FIG. 7.

HIV-1 mutant U5 att end with wt U3 produced host site duplications with a high fidelity. In row A, the circle junction for the wt U3 and mutant U5 ends in the 3.6-kbp plasmid DNA is shown. Two additional nucleotides (TG) were inserted into U5 and are shown in bold with the rest of the wt att site sequences underlined. The NdeI site at the circle junction was maintained. In row B, the plasmid DNA was digested with NdeI with the additional TG nucleotides (bold) shown. In row C, are shown the full-site integration products produced with wt U3 and mutant U5 ends that were isolated from agarose gels, followed by cloning and sequencing of the donor-target junctions. On the right in this row are shown the number of clones with 0, 5, and 7 bp of target site duplications in which the additional TG dinucleotide was removed prior to integration. In row D are shown clones that had the 5-bp target site sequence duplications but where IN did not remove the TG dinucleotides (bold) prior to producing the full-site products. There were three clones sequenced in this category that showed one each of the 18-, 27-, and 50-bp deletions.