Protein targeting and secretion in Toxoplasma

描述（由申请人提供）：弓形虫是一种广泛传播的 机会致病菌导致艾滋病患者严重脑炎。T.弓形虫 也是研究相关顶复门动物的实验模型系统 在艾滋病中重要的寄生虫，包括隐孢子虫属，环孢子虫属，等孢子虫属， 疟原虫是疟疾的病原体。顶复体复制 寄生虫只发生在宿主的细胞内，在一个专门的 在入侵过程中形成的隔室-寄生虫液泡。蛋白 分泌与宿主细胞侵袭密切相关， 寄生泡的建立/维持。因为入侵是 这些步骤对寄生虫的复制至关重要， 抗寄生虫药物或疫苗开发的目标。这项建议旨在 研究蛋白质分泌和靶向在宿主细胞侵袭中的作用， 液泡成熟弓形虫的分泌器高度多样化， 分泌物来自三组细胞器：微丝，棒状体， 和致密颗粒。我们将描述蛋白质运输和从这些 使用体内报告基因的细胞器。使用缺失的序列作图 分析和更微妙的点突变将使我们能够建立 参与这个分类过程的分子信号。条件突变体将是 在表型筛选中分离，富集分泌型多肽的积累， 记者.分离的突变体寄生虫将用于确定分泌物是否 与入侵事件是必要的还是巧合的。突变分析也将 为个体分泌功能提供关键信息 细胞器参与。

DESCRIPTION (provided by applicant): Toxoplasma gondii is a wide-spread opportunistic pathogen causing severe encephalitis in AIDS patients. T. gondii is also an experimental model system for the study of related apicomplexan parasites important in AIDS including Cryptosporidium, Cyclospora, Isospora, and Plasmodium the causative agent of malaria. Replication of apicomplexan parasites takes place only inside the cells of its host, within a specialized compartment formed during invasion - the parasitophorous vacuole. Protein secretion is tightly associated with host-cell invasion and establishment/maintenance of the parasitophorous vacuole. As invasion is essential to parasite replication these steps might also pesent potential targets for anti-parasite drug or vaccine development. This proposal aims to study the role of protein secretion and targeting in host cell invasion and vacuole maturation. The secretory apparatus in T gondii is highly diversified, with secretion occurring from three sets of organelles: micronemes, rhoptries, and dense granules. We will characterize protein trafficking to and from these organelles using in vivo reporter genes. Sequence mapping using deletion analysis and more subtle point-mutations will permit us to establish the molecular signals involved in this sorting process. Conditional mutants will be isolated in a phenotypic screen enriching for the accumulation of a secretory reporter. Isolated mutant parasites will be used to establish if secretion is essential or coincidental with the invasion event. Mutant analysis will also provide critical information towards the function of the individual secretory organelles involved.