Mta30 2g10 3

Commercial human Topo I siRNA was used in this study (human Top1 siRNA, sc-36694; Santa Cruz Biotechnology). TOP1 was analysed by western blotting using a mouse anti-Topo I antibody (C-21) (1:10,000, sc-32736; Santa Cruz Biotechnology). Commercial human MUS81 siRNA was used in this study (human MUS81 siRNA, L-016143-01-0005; Horizon). MUS81 was analysed by western blotting using a mouse anti-MUS81 antibody (MTA30 2G10/3) (1:10,000, ab-14387; Abcam). As a loading control, α-tubulin was analysed with mouse anti-α-tubulin antibody (10G10) (1:10,000, 017-25031; Fujifilm). Horseradish peroxidase (HRP)-conjugated donkey anti-mouse IgG (1:10,000, 715-035-150; Jackson ImmunoResearch Laboratories) and HRP-conjugated anti-rabbit IgG (1:10,000, 711-035-152; Jackson ImmunoResearch Laboratories) were used as secondary antibodies. The bands were visualised with Chemi-Lumi One Super (Nacalai Tesque) and analysed with LAS4000 Mini (GE Healthcare Life Science).

The following antibodies were used for immunoblotting: mouse monoclonal antibodies raised against BRCA1 (1:2,000, OP92, Calbiochem), BRCA2 (1:2,000, OP95, Calbiochem), GAPDH (1:30,000, 6C5, Novus Biologicals), histone H3 (1:1,000, 865R2, Invitrogen), MUS81 (1:1,000, MTA30 2G10/3, Abcam), POLD3 (1:500, 3E2, Abnova), RAD51C (1:1,000, 2H11/6, Novus Biologicals), SLX4 (a gift from Professor John Rouse, University of Dundee) and α-tubulin (1:15,000, TAT1, Cancer Research UK Monoclonal Antibody Service). Rabbit polyclonal antibodies raised against phosphorylated histone H3 Ser10 (1:1,000, Abcam), RAD51 (1:2,000, H92, Santa Cruz) and SMC1 (1:4,000, BL308, Bethyl Laboratories). Additional antibodies used for immunofluorescence detection were: mouse monoclonal antibodies raised against α-tubulin (1:2,000, TAT1, Cancer Research UK Monoclonal Antibody Service), γ-tubulin (1:2,000, GTU-88, Abcam), cyclin A (1:1,000, B-8, Santa Cruz Biotechnology), rabbit polyclonal antibodies raised against 53BP1 (1:5,000, NB100-304, Novus Biologicals), FANCD2 (1:1,000, ab2187, Abcam) and goat polyclonal antibody raised against BLM (1:100, C-18, Santa Cruz Biotechnology).