Yip J W, Yip Y P, Capriotti C
Department of Neurobiology, School of Medicine, University of Pittsburgh, PA 15261, USA.
Brain Res Dev Brain Res. 1995 May 26;86(1-2):297-310. doi: 10.1016/0165-3806(95)00036-d.
During development of the peripheral nervous system, the extracellular matrix molecule tenascin has been found to be closely associated with growing axons. However, its origin and function in peripheral nerve formation are far from clear. In this study, we examined the expression of tenascin during outgrowth of sensory, motor and sympathetic preganglionic axons, and assessed its origin and function in peripheral nerve formation. During outgrowth of sensory and motor axons, a high concentration of tenascin and its mRNA was found to surround sensory and motor axons in the newly formed spinal nerves. The source of this tenascin was examined through a series of surgical manipulations. Neural crest removals did not alter the distribution of tenascin protein or its mRNA surrounding the spinal nerves. Transplantation of quail somites into chick embryos showed that, similar to the distribution of tenascin, there is a high concentration of somitic cells surrounding the spinal nerves. Moreover, somite removals resulted in a reduction of the tenascin and tenascin mRNA surrounding the spinal nerves. Taken together, these results suggest that the majority of the tenascin surrounding the spinal nerves is of somitic origin. Possible functions of tenascin associated with peripheral nerve formation were examined through injections of tenascin or its antiserum into individual somites prior to or during axon outgrowth. Injections of tenascin or its antiserum did not alter the trajectory of peripheral axons in the anterior half of the somite, nor produce gross abnormalities in the morphology of peripheral nerves, suggesting that tenascin does not play a crucial role in the early formation of peripheral nerves.
在周围神经系统发育过程中，已发现细胞外基质分子腱生蛋白与正在生长的轴突密切相关。然而，其在周围神经形成中的起源和功能尚不清楚。在本研究中，我们检测了腱生蛋白在感觉、运动和交感节前轴突生长过程中的表达，并评估了其在周围神经形成中的起源和功能。在感觉和运动轴突生长过程中，发现高浓度的腱生蛋白及其mRNA围绕着新形成的脊神经中的感觉和运动轴突。通过一系列手术操作研究了这种腱生蛋白的来源。去除神经嵴并没有改变腱生蛋白及其mRNA在脊神经周围的分布。将鹌鹑体节移植到鸡胚中显示，与腱生蛋白的分布相似，脊神经周围有高浓度的体节细胞。此外，去除体节导致脊神经周围的腱生蛋白和腱生蛋白mRNA减少。综上所述，这些结果表明，脊神经周围的大部分腱生蛋白起源于体节。通过在轴突生长之前或期间向单个体节注射腱生蛋白或其抗血清，研究了与周围神经形成相关的腱生蛋白的可能功能。注射腱生蛋白或其抗血清并没有改变体节前半部分周围轴突的轨迹，也没有在周围神经形态上产生明显异常，这表明腱生蛋白在周围神经的早期形成中不发挥关键作用。
