The mechanism that specifies the position of the cell division plane in cells about to undergo mitosis has been the subject of much speculation. Mitotic chromosomes, centrosomes and the spindle midzone have all been suggested as holders of positional information, and most models assume a bipolar spindle is essential. But by treating cells with monastrol to prevent centrosome separation, and an antibody to disrupt spindle assembly, Canman et al. trick mitotic cells into inducing an asymmetric monopolar spindle. The cells cleave to produce one cell with DNA and one without. So a bipolar spindle is not vital for normal cell division, which combines two oppositely oriented monopolar spindles (see cover). The chromosomes themselves seem to determine the cytokinetic furrow position and stabilize nearby microtubules.

Determining the position of the cell division plane
JULIE C. CANMAN, LISA A. CAMERON, PAUL S. MADDOX, AARON STRAIGHT, JENNIFER S. TIRNAUER, TIMOTHY J. MITCHISON, GUOWEI FANG, TARUN M. KAPOOR & E. D. SALMON
Nature 424, 1074–1078 (2003); doi:10.1038/nature01860
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