FAM29A controls spindle structure. (A–C) Maximum projections from deconvolved z stacks of representative HeLa cells transfected with siRNAs and stained for FAM29A (green), β-tubulin (red), and DNA (blue). Long exposures of the β-tubulin images are presented here to show the increased amounts of astral MTs. Arrowheads point to astral MTs outside spindle poles. The percentage of metaphase cells with detectable astral MTs among total metaphase cells (B; n = 100 cells for each quantification) as well as the MT fluorescence intensity in metaphase cells (C; n = 10 cells) were quantified and plotted. In C: *, P < 0.01 (two-tailed t test relative to siControl metaphase cells). (D) Lysates of prometaphase HeLa S3 cells were incubated with increasing amounts of exogenously added, taxol-stabilized MTs, followed by sedimentation of MTs. Pellets and supernatants were analyzed by Western blotting. (E) Lysates of prometaphase HeLa S3 cells were incubated with taxol-stabilized MTs, fixed, centrifugated onto coverslips, and stained for FAM29A (green) and β-tubulin (red). Error bars, SEM. Bars, 5 μm.