Signaling and microRNA function in neurons

神经元中的信号传导和 microRNA 功能

• 批准号: 8296468
• 负责人: DAVID L TURNER
• 金额: $ 19.44万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8296468
• 关键词: Affect; Animals; Apoptosis; Axon; Binding; Binding Sites; Biochemical; Biological Process; Biology; Cell Death; Cell Survival; Cell physiology; Cells; Cellular Stress; Cellular Stress Response; Chimeric Proteins; Complex; Cytoplasmic Granules; Development; Event; Exhibits; Gene Expression Regulation; Genes; Genetic; Genetic Transcription; Genetic Translation; Health; Homeostasis; Human; Immunoprecipitation; Individual; Intervention; Knowledge; Link; MAP Kinase Gene; MAP-kinase-activated kinase 2; MAPK14 gene; Mediating; Messenger RNA; Methods; MicroRNAs; Mus; Mutation; Nervous system structure; Neuraxis; Neurodegenerative Disorders; Neuronal Differentiation; Neurons; Pathology; Pathway interactions; Phosphorylation; Phosphotransferases; Physiological Processes; Physiology; Play; Population; Post-Transcriptional Regulation; Process; Protein Binding; Proteins; Regulation; Repression; Research; Role; Signal Pathway; Signal Transduction; Site; Tamoxifen; Tissues; Translations; base; crosslink; extracellular; hearing impairment; improved; mRNA Expression; mRNA Stability; mitogen-activated protein kinase p38; nervous system development; nervous system disorder; neurodevelopment; neurogenesis; prevent; response; synaptic function; tumor

DESCRIPTION (provided by applicant): Post-transcriptional regulation of mRNAs by microRNAs is a widespread and essential component of gene regulation in animals. microRNAs, in association with Argonaute (Ago) proteins, bind to specific sequences in mRNAs to repress translation and/or reduce the level of the target mRNAs. Individual microRNAs may regulate many different genes, while individual mRNAs can be targeted by multiple microRNAs. Numerous microRNAs are expressed in the mammalian central nervous system (CNS), and microRNAs have been implicated in the regulation of a variety of processes in the CNS, including neurogenesis, cell survival and death, cell fate determination, neuronal differentiation, axon outgrowth, and synaptic function. Signal transduction plays essential roles in CNS development and function. Intracellular kinase cascades, activated by extracellular signals, directly modulate most biological processes, including transcription and translation. However, it is not known whether repression of target mRNAs by Ago/microRNA complexes can be modulated directly by signaling pathways. Phosphorylation of the Ago-2 protein by the p38 MAP kinase/MAPKAP kinase 2 (MAPKAP-K2) pathway alters its subcellular localization, and p38 kinase/ MAPKAP-K2 signaling is known to regulate mRNA stability and translation, as well as other biological processes. Phosphorylation of the Ago/microRNA complex and associated proteins by p38/MAPKAP-K2 may promote or prevent assembly of repressive complexes on specific mRNAs, leading to the modulation of microRNA-mediated repression on specific subsets of targets in neurons. We propose to use a recently developed method for biochemical purification and high-throughput sequencing of mRNA fragments associated with the Ago-2 protein to identify microRNA target sites at which Ago-2/microRNA binding is modulated by activation or inhibition of the p38 pathway in primary cerebellar granule neurons. We will further characterize selected target mRNAs that exhibit modulated microRNA binding. Modulation of microRNA binding and repression by signaling pathways would significantly expand the scope of biological processes that could be regulated by microRNAs, and may also explain why some predicted microRNA target sites fail to mediate repression. Both microRNAs and the p38 signaling pathway have been implicated in multiple diseases of the nervous system, and p38 plays critical roles during responses to cellular stress and/or apoptosis, physiological processes that are also linked to microRNA functions. Demonstrating that microRNA function can be rapidly modulated in the CNS by signaling, independent of microRNA expression levels, would impact both our understanding of microRNA biology in the nervous system, and of the role of microRNAs and p38 signaling in neurological disease.

描述（由申请人提供）：microRNA对mRNA的转录后调控是动物基因调控的一个广泛且重要的组成部分。与Argonaute（Ago）蛋白结合的microRNA与mRNA中的特定序列结合以抑制翻译和/或降低靶mRNA的水平。单个microRNA可以调节许多不同的基因，而单个mRNA可以被多个microRNA靶向。许多microRNA在哺乳动物中枢神经系统（CNS）中表达，并且microRNA已经涉及CNS中多种过程的调节，包括神经发生、细胞存活和死亡、细胞命运决定、神经元分化、轴突生长和突触功能。 信号转导在中枢神经系统的发育和功能中起着至关重要的作用。由细胞外信号激活的细胞内激酶级联直接调节大多数生物过程，包括转录和翻译。然而，目前尚不清楚Ago/microRNA复合物对靶mRNA的抑制是否可以通过信号传导途径直接调节。通过p38 MAP激酶/MAPKAP激酶2（MAPKAP-K2）途径磷酸化Ago-2蛋白改变其亚细胞定位，并且已知p38激酶/ MAPKAP-K2信号传导调节mRNA稳定性和翻译以及其他生物学过程。p38/MAPKAP-K2对Ago/microRNA复合物和相关蛋白的磷酸化可以促进或阻止特定mRNA上抑制性复合物的组装，从而调节microRNA介导的对神经元中特定靶点子集的抑制。 我们建议使用最近开发的方法，与Ago-2蛋白相关的mRNA片段的生物化学纯化和高通量测序，以确定microRNA的靶位点，在该位点Ago-2/microRNA的结合是通过激活或抑制p38通路在初级小脑颗粒神经元调制。我们将进一步表征表现出调节的microRNA结合的选定靶mRNA。通过信号通路调节microRNA的结合和抑制将显著扩大可以由microRNA调节的生物过程的范围，并且还可以解释为什么一些预测的microRNA靶位点不能介导抑制。microRNA和p38信号通路都与神经系统的多种疾病有关，p38在细胞应激和/或凋亡反应中起着关键作用，这些生理过程也与microRNA功能有关。证明microRNA功能可以在CNS中通过信号传导快速调节，而不依赖于microRNA表达水平，这将影响我们对神经系统中microRNA生物学以及microRNA和p38信号传导在神经系统疾病中的作用的理解。