DNAI2 Mutations Cause Primary Ciliary Dyskinesia with Defects in the Outer Dynein Arm
DNAI2 Mutations Cause Primary Ciliary Dyskinesia with Defects in the Outer Dynein Arm
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DOI：
10.1016/j.ajhg.2008.10.001
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发表时间：
2008-11-07
影响因子：
9.8
通讯作者：
Omran, Heymut
中科院分区：
文献类型：
--
作者：
Loges, Niki Tomas;Olbrich, Heike;Omran, Heymut
原发性纤毛运动障碍（PCD）是一种遗传异质性疾病，其特征是慢性破坏性气道疾病和随机化的左/右身体不对称。男性通常由于精子尾部功能受损而降低生育能力。复杂的PCD表型是由于气道纤毛和胚胎结的功能障碍以及结构相关的能动精子鞭毛。这与潜在的超微结构缺陷有关，通常涉及产生纤毛和鞭毛运动的外动力蛋白臂（ODA）复合物。应用位置和功能候选基因方法，我们在一个PCD和ODA缺陷家族的四个个体中鉴定了纯合的功能丧失DNAI 2突变（IVS 11 + 1G > A）。对105个不相关PCD家族的进一步突变筛选检测到两种不同的纯合突变，包括无义突变（c.787C > T）和剪接突变（IVS 3 -31' > G），导致框外转录物。ODA中间链DNAI 2的蛋白质表达分析显示在整个呼吸纤毛中亚定位。电子显微镜显示，这些患者的突变呼吸道细胞缺乏DNAI 2蛋白表达，并表现出ODA缺陷。高分辨率免疫荧光成像显示，所有DNAI 2突变体纤毛轴丝中不存在ODA重链DNAH 5和DNAH 9。此外，我们证明了完全或远端缺乏DNAI 2从纤毛轴丝在呼吸细胞的ODA链DNAH 5和DNAI 1，分别编码基因突变的患者。因此，DNAI 2和DNAH 5突变影响近端和远端ODA复合物的组装，而DNAI 1突变主要破坏近端ODA复合物的组装。
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder characterized by chronic destructive airway disease and randomization of left/right body asymmetry. Males often have reduced fertility due to impaired sperm tail function. The complex PCD phenotype results from dysfunction of cilia of the airways and the embryonic node and the structurally related motile sperm flagella. This is associated with underlying ultrastructural defects that frequently involve the Outer dynein arm (ODA) complexes that generate cilia and flagella movement. Applying a positional and functional candidate-gene approach, we identified homozygous loss-of-function DNAI2 mutations (IVS11 + 1G > A) in four individuals from a family with PCD and ODA defects. Further mutational screening of 105 unrelated PCD families detected two distinct homozygous mutations, including a nonsense (c.787C > T) and a splicing mutation (IVS3-31' > G) resulting in out-of-frame transcripts. Analysis of protein expression of the ODA intermediate chain DNAI2 showed sublocalization throughout respiratory cilia. Electron microscopy showed that mutant respiratory cells from these patients lacked DNAI2 protein expression and exhibited ODA defects. High-resolution immunofluorescence imaging demonstrated absence of the ODA heavy chains DNAH5 and DNAH9 from all DNAI2 mutant ciliary axonemes. In addition, we demonstrated complete or distal absence of DNAI2 from ciliary axonemes in respiratory cells of patients with mutations in genes encoding the ODA chains DNAH5 and DNAI1, respectively. Thus, DNAI2 and DNAH5 mutations affect assembly of proximal anddistal ODA complexes, whereas DNAI1 mutations mainly disrupt assembly of proximal ODA complexes.