Western Blot Analysis of Protein Modifications

Cells and tumor tissues were collected and lysed as described before^{44 (link)}. Briefly, 20–100 μg of protein was boiled at 95 °C for 5 min, loaded onto NuPAGE 4–12% Bis-Tris protein gels (Invitrogen) and transferred to nitrocellulose membranes (Bio-Rad) using the Mini-PROTEAN Tetra electrophoresis system (Bio-Rad). Primary antibodies used for membrane staining were anti-PRMT1 (Millipore, 7404; 1:1,000), anti-ADMA (Cell Signaling, 13522S; 1:1,000), anti-GAPDH (Santa Cruz Biotechnology, sc-32233; 1:5,000), anti-pH2A.X (Cell Signaling, 9718S; 1:1,000), anti-β-actin (Santa Cruz Biotechnology, sc-47778; 1:3,000) and anti-dsRNA (J2) (Scicons, 10010200; 1:5,000). Images were collected on an Odyssey scanner (LiCor) or Amershan ImageQuant 80 and analyzed with ImageQuant TL (v8.2.0) and ImageJ (v1.53a).