Fig. 2: Label-free visualization of the complete division process of a COS-7 cell in three dimensions, in which various subcellular structures are observed.

Cell division followed by late nuclear membrane emergence in one representative example of three similar replicates is shown in a–f, and the disintegration of the nuclear membrane in another representative cell is shown in g. a One Z plane of a COS-7 cell is shown at a time point of 00:49:30. b The region enclosed by the dashed yellow box in (a) is enlarged and shown at four different time points, in which the material condensation (middle left), emergence of the membrane structure (middle right, arrows), and final chromatin foci formation (right) are shown. c, d Another Z plane of the COS-7 cell (0.86 μm below the plane in a) is shown at the time point of 00:00:00. c The region enclosed by the dashed yellow box was enlarged and is shown in (d), in which smaller filament structures (upper arrow), bright puncta (lower yellow arrow), large dim vesicles (lower yellow arrowhead), and black vacuole-like vesicles (lower magenta arrow) are shown. e, f The third Z plane of the COS-7 cell (1.72 μm below the plane in a) is shown at the time point of 00:43:10. e The region enclosed by the dashed red box is enlarged and shown at two time points (f), before (left) and after (right) cytokinesis. Freely spanning and twisted worm-like tubular structures are shown in the left panel, and are aligned along the nucleus–cell exterior spindles in the right panel. g A zoomed-in image of another cell shows one plane of the nuclear region before cell division. Five different time points are shown, with clear visualization of the cell nucleus and associated nucleolar structures (0’00”), the deformation of one region in the nuclear membrane (the arrowhead) by many incoming cellular structures (27’30”), the initial rupture of the nuclear membrane in other regions (arrows, 29’10”), emergence of chromosomes (31’10”), and alignment of chromosomes into petal-like arrays (38’10”). Scale bars: (a, c, e) 5 µm and (b, d, f, g) 2 µm.