Cesario M M, Bartles J R
Department of Cell, Molecular and Structural Biology, Northwestern University Medical School, Chicago, IL 60611.
J Cell Sci. 1994 Feb;107 ( Pt 2):561-70.
Western blotting, immunofluorescence and immunogold electron microscopy were used to examine the compartmentalization, processing and redistribution of the integral plasma membrane protein CE9 on the spermatozoa of rats, mice and hamsters. In each species examined, spermatozoal CE9 was found to undergo endoproteolytic processing followed by a net redistribution from the posterior-tail domain into the anterior-tail domain of the plasma membrane during epididymal maturation. Compared to spermatozoa of the rat and mouse, those of the hamster were found to express a greater proportion of their CE9 within the anterior-tail plasma membrane domain at all stages of maturation. As a consequence, CE9 was judged to be a suitable marker for two different spermatozoal plasma membrane domains: the posterior-tail plasma membrane domain (spermatozoa from the testis and caput epididymidis of the rat and mouse) and the anterior-tail domain (spermatozoa from the cauda epididymidis of the hamster). Immunogold electron microscopy was used to pinpoint the positions of the boundaries of these CE9-containing plasma membrane domains at a high level of resolution. In each case, the position of the CE9 domain boundary was found to be strongly correlated with that of the subplasmalemmal electron-dense ring known as the annulus. The precise spatial relationship between the CE9 domain boundary and the annulus was, however, found to differ significantly among species and/or as a function of maturation.
采用蛋白质免疫印迹法、免疫荧光法和免疫金电子显微镜法，研究了大鼠、小鼠和仓鼠精子上完整质膜蛋白CE9的区室化、加工过程及重新分布情况。在所研究的每个物种中，精子CE9在附睾成熟过程中会经历内切蛋白水解加工，随后从质膜的尾后部区域净重新分布到尾前部区域。与大鼠和小鼠的精子相比，发现仓鼠的精子在成熟的各个阶段，其CE9在前尾质膜区域表达的比例更高。因此，CE9被判定为两种不同精子质膜区域的合适标记物：尾后部质膜区域（大鼠和小鼠睾丸及附睾头的精子）和尾前部区域（仓鼠附睾尾的精子）。免疫金电子显微镜法用于在高分辨率水平上精确确定这些含CE9质膜区域边界的位置。在每种情况下，发现CE9区域边界的位置与称为环带的质膜下电子致密环的位置密切相关。然而，发现CE9区域边界与环带之间的确切空间关系在不同物种之间和/或作为成熟的函数存在显著差异。
