Mechanisms and regulation of translation in dendrites.

树突翻译的机制和调控。

• 批准号: 6825704
• 负责人: LESLIE A KRUSHEL
• 金额: $ 32.65万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-12-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6825704
• 关键词: cell line; chemical structure function; computer data analysis; dendrites; developmental genetics; fluorescence microscopy; gene environment interaction; genetic regulation; genetic translation; hippocampus; hypoxia; intermolecular interaction; laboratory rat; messenger RNA; nerve /myelin protein; neural plasticity; neurogenetics; neuroregulation; neurotransmitters; neurotrophic factors; nucleic acid structure; protein biosynthesis; site directed mutagenesis; synapses; time resolved data

Many mRNAs that are located in dendrites encode for proteins that are critically important for particular forms of synaptic plasticity. Indeed, local protein synthesis in dendrites is required for many alterations in synaptic efficacy. Little is known, however, about the mechanism of translation in dendrites and how translation may be regulated by synaptic events. Most eukaryotic mRNAs are thought to initiate translation by a cap-binding/scanning mechanism. Some mRNAs can also initiate translation in a cap-independent manner from internal ribosomal entry sites (IRESes). The working hypothesis is that the 5' leader sequences of dendritically localized mRNAs contain IRESes. The presence of IRESes in mRNAs could increase the efficiency of translation at a cellular site where many of the components of the translational machinery may be limiting. Furthermore, the mechanisms that regulate cap and IRES dependent translation may be unique allowing for differential regulation of translation in response to synaptic stimuli and environmental conditions. The proposed studies will utilize cell lines and primary neurons to 1) examine whether the 5' leaders of dendritically localized mRNAs exhibit IRES activity and determine the cis-elements within the 5' leaders that promote internal initiation, 2) determine the contribution of the cap and IRES to translation in dendrites, and 3) determine whether neural activity or environmental conditions such as hypoxia, differentially affect cap and IRES dependent translation. These studies will provide novel insights into the mechanisms of translation in neurons and provide a better understanding of how synaptic events and stress can lead to alterations in synaptic plasticity, and consequently, to learning and memory.

许多位于树突中的 mRNA 编码的蛋白质对于特定形式的突触可塑性至关重要。 事实上，突触功效的许多改变都需要树突中的局部蛋白质合成。然而，人们对树突的翻译机制以及突触事件如何调节翻译知之甚少。 大多数真核生物 mRNA 被认为是通过帽结合/扫描机制启动翻译的。 一些 mRNA 还可以从内部核糖体进入位点 (IRES) 以不依赖帽子的方式启动翻译。 工作假设是树突状定位 mRNA 的 5' 前导序列包含 IRES。 mRNA 中 IRES 的存在可以提高细胞位点的翻译效率，而在该位点，翻译机制的许多组件可能受到限制。此外，调节 cap 和 IRES 依赖性翻译的机制可能是独特的，允许根据突触刺激和环境条件对翻译进行差异调节。 拟议的研究将利用细胞系和原代神经元来 1) 检查树突状定位 mRNA 的 5' 前导序列是否表现出 IRES 活性，并确定 5' 前导序列内促进内部起始的顺式元件，2) 确定帽的贡献和 IRES 在树突中的翻译，3) 确定神经活动或环境条件（例如缺氧）是否对 cap 和 IRES 依赖的翻译产生不同的影响。 这些研究将为神经元翻译机制提供新的见解，并更好地理解突触事件和压力如何导致突触可塑性的改变，从而导致学习和记忆的改变。