A time for cytokinesis

Think of cell division, and you probably imagine two phases occurring in successive order: first mitosis, then cytokinesis. But unlike in yeast, mitosis in animal cells does not have to come to completion for cytokinesis to commence. Rather, what is important is the inactivation of the mitotic spindle checkpoint, according to new results from Brad Shuster and David Burgess (Boston College, Boston, MA).

Shuster and Burgess have revisited an old experiment, which demonstrated that cytokinesis could be initiated prematurely in embryonic animal cells by shortening the distance between the spindle poles and the cell cortex. “In the old experiments,” says Burgess, “they did not have the ability to image chromosomes, and so they did not know the stage of mitosis when furrows were initiated.” Now, armed with better imaging tools, the authors have...