FIGURE 6.

SV40 mutants are properly assembled. A, integrity of the wild type and mutant viruses produced by transfection and purified by sedimentation was tested. PCR of the viral DNA was performed after treatment of the virus with DNase to determine if the viral capsid protected the DNA. PCR products were resolved by agarose gel electrophoresis. Viruses were also analyzed for VP1 content by performing an immunoblot. B, BS-C-1 cells were transfected for 3 days with wild type SV40 genome and harvested for transmission electron microscopy (TEM), the inset area is shown in C. Scale bar indicates 500 nm. C, representative images of virus particles observed in BS-C-1 cell nuclei after 3 days of transfection with mutant viral genomes as indicated. Scale bar corresponds to 100 nm. Diameter of viral particles observed by TEM as indicated. Standard deviations are from 100 particles measured.