Melatonin inhibited p52 acetylation. (A-B) Nuclear extracts prepared from RAW 264.7 cells treated with LPS/IFNγ in the presence or absence of MT were immunoprecipitated with a p52 antibody (anti-p52) or non–immune IgG (IgG). Acetylated p52 (Ac-p52) was analyzed by Western blots using an acetyl-lysine antibody. To serve as a control, CREB-2 was immunoprecipitated with a CREB-2 antibody, and Ac-CREB-2 was analyzed by Western blots using acetyl-lysine antibody. (C) Cells were treated by E1A or roscovitine (RST) according to procedures described in Figure 5. Ac-p52 in immunoprecipitates was analyzed as described above.