9505
Through this mechanism of gene regulation , YY1 and LSF could contribute to the establishment and maintenance of a population of cells stably but nonproductively infected with HIV-1 .
 YY1, LSF
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:
 YY1, LSF