Actin patches intensity is independent of the relative amount of DNA inside the intercellular canal. (A) Actin patches in cells transfected with negative siRNA (control), siSrc, or siChk1 exhibiting relatively strong or weak DNA staining inside the intercellular canal. The mean fluorescence intensity of control DNA bridges was set to 0.5, and relative DNA intensity values are indicated in the DNA insets. Relative DNA bridge staining >0.5 was taken as strong, and DNA bridge staining <0.5 was classified as weak. (B) Actin patches intensity. Relative green fluorescence intensity from A is shown, and values in strong DNA control were set to 1. Error bars show the SD from the mean. n = 20 cells from three independent experiments. (C and D) Cells expressing GFP, WT GFP-Src resistant to degradation by Src-2 siRNA (siSrc-2), or GFP-Chk1 resistant to degradation by Chk1-2 siRNA (siChk1-2) were transfected with negative siRNA (control), siSrc-2, or siChk1-2. Broken DNA bridges are indicated by dotted arrows and the bases of the intercellular canals are indicated by solid arrows. Relative actin patch intensity values are shown. Insets show 1.6× magnification of the canals bases. Bars, 5 µm. (E) Broken bridges analysis. Error bars show the SD from the mean from three independent experiments. A minimum of 30 cells with chromatin bridges was analyzed per experiment. (F) Actin patches intensity. Relative red fluorescence intensity from C and D is shown, and values in GFP control were set to 1. Error bars show the SD from the mean. n = 30 cells from three independent experiments. ***, P < 0.001 compared with the control. Statistically significant differences were determined by ANOVA and Student’s t test.