MOLECULAR ANALYSIS OF HUMAN SPERM ACROSOMAL MOLECULE H-SP-1 IN SPERM-EGG INTERACTION

两种配子的几种表面分子参与受精过程中的配子识别（Saling，1989）。这些分子负责受精的每个过程和配子之间的物种特异性相互作用。本研究利用人精子特异性抗血清，从人睾丸cDNA文库中筛选出人精子抗原基因（h-Sp-1）。序列分析表明，h-Sp-1基因全长2170 bp，与人突触素基因同源性为45%，该基因被认为在神经末梢突触囊泡的钙依赖性信号转导中起重要作用。对h-Sp- 1基因推导的氨基酸序列分析表明，该基因编码259个氨基酸，含有4个亲水区和4个疏水区。这表明h-Sp- 1基因编码的分子可能是一种类似突触素的跨膜蛋白，具有四个跨膜区。北方印迹分析表明，h-Sp-1基因有2种转录本（2.3kb和1.1kb）。2.3kb转录本在人睾丸中广泛表达，而1.1kb转录本在人睾丸中大量表达。为了表征由h-Sp-1基因编码的分子，通过用基于h-Sp-1基因的合成多肽（氨基酸No 174-198）免疫兔来产生抗血清。Western印迹分析表明，抗血清反应的分子量为40 kDa。用间接免疫荧光法对固定的人精子头部进行染色。纯化的抗血清对人精子穿透去透明带金黄地鼠卵试验有抑制作用。然而，它们没有表现出任何精子固定和凝集活性。这些结果提示h-Sp-1基因编码的分子可能在精卵相互作用中起重要作用。

Several surface molecules of both gametes are involved in gametes recognition during fertilization( Saling, 1989 ). These molecules are responsible for each process of fertilization and species-specific interaction between the gametes. Studies of these molecules may be essential for understanding the mechanism of sperm-egg interaction and for the development of a contraceptive vaccine.We isolated a human sperm antigen gene (h-Sp-l) by screening from human testis cDNA library with human sperm specific antisera. The sequence analysis of the h-Sp-l gene indicated that it contained 2170 bp and had 45% homology to human synaptophysin gene, which was considered to play a crucial role in calcium dependent signal transduction in synaptic vesicles in the terminal end of nerves. The analysis of the deduced amino acids from the h-Sp- 1 gene showed that it encoded 259 amino acids containing four hydrophilic regions and four hydrophobic regions. This indicated that the molecules encoded by the h-Sp- 1 gene might be a transmembrane protein with four membrane spanning regions like the synaptophysin. Northern blot analysis indicated that h-Sp-1 gene had 2 kind of transcripts ( 2.3 kb and 1.1kb ). 2.3kb transcript expressed ubiquitously whereas 1.1kb transcript expressed abundantly in human testis. In order to characterize the molecules encoded by the h-Sp-l gene, the antisera were generated by immunizing rabbits with synthetic polypeptides ( aminoacid No 174-198 ) based on the h-Sp-1 gene. Western blot analysis indicated that the antisera reacted a 40 kDa molecule. The antisera also stained fixed human sperm head by indirect immunofluorescence staining. The purified antisera showed the inhibitory effect on human sperm penetration assay into zona-free hamster eggs. However, they did not show any sperm immobilizing and agglutinating activities. These results suggested that the molecules encoded by the h-Sp-1 gene might play an important role in the sperm-egg interaction.