跨膜蛋白MIG-13调控线虫Q神经前体细胞迁移的机制研究

Cell migration is a fundamental process of metazoan development, and impaired cell migration causes human diseases. Most of current research on cell migration relies on cell lines, however, extracellular matrix and regulatory signals for cell migration cannot be easily mimicked in vitro. C. elegans Q neuroblasts undergo long distance migration during its development and provide an appealing in vivo model system to study cell migration. We established the live cell imaging methodology to study Q neuroblast migration in C. elegans. Our forward genetic screens isolated four mutant alleles that specifically disrupt the anterior migration of Q neuroblasts, and our gene cloning data show that they encode a conserved transmembrane protein, MIG-13. Our proposed study will first address if mig-13 functions autonomously for Q neuroblast migration; we will use live imaging and genetics to assay the polarity initiation and maintenance of Q neuroblast migration in mig-13 mutant. We will also use biochemical approach to isolate the binding partners of MIG-13 protein as well as the transcription factors that specifically turn on mig-13 gene expression during the anterior migration. Given that mouse MIG-13 orthologue is essential for neuronal migration, we expect that our study can provide important insights to cell migration across species and cell migration related diseases.

细胞迁移是多细胞生物发育的重要环节，其异常可导致多种人类疾病。当前细胞迁移的许多重要进展来自体外培养细胞，但是体外系统难以提供真实的胞外基质和调控信号。秀丽隐杆线虫 Q神经前体细胞在形成神经环路过程中经历长距离的迁移，是研究活体细胞迁移的很好模型。申请人的前期工作建立了观察Q细胞在体迁移的荧光时序显微成像方法，通过遗传筛选获得了四个等位突变体导致保守跨膜蛋白MIG-13功能丧失。本课题将首先利用细胞学和遗传学检测MIG-13蛋白是否以细胞自主性的方式发挥功能，采用转盘激光共聚焦活体成像技术观察在mig-13突变体中迁移Q 细胞的极性建成和维持的异常，通过生物化学方法发现MIG-13蛋白的相互作用蛋白和调控mig-13基因特异表达的因子。小鼠mig-13同源基因的失活导致神经细胞迁移的异常，显示mig-13功能的保守性，我们的预期结果对于理解细胞迁移和相关疾病的发生具有科学理论意义。

细胞迁移是多细胞生物发育的重要环节，其异常可导致多种人类疾病。当前细胞迁移的许多重要进展来自体外培养细胞，但是体外系统难以提供真实的胞外基质和调控信号。秀丽隐杆线虫 Q 神经前体细胞在形成神经环路过程中经历长距离的迁移，是研究活体细胞迁移的很好模型。我们的前期工作建立了观察Q 细胞在体迁移的荧光时序显微成像方法，通过遗传筛选获得了四个等位突变体导致保守跨膜蛋白MIG-13 功能丧失。我们利用细胞学和遗传学方法证明MIG-13 蛋白以细胞自主性的方式发挥功能，采用转盘激光共聚焦活体成像技术发现mig-13 突变体导致迁移Q 细胞的极性建成和维持的异常，通过酵母双杂交的方法我们发现MIG-13 胞内结构域和ABL-1存在直接相互作用，暗示MIG1-3通过ABL-1传递信号。Hox基因lin-39转录激活mig-13表达，从而调控QR细胞迁移，在左侧Q细胞（QL）中Hox基因mab-5通过转录抑制Hox基因lin-39的表达，间接抑制mig-13的表达。小鼠mig-13同源基因的失活导致神经细胞迁移的异常，显示mig-13 功能的保守性，我们的实验结果找到了调控Q细胞迁移的表面受体，为进一步研究Q细胞迁移机制开辟了道路，也为高等动物细胞迁移研究提供了新的线索。