Northern blot analysis of p21 expression in synchronized 32D cells during a single cell-cycle progression in the presence or absence of TGF-β1.

32D cells were synchronized by starvation of IL-3 and restimulated with IL-3 plus or minus 20 ng/mL TGF-β1 and were analyzed for mRNA expression by Northern blotting. Single cell-cycle time was approximately 16 hours for 32D cells. The quantitative graph was made using NIHimager software comparing signal intensity at each time point with the time 0 baseline.