Disorganization and reorganization of the Golgi complex and the lysosomal system in association with mitosis.

The fate of the Golgi complex and the lysosomal system during mitosis was studied in L929 mouse fibroblasts by staining with wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) and transmission electron microscopy. In interphase WGA-HRP stained a circumscribed juxtanuclear region encompassing the stacked Golgi cisternae, the trans Golgi network, secretory vacuoles, endosomes, and lysosomes. As the cells entered prophase, WGA-HRP reactive material was spread around the perimeter of the nucleus. Fine structurally, the Golgi complex was found to be disorganized and its stacks were scattered throughout the cytoplasm together with clusters of lysosomes. At the same time, the trans Golgi network atrophied and secretory vacuoles and endosomes decreased in number. The disperse and structurally modified state of the Golgi complex and the lysosomal system persisted until late telophase, when they were reorganized in a defined region, most frequently on the outside of the nucleus as related to the midbody. The disorganization and reorganization of the Golgi complex and the lysosomal system coincided with the breakdown and rebuilding of the microtubular cytoskeleton, and showed striking similarities to the previously described modifications of these organelles during treatment with and after withdrawal of microtubule-disruptive drugs. Based on the findings, a model is presented that links the division of the Golgi complex and the lysosomal system to the loss of the radiating array of interphase microtubules.