Characterization of a novel regulator of cell migration

描述（由申请人提供）：细胞迁移对动物发育和器官发生至关重要，不适当的细胞迁移有助于疾病的进展，如转移性癌症。我们利用两种特殊的秀丽隐杆线虫细胞的迁移，远端尖端细胞（DTC），作为体内模型系统来阐明细胞将细胞外信号转化为细胞迁移行为的机制。控制DTC迁移的基因，包括金属蛋白酶、整合素和Rac gtp酶，与转移过程中所需的基因惊人地相似。这项研究的目的是阐明W03H9.4的作用机制，W03H9.4是一种新的体内细胞迁移调节剂，需要正确的DTC转弯时间和正确的DTC寻路。基于初步证据，我们的工作假设是W03H9.4通过调节蛋白质的表达模式或亚细胞定位（包括netrin引导线索和/或netrin受体蛋白）来控制DTC的细胞极性和定向迁移，从而导致Rac GTPase信号传导改变和细胞引导缺陷。首先，通过对表达GFP融合蛋白的转基因动物进行分析，利用1W03H9.4抗体进行免疫荧光分析，确定需要W03H9.4发挥功能的细胞类型和发育阶段。其次，通过转基因拯救W03H9.4（tm3042）突变动物、W03H9.4细胞型特异性过表达、RNAi对W03H9.4细胞型特异性耗竭等方法研究W03H9.4的作用机制。最后，我们将研究W03H9.4、netrin信号系统和Rac家族GTPases之间的遗传相互作用，并确定W03H9.4水平的破坏对这些信号蛋白的定位或表达的影响。W03H9.4和Rac GTPases之间令人兴奋的联系使这项研究具有巨大的潜力，可以提高我们对动物发育过程中细胞迁移的基本调控和病理条件（如转移性癌症）的理解。公共卫生相关性：我们正在使用线虫秀丽隐杆线虫中的迁移细胞作为模型系统来研究参与细胞迁移过程的基因，特别是那些与转移性癌症相关的基因。这项研究将确定一种名为W03H9.4的新基因如何帮助细胞正确解读细胞外信号，让细胞知道何时迁移，何时停止迁移。W03H9.4与已知的信号级联之间的联系使这项研究具有巨大的潜力，可以提高我们对动物发育过程中和转移性癌症等病理条件下细胞迁移的基本调控的理解。

DESCRIPTION (provided by applicant): Cell migration is critical for animal development and organogenesis, and inappropriate cell migration contributes to progression of diseases such as metastatic cancer. We are using migration of two specialized C. elegans cells, the distal tip cells (DTC), as an in vivo model system to elucidate the mechanisms by which cells convert extracellular cues to cell migratory behaviors. The genes controlling DTC migration, including metalloproteases, integrins, and Rac GTPases, are strikingly similar to the genes required during metastasis. The goal of the proposed study is to elucidate the mechanism of action of W03H9.4, a novel regulator of in vivo cell migration required for correct timing of DTC turns and correct DTC pathfinding. Our working hypothesis, based on preliminary evidence, is that W03H9.4 controls the cell polarity and directional cell migration of the DTC by regulating the expression pattern or sub-cellular localization of proteins, including netrin guidance cues and/or netrin receptor proteins, which results in altered Rac GTPase signaling and defective cell guidance. First, the cell types and developmental stages that require W03H9.4 for function will be determined through analysis of transgenic animals expressing GFP fusion proteins and immunofluorescence with 1W03H9.4 antibodies. Secondly, the mechanism of W03H9.4 action will be investigated through transgenic rescue of W03H9.4(tm3042) mutant animals, cell-type specific overexpression of W03H9.4, and cell-type specific depletion of W03H9.4 by RNAi. Finally, genetic interactions between W03H9.4, the netrin signaling system, and Rac family GTPases will be investigated, and the effect of disrupted W03H9.4 levels on localization or expression of these signaling proteins will be determined. The exciting connection between W03H9.4 and Rac GTPases gives this study tremendous potential to improve our understanding of the fundamental regulation of cell migration during animal development and in pathologic conditions such as metastatic cancer. PUBLIC HEALTH RELEVANCE: We are using migratory cells in the nematode C. elegans as a model system to study genes involved in cell migration processes, particularly those genes that are relevant to metastatic cancer. This study will determine how a novel gene, W03H9.4, helps cells correctly interpret the extracellular cues that let cells know when to migrate and when to stop migrating. The connection between W03H9.4 and known signaling cascades gives this study tremendous potential to improve our understanding of the fundamental regulation of cell migration during animal development and in pathologic conditions such as metastatic cancer.