Implication of amphiphysin 1 and dynamin 2 in tubulobulbar complex formation and spermatid release
Implication of amphiphysin 1 and dynamin 2 in tubulobulbar complex formation and spermatid release
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DOI：
10.1247/csf.07024
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发表时间：
2007-01-01
影响因子：
1.5
通讯作者：
Takei, Kohji
中科院分区：
文献类型：
--
作者：
Kusumi, Norihiro;Watanabe, Masami;Takei, Kohji
管球复合体（TBCs）是由睾丸支持细胞质膜上形成的几个管状内陷组成。在大鼠和小鼠的生精阶段VII，TBC在与精子细胞接触的区域瞬时形成，并且这种TBC形成是精子细胞释放的先决条件。由于TBCs的特征结构表明，内吞作用的分子可能参与TBC的形成，我们在这里调查的本地化和生理作用的内吞蛋白，两栖蛋白1和发动蛋白2，在TBCs。我们证明了免疫荧光的内吞蛋白集中在TBCs，在那里他们与细胞骨架蛋白，如肌动蛋白和黏着斑蛋白共定位。免疫电镜观察发现，两种蛋白均定位于TBC膜上。接下来，我们对两性物理素1缺陷{Amph（-/-）}小鼠的睾丸进行了组织学检查。形态计量学分析显示，在Amph（-/-）中，TBCs的数量显著减少。在Amph（-/-）组中，VIII期曲细精管比例增加，IX期曲细精管比例降低。此外，在第八阶段曲细精管中未释放的精子细胞在Amph（-/-）中增加，表明精子细胞释放和随后从第八阶段到第九阶段的过渡在Amph（-/-）小鼠中延长。这些结果表明，两栖physin 1和dynamin 2参与TBC的形成和精子细胞的释放在支持细胞。
Tubulobulbar complexes (TBCs) are composed of several tubular invaginations formed at the plasma membrane of testicular Sertoli cells. TBCs are transiently formed at the contact region with spermatids at spermatogenic stage VII in rat and mouse, and such TBC formation is prerequisite for spermatid release. Since the characteristic structure of TBCs suggests that the molecules implicated in endocytosis could be involved in TBC formation, we here investigated the localization and physiological roles of endocytic proteins, amphiphysin 1 and dynamin 2, at TBCs. We demonstrated by immunofluorescence that the endocytic proteins were concentrated at TBCs, where they colocalized with cytoskeletal proteins, such as actin and vinculin. Immunoelectron microscopy disclosed that both amphiphysin 1 and dynamin 2 were localized on TBC membrane. Next, we histologically examined the testis from amphiphysin 1 deficient {Amph(-/-)} mice. Morphometric analysis revealed that the number of TBCs was significantly reduced in Amph(-/-). The ratio of stage VIII seminiferous tubules was increased, and the ratio of stage IX was conversely decreased in Amph(-/-). Moreover, unreleased spermatids in stage VIII seminiferous tubules were increased in Amph(-/-), indicating that spermatid release and the following transition from stage VIII to IX was prolonged in Amph(-/-) mice. These results suggest that amphiphysin 1 and dynamin 2 are involved in TBC formation and spermatid release at Sertoli cells.