a–c, Fold change in RNA level relative to day 0 uninfected cells for RB1 (a), or the indicated E2F-responsive genes (b), or the indicated p53-regulated genes (c), 3 and 6 days after transduction of each population with a mixture of shRB1-733 and shRB1-737, or with scrambled control. *P < 0.05, **P < 0.01 (comparing shRB1 and scrambled control). Data are representative of two sets of qPCR analyses. Values and error bars are mean and s.d. of triplicate assays.