a, b, Immunoblots of cyclin A and BRCA1 from whole-cell extracts of FUCCI HeLa cells sorted according to the expression of the G1 marker, mKO2-hCdt1 (a) or the S/G2 phase mAG-hGeminin marker (b). Representative blot from n = 4 experiments. c, Cell-cycle-dependent analysis of DNA damage using γ-H2AX ChIP signals in HeLa FUCCI cells sorted according to the S/G2 hGeminin marker. The results indicate that G1 cells develop as much damage as S/G2 cells. A representative experiment is shown, and the histograms depict the mean ± s.d. fold change of qPCR replicates. d, Immunoblots depicting the expression of BRCA1 during the various phases of the cell cycle after release of T98G cells from serum-starvation-induced G0 synchronization. Representative blot from n = 5 experiments. e, DNA damage analysis of synchronized T98G cells. f, Immunoblots validating the re-expression of BRCA1 (R) or Dicer (Flag-tagged wild-type (WT) and mutant Dicer, detected using a fluorescent quantitative method and showing their quantitative expression) after BRCA1 or DICER1 depletion, respectively, in HMECs and HeLa cells. Representative blot from n = 4 experiments. c, e, Data were analysed by one-way (c) or two-way (e) ANOVA with post hoc Tukey HSD test and compared to an undamaged locus.