果蝇纤毛细胞中特化细胞骨架的结构及其建立的分子基础解析

纤毛是具有重要生理功能的亚细胞结构，在细胞运动及信号转导过程中发挥着重要的作用，它的结构及其发生机制是细胞生物学的基本问题之一。果蝇的感觉神经元中存在初级纤毛，而精细胞中存在动纤毛，因此成为研究多细胞生物中纤毛结构、功能和发育的重要模型。果蝇的I型感觉神经元的树突远端有基于初级纤毛的非中心体微管三维阵列，而精细胞中“9+2”轴丝中的一对中央微管也是非中心体微管。这两类由非中心体微管组成的细胞骨架的三维结构以及它们发生的分子机制都是未知的。在本课题中，申请人计划以上述两种纤毛细胞作为模型，应用原位电子断层成像技术解析两种非中心体微管骨架的在体高分辨三维结构并应用活细胞成像技术实时记录它们的发育过程。同时，申请人计划综合应用包括果蝇遗传学和体外生物化学分析等技术方法对发育过程的机制展开探索，深入解析重要的候选分子（例如已经鉴定出来的Katanin和Patronin家族成员）的工作机理。

Cilia are microtubule-based subcellular entities that play important roles in cell motility and signal transduction. The assembly and maintenance of ciliary structures are fundamental questions in cell biology. Drosophila melanogaster is a multicellular model organism to study the structure and function of primary cilia (ciliated sensory cell) and motile cilia (sperm cell). The distal end of the dendrite in fly type I sensory neurons is specialized into a modified cilium that contains a three-dimensional array of non-centrosomal microtubules. Correspondingly, fly sperm cells contain the central microtubule pair, which are also non-centrosomal microtubules. Despite efforts in understanding cilium assembly, the mechanism underlying the formation of these non-centrosomal microtubule-based cytoskeleton remains elusive. In the present study, the applicant plans to resolve the in situ 3D structure of the abovementioned cytoskeletons and apply live-cell imaging to record their development in real-time. The applicant also plan to combine fly genetics, in vitro biochemistry and other methods to dissect the molecular mechanism of how these cytoskeletons are constructed, including the functional contributions and working mechanisms of important candidate molecules (e.g. katanin and patronin family members). This study will provide insights into the assembly of ciliary structures and open the gate to dissect the molecular mechanism.