Hair cells are specialized sensors located in the inner ear that enable the transduction of sound, motion, and gravity into neuronal impulses. In birds some hair cells contain an iron-rich organelle, the cuticulosome, that has been implicated in the magnetic sense. Here, we exploit histological, transcriptomic, and tomographic methods to investigate the development of cuticulosomes, as well as the molecular and subcellular architecture of cuticulosome positive hair cells. We show that this organelle forms rapidly after hatching in a process that involves vesicle fusion and nucleation of ferritin nanoparticles. We further report that transcripts involved in endocytosis, extracellular exosomes, and metal ion binding are differentially expressed in cuticulosome positive hair cells. These data suggest that the cuticulosome and the associated molecular machinery regulate the concentration of iron within the labyrinth of the inner ear, which might indirectly tune a magnetic sensor that relies on electromagnetic induction.

中文翻译：

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鸽毛细胞的亚细胞分析表明囊泡运输参与角质体的形成和维持


毛细胞是位于内耳的特殊传感器，能够将声音、运动和重力转化为神经元脉冲。在鸟类中，一些毛细胞含有富含铁的细胞器，即角质体，它与磁感有关。在这里，我们利用组织学、转录组学和断层扫描方法来研究角质体的发育，以及角质体阳性毛细胞的分子和亚细胞结构。我们表明，这种细胞器在孵化后迅速形成，其过程涉及囊泡融合和铁蛋白纳米粒子的成核。我们进一步报道，参与内吞作用、细胞外外泌体和金属离子结合的转录物在角质体阳性毛细胞中差异表达。这些数据表明，角质体和相关的分子机制调节内耳迷路内铁的浓度，这可能间接调节依赖电磁感应的磁传感器。