BCL3 upregulation by IL-9 is dependent on RNA transcription. BW5147 cells were preincubated with 100 U/mL IL-9 for 24 hours, extensively washed, and restimulated for 1, 1.5, 2, 2.5, and 3 hours with or without IL-9 and actinomycin D (5 μg/mL) as indicated in the figure. Total RNA was extracted and RT-PCR amplification was performed with oligonucleotides specific for BCL3 orβ-actin. A Southern blot of the PCR products was performed and filters were hybridized with a BCL3 or β-actinoligonucleotide. (A) shows the autoradiography of the blot. (B) shows the intensity of the BCL3 signals from the same blot quantified by PhosphorImager analysis and standardized to theβ-actin level.