Co-precipitation of Abl with Tip60 following DSB induction. (a) 293 cells were transfected with pcDNA3.2 plasmids carrying Flag-Abl and HA-Tip60 cDNA using lipofectamine. At 36 h post-transfection, cells were exposed to 5 Gy of IR 4 h later lysates were formed, adjusted for equal protein content and subjected to immunoprecipitation with anti-HA antibody. Immunoprecipitates were resolved on SDS-PAGE and subjected to western blotting against anti-Flag (top panel) or anti-HA antibody (bottom panel). (b) Abl-null 3T3 cells reconstituted with vector alone or Flag-tagged WT-Abl were exposed to bleomycin (10 μM) and collected 0, 2 and 4 h later. Lysates were formed, adjusted for equal protein concentration and subjected to immunoprecipitation with anti-Flag (Abl) antibody. The immune-complexes were resolved on SDS-PAGE, transferred onto Immobilon-P and probed with anti-HA (Tip60) or anti-Flag (Abl) antibody.