Using microRNA-target chimeras to study post-transcriptional gene regulation in the mammalian CNS

使用 microRNA 靶标嵌合体研究哺乳动物中枢神经系统的转录后基因调控

• 批准号: 10322363
• 负责人: William Thomas Mills
• 金额: $ 4.68万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-21 至 2023-12-20
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10322363
• 关键词: 8 year old; Affect; Area; Behavior; Binding Sites; Biogenesis; Bioinformatics; Biological Process; Brain; Brain-Derived Neurotrophic Factor; Child; Chimera organism; Cognition Disorders; Complement; Complex; Cre driver; Defect; Dendritic Spines; Detection; Development; Developmental Disabilities; Disease; Engineering; FMR1; Family; Fragile X Syndrome; Gene Silencing; Gene Targeting; Genetic; Genetic Transcription; Growth; Heterogeneity; High-Throughput Nucleotide Sequencing; Immunoprecipitation; Impaired cognition; In Vitro; Knockout Mice; Learning; Ligation; Light; Malignant Neoplasms; Mediating; Mediator of activation protein; Memory; Memory impairment; Messenger RNA; Metabolism; Methods; MicroRNAs; Modeling; Molecular; Morphogenesis; Morphology; Mus; Nature; Nervous system structure; Neuronal Plasticity; Neurons; Neurosciences; Nucleotides; Pathway interactions; Physiological; Post-Transcriptional Regulation; Process; Prosencephalon; Protein Biosynthesis; Protein Deficiency; Proteins; Protocols documentation; RNA; RNA Binding; RNA-Binding Proteins; Repression; Research; Resistance; Resolution; Role; Shapes; Signal Transduction; Site; Specificity; Synapses; Synaptic Transmission; Testing; Time; Transcript; Translating; Translations; United States; Work; autism spectrum disorder; base; behavioral phenotyping; brain cell; cell type; cognitive function; crosslink; excitatory neuron; genome-wide; improved; in vivo; insight; knock-down; lens; long term memory; mouse model; overexpression; preference; transcriptome; transcriptome sequencing

Amongst the most intriguing and complex questions in neuroscience is that concerning the molecular mechanisms by which synapses participate in learning and memory. Beginning as early as the 1960s, a growing body of evidence indicates that new protein synthesis is required for learning and long-term memory formation.1 Additionally, it has been shown that activity-dependent protein synthesis is highly specific, as only a small subset of available transcripts are translated following neuronal activity.2,3 There is also evidence that local protein synthesis at synapses mediates plasticity and that perturbations in translation are associated with disorders of cognitive function such as autism.4,5 The realization of the proximity of protein synthesis to the sites of synaptic transmission, the specificity of transcripts that are translated, and its disruption in disease has underscored the importance of understanding the nature of post-transcriptional regulatory mechanisms that shape the complement of proteins in neurons and at synapses. Since their discovery in 1993, microRNAs (miRNAs) have been appreciated for their breadth of function as post-transcriptional regulators of protein synthesis by translation inhibition and transcript destabilization.6 miRNAs regulate neuronal plasticity and dendritic spine morphogenesis, are implicated in higher-order brain functions such as memory and cognitive dysfunction, and proteins involved in miRNA biogenesis and function are found in neurons, including near synapses.1 The evolutionarily conserved let-7 family of miRNAs has emerged as a critical mediator of post-transcriptional gene regulation in many growth-related processes including developmental timing (C. elegans7 and D. melanogaster8,9), body axis programming (M. musculus10), metabolism (M. musculus11), and cancer (M. musculus12 and H. sapiens13). The let-7 family of miRNAs are highly abundant in mature differentiated neurons and work from our lab and others has shown that let-7 miRNA levels can be regulated by neuronal activity3,14-16 and are disrupted in a mouse model lacking the fragile X mental retardation protein (FMRP).31 However, an approach to unambiguously determine the genome-wide identity of mRNA targets for let-7 and other miRNAs has not been possible until recently. This project employs a modified version of the recently developed CLEAR-CLIP technique17 that involves cross-linking and immunoprecipitation followed by intermolecular ligation of endogenous RNAs bound to Argonaute and high-throughput sequencing (CIMERA- seq). CIMERA-seq will allow for critical miRNA targets and miRNA-regulatory mechanisms governing protein synthesis in the mammalian CNS to be explored in great detail. The hypothesis of this proposal is that lowered let-7 miRNA levels observed in vitro and in vivo in the FMRP-deficient brain will produce changes in the miRNA- target profile consistent with altered neuronal plasticity, synapse overgrowth, and protein synthesis observed in a mouse model lacking FMRP.

神经科学中最有趣和最复杂的问题之一是关于分子 突触参与学习和记忆的机制。早在 20 世纪 60 年代开始， 大量证据表明，新的蛋白质合成是学习和长期记忆形成所必需的。1 此外，已经表明，活性依赖性蛋白质合成具有高度特异性，因为只有一小部分 可用转录本的翻译遵循神经元活动。2,3 还有证据表明，局部蛋白质 突触的合成介导可塑性，翻译中的扰动与突触的紊乱有关 认知功能，如自闭症。4,5 实现蛋白质合成与突触位点的接近 传播、翻译转录本的特异性及其对疾病的破坏强调了 了解形成转录后调控机制的性质的重要性 神经元和突触中蛋白质的补充。 自 1993 年被发现以来，microRNA (miRNA) 因其广泛的功能而受到赞赏 通过翻译抑制和转录不稳定作为蛋白质合成的转录后调节剂。6 miRNA 调节神经元可塑性和树突棘形态发生，与高级大脑有关 记忆和认知功能障碍等功能，以及参与 miRNA 生物发生和功能的蛋白质 存在于神经元中，包括突触附近。1 进化上保守的 miRNA let-7 家族 在许多生长相关过程中成为转录后基因调控的关键介质，包括 发育时间（秀丽隐杆线虫7和黑腹果蝇8,9），身体轴编程（肌肉肌10），新陈代谢 （M. musculus11）和癌症（M. musculus12 和 H. sapiens13）。 let-7 miRNA 家族非常丰富 我们实验室和其他实验室的工作表明，在成熟分化的神经元中，let-7 miRNA 水平可以 受神经元活动调节3,14-16，并且在缺乏脆性 X 智力障碍的小鼠模型中被破坏 蛋白 (FMRP)。31 然而，有一种方法可以明确确定 mRNA 的全基因组身份 直到最近，let-7 和其他 miRNA 的靶标才成为可能。该项目采用修改版本 最近开发的 CLEAR-CLIP 技术17涉及交联和免疫沉淀 通过与 Argonaute 结合的内源 RNA 的分子间连接和高通量测序 (CIMERA- 序列）。 CIMERA-seq 将允许关键 miRNA 靶标和控制蛋白质的 miRNA 调节机制 哺乳动物中枢神经系统中的合成有待详细探索。该提案的假设是降低 在 FMRP 缺陷的大脑中体外和体内观察到的 let-7 miRNA 水平将产生 miRNA 的变化 目标概况与观察到的神经元可塑性改变、突触过度生长和蛋白质合成一致 缺乏 FMRP 的小鼠模型。