Effect of the p300 C/H3 domain.

(A) Effect of the complete p300 CH3 domain that lacks acetyl transferase activity. H1299 cells were transfected with the indicated amounts of the p300-C/H3-Flag plasmid, pCB6+p53 (0.2 µg) and 5 µg of pCEFL-HA-VRK1. VRK1 was detected with an anti-HA antibody. P300 was detected with an anti-Flag antibody. (B) Effect of the p300 C/H3Del33 domain lacking the residues required for interaction with SV40 large T antigen. H1299 cells were transfected with the indicated amounts of the p300-C/H3-Del33-Flag plasmid pCB6+p53 (0.2 µg), and 5 µg of pCEFL-HA-VRK1. The CH3 domains were detected with an anti-Flag antibody. The experiments were independently performed three times. The quantification corresponds to the immunoblots shown and is presented in bar graphs.