Subcellular localization of MCM2 and the role of the NLS domains in enhancing doxorubicin-induced apoptosis.

<p><i>HA-Mcm2-FL</i> and <i>HA-</i>mutant-transfected 3T3 cells (<b>A</b>), and <i>FLAG-gp70</i>/<i>HA-Mcm2-FL</i> and <i>FLAG-gp70</i>/<i>HA</i>-mutant-transfected 3T3 cells (<b>B</b>) were treated with 1 µM doxorubicin for 24 h. HA-positive cells containing the MCM2-derived proteins are shown in red (TRITC), and DAPI-stained nuclei are shown in blue. Images were acquired using a BZ-9000 microscope (KEYENCE) with a 400× objective. (<b>C</b>) Schematic diagram of the NLS deletion mutants MCM2-ΔNLS1, MCM2-ΔNLS2, and MCM2-ΔNLS1-2. (<b>D</b>) <i>Mcm2-NLS</i> deletion mutant-transfected 3T3 cells were treated with 1 µM doxorubicin for 24 h, and apoptotic cell ratios were determined with annexin V-staining. Data represent the mean and SD of 3 experiments. The asterisks (*) indicate significant differences between the control and <i>Mcm2-ΔNLS2</i>- or <i>Mcm2-ΔNLS 1-2</i>-transfected cells (*<i>p</i><0.01). Data represent the mean and 95% CI of 3 independent experiments.