Fig. 2

ScaRNA2 is necessary for HR-mediated DNA damage repair. A-B Relative expression of scaRNA2 in HCT116 and HT29 cells detected with an RT–PCR assay at 0, 4, 8, 12 and 24 h after irradiation. C-D Column graphs of scaRNA2 expression in HCT116 and HT29 cells treated with an ATM inhibitor (KU55933, 10 μM), ATR inhibitor (VE821, 10 μM) and DNA-PKcs inhibitor (NU7441, 10 μM) for 2 h before irradiation. E Immunofluorescence staining of γH2AX and 53BP1 in irradiated sg-ctrl and scaRNA2 knockdown HCT116 cells at 0, 0.5, 4, 8, 12 and 24 h after irradiation (6 Gy). Scale bar: 20 μm. F-G Quantification of γH2AX and 53BP1 foci at each time point after irradiation. ***P < 0.001, *P < 0.05 compared with the sg-ctrl group. Ns, nonsignificant. H Representative images and quantification of comet tails (tail moment and tail DNA) at 8 h in irradiated sg-ctrl and scaRNA2 knockdown cells (8 Gy). Scale bar: 50 μm. I Schematic view of NHEJ and HR reporter assays. J-K NHEJ repair and HR repair efficacies were detected with the reporter system and quantified with flow cytometry. L-M Representative images and quantification of BRCA1 foci measured at 8 h in irradiated sg-ctrl and scaRNA2 knockdown HCT116 cells (6 Gy)