Rakic P, Knyihar-Csillik E, Csillik B
Section of Neurobiology, Yale University School of Medicine, New Haven, CT 06511, USA.
Proc Natl Acad Sci U S A. 1996 Aug 20;93(17):9218-22. doi: 10.1073/pnas.93.17.9218.
The active migration of neurons from their sites of origin to their final destinations requires the unidirectional translocation of the nuclei and somatic cytoplasm within the growing leading processes. To explore the cellular machinery underlying this translocation, we determined the polarity of microtubules situated within the leading and trailing processes of migrating cerebellar granule cells in situ. Our analysis reveals that the newly assembled positive ends of the microtubules in the leading process uniformly face the growing tip, while their disintegrating negative ends face the nucleus. In the trailing process, by contrast, microtubule arrays are of mixed polarity. We suggest that the dynamics of slow polymerization in combination with fast disintegration of oriented microtubules create "push" and "pull" forces that contribute to the piston-like saltatory displacement of the nucleus and cytoplasm within the membrane cylinder of the leading process of the migrating neuron.
神经元从其起源部位向最终目的地的主动迁移需要细胞核和体细胞胞质在不断生长的前端突起内进行单向移位。为了探究这种移位背后的细胞机制，我们确定了原位迁移的小脑颗粒细胞前端和后端突起内微管的极性。我们的分析表明，前端突起中微管新组装的正端均朝向生长尖端，而其正在解体的负端则朝向细胞核。相比之下，在后端突起中，微管阵列具有混合极性。我们认为，定向微管缓慢聚合与快速解体的动态过程产生了“推”和“拉”的力，这些力有助于迁移神经元前端突起膜筒内细胞核和细胞质的活塞式跳跃位移。
