FIG. 2.
Intracellular cytoplasmic virus is less dense than extracellular virus. [3H]thymidine-labeled extracellular virus (A and B) or PNS intracellular virus (C and D) from tsProt.A-infected HuH7 cells were subjected to isopycnic centrifugation on a 1.065-g/ml self-forming Percoll gradient. Gradients were fractionated from the top (corresponding to fraction 1), as indicated on the horizontal axes. (A and C) Fractions were assayed for total packaged DNA (open triangles) or proteinase K-protected, enveloped DNA (solid triangles). (B and D) Fractions were titrated for PFU (open circles). Plotted values represent the means of duplicate samples, and error bars indicate the range from the mean.