Wang Jinghan, Li Xiaofei, Zhang Zhibing, Wang Haibo, Li Jianfeng
Department of Otolaryngology-Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Ji'nan 250021, PR China.
Department of Otolaryngology-Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Ji'nan 250021, PR China; Shandong Provincial Key Laboratory of Otology, Ji'nan 250021, PR China.
Neurosci Lett. 2015 Apr 10;592:42-7. doi: 10.1016/j.neulet.2015.03.007. Epub 2015 Mar 4.
Sperm-associated antigen 6 (Spag6) gene, which encodes an axonemal protein (SPAG6), ubiquitously expresses in tissue and organs containing ciliated cells. The present work was to investigate whether SPAG6 expressed in cochlear hair cells and, if so, to explore the presumable correlations between prestin and SPAG6. The distribution of SPAG6 in organ of Corti and the morphological features of hair cells in basilar membrane were investigated by immunofluorescent staining. The amount of prestin in Spag6 mutant mice was measured by Western blotting and real-time PCR, respectively. Additionally, co-immunoprecipitation tests were performed to confirm the presumed interaction between prestin and SPAG6. We observed that SPAG6 expressed in the cuticular plate in outer hair cells (OHCs) and prestin in the lateral wall of OHCs that located along with SPAG6 at this site. In comparison to Spag6 +/+ mice, Spag6 -/- mice showed apparent morphological abnormity of OHCs and lower intensity of prestin fluorescence. The expression of prestin in Spag6 -/- mice reduced significantly at both protein and mRNA levels. Moreover, co-immunoprecipitation tests demonstrated the interaction between prestin and SPAG6. Taken together, these data indicate that SPAG6 is indispensible for the stability of OHCs by maintaining the normal expression of prestin, which implies that Spag6 gene is essential for mechanosensory function of OHCs.
精子相关抗原6（Spag6）基因编码一种轴丝蛋白（SPAG6），在含有纤毛细胞的组织和器官中普遍表达。本研究旨在探讨SPAG6是否在内耳毛细胞中表达，若表达，进一步探究其与prestin之间可能存在的相关性。通过免疫荧光染色研究了SPAG6在柯蒂氏器中的分布以及基底膜中毛细胞的形态特征。分别采用蛋白质免疫印迹法和实时定量聚合酶链反应检测Spag6基因敲除小鼠中prestin的含量。此外，进行了免疫共沉淀试验以证实prestin与SPAG6之间可能存在的相互作用。我们观察到SPAG6在外毛细胞（OHC）的表皮板中表达，而prestin在OHC侧壁中表达，且二者在该部位共定位。与Spag6 +/+小鼠相比，Spag6 -/-小鼠的OHC出现明显的形态异常，prestin荧光强度降低。Spag6 -/-小鼠中prestin在蛋白质和mRNA水平的表达均显著降低。此外，免疫共沉淀试验证实了prestin与SPAG6之间存在相互作用。综上所述，这些数据表明SPAG6通过维持prestin的正常表达对OHC的稳定性不可或缺，这意味着Spag6基因对OHC的机械感觉功能至关重要。
