Tenascin-R as a repellent guidance molecule for newly growing and regenerating optic axons in adult zebrafish
Tenascin-R as a repellent guidance molecule for newly growing and regenerating optic axons in adult zebrafish
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DOI：
10.1016/j.mcn.2004.03.003
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发表时间：
2004-07-01
影响因子：
3.5
通讯作者：
Becker, T
中科院分区：
文献类型：
--
作者：
Becker, CG;Schweitzer, J;Becker, T
在成鱼中，与哺乳动物相反，新的视神经轴突不断添加到视神经投射中，并且视神经轴突在损伤后再生。因此，视神经轴突在发育、成体生长和成体再生过程中的寻路可能依赖于相同的引导线索。我们已经表明，腱生蛋白-R，细胞外基质的一个组成部分，边界的光学通路在发展中的斑马鱼，并作为一个排斥性的指导分子的视神经轴突。在这里，我们分析了腱生蛋白-R的表达模式沿着成年斑马鱼的未损伤和损伤的视通路和测试腱生蛋白-R的影响，在体外生长的成鱼的视轴突。在视神经轴突的视网膜内束和视神经中，新增加的视神经轴突在腱生蛋白-R免疫阴性通路中生长，该通路与腱生蛋白-R免疫反应性相邻。在大脑中，腱生蛋白-R的表达域在腹侧间脑，在非retinorecipient前顶盖核和在一些顶盖层密切边界的视通路在未受损的动物和轴突再生。我们在体外用腱生蛋白-R的尖锐基底边界模拟这些边界情况。从成人视网膜外植体发出的视神经轴突被腱生蛋白-R底物边界排斥。这与腱生蛋白-R作为成人视神经轴突边界中的排斥性引导分子的功能一致。因此，腱生蛋白-R可以引导新添加的和再生的视神经轴突的接触排斥机制在成鱼的视通路。(C)2004年爱思唯尔公司All rights reserved.
In adult fish, in contrast to mammals, new optic axons are continuously added to the optic projection, and optic axons regrow after injury. Thus, pathfinding of optic axons during development, adult growth, and adult regeneration may rely on the same guidance cues. We have shown that tenascin-R, a component of the extracellular matrix, borders the optic pathway in developing zebrafish and acts as a repellent guidance molecule for optic axons. Here we analyze tenascin-R expression patterns along the unlesioned and lesioned optic pathway of adult zebrafish and test the influence of tenascin-R on growing optic axons of adult fish in vitro. Within intraretinal fascicles of optic axons and in the optic nerve, newly added optic axons grow in a tenascin-R immunonegative pathway, which is bordered by tenascin-R immunoreactivity. In the brain, tenascin-R expression domains in the ventral diencephalon, in non-retinorecipient pretectal nuclei and in some tectal layers closely border the optic pathway in unlesioned animals and during axon regrowth. We mimicked these boundary situations with a sharp substrate border of tenascin-R in vitro. Optic axons emanating from adult retinal explants were repelled by tenascin-R substrate borders. This is consistent with a function of tenascin-R as a repellent guidance molecule in boundaries for adult optic axons. Thus, tenascin-R may guide newly added and regenerating optic axons by a contact-repellent mechanism in the optic pathway of adult fish. (C) 2004 Elsevier Inc. All rights reserved.