Molecular regulation of dendrite morphogenesis

树突形态发生的分子调控

基本信息

批准号：
9275550
负责人：
DAVID M MILLER
金额：
$ 34.04万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-06-01 至 2019-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9275550
关键词：
Actins Adaptor Signaling Protein Address Adherens Junction Afferent Neurons Alpha Cell Animal Model Animals Architecture Binding Biological Brain C-terminal Caenorhabditis elegans Cell Adhesion Molecules Cell membrane Cell surface Cells Complex Cues Cysteine Cytoplasmic Tail Dendrites Development Diffuse Disabled Persons Disease EGF gene Epidermis Event F-Actin Genes Genetic Goals Growth Homeodomain Proteins Homologous Gene Human Image Individual Insecta Intercellular Junctions Invertebrates Lateral Lead Length Ligands Location Mammals Mediating Membrane Proteins Methods Microfilaments Modeling Molecular Morphogenesis Morphology Motor Mutate Myosin ATPase Myosin S-1 Nematoda Nervous system structure Neurons Nociception Organism Pain Pathway interactions Pattern Perception Process Proteins Regulation Resolution Role Sensory Signal Pathway Signal Transduction Sister Skin Specific qualifier value Stimulus Structure Subcutaneous Tissue System Techniques Testing Tissues Total Internal Reflection Fluorescent Transmembrane Domain Withdrawal Work axon guidance base experimental study extracellular genetic analysis homeodomain insight neuron development non-muscle myosin novel polymerization public health relevance receptor response time use tool trafficking transcription factor

项目摘要

DESCRIPTION (provided by applicant): Sensory neurons utilize complex, topical networks of dendritic processes to detect external stimuli. Models that seek to explain the creation of these elaborate structures must include mechanisms that control the key events of branch initiation, elongation and termination. These features are universally observed in both vertebrate and invertebrate systems and are therefore likely governed by evolutionarily conserved components. The simple model organism, C. elegans, displays a single pair of PVD nociceptive neurons that envelop the animal with a net-like array of dendritic branches. We used time-lapse imaging to show that the discrete topical region occupied by each branch is defined by a contact-dependent mechanism in which sister dendrites (i.e., dendrites from the same neuron) repel each other to stop outgrowth. "Self-avoidance" is also observed in mammals and insects but the molecular underpinning of this fundamental patterning event is poorly understood. Our work has revealed a novel mechanism in which the diffusible cue UNC-6/Netrin is captured at the tips of PVD dendrites to mediate self-avoidance in a pathway involving the receptors UNC-40/DCC and UNC-5. This discovery is significant because it describes the first example of a role for these highly conserved proteins in dendrite self-avoidance. Now, we have extended these findings to identify multiple downstream components of the UNC-6/Netrin self-avoidance pathway. On the basis of these new results, we propose that UNC-6/Netrin triggers actin filament growth at the tips of contacting sister dendrites to engage a non-muscle myosin motor that drives retraction. Experiments described in Specific Aim 1 exploit the novel application of TIRF microscopy to a living organism to test this model. These studies are significant because little is known of how signals at the cell membrane trigger dendrite withdrawal during self-avoidance. Our work has uncovered a key role for a conserved membrane protein, tomoregulin, in self-avoidance. Specific Aim 2 will define the mechanism of this effect and determine if tomoregulin is necessary for other known short-range UNC- 6/Netrin signaling events. Aim 2 is significant because it addresses the fundamental question of how the UNC-6/Netrin pathway has been uniquely adapted for contact-dependent self-avoidance. To address the mechanism of dendritic outgrowth, we exploited powerful cell-specific profiling methods to identify targets of a conserved LIM-homeodomain transcription factor, MEC-3, that is required for PVD branching. Specific Aim 3 will test a model, based on these results, that dendritic branches are stabilized by interaction with claudin-like proteins and other specific cell-surface components in the adjacent epidermis. These experiments are important because sensory neuron outgrowth is typically executed in close contact with epidermal tissue but the intercellular mechanisms that pattern dendritic architecture in this location are poorly defined. This work in C. elegans is expected to identify key determinants that also specify dendritic architecture in the human nervous system.

描述（由申请人提供）：感觉神经元利用复杂的局部树突网络来检测外部刺激。试图解释这些复杂结构的创建的模型必须包括控制分支起始、伸长和终止等关键事件的机制。这些特征在脊椎动物和无脊椎动物系统中普遍观察到，因此可能受到进化上保守的成分的控制。简单的模型生物体——秀丽隐杆线虫，显示出一对PVD伤害性神经元，这些神经元用网状的树突状分支阵列包围着动物。我们使用延时成像来表明，每个分支占据的离散局部区域是由接触依赖机制定义的，其中姐妹树突（即来自同一神经元的树突）相互排斥以停止生长。在哺乳动物和昆虫中也观察到“自我回避”，但人们对这一基本模式事件的分子基础知之甚少。我们的工作揭示了一种新机制，其中可扩散信号 UNC-6/Netrin 在 PVD 树突尖端被捕获，以在涉及受体 UNC-40/DCC 和 UNC-5 的途径中介导自我回避。这一发现意义重大，因为它描述了这些高度保守的蛋白质在树突自我回避中的作用的第一个例子。现在，我们扩展了这些发现，以确定 UNC-6/Netrin 自我回避途径的多个下游组件。基于这些新结果，我们建议 UNC-6/Netrin 在接触姐妹树突的尖端触发肌动蛋白丝生长，以接合驱动回缩的非肌肉肌球蛋白马达。具体目标 1 中描述的实验利用 TIRF 显微镜在活体中的新颖应用来测试该模型。这些研究意义重大，因为人们对细胞膜信号如何在自我回避过程中触发树突缩回知之甚少。我们的工作揭示了一种保守的膜蛋白托莫调节蛋白在自我回避中的关键作用。具体目标 2 将定义这种效应的机制，并确定托莫调节蛋白对于其他已知的短程 UNC-6/Netrin 信号传导事件是否是必需的。目标 2 很重要，因为它解决了 UNC-6/Netrin 通路如何独特地适应依赖于接触的自我回避的基本问题。为了解决树突生长的机制，我们利用强大的细胞特异性分析方法来识别树突生长的目标保守的 LIM 同源域转录因子 MEC-3，是 PVD 分支所需的。具体目标 3 将根据这些结果测试一个模型，该模型通过以下方式稳定树突分支：与邻近表皮中的紧密蛋白样蛋白和其他特定细胞表面成分相互作用。这些实验很重要，因为感觉神经元的生长通常是在与表皮组织紧密接触的情况下进行的，但在该位置形成树突结构的细胞间机制尚不清楚。这项针对秀丽隐杆线虫的工作预计将确定关键的决定因素，这些决定因素也指定了人类神经系统中的树突结构。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Neuroendocrine modulation sustains the C. elegans forward motor state.

神经内分泌调节维持线虫前进运动状态

DOI：
10.7554/elife.19887
发表时间：
2016-11-18
期刊：
eLife
影响因子：
7.7
作者：
Lim MA;Chitturi J;Laskova V;Meng J;Findeis D;Wiekenberg A;Mulcahy B;Luo L;Li Y;Lu Y;Hung W;Qu Y;Ho CY;Holmyard D;Ji N;McWhirter R;Samuel AD;Miller DM;Schnabel R;Calarco JA;Zhen M
通讯作者：
Zhen M

Mechanisms that regulate morphogenesis of a highly branched neuron in C. elegans.