FIG. 3.

Pulse-chase analysis of wild-type M2-1 protein expression. HEp-2 cells infected with vTF7-3 were transfected with a plasmid bearing the gene expressing the wild-type M2-1 protein. Cells were exposed to [³⁵S]methionine and [³⁵S]cysteine for 15 min at 16 h posttransfection. Following the 15-min labeling period, either cells were harvested (lanes 1 and 2) or the medium was removed and medium containing unlabeled methionine and cysteine was added for 15 (lane 3), 30 (lane 4), or 60 (lane 5) min prior to harvest. Labeled proteins were immunoprecipitated from cytoplasmic extracts using M2-1-specific MAb 1C13. Immunoprecipitated proteins were analyzed by SDS-PAGE under reducing conditions in 11% polyacrylamide gels followed by fluorography. vv, mock transfection.