FATTY ACID BIOSYTHESIS IN CRYPTOSPORIDIUM PARVUM

描述：(改编自申请人摘要)微小隐孢子虫致病原因 艾滋病患者中的一种机会性感染(OI) 治疗方法目前还不得而知。尽管许多药物已经针对OI进行了测试， 关于靶标酶、生物合成途径和 表达或调控几乎是未知的。申请者的初步申请 有数据表明，在C。 Parvum(CpFas)，它们的大小、组织和功能域不同 与人类的不同。这些基因似乎是有功能的，因为它们的 在子孢子和胞内阶段检测到转录本， Fas抑制剂可抑制微小隐孢子虫的体外生长。发现了 CpFas基因提示这种顶端复合体可能合成脂肪酸 Novo，从而为开发治疗隐孢子虫病的药物提供了线索。 由于大多数寄生原生动物都是脂肪酸的营养缺陷型生物，这一发现 也为原生动物生物化学开辟了新的前景。调查员的长期工作 目的是研究apicplexan脂肪酸生物合成作为一种 药物开发的有用靶点。这项建议的具体目标是： 1.鉴定CpFas基因的结构、转录水平和亚细胞 在寄生虫的生命周期中的定位。2.阐明其功能 CpFas的底物选择性、中间体和最终脂肪的分析 利用重组CpFas蛋白在细菌或酵母中表达的酸性产品 3.确定脂肪酸生物合成是否可以作为 体外和体外筛选抗微小弧菌Fas类似物的药物开发 活着。这些具体目标的完成将支持或驳斥 研究人员假设微小隐翅虫的脂肪酸生物合成是 与其宿主足够不同，可用于药物设计靶点 治疗隐孢子虫病。预计的结果是克服一个主要障碍 用于治疗艾滋病患者的这种OI。

DESCRIPTION: (Adapted from Applicant's Abstract) Cryptosporidium parvum causes one of the opportunistic infections (OI) in AIDS patients for which no treatment is yet known. Although many drugs have been tested against the OI, knowledge about the presence of target enzymes, biosynthetic pathways, and expression or regulation are virtually unknown. The applicant's preliminary data indicate that several fatty acid synthase (FAS) genes are present in C. parvum (CpFAS) and that their size, organization and functional domains differ from those of humans. These genes appear to be functional, since their transcripts were detected in sporozoites and intracellular stages and the growth of C. parvum in vitro was inhibited by a FAS inhibitor. The discovery of CpFAS genes suggests that this apicomplexan might synthesize fatty acids de novo, thus providing clues for drug development against cyptosporidiosis. Because most parasitic protozoa are auxotrophs for fatty acids, this discovery also opens a new vista for protozoan biochemistry. The investigator's long term goal is to study the potential of apicomplexan fatty acid biosynthesis as a useful target for drug development. The specific aims of this proposal are: 1.Characterize the CpFAS gene structure, transcription level and subcellular localization during the life cycle of the parasite. 2. Elucidate the function of CpFAS by the analysis of substrate preference, intermediate and final fatty acid products using recombinant CpFAS proteins expressed in bacteria or yeast 3.Determine whether fatty acid biosynthesis can serve as a rational target for drug development by screening FAS analogues against C. parvum in vitro and in vivo. Completion of these specific aims will either support or refute the investigator's hypothesis that fatty acid biosynthesis in C. parvum is sufficiently different from its host to be exploited for drug design target against cryptosporidiosis. The outcome expected is to overcome a major obstacle for therapy against this OI of AIDS patients.