Fig. 5.

Spindle assembly in the presence of an increasing number of spindle poles results in increasing numbers of merotelic KTs. (A and B) Snapshots of the search-and-capture simulation in a bipolar (A) and a tripolar (B) spindle. (Scale bars, 2 μm.) (C) Predicted (red) and observed numbers (blue) of merotelic attachments in prometaphase cells with two, three, four, and six spindle poles. Because cells with more than four spindle poles are rare, the experimental data for cells with five to eight poles were pooled together in the “Hexapolar” category. The data shown represent means and standard errors (bars). (D and E) Bipolar (D) and tripolar (E) prometaphase HT-29 cells immunostained for MTs (green) and KTs (red). Arrowheads point at spindle poles. Images were acquired and processed as described in Methods in SI Text. (Scale bars, 5 μm.) (F) Enlargement of one focal plane from the cell shown in E, in which a merotelic KT (boxed area) is visible. A zoomed view of the boxed area in F is shown on the right.