FIGURE 2.

H3K56 acetylation levels oscillate during cell cycle. A, HeLa cells were synchronized by double thymidine block and released to progress through the cell cycle as described under “Experimental Procedures.” The cells were collected before (Asyn) and after thymidine treatment (0 h) and every 2 h after release (up to 12 h); cell lysates were prepared; and H3K56 acetylation was analyzed by immunoblot. Immunoblotting with anti-pan H3 and anti-β-actin was used as a loading control. B, cell cycle progression was analyzed by monitoring DNA content by flow cytometry as described under “Experimental Procedures.” The dark gray, very light gray, and light gray peaks correspond to cells in the G₁, S, and G₂/M phases of the cell cycle, respectively.