Comparative genomics of gene expression mechanisms of parasitic protozoa using full-length cDNA

寄生原生动物是最简单的真核生物，由于它们在医学上的重要性，其基因组已经被测序。作为研究真核生物基因表达机制的尝试，我们用寡核苷酸封顶的方法构建了来自各种寄生虫的全长cDNA文库，这些寄生虫包括疟原虫、间日疟原虫、鼠疟原虫、伯氏疟原虫、弓形虫、微小隐孢子虫、细小泰勒虫、东方锥虫和柔嫩艾美耳球虫。这些序列已经被映射到各自的基因组序列上，并在基因组浏览器中呈现。为了进行比较基因组分析，我们构建了多房棘球绦虫的全长cDNA文库。研究结果已汇编成数据库Full-Malaria，并在互联网上公布：http：//fullMal.ims.u-tokyo.ac.jp。此外，还建立了比较基因组学数据库--比较网站(http：//compasite.hgc.ip)。这些为比较基因组分析阐明基因表达的确切机制提供了基本信息。此外，利用原有的方法筛选新的疟疾DNA疫苗候选，筛选出了有希望的小鼠疟疾疫苗候选克隆。该方法同样适用于其他真核病原体。

Parasitic protozoa are the simplest eukaryotes of which genomes have been sequenced because of their medical importance. As the attempt to study gene expression mechanism of eukaryotes, we have produced full-length cDNA libraries using the oligo-capping method which we have originated from various parasites including tertian malaria parasite, Plasmodium vivax, murine malaria parasite, P. berghei, Toxoplasma gondii, Cryptosporidium parvum, Theileria parva, T. orientalis, and Eimeria tenella, and determined 5'-end-one-pass sequences from the random clones. These sequences have been mapped onto the respective genome sequences and presented in the genome browsers. For comparative genomic analysis, a full-length cDNA library has been produced from flatworm, Echinococcus multilocularis. The results have been compiled as a database, Full-Malaria and published in internet at http : //fullmal.ims.u-tokyo.ac.jp. Furthermore, comparative genomics database, Comparasite, (http : //comparasite.hgc.ip) has been produced. These provide basic information for comparative genome analysis to elucidate the exact mechanisms of gene expression. In addition, using the original method to screen novel malaria DNA vaccine candidates, promising murine malaria vaccine candidate clones have been selected. This method should be applicable to other eukaryotic pathogens.