Takehashi Masanori, Tanaka Seigo, Stedeford Todd, Banasik Marek, Tsukagoshi-Nagai Hiroe, Kinoshita Noriaki, Kawamata Toshio, Ueda Kunihiro
Laboratory of Molecular Clinical Chemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Gene Expr. 2004;11(5-6):271-8. doi: 10.3727/000000003783992270.
Septin 3 is a novel member of the septin subfamily of GTPase domain proteins. Human septin 3 was originally cloned during a screening of genes expressed in human teratocarcinoma cells induced to differentiate with retinoic acid. Alternative splicing of the septin 3 gene transcript produces two isoforms, A and B, in the human brain, though their regional expression and physiological function remain to be determined. The purpose of the present study was to identify the expression patterns of human septin 3 isoforms in normal human brain and a human neuroblastoma cell line, SH-SY5Y, after retinoic acid-induced differentiation. The expression and distribution patterns of septin 3 isoforms A and B were similar and resembled that of another septin, CDCrel-1. Septin 3A and 3B were expressed in normal human brain in a region-specific manner, with the highest level in the temporal cortex and hippocampus and the lowest level in the brainstem regions. Prominent immunoreactivity was observed diffusely in the neocortices in association with neuropils and punctate structures suggestive of synaptic junctions. Immunoprecipitation studies revealed that septin 3A, 3B, and CDCrel-1 form a complex in the frontal cortex of human brain. These findings, taken together, suggest that septin 3A and 3B, along with CDCrel-1, play some fundamental role(s) in synaptogenesis and neuronal development.
Septin 3是GTPase结构域蛋白的septin亚家族的一个新成员。人Septin 3最初是在筛选用视黄酸诱导分化的人畸胎瘤细胞中表达的基因时克隆出来的。Septin 3基因转录本的可变剪接在人脑中产生两种异构体，A和B，但其区域表达和生理功能仍有待确定。本研究的目的是确定视黄酸诱导分化后正常人脑和人神经母细胞瘤细胞系SH-SY5Y中人Septin 3异构体的表达模式。Septin 3异构体A和B的表达和分布模式相似，与另一种septin CDCrel-1的模式相似。Septin 3A和3B在正常人脑中以区域特异性方式表达，在颞叶皮质和海马中水平最高，在脑干区域水平最低。在新皮质中弥漫性地观察到明显的免疫反应，与神经纤维网和提示突触连接的点状结构有关。免疫沉淀研究表明，Septin 3A、3B和CDCrel-1在人脑额叶皮质中形成复合物。综上所述，这些发现表明Septin 3A和3B与CDCrel-1一起在突触形成和神经元发育中发挥一些基本作用。
