Köster B, Dargatz H, Schröder J, Hirzmann J, Haarmann C, Symmons P, Kunz W
Institut für Genetik, Universität Düsseldorf, F.R.G.
Mol Biochem Parasitol. 1988 Nov;31(2):183-98. doi: 10.1016/0166-6851(88)90169-7.
An abundant 0.9 kb female-specific mRNA in Schistosoma mansoni is thought to code for an egg-shell precursor protein [Bobek et al. (1986) Proc. Natl. Acad. Sci. USA 83, 5544-5548]. This gene contains two ORFs. A recombinant plasmid was constructed that expresses a fusion protein containing a glycine- and tyrosine-rich polypeptide coded for by one of these ORFs. Antisera raised against homogenates of female, but not of male, S. mansoni recognise this fusion protein, providing direct evidence that this ORF is used by S. mansoni. In comparative Western blots of S. mansoni homogenates from males and females affinity purified antibodies that react with the fusion protein react exclusively with proteins from females, recognising a 28 kDa polypeptide and a smear of immunoreactive material probably caused by oxidative crosslinking. In immunohistology, the affinity purified antibodies react with mature vitelline cells in female schistosomes. The immunoreactive material is localised in the so-called 'vitelline droplets' that are morphologically very similar to 'shell globules', known to contain egg-shell precursors, that are found in Fasciola hepatica. In situ hybridisation shows that the eggshell precursor gene is only transcribed in immature vitelline cells and has a short half-life. Taken together, these observations provide persuasive evidence that the 0.9 kb mRNA codes for an eggshell precursor.
曼氏血吸虫中一种丰富的0.9 kb雌性特异性mRNA被认为编码一种卵壳前体蛋白[博贝克等人（1986年），《美国国家科学院院刊》83卷，5544 - 5548页]。该基因包含两个开放阅读框（ORF）。构建了一种重组质粒，其表达一种融合蛋白，该融合蛋白包含由其中一个ORF编码的富含甘氨酸和酪氨酸的多肽。用曼氏血吸虫雌性匀浆而非雄性匀浆制备的抗血清可识别这种融合蛋白，这提供了直接证据，表明曼氏血吸虫使用了这个ORF。在对曼氏血吸虫雄性和雌性匀浆进行的比较蛋白质免疫印迹分析中，与融合蛋白反应的亲和纯化抗体仅与雌性的蛋白质发生反应，识别出一条28 kDa的多肽以及可能由氧化交联导致的免疫反应性物质条带。在免疫组织学中，亲和纯化抗体与雌性血吸虫中的成熟卵黄细胞发生反应。免疫反应性物质定位于所谓的“卵黄小滴”中，这些小滴在形态上与在肝片吸虫中发现的、已知含有卵壳前体的“壳小球”非常相似。原位杂交显示，卵壳前体基因仅在未成熟的卵黄细胞中转录，且半衰期较短。综上所述，这些观察结果提供了有说服力的证据，表明0.9 kb的mRNA编码一种卵壳前体。
