Fig. 5: DTL reduces NHEJ activity to increase DNA DSBs.

(A) Western blot analysis of DNA-PK kinase (DNA-PKcs, KU70/80) expression in HPDE6-C7 and CCC-HPE cells overexpressing DTL after DSBs induction with bleomycin. (B) The effect of DTL on the expression of DNA-PK protein kinases (DNA-PKcs, KU70/80) in MEFs from Dtl transgenic mice. (C) The expression of DNA-PK protein kinases (DNA-PKcs, KU70/80) in HPDE6-C7 and CCC-HPE cells with DTL silencing. (D) The DNA-PKcs protein level was detected by Western blotting in HPDE6-C7 cells stably overexpressing DTL and its point mutants (R246H and R171H) after IR. (E, F) With the NHEJ reporter gene system, I-SceI was used to induce DSBs, and flow cytometry was used to analyze the effect of DTL and its point mutants (R246H and R171H) on NHEJ efficiency. (G) After treatment with bleomycin, a neutral comet assay was performed to analyze the accumulation of DSBs in HPDE6-C7 cells overexpressing DTL (H) After treatment with bleomycin, a neutral comet assay was performed to analyze the accumulation of DSBs in MEFs from Dtl transgenic mice. * p < 0.05, # p < 0.05, and ns = not significant based on Student’s t-test. The data are presented as the means ± SDs of five (E and F) or three (A–D) independent experiments. The scale bars indicate 50 μm in G and H.