1789
Removal of the carboxy terminus enables ERP to interact with a variety of ets-binding sites including the E74 site , the IgH enhancer pi site , and the lck promoter ets site , suggesting a carboxy-terminal negative regulatory domain .
 lck promoter ets site, ets-binding sites, ERP, E74 site, carboxy-terminal negative regulatory domain, carboxy terminus, IgH enhancer pi site
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:
 lck promoter ets site, ets-binding sites, ERP, E74 site, carboxy-terminal negative regulatory domain, carboxy terminus, IgH enhancer pi site