Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK EH8 9XD, UK.
Edinburgh Cancer Research UK Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, EH4 2XU, UK.
Biol Open. 2021 Oct 15;10(10). doi: 10.1242/bio.058812. Epub 2021 Oct 28.
Ciliary motility is powered by a suite of highly conserved axoneme-specific dynein motor complexes. In humans, the impairment of these motors through mutation results in the disease primary ciliary dyskinesia (PCD). Studies in Drosophila have helped to validate several PCD genes whose products are required for cytoplasmic pre-assembly of axonemal dynein motors. Here we report the characterisation of the Drosophila orthologue of the less-known assembly factor DNAAF3. This gene, CG17669 (Dnaaf3), is expressed exclusively in developing mechanosensory chordotonal (Ch) neurons and the cells that generate spermatozoa, The only two Drosophila cell types bearing cilia/flagella containing dynein motors. Mutation of Dnaaf3 results in larvae that are deaf and adults that are uncoordinated, indicating defective Ch neuron function. The mutant Ch neuron cilia of the antenna specifically lack dynein arms, while Ca imaging in larvae reveals a complete loss of Ch neuron response to vibration stimulus, confirming that mechanotransduction relies on ciliary dynein motors. Mutant males are infertile with immotile sperm whose flagella lack dynein arms and show axoneme disruption. Analysis of proteomic changes suggest a reduction in heavy chains of all axonemal dynein forms, consistent with an impairment of dynein pre-assembly.
纤毛运动由一套高度保守的轴丝特异性动力蛋白复合物提供动力。在人类中，这些马达通过突变而受损会导致原发性纤毛运动障碍（PCD）。果蝇的研究有助于验证几种 PCD 基因，其产物是轴丝动力蛋白预组装所必需的。在这里，我们报告了不太知名的组装因子 DNAAF3 的果蝇同源物的特征。该基因 CG17669（Dnaaf3）仅在发育中的机械感觉弦状（Ch）神经元和产生精子的细胞中表达，这是唯一两种带有纤毛/鞭毛的果蝇细胞类型，其中包含动力蛋白。Dnaaf3 的突变导致幼虫失聪，成虫不协调，表明 Ch 神经元功能缺陷。突变的触角 Ch 神经元纤毛特别缺乏动力蛋白臂，而幼虫中的 Ca 成像显示 Ch 神经元对振动刺激的反应完全丧失，这证实了机械转导依赖于纤毛动力蛋白。突变体雄性不育，精子不能运动，其鞭毛缺乏动力蛋白臂，并显示轴丝破坏。蛋白质组变化的分析表明所有轴丝动力蛋白形式的重链减少，这与动力蛋白预组装受损一致。
