Drazba J, Liljelund P, Smith C, Payne R, Lemmon V
Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Brain Res Dev Brain Res. 1997 Jun 18;100(2):183-97. doi: 10.1016/s0165-3806(97)00041-2.
The migration of growth cones on substrates consisting of naturally occurring cell adhesion molecules has been extensively studied in cell culture. However, relatively little is known about how growth cones contact the substrate or how the patterns of contact change as growth cones move forward. We have examined the interactions of chick retinal ganglion cell growth cones with laminin, merosin, N-cadherin, L1 and poly-L-lysine by time-lapse interference reflection microscopy (IRM) using a laser scanning confocal microscope. In images obtained by IRM, areas of a cell that are closely apposed to the substrate appear dark whereas areas that are farther away appear light. Growth cones on Jaminin and merosin were almost uniformly light, indicating that very little of the membrane was in close contact with the substrate. Growth cones on N-cadherin had a mottled appearance with some relatively large dark gray areas. The proximal portions of filopodia often were dark, in contrast to those on laminin and merosin which were light. In addition, growth cones on N-cadherin had numerous dark gray punctate regions of close association with the substrate. Growth cones on L1 had darker regions than growth cones on other substrates and these comprised a larger fraction of their area. There also were differences in the temporal dynamics of growth cone interactions with different substrates and these differences correlated with differences in rates of growth. None of the contacts observed in growth cones were as dark or stable as focal contacts of fibroblasts.
在细胞培养中，已经对生长锥在由天然存在的细胞粘附分子组成的底物上的迁移进行了广泛研究。然而，对于生长锥如何与底物接触，或者随着生长锥向前移动接触模式如何变化，人们了解得相对较少。我们使用激光扫描共聚焦显微镜，通过延时干涉反射显微镜（IRM）研究了鸡视网膜神经节细胞生长锥与层粘连蛋白、含硫层粘连蛋白、N-钙黏着蛋白、L1和聚-L-赖氨酸之间的相互作用。在IRM获得的图像中，细胞与底物紧密贴附的区域显得暗，而距离较远的区域显得亮。生长锥在层粘连蛋白和含硫层粘连蛋白上几乎均匀地发亮，表明很少有细胞膜与底物紧密接触。生长锥在N-钙黏着蛋白上呈现斑驳外观，有一些相对较大的深灰色区域。丝状伪足的近端部分通常较暗，这与层粘连蛋白和含硫层粘连蛋白上的丝状伪足近端部分发亮形成对比。此外，生长锥在N-钙黏着蛋白上有许多与底物紧密相连的深灰色点状区域。生长锥在L1上的较暗区域比在其他底物上的生长锥更多，且这些区域在其面积中占更大比例。生长锥与不同底物相互作用的时间动态也存在差异，这些差异与生长速率的差异相关。在生长锥中观察到的任何接触都不像成纤维细胞的粘着斑那样暗或稳定。
