Chk1 or Src depletion exacerbates chromatin breakage and reduces actin patches in Aurora B–deficient cells. (A) Cells were transfected with negative siRNA (control), Aurora B siRNA (siAurora B), or a combination of siChk1/siSrc and siAurora B (siAurora B + siChk1; siAurora B + siSrc). Broken DNA bridges and intercellular canals are indicated by dotted arrows, midbodies and midbody remnants by arrowheads, and the bases of the intercellular canals by solid arrows. Relative actin patch intensity values are shown. Insets show 1.6× magnification of the canals bases. (B) Percentage of DNA bridges that appear broken. Error bars show the SD from the mean from three independent experiments. A minimum of 50 cells with chromatin bridges was analyzed per experiment. (C) Actin patches intensity. Relative green fluorescence from A is shown, and values in control were set to 1. Error bars show the SD from the mean. n = 30 from three independent experiments. (D) Frequency of cells with broken DNA bridges exhibiting intact midbodies. Error bars show the SD from the mean from three independent experiments. A minimum of 20 cells with chromatin bridges was analyzed per experiment. (E) Localization of Plk1. Insets show 1.6× magnification of the midbodies. Bars, 5 µm. (F) Plk1 midbody intensity. Relative green fluorescence from E is shown, and values in telophase control were set to 1. Error bars show the SD from the mean. n = 20 cells from two independent experiments. ***, P < 0.001 compared with the control. Statistically significant differences were determined by ANOVA and Student’s t test.