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After infection of 293 cells ( which provide complementary E1a - E1b functions ) , both viruses directed equal amounts of P / C - specific mRNA transcription .
 E1a, E1b, P / C - specific mRNA
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 E1a, E1b, P / C - specific mRNA