GENETICALLY ENCODED SPARSE LABELING AND EXPRESSION FOR IN VIVO STUDIES

描述（由申请人提供）：从Ramon y Cajal开始，实验组织的稀疏标记一直是细胞生物学分析的有力方法，Ramon y Cajal使用高尔基体染色详细描述了神经元组织的结构。到目前为止，这种标记对于整个组织中神经元的分析至关重要，因为轴突和树突过程的密度和复杂性使得在无处不在的标记样品中追踪单个细胞几乎是不可能的。稀疏标记技术在检查细胞迁移过程中的行为、确定细胞谱系关系以及评估基因功能的细胞自主性方面也发挥着关键作用。 已经使用了多种方法来稀疏标记固定和活组织中的样品，包括高尔基体染色、单细胞染料注射、DNA构建体的瞬时表达、病毒感染和细胞移植。在脊椎动物系统中，还开发了几种稀疏标记细胞的转基因方法，包括使用在表达中显示广泛杂色的启动子、药物诱导的启动子活化和刺激有丝分裂染色体间重组。然而，这些用于获得稀疏标记的方法都不容易应用于脊椎动物中的大规模分析（遗传筛选或药物筛选）。 我们建议开发一种强大的，可靠的方法来创建转基因动物，将稀疏标记的细胞群，并很容易复制一代又一代。从概念上讲，该想法是使用新描述的CRISPR/Cas9位点特异性核酸酶来驱动选择细胞中的非同源末端连接DNA修复，以将未表达的GFP报告基因修饰为表达的GFP报告基因。如果成功的话，这种方法将广泛适用于分析人类神经元疾病的小鼠或斑马鱼模型中的神经元结构（以及其他细胞类型）。

DESCRIPTION (provided by applicant): Sparse labeling of experimental tissue has been a powerful approach for cell biological analysis from the time of Ramon y Cajal, who used Golgi staining to describe in great detail the structure of neuronal tissue. To this date such labeling i critical for the analysis of neurons in whole tissue as the density and complexity of axonal and dendritic processes make tracing individual cells virtually impossible in ubiquitously labeled samples. Sparse labeling techniques also play critical roles in examining the behavior of cells during migration, in determining lineage relationships of cells, and assessing the cell autonomy of gene function. A variety of approaches have been used to sparsely label samples both in fixed and living tissue including Golgi staining, single cell dye injections, transient expression f DNA constructs, viral infection and cell transplantation. In vertebrate systems, several transgenic approaches to sparsely label cells have also been developed including use of promoters that display extensive variegation in expression, drug inducible activation of promoters and stimulation of mitotic interchromosomal recombination. However, none of these approaches for obtaining sparse labeling are easily applied for large-scale analysis in vertebrates (genetic screens or drugs screens). We propose to develop a robust, reliable method to create transgenic animals that will sparsely label a cell population and be readily reproduced from generation to generation. Conceptually, the idea is to use a newly described CRISPR/Cas9 site-specific nuclease to drive non-homologous end joining DNA repair in select cells to modify a non-expressed GFP reporter into one that expresses. If successful the approach should be widely applicable for the analysis of neuronal structure (and other cell types also) in mouse or zebrafish models of human neuronal diseases.