Fig. 3: Lamin A but not Lamin B1 suppresses aberrant repair in BRCA1-deficient cells treated with PARPi.
a Representative mis-rejoined chromosomes in Brca1F/F Lmna+/+ and Brca1F/F Lmna−/− 96 h after Brca1 deletion with Hit&Run Cre and PARPi treatment for 24 h. DNA is visualized with DAPI. Arrowheads indicate centromeres of chromosomes involved in mis-rejoining events. Scale bar: 10 μm. b, c Quantification of the percentage of mis-rejoined chromosomes per metaphases in Brca1F/F Lmna+/+ and Brca1F/F Lmna−/− (b) or Brca1F/F Lmna+/+ transduced with vec or two shRNAs against (mRNA) LmnB1 (B1) (c) as shown in (a). Each dot represents a metaphase. Bars represent the median for n = 3 independent experiments, with 10 metaphases each (30 metaphases in total). Statistical analysis by ordinary one-way ANOVA for multiple comparisons: (*) P < 0.05 (0.0167 and 0.0441, respectively); (****) P < 0.0001; P ≧ 0.05 is not significant. d Representative survival assay of Brca1F/F Lmna+/+ and Brca1F/F Lmna−/− MEFs treated with or without Hit&Run Cre and/or the indicated concentration of PARPi. Cells were treated with PARPi for 24 h before wash. e Quantification of survival to the indicated concentrations of PARPi in Brca1F/F Lmna+/+ and Brca1F/F Lmna−/− MEFs before or after Cre-mediated deletion of Brca1, as shown in (d). Colonies were stained with Methylene blue and their number in the different conditions was normalized over the number of colonies recovered in the untreated plates. Data represents the average and SEMs from n = 3 independent experiments. f Quantification of survival to the indicated concentrations of PARPi in Brca1F/F Lmna+/+ MEFs transduced with vec or depleted of Lamin-B1 before or after Cre-mediated deletion of Brca1. Data represents the average and SEMs from n = 3 independent experiments. Source data are provided as a Source Data file. See also Supplementary Figs. 2 and 3.
