Fig. 3

Reducing the expression of DDB2 suppresses re-replication induced by CDT2 deficiency. a Silencing of DDB2 inhibited the formation of giant nuclei induced by CDT2 knockdown. HCT116 cells were transfected with indicated siRNAs for 48 h and fixed with 4% paraformaldehyde. DNA was stained by DAPI (4′,6-diamidino-2-phenylindole). Scale bar: 50 µm. Right panel: the percentages of enlarged nuclei in a the error bars indicated SD. Significant difference was observed between CDT2 siRNA- and luciferase siRNA- or DDB2 + CDT2 double siRNA-treated cells, which was evaluated by the two-side Student's t-test (*** indicated P < 0.001). b FACS analysis of DNA contents in a. The percentages of DNA contents were presented in the right panel. The significant difference was observed between CDT2 siRNA- and luciferase siRNA- or DDB2 + CDT2 double siRNA-treated cells with 4N and > 4N DNA contents, which was evaluated by the two-side Student's t-test (*** indicated P < 0.001). c The efficacy of siRNAs in a and b were analyzed by Western blot. Right panel: The relative protein levels were measured using Gel-pro analyzer 4.0, and the P values were evaluated using the two-side Student's t-test (* denoted P < 0.05, ** denoted P < 0.01, *** denoted P < 0.001). The error bars indicated SD