Effect of HDAC2 silencing on B-NHEJ in serum deprived (SD) versus exponentially growing (EG) Lig4-/-MEFs. (A) Western blot of EG and SD cells at different times after transfection of siRNA targeting HDAC2 together with the corresponding controls. The right panel depicts the cell cycle distribution of cells used in the radiation experiments shown in the following panels. Other details are as in Figure 1A. (B) and (C) Induction and repair of DSBs. Other details are as in 1B and 1C. The results shown represent the mean and standard error from 2 - 3 determinations in one experiment. Irradiation and DSB repair analysis was performed 40 h after transfection. 4* represents a non-irradiated control measured at 4 h. Serum deprived cells were prepared and treated as described under “Methods”. (D) Histone H3 acetylation (H3K9Ac) in control and HDAC2 silenced MEFs together with the corresponding controls.