1517
Identification of transcriptional suppressor proteins that bind to the negative regulatory element of the human immunodeficiency virus type 1 .
 DNA: negative regulatory element; protein: transcriptional suppressor proteins
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 DNA: negative regulatory element; protein: transcriptional suppressor proteins