Sumanas Saulius, Larson Jon D, Miller Bever Michele
Discovery Genomics, Inc., 614 McKinley PI. NE, Minneapolis, MN 55413, USA.
Dev Biol. 2003 Sep 15;261(2):443-55. doi: 10.1016/s0012-1606(03)00322-1.
Chaperone proteins are considered to be fairly ubiquitous proteins that promote the correct folding and assembly of multiple newly synthesized proteins. While performing an embryonic screen in zebrafish using morpholino phosphorodiamidate oligonucleotides (MPOs), we identified a role for an endoplasmic reticulum chaperone protein family member, zebrafish GP96. Knockdown of GP96 resulted in a specific otolith formation defect during early ear development. Otolith precursor particles did not adhere to the kinocilia of the tether cells in the GP96-MPO-injected embryos, aggregating instead into a single clump. Although otolith development was abnormal, the patterning of the ear and the differentiation of tether cells and macular sensory and support cells was not affected. We have isolated and sequenced the full open reading frame of zebrafish GP96 and characterized its expression pattern. GP96 is expressed both maternally and zygotically. GP96 RNA is localized within the floorplate, hatching gland, and in the cells of the otic placode and otic vesicle, consistent with the function of GP96 in ear development. We conclude that the GP96 chaperone protein is involved in the otolith formation during normal ear development. This is the first report of a specific function during organism development being attributed to a chaperone class molecule.
伴侣蛋白被认为是相当普遍存在的蛋白质，可促进多种新合成蛋白质的正确折叠和组装。在使用吗啉代磷酰胺寡核苷酸（MPO）对斑马鱼进行胚胎筛选时，我们确定了内质网伴侣蛋白家族成员斑马鱼GP96的作用。敲低GP96会导致早期耳发育过程中出现特定的耳石形成缺陷。在注射了GP96-MPO的胚胎中，耳石前体颗粒未附着在系链细胞的动纤毛上，而是聚集成一个团块。尽管耳石发育异常，但耳的模式以及系链细胞、黄斑感觉细胞和支持细胞的分化并未受到影响。我们已经分离并测序了斑马鱼GP96的完整开放阅读框，并对其表达模式进行了表征。GP96在母源和合子阶段均有表达。GP96 RNA定位于底板、孵化腺以及耳基板和耳泡的细胞中，这与GP96在耳发育中的功能一致。我们得出结论，GP96伴侣蛋白在正常耳发育过程中参与耳石形成。这是首次报道伴侣类分子在生物体发育过程中的特定功能。
