Figure 3.

Suppression of BubR1 expression prevented OS-induced polyploidization in p53-depleted cells. (A) MRC5 cells were transfected with control (cont.) siRNA, p53 siRNA, and BubR1 siRNA, and after 36 h of incubation. siRNA-mediated downregulation of p53 and BubR1 was confirmed by Western blotting. (B) To determine the cell cycle distribution, MRC5 cells were transfected with control siRNA, p53 siRNA, and BubR1 siRNA, and after 36 h of incubation, 0.1 mmol/L KBrO₃ was added. DNA content was analyzed by flow cytometry. The percentages of cells with >4N DNA content are shown. (C) The relative percentages of 0.1 mmol/L KBrO₃-treated cells in the G1 phase (2N; a), S phase (>2N, <4N; b), G2/M phase (4N; c), and polyploidy (>4N; d) are shown as filled black bars; *P > 0.05. Data are shown as means ± SD of triplicate measurements. (D) A binucleate p53 knockdown MRC5 cell with KBrO₃ exposure (nuclei indicated by arrowheads) and a merged immunofluorescence image of α-tubulin (red), lamin A/C (green), and DAPI (blue) are shown; scale bar, 100 μm. (E) Percentages of binucleate cells are shown; *P > 0.05.