Drosophila Hook-Related Protein (Girdin) Is Essential for Sensory Dendrite Formation
Drosophila Hook-Related Protein (Girdin) Is Essential for Sensory Dendrite Formation
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DOI：
10.1534/genetics.115.178954
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发表时间：
2015-08-01
期刊：
影响因子：
3.3
通讯作者：
Avidor-Reiss, Tomer
中科院分区：
文献类型：
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作者：
Ha, Andrew;Polyanovsky, Andrey;Avidor-Reiss, Tomer
感觉神经元的树突被支持细胞包围，并由两个专门的隔室组成：内段和感觉纤毛。感觉树突是如何形成和维持的还不清楚。钩相关蛋白（HkRP）如Girdin，DAPLE和Gipie是肌动蛋白结合蛋白，涉及肌动蛋白组织和细胞运动。在这里，我们表明，果蝇的钩相关蛋白家族，Girdin的单一成员，是必不可少的感觉树突的形成和功能。在筛选无机械感觉功能的果蝇突变体时，鉴定了girdin的突变。生理学，形态学和超微结构的研究表明，支配外部感觉器官（刚毛）的机械感觉神经元最初形成一个纤毛树突后不久退化，其次是他们的细胞体的集群。重要的是，我们观察到，Girdin是短暂表达的树突形态发生在三个以前身份不明的肌动蛋白为基础的结构周围的内段尖端和感觉纤毛。这些肌动蛋白结构在girdin突变体中大部分缺失。在其他感觉器官中也观察到纤毛缺陷，例如介导嗅觉和味觉的感觉器官，这表明Girdin在果蝇中形成感觉树突中具有普遍作用。这表明Girdin暂时在感觉器官内发挥作用，并且这种功能对于通过肌动蛋白结构形成感觉树突是必不可少的。
The dendrite of the sensory neuron is surrounded by support cells and is composed of two specialized compartments: the inner segment and the sensory cilium. How the sensory dendrite is formed and maintained is not well understood. Hook-related proteins (HkRP) like Girdin, DAPLE, and Gipie are actin-binding proteins, implicated in actin organization and in cell motility. Here, we show that the Drosophila melanogaster single member of the Hook-related protein family, Girdin, is essential for sensory dendrite formation and function. Mutations in girdin were identified during a screen for fly mutants with no mechanosensory function. Physiological, morphological, and ultrastructural studies of girdin mutant flies indicate that the mechanosensory neurons innervating external sensory organs (bristles) initially form a ciliated dendrite that degenerates shortly after, followed by the clustering of their cell bodies. Importantly, we observed that Girdin is expressed transiently during dendrite morphogenesis in three previously unidentified actin-based structures surrounding the inner segment tip and the sensory cilium. These actin structures are largely missing in girdin mutant. Defects in cilia are observed in other sensory organs such as those mediating olfaction and taste, suggesting that Girdin has a general role in forming sensory dendrites in Drosophila. These suggest that Girdin functions temporarily within the sensory organ and that this function is essential for the formation of the sensory dendrites via actin structures.