The semicircular canals in the inner ear sense angular acceleration. In zebrafish, the semicircular canals develop from epithelial projections that grow toward each other and fuse to form pillars. The growth of the epithelial projections is driven by the production and secretion of extracellular matrix components by the epithelium. The conserved oligomeric Golgi 4 protein, Cog4, functions in retrograde vesicle transport within the Golgi and mutations can lead to sensory neural hearing loss. In zebrafish cog4 mutants, the inner ear is smaller and the number of hair cells is reduced. Here, we show that formation of the pillars is delayed and that secretion of extracellular matrix components (ECM) is impaired in cog4-/- mutants. These results show that Cog4 is required for secretion of ECM molecules essential to drive the growth of the epithelial projections and thus regulates morphogenesis of the semicircular canals.

中文翻译：

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Cog4 是发育中的半规管中上皮的突出和延伸所必需的

内耳的半规管感知角加速度。在斑马鱼中，半规管由上皮突起形成，这些突起相互靠近并融合形成柱子。上皮突起的生长是由上皮细胞外基质成分的产生和分泌驱动的。保守的寡聚高尔基体 4 蛋白 Cog4 在高尔基体内的逆行囊泡运输中起作用，并且突变可导致感觉神经性听力损失。在斑马鱼 cog4 突变体中，内耳更小，毛细胞数量减少。在这里，我们显示柱子的形成被延迟并且细胞外基质成分 (ECM) 的分泌在 cog4-/- 突变体中受损。