Department of Neurosciences, Institute for Genomic Medicine, Howard Hughes Medical Institute, University of California San Diego, La Jolla, California 92093, USA.
Nature. 2010 Apr 15;464(7291):1048-51. doi: 10.1038/nature08895.
Primary cilia are evolutionarily conserved cellular organelles that organize diverse signalling pathways. Defects in the formation or function of primary cilia are associated with a spectrum of human diseases and developmental abnormalities. Genetic screens in model organisms have discovered core machineries of cilium assembly and maintenance. However, regulatory molecules that coordinate the biogenesis of primary cilia with other cellular processes, including cytoskeletal organization, vesicle trafficking and cell-cell adhesion, remain to be identified. Here we report the results of a functional genomic screen using RNA interference (RNAi) to identify human genes involved in ciliogenesis control. The screen identified 36 positive and 13 negative ciliogenesis modulators, which include molecules involved in actin dynamics and vesicle trafficking. Further investigation demonstrated that blocking actin assembly facilitates ciliogenesis by stabilizing the pericentrosomal preciliary compartment (PPC), a previously uncharacterized compact vesiculotubular structure storing transmembrane proteins destined for cilia during the early phase of ciliogenesis. The PPC was labelled by recycling endosome markers. Moreover, knockdown of modulators that are involved in the endocytic recycling pathway affected the formation of the PPC as well as ciliogenesis. Our results uncover a critical regulatory step that couples actin dynamics and endocytic recycling with ciliogenesis, and also provides potential target molecules for future study.
原发性纤毛是进化上保守的细胞器官，可组织多种信号通路。原发性纤毛的形成或功能缺陷与一系列人类疾病和发育异常有关。模式生物中的遗传筛选已经发现了纤毛组装和维持的核心机制。然而，与其他细胞过程（包括细胞骨架组织、囊泡运输和细胞间黏附）协调原发性纤毛生物发生的调节分子仍有待确定。在这里，我们报告了使用 RNA 干扰 (RNAi) 进行功能基因组筛选以鉴定参与纤毛发生控制的人类基因的结果。该筛选鉴定出 36 个阳性和 13 个阴性纤毛发生调节剂，其中包括参与肌动蛋白动态和囊泡运输的分子。进一步的研究表明，通过稳定中心体周围的前纤毛室（PPC），阻止肌动蛋白组装有利于纤毛发生，PPC 是一个以前未被描述的紧凑的囊泡管状结构，在纤毛发生的早期阶段储存跨膜蛋白。PPC 被回收内体标记物标记。此外，参与内吞体再循环途径的调节剂的敲低会影响 PPC 的形成以及纤毛发生。我们的研究结果揭示了一个关键的调节步骤，该步骤将肌动蛋白动力学和内吞体再循环与纤毛发生联系起来，并为未来的研究提供了潜在的靶标分子。
