Bozzola J J, Polakoski K, Haas N, Russell L D, Campbell P, Peterson R N
Center for Electron Microscopy, Southern Illinois University, Carbondale 62901.
Am J Anat. 1991 Oct;192(2):129-41. doi: 10.1002/aja.1001920204.
The localization of proacrosin was determined by using colloidal gold labeling and electron microscopy of boar germ cells during spermiogenesis to post-ejaculation. Proacrosin was first localized in round spermatids during the Golgi phase of spermiogenesis; it was associated with the electron-dense granule, or acrosomal granule that was conspicuous within the acrosome. It remained within the acrosomal granule during the cap and acrosome phases of spermiogenesis. At these stages, there was no apparent association of the proacrosin molecule with the acrosomal membranes. During the maturation phase of spermiogenesis, proacrosin was seen to become dispersed into all regions of the acrosome except the equatorial segment. When sperm from different segments of the epididymis and ejaculated sperm were examined, localization was observed throughout the acrosome except for the equatorial segment. Here proacrosin appeared to be localized on both the inner and outer acrosomal membranes as well as with the acrosomal matrix, although further studies are required to verify the membrane localization. No labeling was seen on the plasma membrane. These data suggest that the synthesis and movement of proacrosin to sites in the acrosome are controlled by an as yet unknown process. The absence of proacrosin on the plasma membrane of mature ejaculated sperm makes it unlikely that this enzyme plays a role in sperm-zona adhesion prior to capacitation.
利用胶体金标记和电子显微镜技术，对从精子发生到射精后公猪生殖细胞中的前顶体蛋白酶进行定位。前顶体蛋白酶最初定位于精子发生高尔基体期的圆形精子细胞中；它与顶体中的电子致密颗粒即顶体颗粒相关。在精子发生的帽状期和顶体期，它仍保留在顶体颗粒内。在这些阶段，前顶体蛋白酶分子与顶体膜没有明显关联。在精子发生的成熟阶段，可见前顶体蛋白酶分散到顶体除赤道段以外的所有区域。当检查来自附睾不同节段的精子和射出的精子时，在顶体除赤道段以外的所有区域均观察到定位。在这里，前顶体蛋白酶似乎定位于顶体内外膜以及顶体基质，不过需要进一步研究来证实膜定位。在质膜上未观察到标记。这些数据表明，前顶体蛋白酶向顶体部位的合成和移动受一个尚未明确的过程控制。成熟射出精子的质膜上不存在前顶体蛋白酶，这使得该酶在获能前的精子 - 透明带黏附中发挥作用的可能性不大。
