MG132 induces ULBP1 transcription. A, Schematic illustration of the primers used to detect nascent hnRNA (thin arrows flanking exon 3) and mRNA (thick arrows in exon 2 and exon 3). B, FaDu cells were treated with DMSO solvent or MG132 for the times indicated before cell lysis and analysis of relative ULBP1 hnRNA (left panel, hatched bars) and mRNA (right panel, solid bars). PCR amplification of RNA that had not undergone reverse transcription gave uniformly negative results, indicating the absence of genomic DNA. The finding is typical of three independent experiments. C, ULBP1 mRNA is stable. FaDu cells were treated with DMSO or actinomycin D, as indicated. Cells were harvested at the times indicated and ULBP1, c-myc, and GAPDH mRNA was measured by quantitative RT-PCR. The x-axis is not linear; on the y-axis, a lower CT (threshold cycle) value indicates greater mRNA amount. The finding is typical of at least three independent experiments.