NuMA depletion induces reduced tension at kinetochores and lagging chromosomes. (A) Confocal series (frames 1–3) of a NuMA-depleted mitotic cell, showing immunofluorescence staining of kinetochores (using a human CREST autoimmune serum, red), and microtubules (green). On the left, a projection of all sections of the confocal series through the cell is shown. Interkinetochore distances of lagging (#) and aligned (←) chromosomes were quantified and plotted in (B). Error bars represent the SEM (standard error of the mean). Mean values for the aligned chromosomes were significantly different between depleted and control cells (two-tailed τ test, * p < 0.001) (C) NuMA-depleted cell in late anaphase, stained for tubulin (green), NuMA (red), and DNA (blue). Chromosomes are separated to the respective poles, but single lagging chromosomes can be seen, as indicated by the arrow. Bars in A and C, 5 μm.