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However, this region directed extremely low reporter mRNA levels relative to endogenous IL-4 mRNA , suggesting that full gene activity requires additional enhancer elements .
 IL-4 mRNA, enhancer elements, IL-4
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 IL-4 mRNA, enhancer elements, IL-4