Figure 4. Decreased S-phase entry after B-Myb knockdown is rescued by a DNA-binding deficient and RNAi-resistant B-Myb mutant. (A). HepG2 cells expressing doxycyclin-inducible B-Myb N174A mutsiRNA_4 were grown in the absence or presence of doxycyclin, followed by immunofluorescence analysis. Only the cell nuclei are visible. (B). The cells were additionally transfected with control or B-Myb-specific siRNA_4, followed by western blotting with antibodies against B-Myb and β-actin. (C). HepG2 cells expressing doxycyclin-inducible B-Myb N174A mutsiRNA_4 were grown in the presence or absence of doxycyclin and transfected with the indicated siRNAs. The cells were then analyzed for the percentage of EdU-positive cells (top) and by real-time PCR for the expression of the cdc2 and cyclin B1 mRNAs. The asterisks indicate statistical significance (* p < 0.05, ** p < 0.01, Student’s-t-test).