To examine the effect of DP1 knockdown on E2F-mediated apoptosis, we measured the percentage of cells with a sub-G1 DNA content and that stained with annexin V by flow cytometry at 72 h after infection of WI-38 cells with Ad-E2F1 or Ad-12SE1A (Fig. 1B). This evidence concerns the gene TFDP1 and infection.