Lectin labeling of sprouting neurons. II. Relative movement and appearance of glycoconjugates during plasmalemmal expansion.
Lectin labeling of sprouting neurons. II. Relative movement and appearance of glycoconjugates during plasmalemmal expansion.
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DOI：
10.1083/jcb.89.3.547
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发表时间：
1981-06
期刊：
影响因子：
--
通讯作者：
Maylié-Pfenninger MF
中科院分区：
文献类型：
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作者：
Pfenninger KH;Maylié-Pfenninger MF
为了研究神经细胞生长过程中膜成分的动态变化，我们用铁蛋白偶联和非偶联凝集素对体外萌发的交感神经元进行了一系列的脉冲追逐实验。用小麦胚凝集素或蓖麻半乳糖特异性凝集素标记乙醛前缀的培养物，在神经突起的远端附近始终是密集的。相反，如果活的培养物被这些凝集素标记并追逐3-20分钟，无标记的质膜区域出现在生长锥的最外围区域、丝状伪足上，而且还出现在囊泡团(SPV)上。然而，这些无标记的区域含有凝集素受体，这可以通过在醛固定后用相同的凝集素重新标记被追赶的培养物来证明。在进一步的实验中，用饱和浓度的天然凝集素标记培养物，追逐，固定醛，然后用相同凝集素的铁蛋白结合物重新标记。在这种情况下，丝状伪足和SPV簇的表面被选择性地标记为铁蛋白结合物，表明新的凝集素受体插入到生长锥外围的质膜中。这些结果表明，神经元中的质膜扩张是通过极化生长机制发生的，可能涉及SPV作为质膜前体小泡。
To study the dynamics of membrane components during neuritic growth, we carried out a series of pulse-chase experiments with ferritin- conjugated and unconjugated lectins on sympathetic neurons sprouting in vitro. Labeling of aldehyde-prefixed cultures with wheat-germ agglutinin or with the galactose-specific lectin of Ricinus communis is consistently dense near the distal end of the neurites. By contrast, if live cultures are labeled with these lectins and chased for 3-20 min, label-free plasmalemmal areas appear in the most peripheral regions of the growth cone, on filopodia and, furthermore, over vesicle clusters (SPVs). These marker-free areas, however, contain lectin receptors, as can be shown by relabeling the chased cultures with the same lectins after the aldehyde fixation. In a further set of experiments, cultures are labeled with a saturating concentration of native lectin, chased, aldehyde-fixed, and then relabeled with the ferritin conjugate of the same lectin. In this case, the surfaces of filopodia and of SPV clusters are selectively labeled with the ferritin conjugate, indicating the insertion of new lectin receptors into the plasma membrane in the growth cone periphery. These results indicate that plasmalemmal expansion in the neuron occurs by a mechanism of polarized growth, possibly involving SPVs as plasmalemmal precursor vesicles.