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Moreover, ZK161422 , but not ZK157202 , showed preference for gene activation from a promoter carrying a VD response element with a palindromic arrangement of two hexameric receptor binding sites spaced by 9 nucleotides ( IP9 ) rather than for activation from a response element formed by a direct repeat spaced by 3 nucleotides ( DR3 ).
 VD response element, hexameric receptor binding sites, palindromic arrangement, response element, 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:
 VD response element, hexameric receptor binding sites, palindromic arrangement, response element, promoter