Cytokinesis in Animal Cells

ISBN: 9780521019361 出版年：1996 页码：401 R Rappaport Cambridge University Press

The organizers of this meeting probably placed cytokinesis first because it has long been an object of curiosity, speculation and investigation and because it appears to be a relatively simple event. It has been studied for so long because it is obviously important in the life of cells; and, for an activity that is controlled and carried out within the resources of a single cell, it is comparatively easy to see. The observer of cytokinesis in a large, relatively transparent cell like a cleaving sea urchin egg may think he has seen all the important aspects of the process, but appearances are deceptive. He can see the overall cell dimensions, the general form of the mitotic apparatus and the distance between the astral centers, the deformation of the surface contour that comprises division and (with the aid of natural or introduced particles) local changes in surface behavior. He cannot see (but may think he can) the location and nature of the constraints and forces that reshape the cell, the outermost limits of the mitotic apparatus and the location of regions where the action of the mitotic apparatus upon the surface is most intense. Whether cytokinesis can serve as a useful example for analysis of other kinds of cell deformation and shape change is not now clear. It seems evident that all shape changes have similar requirements but they may not be carried out by the same processes. Shape change requires that a forceproducing mechanism be created and used. The cell must put the mechanism in the right place and in the right orientation, and it must activate and deactivate it at the right times.