Anti p300

Antibodies used for the immunoblot and immunostaining were anti-p300 (BD Biosciences, San Jose, CA, USA), anti-α-tubulin (Sigma), anti-myc, anti-Flag, anti-GFP, anti-HA (abm, Richmond, Canada), anti-ubiquitin (Millipore, Billerica, MA, USA), anti-acetylated lysine (Cell signaling, Danvers, MA, USA). Anti-HIPK2 antibody was a kind gift of Dr. K. Isono (RIKEN, Japan) and described previously^{27 (link)}.

Cells were collected by sample buffer and analyzed by electrophoresis. Proteins were transferred to polyvinylidene difluoride (PVDF, Millipore) membrane and TBST buffer (10 mM Tris-HCl, pH 8.0, 150 mM NaCl and 0.05% Tween 20) containing 5% nonfat milk was used for blocking. Anti-USP24 (Proteintech), anti-p300 (BD), anti-actin (Sigma-Aldrich), anti-ubiquitin (Santa Cruz), anti-P-gp (Genetex), anti-ABCG2 (Genetex), anti-MRP1 (Genetex), anti-MRP3 (Genetex), anti-Ezrin (Genetex), lamin A/C (Santa Cruz), anti-γ-H2Ax (abcam), anti-biotin (Genetex), anti-Flag (Genetex), anti-Rad51 (abcam), and anti-BRD7 (Sigma-Aldrich) were used for probing interested proteins. After incubated with primary antibodies, PVDF membranes were then incubated with secondary immunoglobulin antibodies linked with horse radish peroxidase (Millipore, 1:10,000). For detecting immunoprecipitated samples, light chain-specific secondary antibodies were used (Jackson ImmunoResearch, 1:10,000). ECL Western blotting detection system (Millipore) and ChemiDoc-it imager (UVP) were used for detecting signals.