Rosenzvit Mara C, Zhang Wenbao, Motazedian Hossein, Smyth Danielle, Pearson Mark, Loukas Alex, Jones Malcolm K, McManus Donald P
Queensland Institute of Medical Research, 300 Herston Road, Herston, Brisbane, Qld 4029, Australia.
Int J Parasitol. 2006 Jan;36(1):123-30. doi: 10.1016/j.ijpara.2005.09.001. Epub 2005 Oct 4.
The signal sequence trap technique was applied to identify genes coding for secreted and membrane bound proteins from Echinococcus granulosus, the etiologic agent of cystic hydatid disease. An E. granulosus protoscolex cDNA library was constructed in the AP-PST vector such that randomly primed cDNAs were fused with a placental alkaline phosphatase reporter gene lacking its endogenous signal peptide. E. granulosus cDNAs encoding a functional signal peptide were selected by their ability to rescue secretion of alkaline phosphatase by COS-7 cells that had been transfected with the cDNA library. Eighteen positive clones were identified and sequenced. Their deduced amino acid sequences showed significant similarity with amino acid transporters, Krebs cycle intermediates transporters, presenilins and vacuolar protein sorter proteins. Other cDNAs encoded secreted proteins without homologues. Three sequences were transcribed antisense to E. granulosus expressed sequence tags. All the mRNAs were expressed in protoscoleces and adult worms, but some of them were not found in oncospheres. The putative E. granulosus secreted and membrane bound proteins identified are likely to play important roles in the metabolism, development and survival in the host and represent potential targets for diagnosis, drugs and vaccines against E. granulosus.
信号序列捕获技术被用于鉴定编码来自细粒棘球绦虫（囊型包虫病的病原体）的分泌蛋白和膜结合蛋白的基因。在AP-PST载体中构建了细粒棘球绦虫原头节cDNA文库，使得随机引物cDNA与缺乏内源性信号肽的胎盘碱性磷酸酶报告基因融合。通过其拯救已用cDNA文库转染的COS-7细胞分泌碱性磷酸酶的能力，选择编码功能性信号肽的细粒棘球绦虫cDNA。鉴定并测序了18个阳性克隆。其推导的氨基酸序列与氨基酸转运蛋白、三羧酸循环中间产物转运蛋白、早老素和液泡蛋白分选蛋白显示出显著相似性。其他cDNA编码无同源物的分泌蛋白。三个序列与细粒棘球绦虫表达序列标签呈反义转录。所有mRNA在原头节和成虫中均有表达，但在六钩蚴中未发现其中一些。鉴定出的推定细粒棘球绦虫分泌蛋白和膜结合蛋白可能在宿主的代谢、发育和生存中起重要作用，并代表针对细粒棘球绦虫的诊断、药物和疫苗的潜在靶点。
