CBE1 Is a Manchette- and Mitochondria-Associated Protein With a Potential Role in Somatic Cell Proliferation
CBE1 Is a Manchette- and Mitochondria-Associated Protein With a Potential Role in Somatic Cell Proliferation
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DOI：
10.1210/en.2019-00468
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发表时间：
2019-11-01
期刊：
影响因子：
4.8
通讯作者：
O'Bryan, Moira K.
中科院分区：
文献类型：
--
作者：
Pleuger, Christiane;Lehti, Mari S.;O'Bryan, Moira K.
纤毛支气管上皮 1 (CBE1) 是一种微管相关蛋白，在精子发生过程中定位于 manchette 和发育中的鞭毛，与人类精子成熟停滞相关。据推测，CBE1 在微管介导的运输机制和精子尾部形成中发挥作用。为了检验这一假设，我们分析了精子发生过程中的 Cbe1 表达和定位，以及作为纤毛发生模型的小鼠内髓集合管 3 (IMCD3) 细胞中的 Cbe1 表达和定位。此外，我们生成并分析了 Cbe1 突变小鼠品系的生育力。含有 Cbe1 长形式纯合缺失的小鼠的出生频率低于孟德尔遗传预测的频率；然而，成年雄性小鼠具有生育能力。对 Cbe1 基因的深入分析揭示了替代转录物变体，这些变体不受外显子 2 突变的影响。为了评估短变异是否补偿长变异的损失，在 IMCD3 细胞中单独突变外显子 2 和 4（影响所有变异），并分析对细胞增殖和纤毛发生的影响。在野生型 IMCD3 细胞中，两种变体在纤毛组装过程中均上调。 CBE1蛋白不是纤毛的结构成分；相反，CBE1 定位于线粒体和分裂中的 IMCD3 细胞的收缩环。尽管携带长变异体突变的 IMCD3 细胞没有表现出表型改变，但外显子 4 的突变导致增殖率显着降低。这项研究表明，CBE1 的长亚型对于男性生育能力并不是必需的。然而，数据表明 CBE1 与精子尾巴内运输和中段形成有关。
Ciliated bronchial epithelium 1 (CBE1) is a microtubule-associated protein localized to the manchette and developing flagellum during spermiogenesis and is associated with sperm maturation arrest in humans. It was hypothesized that CBE1 functions in microtubule-mediated transport mechanisms and sperm tail formation. To test this hypothesis, we analyzed Cbe1 expression and localization during spermiogenesis, and in mouse inner medullary collecting duct-3 (IMCD3) cells as a model of ciliogenesis. Furthermore, we generated and analyzed the fertility of a Cbe1 mutant mouse line. Mice containing a homozygous deletion in the long forms of Cbe1 were born at a lower frequency than predicted by Mendelian inheritance; however, adult male mice were fertile. An in-depth analysis of the Cbe1 gene revealed alternative transcript variants, which were not affected by the exon 2 mutation. To assess whether short variants compensate for the loss of long variants, exons 2 and 4 (which affect all variants) were individually mutated in IMCD3 cells and the effects on cell proliferation and ciliogenesis were analyzed. In wild-type IMCD3 cells, both variants were upregulated during cilia assembly. CBE1 protein was not a structural component of cilia; rather, CBE1 localized to the mitochondria and the contractile ring of dividing IMCD3 cells. Although IMCD3 cells carrying the mutation in long variants showed no phenotypic alterations, the mutation in exon 4 resulted in a significantly decreased proliferation rate. This study reveals that long isoforms of CBE1 are not essential for male fertility. Data, however, suggest that CBE1 is associated with intramanchette transport and midpiece formation of the sperm tail.