Drug resistance in Plasmodium falciparum

描述（由申请人提供）：疟疾继续对全球健康产生重大影响，每年造成100万至300万人死亡。此外，耐氯喹恶性疟原虫的高流行率也导致了非洲发病率和死亡率的上升。发现氯喹耐药性的遗传相关性不仅将为流行病学研究提供一个标记，而且将指导研究表征耐药性的分子基础。实现这一目标的一个重大进展是最近在pfcrt中发现了一种突变，这种突变一直存在于氯喹耐药寄生虫中。重要的是，这种突变可以在氯喹敏感的分离株中发现，这表明这种突变是必需的，但还有其他遗传位点有助于抗性表型。提出了两种主要的方法来鉴定与氯喹耐药有关的其他基因。第一种方法将通过实地研究，检查pfmdr1和新基因中发现的额外DNA多态性与氯喹抗性的相关性。耐药也可以通过转录水平的改变来介导，这种机制无法通过单点突变分析来检测。因此，第二种补充方法将比较氯喹敏感和耐药寄生虫之间的转录谱。通过任何一种方法鉴定的基因的功能研究将在动物模型系统中进行。

DESCRIPTION (provided by applicant): Malaria continues to have a major impact on global health with rates of 1-3 million deaths annually. In addition, the high prevalence of chloroquine resistant Plasmodium falciparum, has contributed to the rising morbidity and mortality in Africa. Discovery of genetic correlates of chloroquine resistance would not only provide a marker for epidemiologic studies but would guide studies to characterize the molecular basis of resistance. A major advance toward this goal was the recent identification of a mutation in pfcrt, that is consistently found in chloroquine resistant parasites. Importantly, this mutation can be found in chloroquine sensitive isolates, which suggest that this mutation is required, but that there are other genetic loci that contribute to the resistance phenotype. Two major approaches to identify the other genes involved in chloroquine resistance are proposed. The first approach will examine the correlation of additional DNA polymorphisms found in pfmdr1 and novel genes, with chloroquine resistance through field based studies. Drug resistance can also be mediated by alterations in transcription level, a mechanism that cannot be detected by analysis of single point mutations. Therefore a second and complementary approach will compare transcriptional profiles between chloroquine sensitive and resistant parasites. Functional studies of genes identified by either method will be conducted in an animal model system. The long term goal of this proposal is 1) to fully characterize the genetic basis of chloroquine resistance through integration of field observations and standard and innovative laboratory methods 2) provide the investigator with the additional necessary complementary skills of clinical research and molecular methods to develop into an independent investigator in malaria.