C11orf70 Mutations Disrupting the Intraflagellar Transport-Dependent Assembly of Multiple Axonemal Dyneins Cause Primary Ciliary Dyskinesia
C11orf70 Mutations Disrupting the Intraflagellar Transport-Dependent Assembly of Multiple Axonemal Dyneins Cause Primary Ciliary Dyskinesia
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DOI：
10.1016/j.ajhg.2018.03.024
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发表时间：
2018-05-03
影响因子：
9.8
通讯作者：
Mitchison, Hannah M.
中科院分区：
文献类型：
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作者：
Fassad, Mahmoud R.;Shoemark, Amelia;Mitchison, Hannah M.
原发性睫状体运动障碍（PCD）是一种遗传和表型异质性疾病，其特征是破坏性呼吸系统疾病和由于随机左右身体不对称导致的偏侧性异常。PCD主要是由影响运动纤毛的核心轴丝结构的突变引起的，运动纤毛对运动至关重要。当突变时引起PCD的基因包括编码纤毛动力蛋白马达组装所必需的蛋白质和将它们从其细胞质组装位点递送到轴丝中的主动运输过程的基因组。我们使用有针对性的下一代测序面板筛选了一组受影响的个体的致病突变，并确定了两个不相关的家族（三名受影响的儿童），其未表征的C11 orf 70基因（官方基因名称CFAP 300）突变。受影响的儿童共享一个一致的PCD表型，从早期的生活与偏侧缺陷和不动的呼吸纤毛显示内外动力蛋白臂（IDA+ODA）的组合损失。系统发育分析表明，C11 orf 70高度保守，在物种间分布，类似于参与轴丝动力蛋白的鞭毛内运输（IFT）依赖性组装的蛋白质。草履虫C11 orf 70 RNAi敲除导致纤毛IDA+ODA的联合损失，纤毛跳动和游泳速度降低。草履虫和衣原体中标记的C11 orf 70主要定位于细胞质中，少量定位于纤毛组分中。IFFT 139/TTC 21 B（IFT-A蛋白）和FLA 10（IFT驱动蛋白）耗竭实验表明其在纤毛内的转运是IFT依赖性的。在纤毛发生过程中，C11 orf 70以与IFT-B蛋白IFFT 46相似的分布在纤毛尖端积累。总之，C11 orf 70是动力蛋白臂组装所必需的，并且C11 orf 70突变导致纤毛运动缺陷和PCD。
Primary ciliary dyskinesia (PCD) is a genetically and phenotypically heterogeneous disorder characterized by destructive respiratory disease and laterality abnormalities due to randomized left-right body asymmetry. PCD is mostly caused by mutations affecting the core axoneme structure of motile cilia that is essential for movement. Genes that cause PCD when mutated include a group that encode proteins essential for the assembly of the ciliary dynein motors and the active transport process that delivers them from their cytoplasmic assembly site into the axoneme. We screened a cohort of affected individuals for disease-causing mutations using a targeted next generation sequencing panel and identified two unrelated families (three affected children) with mutations in the uncharacterized C11orf70 gene (official gene name CFAP300). The affected children share a consistent PCD phenotype from early life with laterality defects and immotile respiratory cilia displaying combined loss of inner and outer dynein arms (IDA+ODA). Phylogenetic analysis shows C11orf70 is highly conserved, distributed across species similarly to proteins involved in the intraflagellar transport (IFT)-dependant assembly of axonemal dyneins. Paramecium C11orf70 RNAi knockdown led to combined loss of ciliary IDA+ODA with reduced cilia beating and swim velocity. Tagged C11orf70 in Paramecium and Chlamydomonas localizes mainly in the cytoplasm with a small amount in the ciliary component. IFT139/TTC21B (IFT-A protein) and FLA10 (IFT kinesin) depletion experiments show that its transport within cilia is IFT dependent. During ciliogenesis, C11orf70 accumulates at the ciliary tips in a similar distribution to the IFT-B protein IFT46. In summary, C11orf70 is essential for assembly of dynein arms and Cl1orf70 mutations cause defective cilia motility and PCD.