Fig. 7. BRCA1 and DHX9 form a complex that interacts with RNA Pol II-mediated through RNA.

a Western blot showing co-immunoprecipitation of BRCA1 with DHX9 in cells treated with DNA damaging agents; 2 mM hydroxyurea (for 4 h), 2 μM camptothecin (for 2 h), and ionizing radiation (10 Gy) (as indicated). All samples were treated with RNaseA to exclude interactions mediated by RNA. b Western blot of RNA Pol II immunoprecipitation from U2OS cells knocked down for specific genes using siRNAs indicated and treated with 1 μM camptothecin for 2 h (all samples). Blot shows co-purification of BRCA1 and DHX9 with RNA Pol II is dependent on the presence of both DHX9 and BRCA1 in cells. Co-precipitation of DHX9 and BRCA1 with RNA Pol II is also dependent on RNA as the interaction is disrupted in samples treated with RNaseA (indicated). c Fluorescence image (left panel) with quantification (right panel) showing that DNA damage-induced BRCA1 foci are diminished in cells knocked down for DHX9 and in cells treated with RNaseA. Graph (right panel) shows the quantification of n cells (as indicated) from three pooled biologically independent experiments. Mean values were shown to be significantly different using one-way ANOVA with post hoc Tukey’s test (****p < 0.0001). Mean and standard deviation are shown. Source data are provided as a Source Data file.