Fig. 4: ADAR1 silencing in BRCA1-mutant cells causes DNA damage and replication stress.

A–D Representative images and quantifications of γ-H2AX foci (number of γ-H2AX foci per nucleus) in SUM149 BRCA1-Mut and BRCA1-Rev cells (A, B) or MEF Brca1-wildtype (WT) and Brca1-mutant (Δ11) cells (C, D) transfected with ADAR1 siRNA (P, Pool; #1; #2). Violin plots indicate median, lower and upper quartiles; N = 150 values from individual nuclei, representative of n = 3 biologically-independent experiments, two-way ANOVA post hoc Dunnett’s test (B) or Šidák’s test (D). P values, *=0.0101, **=0.0014, ****< 0.0001. E–H Representative images and quantifications of micronuclei (percentage of cells harboring > 1 micronucleus in the assessed population) in SUM149 BRCA1-Mut and BRCA1-Rev cells (E, F) or MEF Brca1-wildtype (WT) and Brca1-mutant (Δ11) cells (G, H) transfected with ADAR1 siRNA (P, Pool; #1; #2). Scatter dot plots indicate mean ± SD; N = 3 values from individual microscopic fields, representative of n = 3 biologically-independent experiments, two-way ANOVA post hoc Dunnett’s test (F) or Šidák’s test (H). P values, **=0.0099, ****< 0.0001. I, J Representative images and quantifications of RPA foci (number of RPA foci per nucleus) in CCNA2-positive SUM149 BRCA1-Mut and BRCA1-Rev cells transfected with ADAR1 siRNA (P, Pool; #1). Violin plots indicate median, lower and upper quartiles; N = 150 values from individual nuclei, representative of n = 3 biologically-independent experiments, two-way ANOVA post hoc Dunnett’s test. P values, ****<0.0001. K, L Western blot of SUM149 BRCA1-Mut and BRCA1-Rev cells (K) or MEF Brca1-wildtype (WT) and Brca1-mutant (Δ11) cells (L) transfected with a concentration range (nM) of ADAR1 siRNA. Data representative of n = 2 biologically-independent experiments. siCTRL, non-targeting, negative control siRNA; siPLK1, PLK1-targeting, positive control siRNA. Source data are provided as a Source Data file.