Jay D G, Keshishian H
Department of Cellular and Developmental Biology, Harvard University, Cambridge, Massachusetts 02138.
Nature. 1990 Dec 6;348(6301):548-50. doi: 10.1038/348548a0.
A molecular mechanism for selective axonal adhesion is a central question of neural development. Cell adhesion molecules have been identified, but it has been difficult to ascribe functions for these proteins in vivo. Here we show that the neuronal membrane glycoprotein fasciclin I has a role in the adhesion of sister axons during the development of the grasshopper limb bud. To do this we used a new technique, chromophore-assisted laser inactivation (CALI), which causes the precisely timed thermal denaturation of specific proteins by laser light targeted through a dye-labelled antibody, without any other observable damage to living cells. This can be achieved by relaxation of the laser-excited dye which releases heat to denature the bound protein; the rapid dissipation of heat with distance insulates unbound proteins from damage. CALI is a molecular analogue of cellular laser ablation and provides an unprecedented level of spatial and temporal resolution. Using dye-labelled antibodies that recognize fasciclin I, CALI disrupts fasciculation of the pioneer neurons without affecting their growth or guidance.
选择性轴突黏附的分子机制是神经发育的核心问题。细胞黏附分子已被识别，但要在体内确定这些蛋白质的功能却很困难。在这里，我们表明神经元膜糖蛋白成束蛋白I在蝗虫肢芽发育过程中对姐妹轴突的黏附有作用。为此，我们使用了一种新技术，即发色团辅助激光失活（CALI），它通过靶向染料标记抗体的激光使特定蛋白质在精确的时间内热变性，而对活细胞没有任何其他可观察到的损伤。这可以通过激光激发染料的弛豫来实现，染料释放热量使结合的蛋白质变性；热量随距离的快速消散使未结合的蛋白质免受损伤。CALI是细胞激光消融的分子类似物，提供了前所未有的时空分辨率水平。使用识别成束蛋白I的染料标记抗体，CALI破坏先驱神经元的成束，而不影响它们的生长或导向。
