FIG. 6.

Tax is a long-lived protein. (A) Tax-transfected 293T cells were metabolically pulse-labeled for 1 h and chased for 0 to 48 h. Tax was immunoprecipitated from lysates with anti-Tax serum BR-76. Following resolution by SDS–10% PAGE, the gel was dried and exposed to X-ray film. The Tax band is indicated. (B) Tax was quantified by densitometry at each time point. Timepoint zero was omitted from the analysis, as the sample had not been completely loaded on the gel. The decay curve predicted a half-life of approximately 15 h.