Mitosis in Vpr-expressing cells (DOX+). MIT23/H2B-EGFP cells were observed on day 2 after the addition of DOX (DOX+). The cells were cultured in a glass-bottomed dish placed on a thermo plate attached to a fluorescence microscope (IX70) to maintain a growth temperature of 37°C. Photographs were taken every 15 s to analyze mitosis.