Fascin-2（Fscn2）是肌动蛋白交联蛋白，fscn2基因突变（R109H）与DBA小鼠的听力减退有关。为深入研究该基因的功能，我们用TALEN 技术敲除B6小鼠的fscn2 基因，小鼠呈早发性渐进性的听力减退。预测Fscn2-TALEN蛋白片段交联肌动蛋白的功能缺失所致的纤毛结构损害及其在内质网的转运障碍引起的毛细胞凋亡在小鼠的听力减退中起重要作用。拟动态电镜观察fscn2敲除小鼠毛细胞纤毛束的超微结构；体外表达Fscn2蛋白和Fscn2-TALEN片段，速度共沉淀确定其与肌动蛋白的结合与交联作用，免疫荧光共定位分析肌动蛋白在fscn2敲除小鼠静纤毛分布的变化；在耳蜗HEI-OC1细胞表达Flag 标记的Fscn2、Fscn2 R109H和Fscn2-TELEN片段，观察变异蛋白的异常转运、内质网应激和特定凋亡通路的活化，在体验证相关通路并干预。为增龄性聋的防治提供新途径或新靶点。

Fascin-2(Fscn2) is an actin cross-linker protein. Mutation in fscn2 gene is related to hearing loss in DBA/2J mice. To fully understand the function of fscn2 gene, we established a mouse model (fscn2-/-) of age-related hearing loss on the B6 background by TALEN technique. We hypothesize that abnormal in structures of filament bundles in hair cells and in transportation of Fscn2-TALEN protein fragment in endoplasmic reticulum is responsible for the hearing loss. Therefore, in this study, we plan, firstly, to identify the features of ultrastructures of the actin filaments by scanning electron microscopy (SEM). Secondly, we will express the Fscn2 and Fscn2-TALEN fragment in vitro, and test their actin binding and bounding ability. We will also localize the positions of the actin isorforms in the filament by immunofluorescent microscopy. Thirdly, we will express the Flag-labeled Fscn2, Fscn2（R109H）and Fscn2-TALEN fragment in HEI-OC1 cells, observe the aggregation of Fscn2-TALEN fragment in endoplasmic reticulum, detect the markers of endoplasmic reticulum stress (ERS) and determine the activation of apoptosis related pathways trigged by ERS. The markers of ERS and apoptosis will be confirmed in the fscn2 mutant mice. The results in this project will provide new ways or targets for prevention and treatment of age-related hearing loss in human.