Mechanisms of retinal axon pathfinding

视网膜轴突寻路机制

• 批准号: 7796623
• 负责人: Chi-Bin Chien
• 金额: $ 37万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-04 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7796623
• 关键词: Address; Affect; Albinism; Alternative Splicing; Anatomy; Animals; Axon; Behavior; Biochemical; Biological Assay; Brain; Cell Adhesion Molecules; Cell Communication; Cells; Complex; Cues; Cytoplasmic Tail; Data; Defect; Development; Disease; Embryo; Exons; Extracellular Matrix; Eye; Fishes; Genes; Genetic; Genotype; Glaucoma; Growth Cones; Human; Human Development; Image; Left; Mediating; Messenger RNA; Methods; Microscopy; Modeling; Molecular; Muscle fasciculation; NCAM1 gene; Nervous system structure; Oligonucleotides; Optic Disk; Optic Nerve; Optic tract structure; Pathway interactions; Peripheral; Plants; Play; Process; Psyche structure; Public Health; RNA Splicing; Receptor Signaling; Research Personnel; Resolution; Rest; Retina; Retinal; Retinal Ganglion Cells; Role; Shapes; Signal Transduction; Stereotyping; Structure; System; Tectum Mesencephali; Testing; Time; Time Study; Transplantation; Vertebrates; Vision; Visual system structure; Work; Zebrafish; axon guidance; axon regeneration; developmental genetics; human disease; in vitro Assay; in vivo; interest; mutant; nervous system disorder; novel; programs; receptor; regenerative therapy; research study; response to injury; retinal axon; retinotectal; time use

DESCRIPTION (provided by applicant): As retinal axons grow along the retinotectal pathway from their origins in the retina to their final targets in the tectum, they are guided by a complex array of signals in the extracellular matrix, and by interactions with other retinal axons. This process is not only critical for the development of visual function, but serves as an accessible model for axon guidance in general. This proposal will use genetic, embryological, and imaging approaches in the zebrafish embryo to analyze retinal axon guidance in vivo, studying how Slit- Robo signaling and axon-axon interactions act to shape the retinotectal projection. We will address three main questions about Slit-Robo signaling. First, can Slits change from repulsive to attractive in different contexts as growth cones pass from one part of their pathway to another? Expression studies, time lapse analysis, in vitro assays, and a novel in vivo method for targeted misexpression will address this question definitively. Second, do different cytoplasmic domains of the Robo2 receptor have different required functions? And third, is the alternative splicing that we have seen in the robo2 gene functionally significant? We will address these two questions by employing splice-blocking morpholino oligonucleotides for a powerful new strategy, targeted exon deletion. Within the retina, our preliminary data show that early-born central RGCs are required for later-born peripheral axons to exit the eye. We will first comprehensively analyze retinal axon pathfinding within the retina, then use time lapse and transplant experiments to ask how early RGCs act to guide later axons. Finally, we will test which cell-adhesion molecules mediate retinal axon fasciculation, and what role they play in guiding retinal axons within the retina, in the chiasm, and in the optic tract. Relevance to public health. Visual system anatomy and genetic control mechanisms are both highly conserved across the vertebrates from fish to humans. Understanding the molecular mechanisms that work together to assemble the zebrafish visual system is thus directly relevant to human development. Furthermore, our data showing the importance of axon-axon interactions during development highlight the necessity of considering such interactions during axon regeneration in response to injury or disease.

描述（由申请人提供）：当视网膜轴突沿着视网膜直直直直径途径从视网膜中的起源到底层中的最终靶标生长，它们的引导是由细胞外基质中的复杂信号阵列以及与其他视网膜轴突相互作用的。这个过程不仅对视觉功能的发展至关重要，而且是轴突指导的可访问模型。该建议将在斑马鱼胚胎中使用遗传，胚胎学和成像方法来分析体内视网膜轴突的指导，研究裂缝机器人信号传导和轴突 - 轴突相互作用如何塑造视网膜直肠投射。我们将解决有关Slit-Robo信号传导的三个主要问题。首先，随着生长锥从其路径的一部分传递到另一种路径，缝隙会在不同情况下从排斥性变为有吸引力吗？表达研究，延时分析，体外测定以及一种新型的靶向敏感性体内方法将确定地解决这个问题。其次，Robo2受体的不同细胞质结构域是否具有不同的所需功能？第三，我们在Robo2基因功能上显着的替代剪接是否存在？我们将通过采用剪接阻断型莫菲利诺寡核苷酸来解决有针对性的外显子删除的强大策略来解决这两个问题。在视网膜中，我们的初步数据表明，后来出生的外围轴突需要早期出生的中央RGC才能退出眼睛。我们将首先全面分析视网膜内的视网膜轴突探路，然后使用时间流失和移植实验来询问早期RGC的作用如何引导后来的轴突。最后，我们将测试哪些细胞粘附分子介导视网膜轴突诱变，以及它们在引导视网膜内，CHIASM和OB片中的视网膜轴突中起什么作用。与公共卫生有关。视觉系统解剖结构和遗传控制机制在从鱼到人类的脊椎动物中都高度保守。因此，了解共同组装斑马鱼视觉系统的分子机制与人类发展直接相关。此外，我们的数据显示在发育过程中轴突 - 轴相互作用的重要性突出了需要考虑轴突再生过程中这种相互作用的必要性，以应对损伤或疾病。