Myosin XVIIIa(Myo18a)是唯一含有PDZ结构域的非常规肌球蛋白，它在各种动物发育过程中的表达图式和作用还不清楚。我们发现斑马鱼的两个Myo18a同源基因(Myo18aa和Myo18ab)主要表达在体节的肌细胞中，初步的功能研究显示抑制它们的功能导致与肌肉萎缩症相似的表型。在此基础上，我们将详细确定这两个基因在斑马鱼发育过程中的表达图式。通过在斑马鱼和小鼠中基因敲除等手段，我们将深入研究这两个基因在肌细胞的形成，结构的稳定性、完整性和功能中的作用，分析它们与肌肉萎缩症相关蛋白的关系。我们还将采取酵母双杂交和免疫共沉淀的方法鉴别与Myo18a相作用的蛋白，并开展对它们的功能研究，确定它们与Myo18a在肌细胞发育过程中相互作用关系。这一研究结果将有助于阐明Myo18a在肌细胞发育和功能中的作用机理，为鉴别参与肌肉萎缩症的新的重要蛋白和将来的药物筛选提供理论基础。

Myosin XVIIIa(Myo18a) is the only unconventional myosin with a PDZ domain, its expression and function in vertebrate embryos is not investigated. We found that the two zebrafish homologues of myo18a (myo18aa and myo18ab) are strongly expressed in muscle cells, knockdown of these two genes results in lesions in muscle cells which are much similar as muscular dystrophy. We plan to first describe in detail the expression pattern of myo18aa and myo18ab genes in zebrafish embryo. Functional analyses will be performed using knockdown or knockout approaches in zebrafish to investigate their implication in muscle cell formation, stability and integrity, as well as their relationship with muscluar dystrophy-related proteins. In addition, we will identify the partners of myo18a using yeast two hybrid and co-immunoprecipitation approaches. The function of these myo18a-interacting proteins in embryonic muscle cells will be analyzed in order to understand how myo18a protein complex regulates muscle function. Furthermore, conditional knockout of myo18a in mouse muscle cells will be performed to demonstrate how myo18a function is required for muscle stability and integrity during mammalian development. These analyses should provide a mechanistic insight into the implication of myo18a protein complex in the regulation of muscle function. They should also help to identify other molecules involved in muscular dystrophies, and thus lead to a better understanding of the pathogenesis of these diseases and development of future therapies.