Söllner Christian, Schwarz Heinz, Geisler Robert, Nicolson Teresa
Max Planck Institut für Entwicklungsbiologie, Spemannstrasse 35, 72076, Tübingen, Germany.
Dev Genes Evol. 2004 Dec;214(12):582-90. doi: 10.1007/s00427-004-0440-2. Epub 2004 Oct 5.
Otoliths in bony fishes and otoconia in mammals are composite crystals consisting of calcium carbonate and proteins. These biominerals are part of the gravity and linear acceleration detection system of the inner ear. Mutations in otopetrin 1 have been shown to result in lack of otoconia in tilted and mergulhador mutant mice. The molecular function of Otopetrin 1, a novel protein that contains ten predicted transmembrane domains, however, has remained elusive. Here we show that a mutation in the orthologous gene in zebrafish is responsible for the complete absence of otoliths in backstroke mutants. We examined the localization of Starmaker, a secreted protein that is highly abundant in otoliths in backstroke mutants. Starmaker protein accumulated within cells of the otic epithelium, indicating a possible defect in secretion. Our data suggest that Otopetrin 1 in zebrafish may be involved in the protein trafficking of components required for formation of biominerals in the ear.
硬骨鱼类的耳石和哺乳动物的耳石膜是由碳酸钙和蛋白质组成的复合晶体。这些生物矿物质是内耳重力和线性加速度检测系统的一部分。已证明otopetrin 1突变会导致倾斜和mergulhador突变小鼠缺乏耳石膜。然而，otopetrin 1是一种含有十个预测跨膜结构域的新型蛋白质，其分子功能仍然难以捉摸。在这里，我们表明斑马鱼直系同源基因中的突变是导致仰泳突变体完全没有耳石的原因。我们研究了Starmaker的定位，Starmaker是一种分泌蛋白，在仰泳突变体的耳石中高度丰富。Starmaker蛋白在内耳上皮细胞内积累，表明可能存在分泌缺陷。我们的数据表明，斑马鱼中的otopetrin 1可能参与了耳内生物矿物质形成所需成分的蛋白质运输。
