FIG. 3.

VP22 pellets with cellular membranes. A7 cells were transfected with the indicated plasmids, harvested at 20 h posttransfection, and incubated in hypotonic buffer. Swollen cells were disrupted by Dounce homogenization, and nuclei were removed by low-speed centrifugation. In order to separate membrane-bound entities from soluble forms, the supernatants underwent centrifugation at 100,000 × g. As a control, replica samples were incubated with 0.5% Triton X-100 prior to centrifugation to solubilize cellular membranes. Following centrifugation, soluble and pellet fractions were collected and analyzed for the presence of GFP chimeras by fluorometry. The fraction pelleted was calculated by dividing the amount pelleted by the total amount of protein in the soluble and membrane fractions (see Materials and Methods). Error bars, standard deviations for three independent experiments.