Rabbit anti p53 ps15

Western blotting was performed with the following primary antibodies: mouse anti-tubulin (Sigma-Aldrich), mouse anti–FLAG-M2 (Sigma-Aldrich), mouse anti-CtIP (mAb 14–1; gift from R. Baer, Columbia University, New York, NY), rabbit anti-CtIP (developed in collaboration with Epitomics), rabbit anti-KAP-1 pS824 (Bethyl Laboratories), rabbit anti–p53 pS15 (Cell Signaling Technology), and rabbit anti-53BP1 (Novus). For RAD51 immunofluorescence, cells were irradiated at 10 Gy allowed to recover for 4 h, and then fixed and processed as previously described (Celeste et al., 2003 (link)). For microirradiation, cells were presensitized in DMEM media containing 0.1 µg/ml of Hoechst 33342 for 60 min before replacing with phenol red free media containing 5 mM Hepes, and then irradiated with the 364-nm laser line on a LSM510 confocal microscope (Carl Zeiss, Inc.) equipped with a heated stage. Cells were allowed to recover for the indicated time before processing for immunofluorescence (Celeste et al., 2003 (link)). Primary antibodies for immunofluorescence were rabbit anti-CtIP and anti-53BP1, mouse anti-FLAG-M2, mouse anti–γ-H2AX (Upstate Biotechnology), and rabbit anti-RAD51 (Santa Cruz Biotechnology, Inc.).