Figure 6. CDC7 contributes to replication‐dependent chromosomal breakages.

U2OS or AS‐CDC7 cells were transfected with control (siCon) or BRCA2 (siBRCA2)‐targeting siRNAs and then either mock‐treated or treated with 4 mM HU for 5 h in the presence or absence of 10 μM XL413 or 3MB‐PP1, respectively. HU was then washed off and nocodazole was added to the medium in order to complete one round of DNA synthesis. Metaphase spreads were prepared and analysed.

• A
  Representative metaphase spread from BRCA2‐depleted U2OS cells treated with HU. Scale bar = 5 μm. Arrows indicate the chromosomes enlarged in the insets, two of which show chromatid breaks (*).
• B, C
  The graphs show the average number of chromatid breaks per spread. In each experiment, 30 chromosome spreads for each condition were analysed and three independent experiments were performed. Error bars represent SEM. Statistical significance was assessed by Student's t‐test (**P ˂ 0.01, ***P < 0.001).
• D, E
  U2OS and AS‐CDC7 cells were transfected with control (siCon) or BRCA2 (siBRCA2)‐targeting siRNAs. Forty‐eight hours post‐transfection, cells were either mock‐treated or treated with 10 μM XL413 or 10 μM 3MB‐PP1, respectively, for 24 h with nocodazole added for the last 16 h of the experiment. The graph shows the average number of chromatid breaks per spread. In each experiment, 30 chromosome spreads for each condition were analysed and three independent experiments were performed. Error bars represent SEM. Statistical significance was assessed by Student's t‐test (*P < 0.05, ***P < 0.001).

Source data are available online for this figure.