The study of plant cell morphogenesis by microtubules

本文的主要研究成果如下。1)蚕豆（Vicia fava L.）在黎明时呈放射状排列，从傍晚到午夜被破坏，这表明它们的放射状皮层MT可能控制着昼夜气孔运动（Fukuda et al. 1998）。2)研究了微丝（MF）在决定皮质MT的方向和组织中的作用，发现MF可能在这一过程中起关键作用（Hasezawa et al. 1998）。3)当从BY-2细胞制备的部分纯化的蛋白质与纯化的猪脑微管蛋白孵育时，MT可以组织成紫菀样形式。研究了这些结构作为MTOC位点和EF-1α的作用（Kumagai等人，1999年）。4)纤维素微纤维（CMF）束似乎沉积在紫杉醇处理的BY-2原生质体中的皮层MT上，这表明MT可以通过某种形式的连接直接附着于纤维素合成复合物，并调节这些复合物在高等植物细胞中的运动（Hasezawa和Nozaki 1999）。5)在稳定表达GFP-TUA 6融合蛋白的转基因拟南芥悬浮细胞中，MT的变化可以通过时间序列观察来监测。我们第一次成功地在整个有丝分裂过程中跟踪活植物细胞中的MT动力学（Hasezawa et al.2000）。

The main fruits of this study are as follows. 1) The cortical microtubules (MTs) of guard cells of Vicia fava L. were found to be organized in a radial array at dawn and be destroyed from evening to midnight, suggesting that the radially-organized cortical MTs of them may control diurnal stomatal movement (Fukuda et al. 1998). 2) The involvement of microfilaments (MFs) in determining the orientation and organization of cortical MTs was studied and found that the MFs may play a key role in this process (Hasezawa et al. 1998). 3) The MTs could be organized in aster-like form when partially purified proteins prepared from BY-2 cells were incubated with purified porcine brain tubulins. The role of these structures as MTOC sites and the EF-1α were studied (Kumagai et al. 1999). 4) The cellulose microfibril (CMF) bundles appeared to be deposited on the cortical MTs in taxol-treated BY-2 protoplasts, suggesting that MTs may attach directly to the cellulose-synthesizing complexes, by some form of linkage, and regulate the movement of these complexes in higher plant cells (Hasezawa and Nozaki 1999). 5) The MT changes in mitotic suspension cells of stable transgenic Arabjdopsis, expressing a GFP-TUA6 fusion protein, could be monitored by time-sequence observation. We have succeeded, in the first time, in following the MT dynamics in living plant cells throughout mitosis (Hasezawa et al. 2000).