9419
Since the DSE and TRE sites cannot bind CREB/ATF homodimers , we propose a mechanism in which the HIV-1 DSE bind heterodimers composed of both AP-1 and CREB/ATF proteins .
 TRE, DSE, DSE, CREB/ATF, heterodimers, CREB/ATF homodimers
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:
 TRE, DSE, DSE, CREB/ATF, heterodimers, CREB/ATF homodimers