Fig. 3.

Genomic (A) and infectious (B) titers of wild-type virus and ZFD insertion mutants. (A) A standard retroviral vector that expresses the tetracycline-OFF transcription factor, and drives GFP expression from a tetracycline-responsive promoter (Fig. S1A), was packaged using pCMV Gag-Pol helper plasmids containing wild-type and ZFD variant gag-pol genes. Vector genomic titers and standard errors of the mean are shown. (B) Infectious titers of viruses were measured via duplicate infections of 293T cells, and standard deviations of infectious titer are shown by bars.