Figure 4.

Nuclear membrane ruptures are frequent but are repaired quickly in cultured B1KO neurons, whereas ruptures are infrequent and prolonged (never undergoing repair) in B2KO neurons. (a) Live-cell fluorescence microscopy images of B1KO and B2KO neurons that express a nuclear-localized green fluorescent protein (NLS-GFP). Red arrows point to cells with nuclear membrane ruptures. Scale bar, 20 μm. (b) Percentages of neurons with nuclear membrane (NM) ruptures in five independent experiments. Numerical ratios show the total numbers of cells with NM ruptures over the total numbers of cells examined. ***P < 0.0001 as defined by a χ² test. (c) NM rupture events in five independent experiments. Numerical ratios show the total numbers of NM ruptures over the total numbers of cells observed. **P < 0.001 as defined by a Student’s t test. (d) Average duration of NM ruptures. Repair of a NM rupture was never observed in a B2KO neuron; thus, the duration of 38.8 h represents the average length of time that ruptures were observed over the entire 50-h period of imaging. ***P < 0.0001 as defined by a Student’s t test. Reproduced with permission from Chen et al. [26].