Fig. 4: XRCC1 recruitment to TOP1ccs depends on macroH2A1.1.

a Western blot for the indicated proteins in nuclear lysates (input) or IP lysates from parental (P) and FLAG-macroH2A1.1 (F-1.1) or FLAG-macroH2A1.2 (F-1.2) knock-in 293 cells in the presence or absence of PARPi. A representative of two independent experiments is shown. b Quantification of XRCC1 foci in MCF7 WT and macroH2A1.1 KO cells in the presence or absence of CPT treatment (1 µM, 30 min), y-axis depicts foci per nucleus (n > 350, see source data for exact n). Similar results were obtained in a second, independent experiment, see Supplementary Fig. 4a for representative images. c Western blot for the indicated proteins in macroH2A1.1 KO (1.1 KO) MCF7 cells reconstituted with empty vector (EV), FLAG-macroH2A1.1 (1.1WT) or FLAG-macroH2A1.1 G224E (1.1GE). One of two independent experiments is shown. d XRCC1 IF in cells from (c) treated with CPT (1 µM, 30 min) or DMSO, scale bar: 10 µm. Foci were quantified as in (b), n > 300 nuclei per sample, see source data for exact n. A representative of two independent 1.1 KO reconstitutions is shown. For violin plots in (b) and (d), center lines (red) reflect the median, white dotted lines depict upper and lower quartiles, and p values are based on two-sided Mann-Whitney U test for the indicated, pairwise comparisons. e Western blot for the indicated proteins in chromatin-bound fractions from WT or TDP1 KO HCT116 cells expressing a control shRNA (C) or sh-macroH2A1.1 (1.1). Cells were treated with DMSO or 1 µM CPT for 30 min, in the presence or absence of PARPi. See Supplementary Fig. 4g for whole cell extracts. Similar results were obtained in a second, independent experiment. Source data for (a–e) are provided as a Source Data file. f CUT&RUN NGS profile plots for XRCC1 or IgG in MDA-MB-231 cells expressing sh-RFP (sh-ctrl) or sh-macroH2A1.1 (sh-1.1), treated with DMSO or 1 µM CPT for 30 min. Averaged RPKM profiles from two independent experiments are shown, centered on TOP1 peaks. g Profile plots of CPT-treated cells from (f), centered on the TSS and separated based on RNA-Seq-derived gene expression as in Fig. 2d.