Figure 2.

Replication capacity conferred by the 2Δ tetO promoter element. (A) Virus-competition experiment. Infectious molecular clones differing only in the number of tetO elements (8, 6, 4, 2, 2Δ) were cotransfected (3 μg each) in SupT1 cells in the presence of dox. The composition of the virus population was determined at the indicated days posttransfection by PCR amplification as described in Fig. 1C. (B) Replication curves of this panel of viruses. SupT1 cells were transfected with 5 μg of the indicated infectious molecular clone, and virus production was monitored by measuring CA-p24 protein in the supernatant. (C) Infectivity of HIV-rtTA 8 tetO 2Δ tetO virus was compared with that of the original HIV-rtTA 8 tetO, the HIV isolates HXB2 and LAI, and the LAI Δnef mutant.