Figure 4 .

Su(z)2 regulates the transcription of dE2f1 and some of the dE2F1 target genes. (A) Knocking down Su(z)2 (gray bars) leads to up-regulation of dE2f1, and some of the dE2F1 target genes, such as PCNA, dCycE, and to a less extent dE2f2 and no effect of Rbf1, based on qRT-PCR assay. The samples treated with dE2f1-dsRNAs (white bars) serve as a positive control, and T7-dsRNA treated samples are negative controls. (B) Codepletion (gray bars) of Su(z)2 and dE2f1 suppresses the effect of dE2f1-dsRNA treatment and leads to increased expression of dE2f1, PCNA, dCycE, stg, and mcm5. The total dsRNAs are normalized with T7-dsRNA. (C and D) Effect of dsRNA treatment of the growth of SL2 cells: knocking down of Su(z)2 (C), but not Psc (D), suppresses the effect of dE2f1-dsRNA treatment at day 5. For each sample, the total amount of dsRNA is normalized with white-dsRNA and cell viability was determined by using the dimethyltriazoldiphenyl tetrazolium-formazan assay after 1, 3 or 5 days of dsRNA treatment.