FIG. 2.
Determination of the relative amounts of Vpr and CA in virus lysates. (A) Aliquot of a purified 35S-labeled virus sample used for quantitative analysis. The sample was analyzed by SDS-PAGE followed by silver staining as described by Heukeshoven and Dernick (19) (lane 1) as well as phosphorimage detection (lane 2). (B) Radioactivity in bands corresponding to Vpr, MA, CA, and IN contained in virus samples as determined by phosphorimage analysis. After normalizing for the number of cysteines present, average numbers of molecules were calculated relative to the intensity of the CA band in the same lane, which was arbitrarily set at 100%. Data shown represent the mean relative value calculated for each protein. (C) Relative amounts of virion-associated CA and Vpr as determined by immunoblotting. Various amounts of purified virus were separated by SDS-PAGE in parallel to serial dilutions of recombinant CA protein or synthetic Vpr protein of known concentration. Proteins were detected by immunoblotting using rabbit antisera directed against CA or Vpr followed by enhanced chemiluminescence staining. Band intensity was measured by densitometry using a Desaga CD50 instrument.