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.

毛细胞是位于内耳的专用传感器，可将声音，运动和重力转换为神经元冲动。在鸟类中，一些毛细胞含有富含铁的细胞器，即表皮小体，这与磁性有关。在这里，我们利用组织学，转录组学和层析成像方法来研究角质层的发展，以及角质层阳性毛细胞的分子和亚细胞结构。我们显示，在涉及囊泡融合和铁蛋白纳米颗粒成核过程中，孵化后该细胞器迅速形成。我们进一步报告参与内吞，胞外外来体和金属离子结合的转录本在角质层阳性毛细胞中差异表达。