FIG. 4.

Frameshift transplant mutants produce the expected Gag proteins. A Western blot probed with polyclonal antibody R2-F, which recognizes Gag, is shown. Five micrograms of total yeast lysate from strain YH51 was loaded in each lane. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (9% polyacrylamide) was used to separate the Gag species. Lysates from a PR active site mutant (derived from pGM17) (16) are shown for comparison. pRS refers to plasmid pRS326, a 2μm, URA3-marked plasmid. The Gag immunoreactive band in the fst1 lane migrates as a tight doublet. The doublet cannot be resolved to a singlet with phosphatase treatment. The mobilities of the upper band in the fst1 doublet and of the 56-kDa fst2 species are consistent with the predicted mobilities of the unprocessed Gag species for these mutants. WT, wild type.