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We also demonstrate that two other sites contribute to promoter activity in B cells ; an Sp1 binding site adjacent to the octamer site , and the PU.1 autoregulatory site .
 PU.1 autoregulatory site, B cells, octamer site, PU.1, Sp1 binding 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:
 PU.1 autoregulatory site, B cells, octamer site, PU.1, Sp1 binding site