FIG. 3.

Proliferative properties of SL2 cells depleted of dE2F1, dE2F2, or dDP. (A) Cells depleted of dE2F1, dE2F2, and dDP or their combinations were labeled with BrdU, and the percentage of BrdU-positive cells were assayed by FACS. The number of BrdU-positive cells is dramatically reduced in the absence of dE2F1. Removal of dE2F2 does not significantly affect the number of BrdU-positive cells but restores BrdU incorporation lost in cells depleted of dE2F1. Note that dE2F1/dE2F2-, dDP-, dE2F1/dDP-, and dE2F1/dE2F2/dDP-depleted cells show similar values of BrdU incorporation. The error bars indicate standard deviations. NS, nonspecific dsRNA. (B) Total RNA was isolated from dsRNA-treated cells, and the levels of PCNA, cyclin E, RNR2, and MCM3 transcripts were followed by Northern blot analysis. (C) Northern analysis of total RNAs isolated from eye disks of different genotypes shows that E2F-regulated genes are expressed at similar levels in dDP mutant and de2f1 de2f2 double-mutant animals.