As cells divide, they must place the two new nuclei into separate daughter cells. Cells precisely control the timing and positioning of cleavage (cytokinesis) in order to avoid the generation of anucleate and multinucleate daughters, but how animal cells specify the plane of division is not well understood. From their studies on Caenorhabditis elegans embryos, Dechant and Glotzer present evidence that the low density of microtubules between daughter nuclei (after spindle elongation has taken place) can signal where the cell will form a cleavage furrow. If the microtubule density remains high because of a reduction in chromosomal separation during anaphase, furrow formation is delayed. Therefore, not only is the mitotic spindle important for partitioning chromosomes to daughter cells, but after completing this job, it helps to specify when and where cleavage into daughter cells occurs. — SMH
Dev. Cell4, 333 (2003).