FIGURE 6.

HP1-β knockdown alleviates the requirement for KAP-1 Ser-473 phosphorylation. A–C, HeLa cells were transfected with HP1-β siRNA for 24 h and then transfected with FLAG-CMV, FLAG-KAP-1 WT, or FLAG-KAP-1 S473A. Transfected cells were treated with 2 Gy of IR 48 h after siRNA transfection before fixation and staining with γH2AX (A and C) or 53BP1 (B and C) antibodies at the indicated times. The data shown represent the average and S.E. of three independent experiments. * indicates a two-tailed p value of < 0.04. ** indicates a two-tailed p value of < 0.02. Con si, control siRNA.