CENTROSOME REPOSITIONING IMMEDIATELY FOLLOWING KARYOKINESIS AND PRIORTO CYTOKINESIS

The behaviour of the centrosome immediately following cell division in tissue culture cells has been investigated. We find that following ka ryokinesis, but preceding cytokinesis, sister centrosomes relocate fro m the spindle poles to a position adjacent to the intercellular bridge . This repositioning is accompanied by the appearance of a microtubule bundle that extends from the poleward region of the cell to the centr osome and increases in length as the centrosome approaches the interce llular bridge. Disruption of this bundle with colcemid interrupts cent rosome repositioning. In contrast, centrosome repositioning persists i n late mitotic cells grown in the presence of cytochalasin D. However, the position of the microtubule-centrosome complex within the cell is randomized suggesting that the path, but not the process, of centroso me repositioning is dependent on an intact actin filament network. Thi s study points out, for the first time, that the complex migration of the centrosome preceding mitosis is paralleled by an equally complex s et of events following cell division. We suggest that post-mitotic cen trosome repositioning may play a role in ensuring that daughter cells have equal but opposite polarity and may reflect an interrelationship between the establishment of the interphase cytoskeleton and the compl etion of cytokinesis. (C) 1993 Wiley-Liss, Inc.