5232
Analysis of long terminal repeat -driven secreted alkaline phosphatase activity in transient assays showed that, unlike human immunodeficiency virus type 1 , the SIV long terminal repeat possesses an enhancer region just upstream of the NF-kappaB element which maintains significant levels of basal transcription in the absence of NF-kappaB and Sp1 sites .
 enhancer region, NF-kappaB element, SIV long terminal repeat, long terminal repeat, alkaline phosphatase, NF-kappaB
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:
 enhancer region, NF-kappaB element, SIV long terminal repeat, long terminal repeat, alkaline phosphatase, NF-kappaB