Developmental Gene Regulation in Schistosoma mansoni

描述(申请人提供)：血吸虫病是一种重要的热带寄生虫病，在70多个国家有2亿多人感染。据估计，撒哈拉以南非洲每年因血吸虫感染而死亡的人数为28万人，另有2000万人出现严重的疾病症状。目前，药物治疗是基于一种单一的药物--吡喹酮，而且有证据支持出现抗药性寄生虫。由于没有合适的替代疗法或疫苗可用，因此迫切需要开发新的化疗药物和疫苗。有关血吸虫基本生物学的更详细信息将有助于疫苗和新药设计。我们认为，识别哺乳动物宿主中控制蠕虫发育和性别分化的因素将为药物和疫苗提供新的靶点。对哺乳动物宿主发育过程中蠕虫全基因组基因表达模式的研究将提供影响寄生虫适应宿主环境的血吸虫生物学途径的连贯图景。我们建议利用基因表达序列分析(SAGE)来监测寄生虫发育和性别分化过程中全基因组范围的mRNA表达水平。为了检测与发育相关的基因的差异转录，我们将从尾蚴、血吸虫、未成熟蠕虫、性成熟和处女虫以及卵子中分离出约75,000个20 bp的序列标签，从而执行SAGE。SAGE是研究寄生虫发育和性别分化过程中全球基因表达的理想方法。这项研究将导致鉴定在发育和性别分化期间表达的新基因，这些基因允许寄生虫逃避免疫反应并持续存在于哺乳动物宿主中。随着曼氏血吸虫的基因组测序接近完成，功能基因组研究将是利用正在产生的庞大基因组数据库的关键。SAGE分析将补充正在进行的曼氏血吸虫基因组注释和使用DNA微阵列进行的研究。此外，我们还将验证SAGE技术在曼氏血吸虫差异表达基因研究中的应用。

DESCRIPTION (provided by the applicant): Schistosomiasis is an important tropical parasitic disease with more than two hundred million human infections in more than 70 countries. The mortality due to schistosome infections in sub-Saharan Africa is estimated to be 280,000 per year and an additional 20 million individuals suffer severe disease symptoms. Currently, drug treatment is based on a single agent, praziquantel, and there is evidence supporting the emergence of drug resistant parasites. Because no suitable alternative therapy or vaccine is available, there is an urgent need for the development of novel chemotherapeutic agents and vaccines. More detailed information about the basic biology of schistosomes will facilitate vaccine and novel drug design. We suggest that identification of factors controlling worm development and sexual differentiation in the mammalian host will provide new targets for drugs and vaccines. Examination of genome-wide gene expression patterns in worms during development in the mammalian host will provide a coherent picture of schistosome biological pathways that influence parasite adaptation to the host environment. We propose to utilize Serial Analysis of Gene Expression (SAGE) to monitor genome-wide levels of mRNA expression during parasite development and sexual differentiation. To detect differential transcription of genes related to development, we will perform SAGE by generating ~75,000 20 bp sequence tags from the mRNA isolated from cercariae, schistosomula, immature worms, sexually mature and virgin worms, and eggs. SAGE is ideal to investigate global gene expression during parasite development and sexual differentiation. This research will lead to the identification of novel genes expressed during development and sexual differentiation and that allow the parasite to evade the immune response and persist in the mammalian host. As genome sequencing of Schistosoma mansoni is nearly complete, functional genomic studies will be essential to capitalize on the massive genomic database being generated. SAGE analysis will complement the ongoing annotation of the S. mansoni genome and studies using DNA micro arrays. Furthermore, we will validate the use of SAGE technology to study differential global gene expression in S. mansoni.