Kinetic-structural analysis of neuronal growth cone veil motility
Kinetic-structural analysis of neuronal growth cone veil motility
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DOI：
10.1242/jcs.03384
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发表时间：
2007-03-15
影响因子：
4
通讯作者：
Borisy, Gary G.
中科院分区：
文献类型：
--
作者：
Mongiu, Anne K.;Weitzke, Elizabeth L.;Borisy, Gary G.
用相关光镜和电镜观察了鸡背根神经节细胞生长锥突的变化。根据生长锥中负责突出运动的两个主要细胞器，即绒毛和丝状足，对进展进行了分析。面纱在快速的前伸和后收阶段交替。电子显微镜显示了相之间的特征结构差异。我们的研究结果在三个方面提供了显著的进展：首先，突出的面纱是由肌动蛋白丝的密集分支网络组成的，其外观呈板足状，包括Arp2/3复合体。基于这一结构和生物标志物的证据，我们推断生长锥的膜突和成纤维细胞的运动一样，树突成核和/或阵列踩踏机制是保守的；第二，缩回的面纱缺乏树枝状组织，但包含一个稀疏的长细丝网络；第三，生长锥体丝状伪足具有沿其长度形成树突网络的能力，这一特性与光微观水平上看到的面纱形成一致，但以前没有在超分子术语中被理解。当结合在一起时，这些纱状和丝状组织的元素为理解生长锥推进的结构基础提供了一个概念性框架。
Neuronal growth cone advance was investigated by correlative light and electron microscopy carried out on chick dorsal root ganglion cells. Advance was analyzed in terms of the two principal organelles responsible for protrusive motility in the growth cone-namely, veils and filopodia. Veils alternated between rapid phases of protrusion and retraction. Electron microscopy revealed characteristic structural differences between the phases. Our results provide a significant advance in three respects: first, protruding veils are comprised of a densely branched network of actin filaments that is lamellipodial in appearance and includes the Arp2/3 complex. On the basis of this structural and biomarker evidence, we infer that the dendritic nucleation and/or array-treadmilling mechanism of protrusive motility is conserved in veil protrusion of growth cones as in the motility of fibroblasts; second, retracting veils lack dendritic organization but contain a sparse network of long filaments; and third, growth cone filopodia have the capacity to nucleate dendritic networks along their length, a property consistent with veil formation seen at the light microscopic level but not previously understood in supramolecular terms. These elements of veil and filopodial organization, when taken together, provide a conceptual framework for understanding the structural basis of growth cone advance.