FA core complex foci form during S-G2 phases of the cell cycle.

<p>(A) U2OS cells were treated with MMC for 1h at 60ng/ml, then released into fresh media and fixed at the indicated time points. Cells were immunostained with the indicated antibodies and quantified. The percentage of cells with more than 5 foci is shown. (B) Cells were arrested in M-phase with nocodazole, re-seeded in fresh media and collected at the indicated times. The upper panel shows cell cycle profiles (PI staining). The lower panel shows percentage of cells with more than 5 FANCA foci (n = 3, mean ± SD). Cells were untreated or irradiated with 10Gy IR 1h before each time point. (C) Cells were irradiated with 10Gy IR 2h before fixation. Graph shows percentage of cyclin A-positive and -negative cells in the FANCA-, FANCG- or FANCD2-foci containing cells population (n = 3, mean ± SD). Upper panel shows representative images. (D) Cells were transfected with indicated siRNAs and irradiated with 10Gy IR 2h before fixation. Graph shows percentage of cyclin A-positive and -negative cells in the FANCA-foci containing cells (n = 3, mean ± SD).