20740
With a combination of in silico screening , promoter mutation in cell - based reporter assays , siRNA knockdown and chromatin immunoprecipitation studies , we identified a functional HNF4 alpha binding site close to the transcription start site ( - 17 to - 4 bp ) .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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