Tiedge H, Zhou A, Thorn N A, Brosius J
Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York, New York 10029.
J Neurosci. 1993 Oct;13(10):4214-9. doi: 10.1523/JNEUROSCI.13-10-04214.1993.
Ample evidence indicates that in nerve cells, several individual proteins are locally synthesized in postsynaptic domains in dendrites. By contrast, axonal terminals, at least in mammals, are generally thought to lack protein synthetic capacity. However, axonal nerve endings of the hypothalamo-neurohypophyseal tract have recently been shown to contain mRNAs encoding vasopressin, oxytocin, dynorphin, and neurofilament. In this report, we identify BC1 RNA, a small RNA polymerase III transcript that is specifically expressed in neurons, in hypothalamo-neurohypophyseal axons. BC1 RNA has previously been shown to be located in somatic and dendritic domains of various types of neurons in the rat nervous system. Here we present evidence to show that BC 1 RNA, like several neuropeptide mRNAs, is axonally transported from magnocellular hypothalamic neurons to neurosecretory nerve endings in the posterior pituitary. BC1 RNA, which has been reported to be a component of a ribonucleoprotein particle, is thus colocalized with dendritic mRNAs in dendritic domains and with axonal mRNAs in axonal domains, respectively. Such colocalization is indicative of functional interactions of BC1 RNA with those mRNAs that are targeted to extrasomatic domains of nerve cells.
大量证据表明，在神经细胞中，几种单个蛋白质在树突的突触后区域进行局部合成。相比之下，至少在哺乳动物中，轴突终末通常被认为缺乏蛋白质合成能力。然而，最近研究表明，下丘脑 - 神经垂体束的轴突神经末梢含有编码抗利尿激素、催产素、强啡肽和神经丝的信使核糖核酸（mRNA）。在本报告中，我们在下丘脑 - 神经垂体轴突中鉴定出BC1 RNA，这是一种在神经元中特异性表达的小RNA聚合酶III转录本。此前已证明BC1 RNA位于大鼠神经系统中各种类型神经元的胞体和树突区域。在此我们提供证据表明，BC1 RNA与几种神经肽mRNA一样，从下丘脑大细胞神经元轴突运输至垂体后叶的神经分泌神经末梢。据报道，BC1 RNA是核糖核蛋白颗粒组分，因此分别与树突区域的树突mRNA以及轴突区域的轴突mRNA共定位。这种共定位表明BC1 RNA与靶向神经细胞胞外区域的那些mRNA之间存在功能相互作用。
