Live spheroid imaging by SPIM. A: Maximum projection of z-stacks of an H2B-HcRed-expressing spheroid recorded at the indicated times. The images are taken from Additional file 9. Stacks of 100 slices were recorded by SPIM (10× objective, NA = 0.3) every 3 minutes with a slice spacing of 1 μm. The white arrow shows a dividing cell. Scale bar, 100 μm. B: 3D visualization of an enlarged region of the spheroid at the indicated times. The progress of mitosis can be seen in two cells (arrows). C: 3D reconstruction of the interphase nuclei (blue) and condensed chromosomes (red) of one mitotic cell within the 4D stack. The arrow indicates a sister chromatid disjunction. Scale bar, 10 μm. D: 3D reconstruction of a region of a spheroid treated with paclitaxel showing three mitotic cells (red) blocked in mitosis over 60 minutes. Scale bar, 20 μm.