FIG. 1.
(A) HIV-1 vector used in the in vivo mutation rate studies. The vector is shown in the proviral DNA form and has been described previously (21, 23). (B) Protocol for one cycle of HIV-1 vector virus replication. The steps, going from a parental shuttle vector provirus in the step 2 cell to a vector provirus in the step 3 cell, constitute a single cycle of replication.