Skip to main content
. 2015 Jul 22;43(16):7931–7944. doi: 10.1093/nar/gkv722

Figure 1.

Figure 1.

SETDB1, SUV39 and HP1 are dispensable for DSB repair in G1 phase but essential in G2. (A) 1BR3 hTERT cells were transfected with siRNAs targeting control (CTR), SETDB1, SUV39, HP1α/β and γ and BRCA1. Knockdown of each component was verified by immunoblotting and H3K9me3 levels assessed in whole cell extracts. (B) Quantification of the reduction in H3K9me3 levels. Note that in panels A and B we used combined oligonucleotides for HP1α/β and γ. (C and D) Following siRNA mediated knockdown as indicated, 1BR3 hTERT cells were irradiated with 3 Gy and γH2AX foci enumerated at the indicated times in (C) G1 (CENPF−) and (D) G2 (CENP+) cells. (E and F) Representative images from experiments (C and D). Staining for γH2AX, CENPF and DAPI is as indicated. Asterisks denote statistically significant differences (P < 0.05); t-test). Results represent the mean ± S.E.M of 3 experiments. (G) Chromosomal breaks were determined by premature chromosome condensation (PCC) breakage analysis. 1BR3 hTERT cells were subjected to siRNA mediated knockdown of control (CTR) and SETDB1 and irradiated with 2 Gy IR. Chromosomal breaks were assessed at 8 h post IR. Data are represent the mean ± S.E.M of three experiments.