Mitosis (image 2 of 6). Digital three-dimensional immunofluorescent light micrograph of a section through a mammalian cell during the early prometa- phase stage of mitotic cell division. The nuclear membrane (not seen) that encloses the chromosomes (blue) is breaking down. The actin microfilaments (red) and tubulin microtubules (green) of the cytoskeleton maintain the structure of the cell. The two centrosomes (pink dots, upper left & lower right) are microtubule-organizing centres. Mitosis results in the formation of two identical daughter cells. This is a rat kangaroo kidney epithelial cell. Magnification: x500 at 6x7cm size. For a sequence of mitosis see images P673/052-057.