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Analysis of reorganization of cortical microtubules in cell morphogenesis at M/G_1 interface.

M/G_1 界面细胞形态发生中皮质微管重组的分析。

基本信息

批准号：
07454223
负责人：
HASEZAWA Seiichiro
金额：
$ 5.12万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

We have shown by immunofluorescence microscopy that, during the cell cycle transition from M to G_1 phase in synchronized tobacco BY-2 cells, MTs were organized on the perinuclear region. MT elongation up to the cell cortex was followed by further elongation parallel to the long axis of cells. As soon as the tips of the elongated MTs reached the distal end of the division plane, the transversely oriented MTs were formed proximal to the division plane. Although the nuclear surface is the site of MT organization, the organized MTs are not the direct precursors of the cortical MTs. To examine the sites of MT reorganization, the MTs of BY-2 cells were completely destroyed by a combination of cold and propyzamide treatment. After the cells were washed and cultured, the sites of MT reorganization at M/G_1 interface were identified solely on the perinuclear region or on the perinuclear region and on the cell cortex(Hasezawa et al.1997). These patterns of MT organization correspond to the five … More types observed during the cell cycle transition from M to G_1 phase ; reorganization of MTs solely on the perinuclear region reflecting earlier types of the patterns and MT reorganization on both the perinuclear region and the cell cortex reflecting later types of them.We have also shown that EF-1 alpha(a 49 kDa protein)is associated with organizing MTs in tobacco BY-2 cells, and this association occurs exclusively with organizing MTs on the perinuclear region during the cell cycle transition from M to G_1 phase(Kumagai et al.1995). We prepared partially purified protein fractions which had a microtubule organizing center(MTOC)activity and involved EF-1 alpha, from evacuolated protoplasts of BY-2 cells. Using these fractions, we developed a system, in which the addition of purified tubulin caused the formation of small aster-like structure. We called them"aster". Our efforts to find factors affecting the formation of the"aster"would be expected to provide further insight into MT organization in plant cells. Less

我们通过免疫荧光显微镜证明，在同步化烟草BY-2细胞中从M期到G_1期的细胞周期转变期间，MT在核周区域组织。 MT 伸长至细胞皮层，随后平行于细胞长轴进一步伸长。一旦细长 MT 的尖端到达分割平面的远端，横向取向的 MT 就会在分割平面附近形成。虽然核表面是 MT 组织的场所，但组织化的 MT 并不是皮质 MT 的直接前体。为了检查 MT 重组的位点，BY-2 细胞的 MT 通过冷处理和丙吡酰胺处理的组合被完全破坏。细胞经洗涤和培养后，M/G_1界面的MT重组位点仅在核周区域或在核周区域和细胞皮层上被识别(Hasezawa et al.1997)。这些 MT 组织模式对应于细胞周期从 M 期过渡到 G_1 期期间观察到的五种类型；仅在核周区域上的 MT 重组反映了模式的早期类型，而在核周区域和细胞皮层上的 MT 重组则反映了它们的较晚类型。我们还表明，EF-1 α（一种 49 kDa 蛋白）与烟草 BY-2 细胞中的 MT 组织相关，并且这种关联仅发生在细胞周期转变期间核周区域上的 MT 组织中从 M 到 G_1 阶段（Kumagai 等人，1995）。我们从 BY-2 细胞的空泡原生质体中制备了具有微管组织中心 (MTOC) 活性并涉及 EF-1 α 的部分纯化的蛋白质组分。使用这些级分，我们开发了一个系统，其中添加纯化的微管蛋白导致形成小的紫苑状结构。我们称它们为“紫苑”。我们寻找影响“aster”形成的因素的努力有望为植物细胞中的MT组织提供进一步的见解。较少的