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. 2018 Oct 23;115(45):E10642–E10651. doi: 10.1073/pnas.1803177115

Fig. 4.

Fig. 4.

BRCA1 promotes MRE11-mediated removal of TOP2ccs. (A) MRE11+/H129N/53BP1−/−/BRCA1−/− and MRE11+/H129N TK6 cells were treated with 4-OHT for 3 d to inactivate the wild-type MRE11 allele. Cells were then treated with etoposide (10 μM) for 2 h. Data are shown as in Fig. 3 B and C. (B) Quantification of TOP2cc in the indicated genotypes from A. Data are shown as in Fig. 3D. Error bars were plotted for SD from three independent experiments. The single asterisk indicates P < 0.02 whereas the double asterisk indicates P > 0.3 (not statistically significant difference), calculated by Student’s t test. (C) Etoposide-induced MRE11 foci in serum-starved MCF-7 cells. We examined the indicated genotypes and wild-type MCF-7 cells treated with siRNA targeting BRCA1 (siBRCA1) and control siRNA (siControl). We pulse-exposed cells to etoposide (10 μM) for 30 min. (D) Quantification of MRE11-positive cells with at least 10 foci per nucleus. Error bars were plotted for SD from three independent experiments. The single and double asterisks indicate P < 0.02 and P < 0.03, respectively, calculated by Student’s t test.