优雅蝈螽精子形成过程中F-肌动蛋白的动态变化

为阐明F-肌动蛋白在优雅蝈螽Gampsocleis gratiosa Brunner von Wattenwyl精子形成过程中的动态变化， 本研究利用微分干涉相衬技术和免疫荧光技术首次对优雅蝈螽精子形成过程中的F-肌动蛋白进行了细胞定位， 利用透射电镜技术从超微水平观察了优雅蝈螽精子顶体复合体的结构。结果显示： 精子形成早期， F-肌动蛋白富集于亚顶体区域， 形态由“球状”转变为“棒锥状”； 精子形成中期， F-肌动蛋白呈“倒Y型”分布于亚顶体区域和细胞核前端两侧； 精子形成后期， 亚顶体区域的F 肌动蛋白解聚消失， F-肌动蛋白呈“箭头状”， 仅分布于顶体复合体扩张的两翼中。F-肌动蛋白动态变化伴随着细胞核和精子头部的形态改变， F-肌动蛋白的动态装配在精子顶体复合体形态构建和细胞核的形变中起着重要的作用。本研究还发现未成熟的精子尾部有一些富含F-肌动蛋白的细胞质微滴， 与精子形成过程中多余细胞质和细胞器的外排有关。F-肌动蛋白的动态变化研究为进一步阐明细胞骨架蛋白在昆虫精子形成过程中的功能和作用机制奠定了基础。

Dynamics of F-actin during spermiogenesis in Gampsocleis gratiosa(Orthoptera:Tettigoniidae)

In order to understand the dynamics of F-actin during spermiogenesis in Gampsocleis gratiosa Brunner von Wattenwyl,we demonstrated the cellular localization of F-actin during spermiogenesis using differential interference contrast microscopy and immunofluorescence microscopy,and observed the ultrastructure of the acrosomal complex using transmission electron microscopy.The results show that F-actin is detected in the subacrosomal space at the early spermatid stage,with shape from globular to rod-cone-like.At the middle spermatid stage,F-actin is detected in the subacrosomal space and two sides of the nuclear forepart,and looks like an inverted Y.At the late spermatid stage,F-actin looks like an arrow only in the extension wings of the acrosomal complex.F-actin was depolymerized and disappeared,only being located at subacrosomal region at the middle spermatid stage.The results suggest that the dynamics of F-actin is associated with the shape of spermatid nucleus and sperm head,and the acrosomal architecture and nuclear morphogenesis are supported by a dynamic F-actin skeleton during spermiogenesis.In addition,we discovered some cytoplasm droplets in the tail of immature sperm.Immunocytochemical and ultrastructural analysis indicated that these cytoplasm droplets contain abundant F-actin.The F-actin of cytoplasm droplets can be involved in expelling redundant cytoplasm and organelles during spermiogenesis.This study on the dynamics of F-actin provides the foundation to clarify the function and mechanism of cytoskeletal proteins during insect spermiogenesis.