Cross-sectional structure of the central mitotic spindle of Diatoma vulgare. Evidence for specific interactions between antiparallel microtubules.
Cross-sectional structure of the central mitotic spindle of Diatoma vulgare. Evidence for specific interactions between antiparallel microtubules.
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DOI：
10.1083/jcb.83.2.443
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发表时间：
1979-11
期刊：
影响因子：
--
通讯作者：
McIntosh JR
中科院分区：
文献类型：
--
作者：
McDonald KL;Edwards MK;McIntosh JR
在从前中期到中期的过渡期间，Diatoma的中央纺锤体的横截面积减少了近两倍，无论是在两极还是在纺锤体赤道附近的重叠微管（MT）区域。纺锤体MT包装的密度在整个有丝分裂过程中保持大致恒定。电子显微镜的光学衍射分析表明，在有丝分裂的所有阶段，在两极的MT的包装是类似于预期的二维液体。重叠区域的分析揭示了更多的包装规则性：在前中期，出现一个正方形包装，显示足够的组织由后期中期产生五个衍射级;在后期的重叠区域的包装转移到六角形;在末期，它返回到正方形。从中央纺锤体的连续截面重建所提供的数据中，可以识别几乎每个纺锤体MT的极性，也就是说，识别MT与之相关的一个极点。对重叠区横截面中MT的近邻分析表明，MT更喜欢反平行近邻。这些近邻最常以大约40 nm中心到中心的间距发现，而重叠区中的平行近邻基本上随机间隔。这些结果证明了反平行MT之间存在特定相互作用。在某些部分，可以看到MT之间的明确桥梁。我们的研究结果表明，一定的必要条件的后期纺锤体伸长的滑动丝模型得到满足。
During the transition from prometaphase to metaphase, the cross- sectional area of the central spindle of Diatoma decreases by a factor of nearly two, both at the poles and at the region of overlapping microtubules (MTs) near the spindle equator. The density of spindle MT packing stays approximately constant throughout mitosis. Optical diffraction analysis of electron micrographs shows that the packing of the MTs at the poles at all stages of mitosis is similar to that expected for a two-dimensional liquid. Analysis of the region of overlap reveals more packing regularity: during prometaphase, a square packing emerges that displays sufficient organization by late metaphase to generate five orders of diffraction; during anaphase the packing in the overlap region shifts to hexagonal; at telophase, it returns to square. From the data provided by serial section reconstructions of the central spindle, it is possible to identify the polarity of almost every spindle MT, that is, to identify one pole with which the MT is associated. Near neighbor analyses of MTs in cross sections of the overlap region show that MTs prefer antiparallel near neighbors. These near neighbors are most often found at a spacing of approximately 40 nm center-to-center, while parallel near neighbors in the zone of overlap are spaced essentially at random. These results are evidence for a specific interaction between antiparallel MTs. In some sections definite bridges between MTs can be seen. Our findings show that certain necessary conditions for a sliding filament model of anaphase spindle elongation are met.