Dynamic changes in microtubule configuration correlate with nuclear migration in the preblastoderm Drosophila embryo.
Dynamic changes in microtubule configuration correlate with nuclear migration in the preblastoderm Drosophila embryo.
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DOI：
10.1083/jcb.122.1.113
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发表时间：
1993-07
期刊：
影响因子：
--
通讯作者：
Schubiger G
中科院分区：
文献类型：
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作者：
Baker J;Theurkauf WE;Schubiger G
果蝇胚胎发生是由一系列的合胞体有丝分裂开始的。前九个分裂是内部的，并伴随着两个时间上不同的核运动，导致形成一个合胞胚盘与一个统一的单层皮层核。第一种运动，我们称之为轴向扩张，发生在分裂周期4-6，并将细胞核分布在皮层下的中空椭圆体中。随后是皮质迁移，在周期7-10期间，将细胞核置于皮质的均匀单层中。在这里，我们报告说，这两个运动不同的几何形状，速度，细胞周期的依赖性，和蛋白质合成的要求。因此，我们得出结论，轴向扩张和皮质迁移在机制上是不同的，放大了基于药理学数据的类似结论（Zalokar和Erk，1976）。我们已经研究了微管组织在皮层迁移，并发现，相互交错的微管网络连接迁移的细胞核。这些反平行微管阵列之间的迁移核和卵黄核位于胚胎更深处观察。这些阵列在核运动期间存在，但当核不运动时就分解了。我们提出，皮质迁移是由微管依赖的力量，排斥相邻的核，导致轴向扩张建立的核椭球体的扩张。
Drosophila embryogenesis is initiated by a series of syncytial mitotic divisions. The first nine of these divisions are internal, and are accompanied by two temporally distinct nuclear movements that lead to the formation of a syncytial blastoderm with a uniform monolayer of cortical nuclei. The first of these movements, which we term axial expansion, occurs during division cycles 4-6 and distributes nuclei in a hollow ellipsoid underlying the cortex. This is followed by cortical migration, during cycles 7-10, which places the nuclei in a uniform monolayer at the cortex. Here we report that these two movements differ in their geometry, velocity, cell-cycle dependence, and protein synthesis requirement. We therefore conclude that axial expansion and cortical migration are mechanistically distinct, amplifying a similar conclusion based on pharmacological data (Zalokar and Erk, 1976). We have examined microtubule organization during cortical migration and find that a network of interdigitating microtubules connects the migrating nuclei. These anti-parallel microtubule arrays are observed between migrating nuclei and yolk nuclei located deeper in the embryo. These arrays are present during nuclear movement but break down when the nuclei are not moving. We propose that cortical migration is driven by microtubule-dependent forces that repel adjacent nuclei, leading to an expansion of the nuclear ellipsoid established by axial expansion.