斑马鱼纤毛动力蛋白Kinesin2的功能研究

Defects in cilia formation can cause many human genetic disorders, so-called ciliopathies. How are cilia formed and how are proteins transported inside the cilia are two key questions remain to be answered. Kinesin-2 family proteins are the only known plus-end motor proteins that function during vertebrate ciliogenesis. Till now, all we know about the mechanism of these proteins are based on those studies done in invertebrate, including c. elegans and chlamydomonas. On the contrary, little is known about their mechanism in ciliogenesis in vertebrate animals. Here, we are going to study the function of this protein family using one of the popular vertebrate models: zebrafish, which has many advantages including fast development and body transparency. We plan to investigate the function of two members of this family: Kif3c and Kif3a, using genetic screen and transgenic approach.Our goals include: (1) Determine the function of Kif3a during zebrafish cilia formation ; (2) Screen and identify zebrafish kif3c mutant and uncover its function; (3) Comebine our previously results on kif3b and kif17 studies, build the final schematic model of Kinesin 2 family during vertebrate cilia formation . Through these studies, it will not only help us to understand the function of vertebrate Kinesin 2 proteins, but also benefit the study of the fundamental molecular basis of human ciliopathy diseases.

纤毛发育缺陷可导致多种人类遗传疾病，对其形成及内部蛋白运输机制的研究是当前的一个热点。Kinesin2蛋白家族是纤毛内的主要运输蛋白，目前，对其分子机理的认识主要来自于低等模型生物（衣藻、线虫），而对其在脊椎动物纤毛内的作用机理知之甚少。本立项拟以斑马鱼为模式生物，利用其胚胎透明,快速发育等优点,结合突变体筛选及转基因技术,综合研究Kinesin2蛋白家族成员Kif3a与Kif3c在脊椎动物纤毛发生中的功能。预期目标包括：（1）鉴定出斑马鱼kif3a突变体，并阐明Kif3a在纤毛发生中的功能（2）筛选鉴定出Kif3c相互作用的蛋白，并阐明其在纤毛内的运输机制（3）绘制出Kinesin2家族成员在脊椎动物不同纤毛内的功能模式图。通过本项研究的开展，将加深对Kinesin2蛋白在脊椎动物不同纤毛内功能的认识，为进一步研究人类纤毛遗传病的器官特异性提供理论依据。

本项目以斑马鱼为模式生物，研究了Kinesin-2家族蛋白成员在纤毛发生及感光细胞凋亡过程中的功能。项目取得的主要结果包括：1）通过筛选kif3a，kif3c等基因突变体，发现Kif3a是斑马鱼胚胎纤毛发生必需马达蛋白，而Kif3c非必需马达蛋白；2）首次在体内证明Kif3c与Kif3b功能上存在冗余，且该冗余性是导致Kif3b体内部分纤毛仍然存在的原因；3）发现Kif3a及Kif3b的功能缺陷可导致胚胎感光细胞的迅速凋亡，并证明视蛋白的过度累积是导致其凋亡的主要原因；4）发现视蛋白的C末端在其所介导的感光细胞凋亡过程中的重要作用。上述发现系统的阐述了Kinesin-2家族成员在纤毛发生及感光细胞发育过程中的重要功能，并首次发现视蛋白C末端在感光细胞凋亡过程中的重要功能，为人类感光细胞凋亡所导致的眼睛视网膜色素变性遗传疾病的研究提供了重要参考依据。