Bronson R, Peresleni T, Golightly M, Preissner K
Department of Obstetrics and Gynecology, State University of New York at Stony Brook, New York 11794-8091, USA.
Mol Hum Reprod. 2000 Nov;6(11):977-82. doi: 10.1093/molehr/6.11.977.
Vitronectin plays a role in the regulation of complement and thrombin activities and in cell surface proteolysis. Vitronectin is also an intrinsic protein of human spermatozoa. Vitronectin message has been detected in whole testis poly-A mRNA and localized by in-situ reverse transcription-polymerase chain reaction to spermatocytes. The proportion of spermatozoa that express vitronectin increases following their capacitation. In this study, spermatozoa from a man of proven fertility were probed with an anti-vitronectin monoclonal antibody (VN7) before and after their permeabilization with 0.1% Triton X-100. Of fresh spermatozoa observed by confocal microscopy, 0-8% showed vitronectin staining. However, 75% of those observed displayed vitronectin following permeabilization. Serial confocal sections through the sperm head confirmed the internal localization of vitronectin. The acrosomal status of capacitated spermatozoa that expressed vitronectin was then determined. Dual colour microscopy with rhodamine-conjugated anti-vitronectin antibody and a fluorescein-conjugated antibody directed against CD46 (a complement regulatory protein expressed on the inner acrosomal membrane) revealed that only acrosome-reacted (CD46-positive) spermatozoa displayed vitronectin. Two populations of these spermatozoa were observed. Fifty-seven of 260 (22%) were CD46-positive/vitronectin-positive and 72 of 260 (28%) were CD46-positive/vitronectin-negative. No spermatozoa were CD46-negative/vitronectin-positive. These results confirm that vitronectin is released from a sequestered location within the spermatozoon following the acrosome reaction.
玻连蛋白在补体和凝血酶活性调节以及细胞表面蛋白水解过程中发挥作用。玻连蛋白也是人类精子的一种内在蛋白。在整个睾丸的多聚腺苷酸mRNA中检测到了玻连蛋白信息，并通过原位逆转录聚合酶链反应将其定位到精母细胞。表达玻连蛋白的精子比例在获能后增加。在本研究中，来自一名已证实具有生育能力男性的精子，在用0.1% Triton X - 100使其通透化前后，用抗玻连蛋白单克隆抗体（VN7）进行检测。通过共聚焦显微镜观察新鲜精子，0 - 8%显示玻连蛋白染色。然而，通透化后观察到的精子中有75%显示有玻连蛋白。穿过精子头部的系列共聚焦切片证实了玻连蛋白的内部定位。然后确定表达玻连蛋白的获能精子的顶体状态。用罗丹明偶联的抗玻连蛋白抗体和针对CD46（顶体内膜上表达的一种补体调节蛋白）的荧光素偶联抗体进行双色显微镜观察发现，只有顶体反应（CD46阳性）的精子显示有玻连蛋白。观察到这些精子有两个群体。260个中有57个（22%）是CD46阳性/玻连蛋白阳性，260个中有72个（28%）是CD46阳性/玻连蛋白阴性。没有精子是CD46阴性/玻连蛋白阳性。这些结果证实，顶体反应后玻连蛋白从精子内的一个隔离位置释放出来。
