Dynamics of interphase microtubules in Schizosaccharomyces pombe
Dynamics of interphase microtubules in Schizosaccharomyces pombe
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DOI：
10.1016/s0960-9822(00)00570-4
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发表时间：
2000-06-29
期刊：
影响因子：
9.2
通讯作者：
Cross, RA
中科院分区：
文献类型：
--
作者：
Drummond, DR;Cross, RA
背景：裂殖酵母间期的微管对于维持这些细胞的线性生长习性至关重要。到目前为止，这些微管组装和去组装的动力学特征尚未明确。
结果：用增强型绿色荧光蛋白标记的ctl微管蛋白的活细胞共聚焦成像显示出纵向排列、动态不稳定的间期微管组装体（IMAs）。除了在靠近其中心通常存在一个荧光强度约为两倍的区域外，IMAs沿其长度均匀明亮。每个IMA的末端以每分钟1.0次的频率从生长（约3.0μm/分钟）转变为收缩（约4.5μm/分钟），并以每分钟1.9次的频率从收缩转变为生长，并且两个末端具有同等的动态性，表明结构相同。因此，我们提出了一个IMA内微管排列的对称模型，其中微管正端向外并在靠近细胞赤道处重叠。IMA可能包含此结构模式的多个副本；如果是这样，那么在每个IMA末端内，微管末端必须同步灾难（解聚）和拯救（聚合）。当一个IMA的两端位于半球形细胞末端时，IMAs在压缩下开始弯曲，并且其总体生长速率被抑制约两倍。在大小从正常长度的一半到两倍的细胞中观察到了类似的微管动力学。模式化光漂白表明在间期没有可检测到的踏车运动或微管滑动。
结论：所描述机制的结果是微管末端持续募集到生长细胞的末端，支持基于微管的向细胞末端的运输，并从性质上解释了微管在指导裂殖酵母线性细胞生长中的关键作用。（C）2000 Elsevier Science Ltd.保留所有权利。
Background: Microtubules in interphase Schizosaccharomyces pombe are essential for maintaining the linear growth habit of these cells. The dynamics of assembly and disassembly of these microtubules are so far uncharacterised.Results: Live cell confocal imaging of ctl tubulin tagged with enhanced green fluorescent protein revealed longitudinally oriented, dynamically unstable interphase microtubule assemblies (IMAs). The IMAs were uniformly bright along their length apart from a zone of approximately doubly intense fluorescence commonly present close to their centres. The ends of each IMA switched from growth (similar to 3.0 mu m/min) to shrinkage (similar to 4.5 mu m/min) at 1.0 events per minute and from shrinkage to growth at 1.9 events per minute, and the two ends were equivalently dynamic, suggesting equivalent structure. We accordingly propose a symmetrical model for microtubule packing within the IMAs, in which microtubules are plus ends out and overlap close to the equator of the cell. IMAs may contain multiple copies of this motif; if so, then within each IMA end, the microtubule ends must synchronise catastrophe and rescue. When both ends of an IMA lodge in the hemispherical cell ends, the IMAs start to bend under compression and their overall growth rate is inhibited about twofold. Similar microtubule dynamics were observed in cells ranging in size from half to twice normal length. Patterned photobleaching indicated no detectable treadmilling or microtubule sliding during interphase.Conclusions: The consequence of the mechanisms described is continuous recruitment of microtubule ends to the ends of growing cells, supporting microtubule-based transport into the cell ends and qualitatively accounting for the essential role for microtubules in directing linear cell growth in S. pombe. (C) 2000 Elsevier Science Ltd. All rights reserved.