ORGANIZATION OF CYTOSKELETAL ELEMENTS AND ORGANELLES PRECEDING GROWTH CONE EMERGENCE FROM AN IDENTIFIED NEURON INSITU
ORGANIZATION OF CYTOSKELETAL ELEMENTS AND ORGANELLES PRECEDING GROWTH CONE EMERGENCE FROM AN IDENTIFIED NEURON INSITU
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DOI：
10.1083/jcb.108.5.1737
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发表时间：
1989-05-01
影响因子：
7.8
通讯作者：
BENTLEY, D
中科院分区：
文献类型：
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作者：
LEFCORT, F;BENTLEY, D
本研究的目的是研究细胞骨架元件和细胞器在一个已确定的神经元生长锥体出现的原位位置，就在轴突发生之前和同时发生。Til先锋神经元是蝗虫胚胎肢体中最早分化的一对传入神经元。它们出现在肢芽上皮的远端，是单个前体细胞的子细胞，先锋母细胞（PMC）。利用免疫组织化学标记，我们表征了PMC通过轴突发生有丝分裂的微管、中心体、高尔基体、中间体、肌动蛋白丝和染色质的组织。就在轴突发生发生之前和同时，微管蛋白、肌动蛋白丝和高尔基体的特征性排列位于近端先锋神经元的近极。近端细胞的生长锥典型地起源于这个部位。虽然远端细胞的轴突通常在近端生长，但偶尔也会从远端产生；在这样的肢体中，来自姐妹细胞的轴突从它们躯体上镜像对称的位置延伸出来。在细胞松弛素D存在的情况下，PMC进行核分裂，但不进行细胞分裂，尽管其他神经元表型得到表达，但轴突发生受到抑制。我们的数据表明，内在信息决定了生长锥出现的位置，一个已识别的神经元在原位。
The purpose of this study was to investigate the arrangement of cytoskeletal elements and organelles in an identified neuron in situ at the site of emergence of its growth cone just before and concurrent with the onset of axonogenesis. The Til pioneer neurons are the first pair of afferent neurons to differentiate in embryonic grasshopper limbs. They arise at the distal tip of the limb bud epithelium, the daughter cells of a single precursor cell, the Pioneer Mother Cell (PMC). Using immunohistochemical markers, we characterized the organization of microtubules, centrosomes, Golgi apparatus, midbody, actin filaments, and chromatin from mitosis in the PMC through axonogenesis in the Tils. Just before and concurrent with the onset of axonogenesis, a characteristic arrangement of tubulin, actin filaments, and Golgi apparatus is localized at the proximal pole of the proximal pioneer neuron. The growth cone of the proximal cell stereotypically arises from this site. Although the distal cell''s axon generally grows proximally, occasionally it arises from its distal pole; in such limbs, the axons from the sister cell extend from mirror symmetric locations on their somata. In the presence of cytochalasin D, the PMC undergoes nuclear division but not cytokinesis and although other neuronal phenotypes are expressed, axonogenesis is inhibited. Our data suggest that intrinsic information determines the site of growth cone emergence of an identified neuron in situ.