A sperm motility inhibitor of seminal plasma.

精浆运动抑制因子(SPMI)是最近从猪精浆中分离得到的一种活性物质，分子筛法测得其分子量为5万，变性条件下SDSPAGE检测到14K、16K、18K三种多肽。我们成功地克隆了猪14k SPMI基因。对645个碱基对的SPMI基因进行核苷酸序列分析，预测其编码137个氨基酸残基，包括一个21个残基的信号肽和一个116个残基的分泌蛋白，并用编码SPMI基因开放阅读框的探针进行Northn杂交分析。人们很快注意到，猪精囊中含有异常丰富的SPMI mRNA(3小时后)。相比之下，SPMI在猪的睾丸、附睾腺、前列腺、球状腺、膀胱、肝脏、脾、生殖器官和人类精囊中均未检测到表达水平。因此，SPMI基因的表达具有高度的精囊特异性。我们成功地从克隆的SMPI基因中表达了蛋白，表达的蛋白与SPMI抗体发生免疫印迹反应。虽然表达的SPMI蛋白能被一些缓冲液增溶，但SPMI生物活性丧失。这个问题还需要进一步的研究来解决。弱精子症(精子活动能力差的患者)的原因仍然不清楚。我们已经观察到，精子活力低下患者的精浆对精子活力的抑制能力与精子活力良好的正常生育男性的精浆没有显著差异。现在我们正在研究在活动能力较差的精子中是否存在一种与SPMI相同的运动抑制物，但目前我们还不能证明

The seminal plasma motility inhibitor (SPMI) has recently been purified from boar seminal plasma where its molecular weight has estimated at 50,000 by molecular sieving but three peptides of 14k, 16k, 18k were detected after SDSPAGE in denaturing conditions. We succeeded the cloning of boar 14k SPMI cDNA gene. Nucreotide sequence analysis of the 645-base pair SPMI cDNA predicts a code peptide of 137 amino acid residues which includes a 21residue signal peptide and a 116-residue secreted protein.The levels of SPMI gene expression were determined by Northrn blot analysis using the probe DNAe encoding the open reading frame of the cloned SPMI cDNA gene. It was soon noticed that the boar seminal vesicle is extrordinarily abundant in SPMI mRNA (after 3 hrs expousure). In contrast, there was no detectable level of SPMI expression in the testis, epididymis, prostate, bulbourethral gland, urinary bladder, liver, spleen, as well as in the reproductive organs of the sow and also human seminal vesicles. Thus it would appear that the expression of the SPMI gene is highly specific to the seminal vesiclesWe succeeded the expression of protein from the cloned SMPI cDNA gene.Expressed protein reacted against SPMI antibody by western blotting. Although this expressed SPMI protein was able to solubilize with some buffers, SPMI biological activity was lost. Further studies needs to resolve this problem.The causes of asthenozoospermia (patient with poor motile sperm) were still not clear. We already observed that the inhibitory capacity of seminal plasma from patients with poor sperm motility was not significantly different from that of seminal plasma from normal fertile men with good sperm motility. Now we are studying whether a motility inhibitor within poor motile spermatozoa present and is identical to SPMI.But, presently, we can not show