FIG. 5.

Comparison of retroviral cis-acting sequences important during reverse transcription and integration, including the following: (A) PBS, primer binding site; (B) PPT, polypurine tract; (C) U3 att, 3′ attachment site in the U3 region of the 3′ LTR; and (D) U5 att, 5′ attachment site in the U5 region of the 5′ LTR. The canonical TG dinucleotide in the U3 att sequences and CA dinucleotide in the U5 att sequences are boxed. All sequences are shown in comparison to HIV-1, where “–” indicates homology with HIV-1, while differences are shown by the actual nucleotide. Columns to the right indicate the percent homology of each viral sequence to either HIV-1 or FIV with homology to self indicated as 100%.