Converting stochastic olfactory receptor expression to stereotypic axon guidance programs

将随机嗅觉受体表达转换为刻板的轴突引导程序

• 批准号: 10515666
• 负责人: Stavros Lomvardas
• 金额: $ 53.07万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2026-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10515666
• 关键词: Affect; Alleles; Amino Acid Sequence; Amino Acid Substitution; Anterior; Astronomy; Axon; Bar Codes; Binding; Biochemical; Brain; Cell Adhesion; ChIP-seq; Chemical Structure; Chemicals; Cilia; Code; Cognition Disorders; Computational algorithm; Computer Analysis; Data; Experimental Designs; Fingers; Gene Expression; Generations; Genes; Genetic; Genetic Transcription; Genomics; Maps; Mediating; Memory; Memory Disorders; Molecular; Nerve Degeneration; Neurodevelopmental Disorder; Neurons; Neuropil; Odorant Receptors; Odors; Olfactory Epithelium; Olfactory Pathways; Output; Pathway interactions; Phase; Play; Process; Reading; Receptor Gene; Regulation; Reporter; Role; Seminal; Series; Signal Transduction; Smell Perception; Specificity; Stereotyping; Stress; Structure; Synapses; Transcriptional Regulation; Translating; Volatilization; Work; axon guidance; brain disorder therapy; design; endoplasmic reticulum stress; experimental study; extracellular; fascinate; insight; neural circuit; neuronal patterning; novel; olfactory bulb; olfactory receptor; olfactory sensory neurons; programs; receptor expression; single-cell RNA sequencing; transcription factor; transmission process

Summary The mammalian olfactory system has the remarkable ability to detect and identify an astronomical number of volatile chemicals, termed odorants. Odorants are detected by olfactory receptors (ORs) at the cilia of olfactory sensory neurons (OSNs), which transform chemical information into electrical signals transmitted to the olfactory bulb (OB). Each one of the ~1000 OR genes is expressed in a monogenic, monoallelic, and seemingly stochastic fashion in the main olfactory epithelium (MOE), yet axons from OSNs with the same OR converge to distinct and stereotypic neuropil structures at the OB called glomeruli. Because each OR identity is represented by corresponding glomeruli, odor binding to distinct OR repertoires activates an odor-specific combination of glomeruli, providing the basis of odor perception. Here, we investigate molecular mechanisms that transform the random expression of a single OR in the MOE to stereotypic and highly coordinated axon targeting programs in the OB. Previous work revealed that the OR sequence plays an essential regulatory function in this axon guidance process, in part, by directing the expression programs of genes involved in axon guidance and cell adhesion. We reveal that the OR identity may inform this process by eliciting distinct levels of endoplasmic reticulum (ER) stress, which in turn, influence transcriptional programs controlling axon targeting specificity. With the generation of a translational fluorescent reporter that quantifies the levels of ER stress-induced Perk signaling, we demonstrate that OSNs have distinct levels of ER stress according to the identity of the OR they express. Furthermore, by deconvoluting transcriptional networks, we identified transcription factors that transform ER stress levels into distinct axon guidance outputs. Based on these preliminary findings, we propose experiments that will decipher the function of ER stress-responsive transcription factors and will identify extracellular barcodes corresponding to various levels of ER stress. Moreover, we propose experiments that will untangle the contribution of OR identity and OSN origin to the cellular levels of ER stress and will identify OR protein sequences with a major role in this process. Our experiments promise to provide novel insight into a fascinating problem that has remained poorly understood for decades. Moreover, this work will uncover generalizable mechanisms responsible for converting cellular and molecular identity of neurons into precise axon guidance specificity, with immense basic and translational ramifications.

概括 哺乳动物嗅觉系统具有出色的检测和识别天文数量的能力 挥发性化学物质，称为气味剂。气味通过嗅觉的嗅觉受体（OR）检测到嗅觉 感觉神经元（OSN），将化学信息转化为传播到嗅觉的电信号 灯泡（OB）。 〜1000或基因中的每一个均以单基因和看似随机的方式表达 主要嗅觉上皮（MOE）中的时尚，但来自OSN的轴突相同或收敛到独特的和 OB处的刻板神经胶质结构称为肾小球。因为每个或身份都由 相应的肾小球，气味与不同的或曲目结合，激活了异味的特定组合 肾小球，提供气味的基础。在这里，我们研究了转化的分子机制 单个或在MOE中的随机表达在刻板印象和高度协调的轴突靶向程序中的随机表达 OB。先前的工作表明，或序列在此轴突中起着必不可少的调节功能 指导过程部分通过指导轴突引导和细胞中涉及的基因的表达程序 粘附。我们透露，或身份可以通过引起不同水平的内质含量来告知这一过程 网状（ER）应力反过来影响控制轴突靶向特异性的转录程序。和 量化ER应力诱导的PERK的水平的转化荧光记者的生成 信号传导，我们证明OSN根据OR的身份具有不同的ER应力水平 表达。此外，通过对转录网络进行反应，我们确定了转录因子 将ER应力水平转变为不同的轴突引导输出。根据这些初步发现，我们提出了 将破译ER应力响应转录因子功能的实验，并将确定 细胞外条形码对应于各种水平的ER应力。而且，我们提出的实验将 解开或身份和OSN来源对ER应力的细胞水平的贡献，并将识别或 在此过程中具有主要作用的蛋白质序列。我们的实验承诺将提供新颖的见解 几十年来，人们一直了解的令人着迷的问题。而且，这项工作将揭开 负责将神经元转化为精确轴突的细胞和分子身份的概括机制 指导特异性，具有巨大的基本和翻译后果。