8820
The importance of these sites for transcriptional activation was studied by site - directed mutagenesis followed by promoter function analysis of the mutants with a chloramphenicol acetyltransferase reporter system .
 chloramphenicol acetyltransferase reporter
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 chloramphenicol acetyltransferase reporter