Fig. 6: MRNIP condensation promotes DNA end resection.

a, b MRNIP condensates promoted MRE11/RAD50-mediated dsDNA degradation in vitro. c The impact of PEG-8000 on MRNIP participated degradation of dsDNA by MRE11/RAD50 complex. For (b, c), the final concentration of GFP, MRNIP-GFP or ΔIDR1-GFP was 10 μM (b) and 2 μM (c). d, e ssDNA fiber length was examined via IF assay with anti-BrdU antibody. Data are presented as means ± SEM. Two-tailed unpaired Student’s t test. d, n = 40 (WT), n = 59 (KO-MRNIP). e n = 41 (EV), n = 52 (MRNIP-GFP), n = 50 (ΔIDR1). f In situ detection of ssDNA in cells confirmed that MRNIP condensates promote radiation-induced ssDNA formation. Data are presented as means ± SEM. Two-tailed unpaired Student’s t test. Middle panel: n = 3 biological replicates; Right panel: n = 91 (EV), n = 95 (MRNIP-GFP), n = 78 (ΔIDR1). g Restoration of MRNIP in HeLa-MRNIP-KO cells increased RAD51 foci. Data are presented as means ± SEM. Two-tailed unpaired Student’s t test. Middle panel: n = 3 biological replicates; Right panel: n = 205 (EV), n = 211 (MRNIP-GFP), n = 167 (ΔIDR1). h MRNIP knockout reduced radiation-induced RPA1 foci. Data are presented as means ± SEM; n = 3 biological replicates. Two-tailed unpaired Student’s t test. i Restoration of MRNIP in HeLa-MRNIP-KO cells increased RPA1 foci. Data are presented as means ± SEM, n = 3 biological replicates. Two-tailed unpaired Student’s t test. For (d–i), cells were treated with 10 Gy X-rays and recovered for 8 h (f), 4 h (g) or 1 h (h, i) before analysis. For (e–g, i), HeLa-KO-MRNIP cells stably expressing sgRNA-resistant MRNIP-GFP, MRNIP-ΔIDR1-GFP (ΔIDR1) and empty vector (EV) were used. ns, no significance.