FIG. 2.

Replication potential of the WT and mutant viruses in CEM-SS cells. (A) Growth curves of selected viral pairs. ▾, R7/3; , R7/3 Bru F; ⧫, R7/3 RRR; ▴, R7/3 Bru RRR F; ○, D116A (a catalytically inactive mutant included as a replication-defective control). (B) Summary of the replication statuses of all viruses at the end point. Viral infections were followed over 12 days and scored for replication by syncytium formation and p24 or RT production. The genotype for each is schematically indicated. The vertical lines represent the RRR substitution mutation. The presence of the FLAG tag (F) is denoted as a star. The rectangle is the integrase amino acid sequence from R7/3; the rounded rectangle, the integrase sequence from Bru (three amino acid differences exist between the two sequences). The experiments were performed using the specified integrase cassette (XbaI/SacII) in the otherwise isogenic R7/3 proviral background. Data generated using the complete Bru provirus were provided by the study of Cereseto et al. (3).