Cloned viral 2-LTR circle junction sequences. PBMCs were isolated from FIV-infected cats 6 weeks (184) and 12 weeks (165) PI and cultured ex vivo. DNA was isolated from ex vivo-cultured cells and 2-LTR CJ PCR was performed (CJ primer set C). 2-LTR CJ PCR products were cloned and sequenced from cat 184 PBMCs incubated ex vivo for 3 days (*) and from cat 165 PBMCs incubated 4 (#) and 6 days (+). Circled nucleotides represent the invariant CA and TG dinucleotides within the U5 and U3 regions, respectively, while the underlined nucleotides represent a portion of the primer binding site within the gag leader.