a, b, Western blot analysis of H3K9me3 levels in the following cells with or without treatment with 2 mM αKG for 96 h: SNU1079 IDH1R132C/+ cholangiocarcinoma cells (a), U87 IDH1WT and IDH1R132H/+ glioblastoma cells (b), UOK 262 FH−/− renal cell carcinoma cells with and with FH cDNA complementation, and YUNK1 cells with shRNA suppression of SDHB (shSDHB) or FH (shFH). These experiments were repeated twice with similar results. c, Quantification of cells with TIP60 foci-positive nuclei (>10 foci per nucleus) at 1 h post 2 Gy ionizing radiation in the following cells with or without treatment with 2mM αKG for 96 h: IDH1WT and IDH1R132H/+ U87 glioblastoma cells, IDH1WT and IDH1R132H/+ HeLa cells, UOK 262 FH−/− renal cell carcinoma cells, YUNK1 cells with shRNA suppression of SDHB (shSDHB) or FH (shFH), compared to non-targeting control shRNA (shCTRL), and HEK293FT cells with shRNA suppression of SDHB (shSDHB) or FH (shFH) compared to non-targeting control shRNA (shCTRL). d–f, Quantification of cells with pATM S1918 foci-positive nuclei (>10 foci per nucleus) at 1 h after 2 Gy ionizing radiation in the following cells treated or not with 2 mM αKG for 48 h as indicated: HEK293FT cells with shRNA suppression of SDHB (shSDHB) or FH (shFH) compared to non-targeting control shRNA (shCTRL) (d), IDH1WT and IDH1R132H/+ HeLa cells (e), and YUNK1 cells with shRNA suppression of SDHB (shSDHB) or FH (shFH) compared to non-targeting control shRNA (shCTRL) (f). g, Quantification of cells with RAD51 foci-positive nuclei (>10 foci per nucleus) at 4 h post 2 Gy ionizing radiation in U87 IDH1WT and IDH1R132H/+ glioblastoma cells treated with either 2 mM αKG for 48 h or with DMSO control. h, Quantification of cells with RAD51 foci-positive nuclei (>10 foci per nucleus) at 4 h post 2 Gy ionizing radiation in SNU1079 (IDH1R132C/+) cholangiocarcinoma cells pre-treated with DMSO, 2 mM αKG or AGI-5198 for 48 h. i, Western blot analysis of H3K9me3 and total H3 levels in U2OS EJ-DR cells treated with DMSO (control), 2 mM αKG, 500 μM octyl-R-2HG, 2 mM succinate, 30 μM dimethyl fumarate, or the indicated combinations of αKG plus 2HG, succinate or fumarate. This experiment was repeated twice with similar results. j, ChIP analysis of H3K9me3 occupancy at the DSB–ChIP reporter locus in U2OS cells in the absence of a DSB after treatment with DMSO (control), 500 μM octyl-R-2HG, 2 mM succinate or 30 μM dimethyl fumarate, in all cases with or without 2 mM αKG, as indicated. k–r, Heat maps of the relative occupancy of the indicated factors at the site-directed DSB in U2OS cells as measured by ChIP and normalized to the uninduced controls. The assay was performed at the indicated time points post addition of Shield-1 and triamcinolone in DMSO-treated cells (control) (k), cells treated with 2 mM αKG (l), cells treated with 500 μM octyl-(R)-2HG (m), cells treated with 2 mM αKG and 500 μM octyl-(R)-2HG (n), cells treated with 2 mM succinate (o), cells treated with 2 mM succinate and 2 mM αKG (p), cells treated with 30 μM dimethyl fumarate (q), and cells treated with 30 μM dimethyl fumarate and 2 mM αKG (r). The heat maps for 2HG alone, succinate alone, fumarate alone and DMSO control alone are reproduced from Fig. 2b and are presented again here for comparison. s–aa, Line graphs of percent input values for DSB–ChIP assays with antibodies (corresponding to the heat maps in l, n, p, r) for γH2A.X (s; αKG + 2HG, F = 0.04, df = 1; αKG + succinate, F = 2.76, df = 1; αKG + fumarate, F = 0.18, df = 1); SUV39H1 (t; αKG + 2HG, F = 0.73; df = 1, αKG + succinate, F = 0.55, df = 1; αKG + fumarate, F = 0.09, df=1); H3K9me3 (u; αKG + 2HG, F = 0.076, df = 1; αKG + succinate, F = 4.05, df = 1; αKG + fumarate, F = 8.910, df = 1); TIP60 (v; αKG + 2HG, F = 1.32, df = 1; αKG + succinate, F = 1.98, df = 1; αKG + fumarate, F = 107.8, df = 1); MRE11 (w; αKG + 2HG, F = 0.53, df = 1; αKG + succinate, F = 1.2, df = 1; αKG + fumarate, F = 2.3, df = 1); ATM (x; αKG + 2HG, F = 14.8, df = 1, αKG + succinate, F = 0.31, df = 1; αKG + fumarate, F = 8.67, df = 1); BRCA1 (y; αKG + 2HG, F = 3.3, df = 1; αKG + succinate, F = 2.1, df = 1; αKG + fumarate F = 1.5, df = 1); RPA32 (z; αKG + 2HG, F = 0.003, df = 1; αKG + succinate, F = 1.78, df = 1, αKG + fumarate, F = 0.57, df = 1); and RAD51 (aa; αKG + 2HG, F = 1.4, df = 1; αKG + succinate, F = 2.4, df = 1; αKG + fumarate, F = 3.10, df = 1) at the indicated time points after addition of triamcinolone and Shield-1 to induce an I-SceI break in the U2OS DSB–ChIP cells. Line graphs corresponding with k, m, o, q, are presented in Extended Data Fig. 3b–j. ab, Quantification of HDR efficiency as measured by restoration of a functional GFP gene following I-SceI induction of a DSB in the DR–GFP reporter in U2OS cells following pre-treatment with DMSO, 500 μM octyl-R-2HG, 2 mM succinate or 30 μM dimethyl fumarate, and with no αKG, 1 mM αKG or 2 mM αKG as indicated. In c–h, j, and ab, data are mean ± s.e.m. with n = 3 biological replicates; statistical analysis by two-tailed unpaired t-test; df=4. In s–aa, lines run through the mean ± s.e.m. with n = 3 biological replicates for each time point; statistical analysis by ANOVA; P values are indicated. Source Data