Fouquet J P, Kann M L, Courtens J L, Plöen L
Laboratoire d'Histologie, UFR Biomédicale, Paris, France.
Gamete Res. 1989 Nov;24(3):281-90. doi: 10.1002/mrd.1120240305.
Immunogold procedures for actin detection were used in combination with experimental cryptorchidism in the rabbit as a model to shed more light on the function of subacrosomal actin during spermiogenesis. In the normal testis, actin was localized in the perinuclear substance (PNS) from round spermatid onward but it was not detected in late spermatids. Actin labeling in each type of spermatid was essentially unmodified after 24 hr of cryptorchidism. However, among relevant immediate and delayed effects, discontinuous acrosomes overlying a continuous PNS with normal actin labeling were noted. Nuclear invaginations were seen in combination with subacrosomal dilatations; at this site actin labeling was found only in the PNS closely apposed to the nuclear envelope. In subacrosomal areas lacking PNS, actin labeling also was lacking. These results suggest that the subacrosomal actin (F-actin) is a component of the PNS that is tightly bound to the nuclear envelope rather than the overlying inner acrosomal membrane. Therefore, a function for the subacrosomal actin either in anchoring the acrosome to the nucleus or in capping the inner acrosomal membrane appears unlikely. The data rather suggest a capping function for the nuclear membrane during spermiogenesis.
采用免疫金法检测肌动蛋白，并结合兔实验性隐睾模型，以更深入了解精子发生过程中亚顶体肌动蛋白的功能。在正常睾丸中，从圆形精子细胞开始，肌动蛋白定位于核周物质（PNS）中，但在晚期精子细胞中未检测到。隐睾24小时后，每种类型精子细胞中的肌动蛋白标记基本未改变。然而，在相关的即时和延迟效应中，观察到覆盖在具有正常肌动蛋白标记的连续PNS上的不连续顶体。可见核内陷与亚顶体扩张同时出现；在此部位，仅在紧邻核膜的PNS中发现肌动蛋白标记。在缺乏PNS的亚顶体区域，也缺乏肌动蛋白标记。这些结果表明，亚顶体肌动蛋白（F-肌动蛋白）是PNS的一个组成部分，紧密结合于核膜而非覆盖其上的顶体内膜。因此，亚顶体肌动蛋白在将顶体锚定到细胞核或封闭顶体内膜方面的功能似乎不太可能。这些数据反而提示在精子发生过程中核膜具有封闭功能。
