肌动蛋白、α-辅肌动蛋白和血影蛋白与牛精子顶体后区和顶体区有特定关联。

Actin, alpha-actinin, and spectrin with specific associations with the postacrosomal and acrosomal domains of bovine spermatozoa.

作者信息

Yagi A, Paranko J

机构信息

Department of Anatomy, University of Turku, Finland.

出版信息

Anat Rec. 1995 Jan;241(1):77-87. doi: 10.1002/ar.1092410111.

DOI:10.1002/ar.1092410111

PMID:7879926

Abstract

BACKGROUND

Characteristic membrane changes in spermatozoa culminating in acrosome reaction and sperm-egg fusion, and suspected involvement of actin-containing cytoskeleton in membrane changes in general, prompted us to investigate subcellular distribution of actin and actin-binding proteins in bovine spermatozoa subjected to various extractions which sequentially denude the sperm investments.

METHODS

Spermatozoa were treated with either 1% SDS, 0.1% Triton X-100, 0.1% Hyamine, or 1 M MgCl2 or were sonicated. Immunostaining of actin, alpha-actinin, spectrin, and acrosin as well as electron microscopic analysis of extracted spermatozoa were carried out.

RESULTS

Extractions caused evagination of the acrosomal lamina which retained focal contacts with the inner acrosomal membrane. Extractions further revealed lateral prongs at the anterior border of the postacrosomal sheath. Labeling for alpha-actinin and spectrin was localized in the acrosin-positive acrosomal lamina, neck, and principal piece, the latter containing also relatively extraction-resistant oligomeric or polymerized actin. In the postacrosomal area, actin was accumulated in the extraction-resistant posterior ring structure and anteriorly at the sites apparently related to the lateral prongs. Notably, spectrin reactivity was enhanced by MgCl2 in head, neck, and principal piece, and sonication abolished cytoskeletal immuno-reactivity in the head.

CONCLUSIONS

Destabilization of membranes with selected extractions induces changes in the acrosomal lamina mimicking acrosomal vesicle formation. The lateral prongs and posterior ring structure, respectively, may serve as anterior and posterior anchors for the extraction-resistant post-acrosomal sheath. The lateral prongs may also be a merger zone for actin, alpha-actinin, and spectrin with important implication on sperm function. The latter two proteins may be involved in acrosomal vesicle formation. It is apparent that extractions have a significant effect on the detectability of sperm cytoskeletal elements.

摘要

背景

精子中特征性的膜变化最终导致顶体反应和精卵融合，并且一般认为含肌动蛋白的细胞骨架参与膜变化，这促使我们研究经各种提取方法处理后牛精子中肌动蛋白和肌动蛋白结合蛋白的亚细胞分布，这些提取方法会依次去除精子的外层结构。

方法

用1%十二烷基硫酸钠（SDS）、0.1% Triton X - 100、0.1%海明或1 M氯化镁处理精子，或对精子进行超声处理。对肌动蛋白、α - 辅肌动蛋白、血影蛋白和顶体蛋白酶进行免疫染色，并对提取后的精子进行电子显微镜分析。

结果

提取导致顶体片层外翻，其与顶体内膜保持局部接触。提取还进一步揭示了顶体后鞘前缘的侧向分支。α - 辅肌动蛋白和血影蛋白的标记定位于顶体蛋白酶阳性的顶体片层、颈部和主段，主段还含有相对抗提取的寡聚或聚合肌动蛋白。在顶体后区域，肌动蛋白积聚在抗提取的后环结构中，并在与侧向分支明显相关的部位向前积聚。值得注意的是，在头部、颈部和主段，氯化镁增强了血影蛋白的反应性，超声处理消除了头部细胞骨架的免疫反应性。

结论

用选定的提取方法使膜不稳定会诱导顶体片层发生变化，模拟顶体小泡形成。侧向分支和后环结构可能分别作为抗提取的顶体后鞘的前部和后部锚定结构。侧向分支也可能是肌动蛋白、α - 辅肌动蛋白和血影蛋白的融合区域，对精子功能具有重要意义。后两种蛋白质可能参与顶体小泡的形成。显然，提取对精子细胞骨架成分的可检测性有显著影响。