Fig. 4: RAD51 loading at PrimPol-dependent single-stranded DNA gaps requires DNA end resection.

a Schematic of MRE11 and EXO1 nuclease activities and targeting by MRE11 inhibitors PFM01 and mirin. b Top: Strategy for SMART analysis of single-stranded DNA quantifications. Bottom: Protein levels of EXO1 and α-Tubulin (loading control) in U2OS cells after 48 h depletion with EXO1 or nonT siRNA. Images are from n = 1. c SMART analysis of single-stranded DNA after release from 20 min of 50 nM BPDE or solvent (-) for 4 h, in presence of nonT (-), PrimPol, or EXO1 siRNA. Images are representative of n = 3. Scale bars: 10 μm. d Quantification of SMART analysis after BPDE as in (c). Lines represent mean. Data from 3 repeats. e Strategy for SMART analysis with MRE11 inhibitor (MRE11i) PFM01 and representative images of native BrdU tracts. Scale bars: 5 μm. f SMART analysis of single-stranded DNA after release from 20 min of 50 nM BPDE for 4 h, in the presence or absence of MRE11 inhibitor PFM01. Lines represent mean. Data from 3 repeats. g Percentages of cells with >5 RAD51 foci after release from 50 nM BPDE, in the presence or absence of MRE11 inhibitors mirin or PFM01 as in (e). n = 3. h Percentages of cells with >5 RAD51 foci after release from 50 nM BPDE, in the presence of nonT or EXO1 siRNA for 48 h. n = 3 Source data are provided as a Source Data file. The means and SEM (bars) of at least three independent experiments are shown. Asterisks indicate p-values (one-way ANOVA for D, G, one-sided Mann–Whitney for F, one-sided student’s t-test for H, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001).