1383
Inhibition of endogenous C/EBP proteins , using either an excess of C/EBP binding sites or a trans- dominant negative inhibitor , demonstrated that C/EBP proteins are required for basal and activated levels of HIV-1 LTR transcription in the promonocytic cell line U937 .
 cell line: promonocytic cell line U937; protein: C/EBP proteins; DNA: C/EBP binding sites; DNA: trans- dominant negative inhibitor; protein: endogenous C/EBP proteins; DNA: HIV-1 LTR; DNA: LTR; protein: C/EBP 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:
 cell line: promonocytic cell line U937; protein: C/EBP proteins; DNA: C/EBP binding sites; DNA: trans- dominant negative inhibitor; protein: endogenous C/EBP proteins; DNA: HIV-1 LTR; DNA: LTR; protein: C/EBP proteins