1518
Two different proteins which independently bound to neighboring sequences within the negative regulatory element ( NRE ) of human immunodeficiency virus type 1 ( HIV-1 ) were detected in the nuclear extract of a virus-infected human T cell line .
 DNA: NRE; cell line: virus-infected human T cell line; DNA: negative regulatory element
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: NRE; cell line: virus-infected human T cell line; DNA: negative regulatory element