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On the other hand, the 3'NF-E2/AP1 motif is able to exert both positive and negative regulatory effects on the zeta 2-globin promoter activity in K562 cells , and this dual function appears to be modulated through differential binding of the ubiquitous AP1 factors and the erythroid-enriched NF-E2 factor .
 3'NF-E2/AP1 motif, K562 cells, zeta 2-globin promoter, ubiquitous AP1 factors, erythroid-enriched NF-E2 factor
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:
 3'NF-E2/AP1 motif, K562 cells, zeta 2-globin promoter, ubiquitous AP1 factors, erythroid-enriched NF-E2 factor