Fig. 6

The N-terminus of CSB mediates its chromatin remodeling activity to repress RIF1 accumulation at sites of DSBs. a Relative occupancy of histone H2A in ddI-PpoI-expressing CSB KO hTERT-RPE cells complemented with various alleles as indicated. Both x- and y-axes are as described in Fig. 5a. SEM from three independent experiments are indicated. b Relative occupancy of histone H2B in ddI-PpoI-expressing CSB KO hTERT-RPE cells complemented with various alleles as indicated. Both x- and y-axes are as described in Fig. 5a. SEM from three independent experiments are indicated. c Western analysis of hTERT-RPE-IPpoI-CSB KO cells expressing various alleles as indicated. d Quantification of the percentage of Myc-CSB and Myc-CSB-ΔN30-expressing U2OS-265 cells exhibiting anti-Myc staining at FokI-induced DSBs. A total of 250 cells positive for anti-Myc staining were scored for each independent experiment in a blind manner. SDs from three independent experiments are indicated. e Quantification of the percentage of cyclin A- and cyclin A + cells with 10 or more IR-induced RIF1 foci. hTERT-RPE CSB KO cells stably expressing various alleles as indicated were treated with 2 Gy IR and fixed 1 h post IR. A total of 500–550 cells were scored for each independent experiment in a blind manner. SDs from three independent experiments are indicated. *P < 0.05. ns: P > 0.05 (Student t test). f Quantification of the percentage of cyclin A + cells with ≥ 10 IR-induced BRCA1 foci. Scoring was done as in e. SDs from three independent experiments are indicated. *P < 0.05. ns: P > 0.05 (Student t test). g Quantification of the percentage of cyclin A + cells with 10 or more IR-induced RAD51 foci. hTERT-RPE CSB KO cells stably expressing various alleles as indicated were treated with 2 Gy IR and fixed 4 h post IR. Scoring was done as in e. SDs from three independent experiments are indicated. *P < 0.05. ns: P > 0.05 (Student t test). h Clonogenic survival assays. SDs from three independent experiments are indicated. *P < 0.05 (Student t test) for comparison between CSB and ΔN30. i HR-mediated repair. SDs from three independent experiments are indicated. *P < 0.05. ns: P > 0.05 (Student t test). j Western analysis of U2OS-DR-GFP parental and CSB KO cells