Figure 4.

Varying the packaging to transfer plasmid transfection ratio impacts packaging efficiency

(A) The single packaging construct used in co-transfections is illustrated. Striped ovals represent 2 copies of the chicken cSH4 element, while rectangle boxes are expression cassettes. The synGP, VSVg, and Rev expression cassettes are under the control of the TetR, which is expressed constitutively. Bacterial elements are not shown. (B and C) This construct was co-transfected at various ratios with transfer plasmids encoding small, medium, or large genomes, and the resulting supernatant was assayed for physical titer (B) and genomic titer (C). The impact of the construct ratios on packaging efficiency for each genome size is shown in (D). In plots (B)–(D), the data points show the mean average from triplicate transfections and the error bars show the range. Lines connect the mean averages for each genome size. Data are representative of two independent experiments.