SUBCELLULAR LOCALIZATION OF MRNAS IN MAMMALIAN NEURONS

描述（研究者摘要）： 研究通过检查过程寻路和调制器的反应， 过程副产物。 在发育和成熟的神经元中， 神经元过程的功能对可塑性能力至关重要 的细胞。 神经元突起是特化的细胞结构 其功能使得神经元极性被建立， 来自突触前细胞的信息通过树突到达， 到突触后细胞的作用通常通过轴突的功能发生。 这些神经元结构中蛋白质的表征一直是一个重要的研究领域。 密集的研究领域产生的信息表明， 细胞蛋白质在该过程中富集。 这种浓缩可能 导致这些细胞结构的特殊功能。 在过去的十年里，一些mRNA同样被定位于 树突状的过程和一些mRNA已经被证明是 存在于特化神经元细胞类型的轴突中。 与 这些mRNAs的发现和细胞超微结构的定位 核糖体树突，这是合理的假设，当地的蛋白质 合成可能有助于树突的功能。 最近， 这些研究人员已经证明，蛋白质合成确实发生， 在海马神经元的树突和生长锥中。 作为 他们对存在于这种细胞中的mRNA的初步调查的一部分， 在亚细胞位点，他们意外地发现编码cAMP的mRNA 反应元件结合蛋白（CREB）存在于发育中。 树突 他们进一步表明，CREB mRNA被翻译成 这种CREB可以与DNA结合， CREB扩散到这些过程中移动到细胞核。 这些数据表明CREB和其他转录因子 这些因子可能在神经过程中产生，在发育过程中， 这一过程被称为核印记， 树突环境与细胞核的通讯。 在这份修订后的拨款申请中，他们建议将 CREB在神经元过程中的生物化学及其在 核印记通过确定是否翻译和后 位于神经元中的CREB的跨国加工 这个过程被突触信号所改变。 因为潜在的 考虑到这一观察结果的重要性，他们进一步建议延长 核印记的概念，以确定分子参与者 在这个调控过程中，通过做一个详细的表达谱， 使用单细胞aRNA在“发育”期间的树突状生长锥 扩增技术和DNA芯片（筛选14，000 不同的mRNA同时）以及一种新的差异显示 他们最近开发的一个协议。

DESCRIPTION (Investigator's Abstract): Neuronal development has been studied by examining process pathfinding and responses to modulators of process outgrowth. In both the developing and mature neuron the functioning of neuronal processes is critical to the plasticity capacity of the cells. Neuronal processes are specialized cellular structures which function such that neuronal polarity is established with information from presynaptic cells arriving via dendrites while output to post-synaptic cells generally occurs via functioning of the axon. Characterization of proteins in these neuronal structures has been an area of intense study yielding information showing that particular cellular proteins are enriched in the processes. This enrichment likely results in the specialized functioning of these cellular structures. Over the last decade a handful of mRNAs have likewise been localized to the dendritic class of processes and a few mRNAs have been shown to be present in axons of specialized neuronal cell types. With the discovery of these mRNAs and the ultrastructural localization of ribosomes to dendrites it was reasonable to assume that local protein synthesis may contribute to the functioning of dendrites. Recently, these investigators have proven that protein synthesis does indeed occur in individual dendrites and growth cones of hippocampal neurons. As part of their preliminary survey of mRNAs which are present in this subcellular site, they unexpectedly found that the mRNA encoding cAMP responsive element binding protein (CREB) is present in developing dendrites. They have further shown that this CREB mRNA is translated into CREB protein, that this CREB can bind to DNA and that fluorescent CREB which is diffused into these processes moves to the cell nucleus. These data suggest a critical role for CREB and other transcription factors which may be made in neuronal processes, in a developmental process called nuclear imprinting which facilitates the direct communication of dendritic environment with the nucleus of the cell. In this revised grant application, they propose to characterize the biochemistry of CREB in neuronal processes and its potential role in nuclear imprinting by determining whether the translation and post- transnational processing of the CREB that is localized in the neuronal process is altered by synaptic signaling. Because of the potential importance of this observation, they further propose to extend the concept of nuclear imprinting to determine the molecular participants in this regulatory process by doing a detailed expression profile of dendritic growth cones during "development" using the single cell aRNA amplification technology and the DNA chip (screening for 14,000 different mRNAs simultaneously) as well as a novel differential display protocol they have recently developed.