5228
Reversions or additional mutations were not detected in the U3 and R regions of proviral DNA from CEMxl74 cells infected with the SIVmac239 mutants .
 ( DNA: proviral DNA, None) , ( cell line: CEMxl74 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:
 ( DNA: proviral DNA, None) , ( cell line: CEMxl74 cells, None) 