Sites of microtubule reorganization in tobacco BY-2 cells during cell-cycle progression

The sites of microtubule (MT) reorganization were examined in synchronized tobacco BY-2 cells. The MTs of these cells were completely destroyed by a combined cold and drug treatment at 0 degrees C with 100 mu M propyzamide for 3 h. After the cells were washed and cultured at 30 degrees C, the reorganization of MTs was observed in detail. Sites for MT reorganization at each stage of the cell cycle were identified on the cell cortex and nuclei, the mitotic apparatus, the nuclei (or the nuclei and cell cortex), and the cell cortex in the S-G(2) phase, M phase, M/G(1) interface, and G(1) phase, respectively. The polypeptide synthesis elongation factor (EF)-1 alpha is co-localized with these sites of MT reorganization. Ar some stages, microfilaments (MFs) were found to be involved in the reorganization of MTs. Based on these results, the mode of MT reorganization during cell cycle progression is discussed.