Chloramphenicol acetyltransferase expression constructs, None) , ( DNA: collagenase-1 promoter, None) , ( DNA: human collagenase-1 promoter, None) , ( cell line: U937 cells, 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:
 ( protein: Chloramphenicol acetyltransferase, None) , ( protein: collagenase-1, None) , ( DNA: Chloramphenicol acetyltransferase expression constructs, None) , ( DNA: collagenase-1 promoter, None) , ( DNA: human collagenase-1 promoter, None) , ( cell line: U937 cells, None) 