De novo protein synthesis is not required for the IFN-γ–induced enhance expression of B7-2 mRNA. MM6 cells were incubated for 12 hours in the absence or presence of 500 U/mL of IFN-γ and in the absence or presence of 10 μg/mL of CHX. Total cellular RNA was extracted and analyzed by Northern blot for B7-2 mRNA expression (upper panel). Data shown are from 1 of 3 similar experiments. The graph represents the quantitative analysis of B7-2 mRNA expression (lower panel). As stated in Materials and Methods, the bands’ intensities were normalized to the GAPDH housekeeping gene control, and the graph was generated with the relative values obtained after normalization.