Anillin和Septin调控线虫神经前体细胞迁移的机制研究

Cell migration is essential for metazoan development. Despite the wealth of information about guidance cues, receptors and the machinery that powers motility, our understanding of the connection between receptor activation and the actin cytoskeleton remains elusive. Previous studies reported that the C. elegans RhoG homolog, MIG-2, is required for neuronal migration, but its downstream effector is largely unexplored. Our preliminary results showed that an actin-binding protein Anillin regulates cell migration by stabilizing the F-actin network at the leading edge of the migrating cell. Our results also demonstrated that Anillin can bind to RhoG/MIG-2 in vitro, indicating that Anillin may provide a previously unknown connection between RhoG/MIG-2 and F-actin network. Moreover, we found that an Anillin-binding protein, Septin, also can regulate Q cell migration. We propose to further address whether Anillin and Sepitn bind to RhoG and how they regulate the actin cytoskeleton during neuronal migration. We expect that our study will provide a novel mechanism for stabilizing actin filaments at the leading edge during neuronal migration, and shed light on the cell migration related diseases.

细胞迁移是多细胞生物发育的重要环节。尽管调控细胞迁移的信号和受体等关键因子已被发现，但是胞外信号如何通过膜上受体传递到微丝骨架上从而驱动细胞迁移还不清楚。前人的研究表明线虫的RhoG同源蛋白MIG-2在神经细胞迁移过程中发挥功能，但是其下游效应因子未知。我们的前期工作表明微丝结合蛋白Anillin富集在迁移细胞的前导端，稳定微丝网络，调控Q神经前体细胞迁移，而且发现Anillin结合MIG-2。我们推测Anillin可能是连接RhoG信号通路和微丝骨架之间的关键因子。我们的前期工作还表明Anillin的结合蛋白Septin也分布在迁移细胞的前导端，调控微丝骨架和细胞迁移。本课题将深入研究RhoG信号如何通过Anillin和Septin的传递，调控细胞前导端的微丝骨架稳定性促进细胞迁移。预期的成果将有助于更好的理解细胞迁移的机制，为相关疾病的发生及治疗提供新的思路。

在 Q 细胞长距离迁移和神经丝生长过程中，我们发现胞质分裂脚手架蛋白Anillin 定位在细胞前导端。为了绕过 Anillin 在胞质分裂过程中的功能， 我们利用了体细胞 CRISPR-Cas9 技术构建了 Anillin 条件性敲除突变体。我们证明了 Anillin通过稳定细胞前导端的微丝调控了细胞迁移和生长锥延伸。 生化实验揭示了Anillin 的微丝结合结构域能够通过拮抗 Cofilin 的微丝剪切活性稳定微丝。 我们进一步发现活化形式的 RhoG/MIG-2 直接结合并招募 Anillin 到细胞前导端。 我们的结果揭示了一条新的调控神经细胞迁移和神经丝生长的信号通路： Anillin 转导RhoG 信号到细胞微丝骨架调控神经细胞迁移和神经丝生长。