Fig 1: (A) Western blotting analyses of the indicated pro-homologous recombination (HR) factors in total cell extracts from GCT27 paired cell lines. Graph bars quantify protein level differences among GCT27 cell lines. Data are mean values ± s.d. of either three (breast cancer type 1 susceptibility protein, BRCA1) or six (C-terminal binding protein-1 interacting protein, CtIP) independent experiments. Original blots see Figure S3C. Statistical analyses were performed using a two-tailed t-test (* p < 0.05; ** p < 0.01). (B) Western blotting analyses of the indicated pro-HR factors in chromatin extracts from GCT27 paired cell lines. Cells were treated with a pulse of 3 μM cisplatin for 6 h and analyzed 16 h after culture in drug-free media. Histone H3 (H3) was used as a loading control. Original blots see Figure S3D. (C) Quantification of BRCA1 foci number in GCT27 paired cell lines before (Ctr) and after treatment with 3 μM cisplatin. Treated cells were collected both at the end of treatment (6 h) and 16 h after drug washout. Data are mean values ± s.d. of two independent experiments, each performed in duplicate. (D) Western blotting analyses of the indicated pro-HR factors in total cell extracts of 2102EP paired cell lines. Tubulin and cyclin A were assessed to detect differences in protein loading and cell cycle phase distribution, respectively. Original blots see Figure S3C. (E) Western blotting analyses of the indicated pro-HR factors in chromatin extracts from the indicated cell lines, before and after treatment with 3 μM cisplatin for 6 h. Cell extracts were prepared from cells collected 16 h after drug removal. H3 was used as a loading control. Original blots see Figure S3D. (F,G) Western blotting analyses of the indicated pro-non-homologous end joining (NHEJ) factors in total cell extracts of 2102EP and GCT27 cell lines. Clathrin was used as a loading control for 53BP1 and DNA-PKcs, while KU70 expression was normalized using tubulin. Graph bars quantify protein levels difference among cell lines. Original blots see Figure S3E. Data are mean values ± s.d. of six (53BP1) or three (DNA-PKcs) independent experiments. In all quantifications, the expression of the indicated proteins was normalized on the expression of either tubulin or clathrin. Cyclin A was assessed to detect possible differences in cell cycle phase distribution among cell lines. Statistical analyses were performed using a one-tailed t-test (* p < 0.05; ** p < 0.01; **** p < 0.0001). A.U. = arbitrary units.