Topp K S, Meade L B, LaVail J H
Neuroscience Program, University of California San Francisco 94143.
J Neurosci. 1994 Jan;14(1):318-25. doi: 10.1523/JNEUROSCI.14-01-00318.1994.
The directional movement of many cellular organelles in neurons is dependent on polarized microtubules and direction-specific motor molecules. Microtubules are also thought to mediate the retrograde transport of herpes simplex virus (HSV) in sensory neurons. To define the cellular machinery responsible for retrograde axonal transport of HSV, we have investigated the polarity of microtubules in the peripheral axons of trigeminal ganglion neurons. The long ciliary nerves of rabbits were prepared for a standard "hook assay" of microtubule polarity. Axons in cross-sectioned nerves contained microtubules with almost uniform orientation. The fast-growing, plus ends of these axonal microtubules are located distal to the cell body and the slow-growing, minus ends are directed centrally. To determine the role played by microtubules in the retrograde transport of HSV in these axons, we injected the retrobulbar space of mice with the microtubule-inhibiting drugs colchicine, vinblastine, or nocodazole or with the microfilament inhibitor cytochalasin D and 1 d later inoculated the cornea with HSV. We found that colchicine, vinblastine, or nocodazole reduced by 52-87% the amount of virus recovered from the ganglion 3 d postinoculation, compared to vehicle-treated animals. In contrast, cytochalasin D or beta-lumicolchicine did not significantly reduce the amount of HSV recovered from the ganglion. We conclude that the retrograde axonal transport of HSV from axon endings in the cornea to the trigeminal ganglion cell bodies requires intact microtubules and occurs in a plus-to-minus direction on the microtubules. Our data are consistent with the hypothesis that the retrograde axonal transport of HSV is mediated by a minus end-directed motor molecule, for example, cytoplasmic dynein.
神经元中许多细胞器的定向移动依赖于极化的微管和方向特异性的运动分子。微管也被认为介导单纯疱疹病毒（HSV）在感觉神经元中的逆行运输。为了确定负责HSV逆行轴突运输的细胞机制，我们研究了三叉神经节神经元外周轴突中微管的极性。制备兔的长睫状神经用于微管极性的标准“钩试验”。横切神经中的轴突含有方向几乎一致的微管。这些轴突微管的快速生长的正端位于远离细胞体的远端，而缓慢生长的负端则指向中央。为了确定微管在这些轴突中HSV逆行运输中所起的作用，我们向小鼠的球后间隙注射微管抑制药物秋水仙碱、长春花碱或诺考达唑，或微丝抑制剂细胞松弛素D，1天后用HSV接种角膜。我们发现，与用赋形剂处理的动物相比，秋水仙碱、长春花碱或诺考达唑使接种后3天从神经节中回收的病毒量减少了52 - 87%。相比之下，细胞松弛素D或β - 光秋水仙碱并没有显著减少从神经节中回收的HSV量。我们得出结论，HSV从角膜轴突末端到三叉神经节细胞体的逆行轴突运输需要完整的微管，并且在微管上以正端到负端的方向发生。我们的数据与HSV逆行轴突运输由负端定向的运动分子（例如，胞质动力蛋白）介导的假设一致。
