11070
Human T cell lymphotropic virus type I ( HTLV-I ) encodes the transactivator protein , Tax , which facilitates viral transcription from three 21 bp repeated elements within the U3 region of the long terminal repeat ( LTR ).
 LTR, transactivator protein, 21 bp repeated elements, U3 region, Tax, long terminal repeat
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:
 LTR, transactivator protein, 21 bp repeated elements, U3 region, Tax, long terminal repeat