Mechanisms of early axonal pathfinding in the olfactory system of larval zebrafish

斑马鱼幼虫嗅觉系统早期轴突寻路机制

• 批准号: 10569006
• 负责人: Jessica Nicole Brandt
• 金额: $ 4.68万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10569006
• 关键词: Affect; Alleles; Alzheimer' s Disease; Anosmia; Axon; Biological Models; Detection; Development; Developmental Process; Docking; Elderly; Embryo; Embryonic Development; Ensure; Event; Family; Fishes; Foundations; G-Protein Signaling Pathway; G-Protein-Coupled Receptors; GTP-Binding Proteins; Genes; Human; Image; Individual; Interneurons; Location; Maps; Mediating; Molecular; Monitor; Mus; Mutate; Mutation; Natural regeneration; Neurons; Neuropil; Odorant Receptors; Olfactory Epithelium; Olfactory Pathways; Parkinson Disease; Pattern; Positioning Attribute; Process; Receptor Gene; Reproducibility; Research; Role; Signaling Protein; Site; System; Testing; Time; Translating; Vertebrates; Zebrafish; axon guidance; axonal pathfinding; calcium indicator; designer receptors exclusively activated by designer drugs; early embryonic stage; experience; experimental study; fly; neural circuit; olfactory bulb; olfactory receptor; olfactory sensory neurons; prenatal; prevent; protein function; receptor expression; recombinase-mediated cassette exchange; relating to nervous system; repaired; segregation; single-cell RNA sequencing; transcription factor

Abstract In the olfactory system precise connections create a functional topographic map that translates odorant experience into ordered patterns of odorant-specific neural activity. This map is established early in development. Olfactory Sensory Neurons (OSNs) stochastically choose to mono-allelically express one Odorant Receptor (OR), which belong to the G-Protein Coupled Receptor (GPCR) family, from a large gene repertoire. Each OSN projects a single axon from the Olfactory Epithelium (OE) to the Olfactory Bulb (OB). Axons of OSNs first target larger identifiable neuropils called protoglomeruli. In zebrafish, our lab has found that the protoglomerulus an OSN axon targets correlates with the family or homology clade of its chosen OR. OSNs expressing ORs from different homology clades target different protoglomeruli. Subsequent to this initial protoglomerular targeting, the axons of OSNs expressing the same OR ultimately coalesce into smaller, distinct, and reproducible neuropil regions known as glomeruli. Thus, the target location of each axon on the OB is coordinated with its chosen OR. Previous research has shown that an OSN’s chosen OR and OR-driven neural activity are important for glomerular segregation. However, it is not known how clade-specific protoglomerular targeting and OR-specific glomerular segregation are achieved. Previous studies performed in the mouse may have conflated initial targeting processes with glomerular segregation due to the relative inaccessibility of early developmental stages. The foundational research in olfactory development utilized static imaging after development was complete, often leading to developmental processes being inferred rather than investigated. We believe protoglomerular targeting is determined by the coordinated expression of the OR locus and axon guidance loci, rather than OR protein function. We have shown through single-cell RNA sequencing that OSNs expressing ORs within the same homology clade also express similar transcription factors and axon-guidance-related factors. Further, OSNs expressing closely related ORs target nearby glomeruli. Thus, I hypothesize that regulators controlling OR choice in OSNs also regulate axonal guidance receptor expression, while OR-specific neural activity regulates the subsequent segregation of OR-specific glomeruli. Utilizing a recombinase-mediated cassette exchange approach, my proposed experiments will disambiguate the relative contributions of OR identity and OR-driven neural activity to protoglomerular and glomerular targeting.

抽象的 在嗅觉系统中，精确连接创建了一个功能地形图，该图可以翻译好odorint 经验到有序特异性神经元活性的有序模式。该地图是在开发初期建立的。 嗅觉感觉神经元（OSN）随机选择单相表达一个气味受体 （OR），属于大型基因曲目的G蛋白偶联受体（GPCR）家族。每个OSN 将一个轴突从嗅觉上皮（OE）投射到嗅球（OB）。 OSN的轴突第一个目标 较大的可识别神经胶质称为原胶质膜。在斑马鱼中，我们的实验室发现prodoglomerulus an OSN轴突靶标与其所选或同源性进化枝相关。 OSN表达ORS 不同的同源进化枝靶向不同的原胶质素。在此初始质量表靶向之后， OSN的轴突表达相同或最终合并为较小，独特和可重复的神经皮质 被称为glomerulli的地区。那就是OB上每个轴突的目标位置与所选或所选的。 先前的研究表明，OSN选择或OR-OR-wrion神经活动对于 肾小球分离。但是，尚不知道进化枝特异性的质量靶向和特异性靶向 实现了肾小球隔离。在鼠标中进行的先前研究可能已经混合了初始 由于早期发育阶段的相对无法访问性，以肾小球隔离的靶向过程。 开发完成后，嗅觉开发的基础研究利用静态成像， 通常导致开发过程被推断而不是研究。我们相信质量表 靶向由OR基因座和轴突指导基因座的协调表达确定，而不是或 蛋白质功能。我们已经通过单细胞RNA测序显示了OSN在 相同的同源进化枝还表达了相似的转录因子和与轴突相关的因子。更远， OSN表达密切相关的OR靶向附近glomerulli。我假设控制机构 或OSN中的选择还调节轴突引导受体表达，而或特定的神经活动 调节或特异性glomerulli的后续分离。利用重组酶介导的盒子 交换方法，我提出的实验将消除歧义或身份的相对贡献和 对原成角和肾小球靶向的神经活动。