2344
It is striking that the active CHO spacer promoter violated the otherwise universal rule that metazoan RNA polymerase I promoters all have a G residue at position - 16 .
 metazoan RNA polymerase I promoters
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 metazoan RNA polymerase I promoters