13476
Fusion of the upstream portion of the delta promoter to the truncated beta globin promoter yielded a modest increase in promoter strength relative to the truncated beta gene promoter , indicating the presence of a positive transcriptional element (s) in the upstream delta globin regulatory region .
 upstream delta globin regulatory region, upstream portion, truncated beta gene promoter, positive transcriptional element, beta globin promoter, delta promoter
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:
 upstream delta globin regulatory region, upstream portion, truncated beta gene promoter, positive transcriptional element, beta globin promoter, delta promoter