Figure 5.

Up‐regulation of p21 mRNA after BeSO ₄ treatment is p53 dependent. A172 cells with or without siRNA‐based p53 knockdown were cultured in the presence or absence of 10 μm BeSO ₄ for 48 h, and then mRNA levels of p53 (a) or p21 (b) were quantified using RT‐PCR. In each sample, actin mRNA was also quantified and used for normalization. Actin‐normalized mRNA quantities are expressed as percent of untreated control. Error bars bracket a confidence interval that is equivalent to the mean ± SD. Using a similar approach, p21 mRNA at 48 hours was measured in cells that carry a p53‐suppressing E6 expression vector or a neomycin control vector (c).