Fig. 2. Effect of IFN- and IL-2 on p27 expression levels and stability. Analysis of p27 regulation in quiescent (Day 0), PHA-treated (Day 3), IL-2-treated (Days 46), and IL-2/IFN--treated (Days 46) cells by immunoblotting (A), Northern blotting (B), and pulse-chase analysis (Day 3; C) of p27 synthesis (4-h pulse) and turnover rate (20-h chase). 18S and 28S rRNA served as controls for equal loading because the GAPDH expression varies between cells cultured in the absence or presence of IFN-.