KEN binding sites. (A) HeT-A 5′ UTR alignment; KEN binding site is conserved in three of the six HeT-A sequences analyzed. (B) TART Gag alignment; KEN binding site is conserved in the three TART subfamilies. (C) TART Gag alignment; the second KEN binding site is only conserved in the TART A subfamily. Nucleotide sequence alignment was performed using ClustalW software. The alignment was performed for each domain, 5′ UTR, open reading frame, and 3′ UTR, but only the region corresponding to the DREF binding site is shown. Numbers on the right of the alignment refer to the position corresponding to each sequence.