Fig. 2

Loss of βarr1 augments 53BP1 foci formation and cell survival following ionizing radiation (IR). a Representative confocal immunofluorescence microscopy images of WT and βarr1^−/− MEF cells 10 min after 4 Gy IR, probed with anti-53BP1 or anti-γ-H2AX antibodies. Merged image reveals colocalization of 53BP1 foci with γ-H2AX foci and increased 53BP1-containing DNA-repair foci formation in βarr1^−/− MEFs compared with WT MEFs in response to IR. Scale bar, 5 µm. b Confocal images were used to quantify the number of 53BP1 foci per nucleus in both βarr1^−/− and WT MEF cells (***p < 0.0001). c, d Clonogenic cell survival analysis of WT and βarr1^−/− MEFs following exposure to increasing doses of IR. Experiments (n = 3) were carried out in triplicate (**p < 0.05 at all doses of IR tested)