FATTY ACID BIOSYTHESIS IN CRYPTOSPORIDIUM PARVUM

描述：（改编自申请人的摘要）隐孢子虫引起 艾滋病患者的机会性感染（OI）之一， 治疗是已知的。虽然许多药物已经被测试对OI， 了解目标酶的存在，生物合成途径， 表达或调节几乎是未知的。申请人的初步 数据表明，几个脂肪酸合成酶（FAS）基因存在于C. 它们的大小、组织和功能域不同， 与人类不同这些基因似乎是功能性的，因为它们 在子孢子和细胞内阶段检测到转录物， C.生长FAS抑制剂可抑制离体小孢子虫的生长。的发现 CpFAS基因表明，这种顶复体可能合成脂肪酸， novo，从而为抗隐孢子虫病的药物开发提供线索。 由于大多数寄生原生动物都是脂肪酸营养缺陷型， 也为原生动物生物化学开辟了新的前景。研究者的长期 目的是研究顶复体脂肪酸生物合成作为 用于药物开发的有用靶点。这项建议的具体目标是： 1.对CpFAS基因结构、转录水平和亚细胞水平进行表征 在寄生虫的生命周期中定位。2.阐明功能 通过对底物偏好、中间和最终脂肪酸的分析， 使用在细菌或酵母中表达的重组CpFAS蛋白的酸性产物 3.确定脂肪酸生物合成是否可以作为一个合理的目标， 通过筛选FAS类似物对抗C.小孢子在体外和体内 vivo.这些具体目标的完成将支持或反驳 研究者假设C.帕尔武姆群岛 与其宿主足够不同以用于药物设计靶向 对抗隐孢子虫病预期的结果是克服一个主要障碍 来治疗艾滋病患者的感染

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.