Fig. 4: INTS3 dimerization and its interaction with INTS6 are required for DNA repair.

a Cells stably expressing siRNA-resistant wild-type INTS3 or its mutants defective in INTS6 binding (V767A/D769A, F806A/E839A) or the dimer formation (Δ791−831, Δ832−872) under the control of a tetracycline-inducible promoter were generated. The cell lines were transfected twice with INTS3 siRNA. Twenty-four hours after the second transfection, cells were cultured with doxycycline for 24 h and treated with IR (10 Gy) for 6 h. Cells were then fixed and processed for RAD51 immunofluorescence. b The quantification of foci-positive cells was performed by counting a total of 300 cells per sample. c Cells that express siRNA-resistant wild-type INTS6 or its point mutant defective in binding to INTS3 (F858A/E859A) under the control of a tetracycline-inducible promoter were generated. The resulting cell lines were transfected twice with INTS6 siRNA. Twenty-four hours after the second transfection, cells were cultured with doxycycline for 24 h and treated with IR (10 Gy) for 6 h. Cells were then fixed and processed for RAD51 immunofluorescence. d The quantification of foci-positive cells was performed by counting a total of 300 cells per sample. e, f Cells that express siRNA-resistant wild-type INTS3/INTS6 or their mutants under the control of a tetracycline-inducible promoter were generated. The resulting cell lines were transfected twice with control or INTS3/INTS6 siRNAs. After IR treatment, cells were incubated for 14 days before staining. Experiments were done in triplicates. The results shown are the averages of three independent experiments.