Abstract
Actin microfilaments (MFs) show various organizations such as bundles and fine meshworks in cell division, elongation and differentiation processes in plants. It has been observed that MFs changes from bundles into fine meshwork in mitosis, however, their roles are largely unknown. We examined the effects of actin polymerization inhibitor Latrunclin B (LatB) and actin stabilizer TIBA on the mitotic apparatus dynamics using live imaging techniques. Using the transgenic tobacco BY-2 cells constitutively expressing the microtubule (MT) plus-ends reporter GFP-EB1, we found that TIBA treatment resulted in decreased MT polymerization in mitotic spindles and phragmoplasts whereas LatB treatment did not. In G1 phase, conversely, only LatB treatment resulted in decreased cortical MT polymerization. These results imply that MFs involve in MT polymerization in cell cycle dependent manner. Now we assess the effects of these inhibitors on the mitotic spindle formation and division plane determination. Together with the updated results, we would discuss the roles of actin organization on plant cell division.
