Garner J A
Department of Anatomy and Cell Biology, USC School of Medicine, Los Angeles 90033.
Brain Res. 1988 Aug 23;458(2):309-18. doi: 10.1016/0006-8993(88)90473-8.
The transport of tubulin and neurofilament protein subunits from the preterminal axons of guinea pig retinal ganglion cells into their presynaptic terminals in the superior colliculus was examined. Newly synthesized tubulin and neurofilament proteins were radiolabeled with tritiated amino acids in the cell bodies and were allowed to be axonally transported through the optic axons and into the terminals in the superior colliculi. Superior colliculi were harvested at appropriate times, synaptosomes were prepared, and radiolabeled proteins were examined by gel electrophoresis and fluorography. Proteins in the radiolabeled synaptosomes were compared with those in the portion of the optic tract immediately proximal to the superior colliculus. Tubulin subunits entered the terminals by 100 days after intraocular labeling, and at least one isoform of tubulin appeared to persist as long as 400 days. Neurofilament proteins, despite the fact that they are axonally transported and delivered to the terminals in concert with the tubulin subunits, disappear rapidly upon entry into the terminals themselves.
研究了豚鼠视网膜神经节细胞终末前轴突中的微管蛋白和神经丝蛋白亚基向其在中脑上丘的突触前终末的运输。新合成的微管蛋白和神经丝蛋白在细胞体中用氚标记的氨基酸进行放射性标记，然后通过视神经轴突进行轴突运输并进入中脑上丘的终末。在适当的时间采集上丘，制备突触体，并通过凝胶电泳和荧光自显影检查放射性标记的蛋白质。将放射性标记突触体中的蛋白质与紧邻上丘的视束部分中的蛋白质进行比较。眼内标记后100天，微管蛋白亚基进入终末，并且至少一种微管蛋白异构体似乎持续长达400天。尽管神经丝蛋白与微管蛋白亚基一起通过轴突运输并递送至终末，但它们在进入终末后会迅速消失。
