Formation of Perinuclear and Spindle Actin during Prometaphase
(A) Confocal scans of glutaraldehyde-fixed NIH 3T3 cells in indicated z direction, stained for F-actin (phalloidin, green, and black and white) and DNA (DAPI, blue). Note the aster-like F-actin structures below and on top of the nucleus (at 6.0 and 9.0 μm) as well as perinuclear F-actin (7.5 μm). Scale bar, 5 μm.
(B) Incidence of spindle actin during prometaphase in different mammalian cell lines. Data are shown as mean of two independent experiments together with individual data points; n > 13 cells in prometaphase per data point.
(C) Cropped, orthogonal projections of phalloidin staining (black and white) as indicated in (A) (7.5 μm) by dashed, violet lines. Scale bar, 5 μm. Arrowheads indicate F-actin structures protruding into the nuclear compartment.