Detection of Human RPB3 by Western Blot and Immunoprecipitation. Samples: Whole cell lysate from HeLa (15 and 50 ug for WB; 1 mg for IP, 20% of IP loaded), 293T (T; 50 ug) and Jurkat (J; 50 ug) cells. Antibodies: Affinity purified rabbit anti-RPB3 antibody used for WB at 0.1 ug/ml (A) and 1 ug/ml (B) and used for IP at 6 ug/mg lysate. RPB3 was also immunoprecipitated by rabbit anti-RPB3 antibody BL13244, which recognizes an upstream epitope. Detection: Chemiluminescence with exposure times of 3 minutes (A) and 10 seconds (B).