C Quantitative PCR of FBXO5 transcripts in HeLa cells treated with siRNA against E2F7 or E2F8. Cells were harvested 6 hours after release from HU block to enrich for cells in mid- to late S phase. Bars in (B) and (C) indicate mean ± sem (n=3); asterisks indicate P<0.05 versus vehicle and scrambled siRNA, respectively. 