6753
In synchronized HeLa cells , expression of luciferase activity was induced at the beginning of DNA synthesis and was dependent on the presence of an E2F - binding site in the H2A . 1 promoter .
 luciferase, E2F - binding site, H2A . 1 promoter
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 luciferase, E2F - binding site, H2A . 1 promoter