Neuronal Activity-dependent Pomoter Usage

摘要 神经回路的经验依赖性重塑使动物能够适应他们的行为， 不断变化的环境神经元活动依赖的分子改变，由感觉输入引起， 从转录到翻译后修饰的水平是神经重新布线的基础。毫不奇怪， 对神经元活动的分子反应受损是广泛的认知功能障碍的共同标志。 抑郁症、精神分裂症和自闭症等疾病。因此，理解活性依赖性分子 这些变化对于理解这些精神障碍的机制至关重要。在过去的几年里， 广泛的研究已经在转录组中的活性依赖性变化的谱分析方面取得了很大进展， 可变剪接和蛋白质组。这些研究提供了重要的新见解，了解大脑如何 整合感官输入并重组特定的神经网络。 然而，RNA分子的一部分已经逃脱了全基因组的审查-5 '端。广泛使用 RNA-seq方法不能充分代表RNA的5 '-末端。分析转录起始位点的现有方法 (TSS)然而，主要代表5'端;因此，在这样的转录组中，大部分转录组是不存在的。 这使得将TSS使用与动态mRNA表达联系起来具有挑战性。 我们最近开发了一种全长新生转录组分析方法Bru-seq-DLAF， 结合了TSS的灵敏检测和新生RNA测序。通过Bru-seq-DLAF，我们揭开了 数十个基因在减少或增加网络活动时动态改变TSS。大多数TSS 导致多肽在其氨基末端的改变。此外，蛋白质异构体是保守的 小鼠和人类之间，表明活动依赖性TSS的使用可能代表了一个保守的新的 突触可塑性的基因调控层。拟议的研究目标是：1）彻底 在小鼠模型中表征这种新现象，2）确定活性依赖性TSS在 突触可塑性我们假设，神经元活动依赖性TSS控制突触可塑性， 改变蛋白质的亚细胞定位。我们的团队是唯一准备测试这一假设与其 在基因组学和突触可塑性方面的专业知识。 一个积极的结果，拟议的研究是照亮活动依赖TSS的选择， 突触可塑性的复杂分子机制。据我们所知，我们的数据代表了第一个基因组- 广泛表征动物细胞中细胞外刺激后TSS改变。此外，许多基因 这些经历活动依赖性TSS选择的细胞与精神障碍如精神分裂症有关， 和自闭症谱系障碍。因此，这项研究将改善精神障碍的遗传学， 指导未来疾病相关基因的功能研究。

ABSTRACT Experience-dependent remodeling of neural circuits enables animals to adapt their behavior to ever- changing environments. Neuronal activity-dependent molecular alterations, elicited by sensory inputs, at all levels from transcription to post-translational modifications are the basis of neural rewiring. Not surprisingly, impaired molecular responses to neuronal activity are a common hallmark of a broad range of cognitive disorders, such as depression, schizophrenia, and autism. Thus, comprehending activity-dependent molecular changes is crucial to understanding the mechanisms of these mental disorders. Over the past several years, extensive studies have made excellent strides in profiling activity-dependent changes in the transcriptome, alternative splicing, and proteome. These studies have provided significant new insights into how the brain integrates sensory inputs and reorganizes specific neural networks. However, a portion of the RNA molecule has escaped genome-wide scrutiny―the 5'-ends. Widely-used RNA-seq methods underrepresent the 5'-ends of RNAs. Existing methods to profile transcription start sites (TSS), however, predominantly represent the 5' ends; therefore, most of the transcriptome is absent in such libraries, making it challenging to connect TSS usage to dynamic mRNA expression. We recently developed a full-length nascent-transcriptome profiling method, Bru-seq-DLAF, which combines sensitive detection of TSS and nascent RNA sequencing. With Bru-seq-DLAF, we have unveiled tens of genes that dynamically change TSS upon reducing or increasing network activity. Most of these TSS led to alterations in polypeptides at their amino termini. Furthermore, the protein isoforms were conserved between mice and humans, indicating that activity-dependent TSS usage may represent a conserved new layer of gene regulation underlying synaptic plasticity. The proposed research goals are to 1) thoroughly characterize this novel phenomenon in mouse models and 2) determine the roles of activity-dependent TSS in synaptic plasticity. We hypothesize that neuronal activity-dependent TSS controls synaptic plasticity by changing the subcellular localization of proteins. Our team is uniquely poised to test this hypothesis with its unified expertise in genomics and synaptic plasticity. A positive outcome of the proposed study is to illuminate activity-dependent TSS selection as an intricate molecular mechanism for synaptic plasticity. To our knowledge, our data represent the first genome- wide characterization of TSS alterations upon extracellular stimuli in animal cells. Furthermore, many genes that undergo activity-dependent TSS selection have been implicated in mental disorders such as schizophrenia and autism spectrum disorders. Thus, the proposed study will improve the genetics of mental disorders and guide future functional studies on disease-associated genes.