Joining activity confirmed with gel electrophoresis. Left, sequences of the donor oligodeoxynucleotides used in the joining assay. The location of carboxyfluorescein (FAM), 5' radioactive 32P, and 3' biotin are shown. The -A substrate removes only the A of the conserved CA dinucleotide while the -CA substrate removes both residues. Right, lanes 1 through 3 show HIV-1 IN joining activity on its substrate after 0, 60, 120 min of incubation, respectively. Lanes 4 through 6, 7 through 9, and 10 through 12, show ASV IN joining activity after 0, 15, 30 min of incubation.