Wang Xiao-Hui, Streeter Michele, Liu Ying-Peng, Zhao Hong-Bo
Department of Surgery-Otolaryngology, University of Kentucky Medical Center, Lexington, Kentucky 40536, USA.
J Comp Neurol. 2009 Jan 20;512(3):336-46. doi: 10.1002/cne.21898.
The gap junction in vertebrates is encoded by the connexin gene family. Recently, a new gene family termed pannexin (Panx) has been identified in vertebrates and found to encode gap junctional proteins as well. To date, three pannexin isoforms (Panx1, 2, and 3) have been cloned from mouse and human genomes. In this study, expression of pannexins in the mouse and rat cochlea was investigated. Polymerase chain reaction and Western blot analysis showed that all three pannexin isoforms were expressed in the cochlea. Immunofluorescent staining showed that Panx1 expression was extensive. In the organ of Corti, Panx1 labeling was found in supporting cells, including pillar cells, Hensen cells, Claudius cells, and Boettcher cells. Both surface plaque-like punctate labeling and diffuse-cytoplasmic labeling were visible. However, the labeling was weak and rare in Deiters cells. No labeling was found in the hair cells. Intense labeling for Panx1 was also observed in the interdental cells in the spiral limbus, the inner and outer sulcus cells, and the type II fibrocytes in the spiral prominence and central region in the cochlear lateral wall. In addition, Panx1 labeling was detectable in Reissner's membrane and strial blood vessel cells. Panx2 labeling was restricted to the basal cells in the stria vascularis and was also detectable in the spiral ganglion neurons. However, no overlapping labeling for Panx1 and Panx2 was observed. Finally, Panx3 labeling was exclusively observed in the cochlear bone. Thus, Panx1, 2, and 3 are abundantly expressed in the mammalian cochlea and demonstrate distinct cellular distributions. Like connexins, they may play an important role in hearing.
脊椎动物中的间隙连接由连接蛋白基因家族编码。最近，在脊椎动物中发现了一个新的基因家族，称为泛连接蛋白（Panx），并且发现它也编码间隙连接蛋白。迄今为止，已从小鼠和人类基因组中克隆出三种泛连接蛋白异构体（Panx1、2和3）。在本研究中，对小鼠和大鼠耳蜗中泛连接蛋白的表达进行了研究。聚合酶链反应和蛋白质印迹分析表明，所有三种泛连接蛋白异构体均在耳蜗中表达。免疫荧光染色显示Panx1表达广泛。在柯蒂氏器中，在支持细胞中发现了Panx1标记，包括柱细胞、亨森细胞、克劳迪乌斯细胞和博伊特彻细胞。表面斑块状点状标记和弥漫性细胞质标记均可见。然而，在代特细胞中的标记较弱且稀少。在毛细胞中未发现标记。在螺旋缘的齿间细胞、内沟和外沟细胞以及耳蜗外侧壁螺旋隆起和中央区域的II型纤维细胞中也观察到了强烈的Panx1标记。此外，在Reissner膜和血管纹血管细胞中可检测到Panx1标记。Panx2标记仅限于血管纹中的基底细胞，并且在螺旋神经节神经元中也可检测到。然而，未观察到Panx1和Panx2的重叠标记。最后，仅在耳蜗骨中观察到Panx3标记。因此，Panx1、2和3在哺乳动物耳蜗中大量表达，并表现出不同的细胞分布。与连接蛋白一样，它们可能在听力中起重要作用。
