Development of genetically encoded neural tracers for electron microscopy

用于电子显微镜的基因编码神经示踪剂的开发

基本信息

批准号：
8327806
负责人：
LINNAEA E OSTROFF
金额：
$ 15.4万
依托单位：
NEW YORK UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-09-06 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8327806
关键词：
Adult Amygdaloid structure Architecture Area Axon Behavioral Binding Brain Calcium/calmodulin-dependent protein kinase Cell Density Cell membrane Cells Characteristics Cytoskeleton Data Dendrites Dependovirus Destinations Detergents Development Electron Microscopy Functional disorder Gene Expression Genes Goals Horseradish Peroxidase Immediate-Early Genes Infection Injection of therapeutic agent Label Lateral Learning Light Literature Maps Membrane Methods Microscopic Morphology Neuroanatomy Neurobiology Neurons Neurosciences Organelles Output Phaseolus vulgaris leucoagglutinin Proteins Rattus Reporter Genes Research Site Specificity Structure Synapses System Temporal Lobe Testing Tissue Preservation Tissues Tracer Training Transfection Travel Viral Viral Vector Virus Work brain cell calmodulin-dependent protein kinase II conditioned fear excitatory neuron experience in vivo interest light microscopy nervous system disorder neural circuit neuronal cell body novel prevent promoter relating to nervous system research study response retrograde transport success tool uptake

项目摘要

DESCRIPTION (provided by applicant): The connections between neurons compose the basic structure of the brain, through which all of its functions are expressed. Mapping and characterizing these connections is fundamental to neuroscience, as no brain system can be understood if its architecture is unknown. Neuroanatomical tracers have been used for decades to reveal connectivity in much of the brain, but the information they provide is limited. Tracers are compounds which are transported along axons and allow their origin, destination, or both to be visualized. It is difficult to control the specificity of existing tracers, which leads to inconsistent and unreliable results. To accurately map connectivity, the existence of synaptic connections between identified neurons must be verified at the electron microscopy (EM) level. Furthermore, EM studies of synapse morphology should ideally be carried out on labeled connections. The few existing tracers that are compatible with EM are not compatible with morphological studies due to severely compromised ultrastructure. We have conducted extensive morphological and neuroanatomical tracer studies at the EM level on our system of interest, the adult rat lateral amygdala. We propose to develop novel tracers which will label specific cells for light microscopy and EM while preserving high quality ultrastructure for morphological studies. Using a viral vector, we will express a membrane-targeted form of the EM label horseradish peroxidase (HRP) in adult rat neurons. Unlike current tracers, HRP can be visualized without subjecting tissue to detergents which damage EM ultrastructure. This allows good preservation of tissue morphology, while restricting the HRP to the membrane prevents the label from obscuring any cellular organelles. We will place the membrane-bound HRP gene under the control of one of two different promoters. The first, the calcium/calmodulin-dependent protein kinase II promoter, will restrict expression of the label to excitatory neurons. Combined with the fact that viral transfection is restricted to cell bodies (which conventional tracer uptake is not), this will be the most spatially and functionally specific tracer available. The second promoter will be from the activity-regulated cytoskeleton-associated protein Arc, which is expressed in response to strong synaptic activation and behavioral experience. This will allow identification of the axons and dendrites of cells activated during learning and plasticity experiments such that their synapses can be specifically examined. The tools we propose to create will have a broad range of applications in neuroanatomy, neurobiology, and plasticity studies throughout the brain.

描述（由申请人提供）：神经元之间的连接构成了大脑的基本结构，其所有功能都被表达。这些连接的映射和表征是神经科学的基础，因为如果未知的结构未知，则无法理解大脑系统。数十年来，神经解剖示踪剂已被用于揭示大脑的连通性，但是它们提供的信息是有限的。示踪剂是沿轴突运输的化合物，并允许其起源，目的地或两者都可以看到。很难控制现有示踪剂的特异性，从而导致不一致和不可靠的结果。为了准确绘制连通性，必须在电子显微镜（EM）水平上验证已识别神经元之间的突触连接。此外，理想情况下应在标记的连接上进行突触形态的EM研究。与EM兼容的少数现有示踪剂由于严重损害的超微结构而与形态学研究不兼容。我们在EM级别进行了广泛的形态和神经解剖示踪剂研究，我们感兴趣的系统，成年大鼠侧杏仁核。我们建议开发新型的示踪剂，这些示踪剂将标记特定细胞的光学显微镜和EM，同时保留高质量的超微结构用于形态学研究。使用病毒载体，我们将在成年大鼠神经元中表达EM标记辣根过氧化物酶（HRP）的膜靶向形式。与目前的示踪剂不同，可以将HRP可视化，而无需对组织损害EM超微结构的洗涤剂。这可以很好地保存组织形态，同时将HRP限制在膜上可以防止标签掩盖任何细胞细胞器。我们将将膜结合的HRP基因置于两个不同启动子之一的控制下。首先，钙/钙调蛋白依赖性蛋白激酶II启动子将限制标记的表达为兴奋性神经元。结合病毒转染仅限于细胞体（常规的示踪剂吸收）的事实，这将是空间和功能上最特定的示踪剂。第二个启动子将来自活性调节的细胞骨架相关蛋白ARC，该蛋白弧反应响应强突触激活和行为经验。这将允许在学习和可塑性实验中激活的细胞的轴突和树突鉴定，以便可以特别检查它们的突触。我们建议创建的工具将在整个大脑的神经解剖学，神经生物学和可塑性研究中具有广泛的应用。