10270
In a PC12 cell mutant that is deficient in protein kinase A activity ( AB . 11 ) , all three differentiating agents were unable to down - regulate nrg - 1 mRNA .
 protein kinase A, nrg - 1 mRNA
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 protein kinase A, nrg - 1 mRNA