Fig. 5: FANCL promotes end resection at DNA double-strand breaks.

a, b U2OS FANCL^KO clones (Cl.) and wild-type control cells (Con.) were exposed to 10 Gy ionizing radiation (IR), followed by IF microscopy to detect foci containing S4/8 phosphorylated RPA (pRPA) in S-phase (EdU + ) nuclei. Panel (a) shows representative images (scale bar = 10 μM), and panel (b) shows the quantification (n = 4 independent biological replicates; mean ± SEM; one-way ANOVA with post-hoc Dunnett’s). c As in panel (b), but now plotting total pRPA foci intensity per nucleus in FANCL^KO cells reconstituted with FANCL WT or LD (n = 3 independent biological replicates; mean ± SEM; one-way ANOVA with post-hoc Dunnett’s). d Schematic of the qPCR-based quantification of end resection in AsiSI cells. e Western blot of MMC-treated (500 nM, 24 h) U2OS AsiSI cells. f Quantification by qPCR of single-strand DNA (ssDNA) at 335 bp or 1618 bp distance from a defined AsiSI-induced DSB (n = 6 for control cells, n = 3 for KO cells, all independent biological replicates; one-way ANOVA with post-hoc Dunnett’s). g As in panel (f), but now including treatment with the DNA-PKcs inhibitor NU7441 (PKi; 2 μM; n = 5 independent biological replicates; mean ± SEM; paired t-test, two-sided). h As in panel (g), now in FANCL^KO cells that express either an empty vector (EV), FANCL wild-type (WT), or FANCL ligase-dead (LD; n = 3 independent biological replicates; mean ± SEM; one-way ANOVA with post-hoc Dunnett’s). i, j As in panels (a) and (b), respectively, but now analyzing total Rad51 foci intensity per S-phase nucleus (n = 4 independent biological replicates; mean ± SEM; one-way ANOVA with post-hoc Dunnett’s; scale bar = 10 μM). Source data are provided as a Source Data file.