Fig. 3
ScaRNA2 is required for efficient Mre11- and Exo1-mediated DNA end resection. A Immunofluorescence staining of RAD51 and RPA2 foci in irradiated sg-ctrl and scaRNA2 knockdown HCT116 cells at the indicated time points after irradiation (6 Gy). Scale bar: 20 μm. B, C The numbers of RAD51 foci and RPA2 foci per nucleus in irradiated HCT116 cells with/without scaRNA2 knockdown. ***P < 0.001, **P < 0.01 compared with the sg-ctrl group. D, E After labelling with BrdU for 24 h, sg-ctrl and scaRNA2 knockdown HCT116 cells were irradiated at a dose of 6 Gy. At 4 and 8 h later, the cells were fixed and stained for BrdU together with DAPI. Scale bar: 20 μm. The number of BrdU foci per nucleus was counted for statistical analysis. ****P < 0.0001 compared with the sg-ctrl group at the same radiation dose. F-M The main endonucleases for DNA end resection accounting for DSB level, including Mre11 (F, G), Exo1 (H, I), DNA2 (J, K) and CtIP (L, M), were detected with immunofluorescence staining in HCT116 cells at 8 h after 6 Gy irradiation. Quantification of the foci number in each group is provided as a column graph. ****P < 0.0001, ***P < 0.001 compared with the sg-ctrl group