Role of cysteine proteases in malaria transmission

超出提供的空间。由原生动物寄生虫恶性疟原虫引起的疟疾估计每年造成100-200万人死亡。其控制的主要障碍之一是寄生虫复杂的生命周期；每个发育阶段都是不同的，可以对干预措施做出不同的反应。因此，对整个生命周期中涉及的分子事件有一个全面的了解是很重要的。从一个人传播到另一个人需要成熟的红细胞内有性期寄生虫，配子体，在血餐期间被蚊子从受感染的人类宿主那里带走。这种转变刺激配子体从红细胞中出来，并在接下来的24小时内发育成卵囊，产生数千个对人类具有感染性的子孢子。我们已经证明，对羽化的刺激导致了半胱氨酸蛋白酶对配子体表面蛋白Pfs230的蛋白分解过程，我们的合作者有初步证据表明，半胱氨酸蛋白酶抑制剂E64d可以阻断寄生虫感染蚊子的能力。最近，我们发现Fallcipain 1、3和PFL2290w是在配子体和配子中表达的主要半胱氨酸蛋白酶。在恶性疟原虫基因组中发现的另外6个与半胱氨酸蛋白酶同源的基因在这些阶段不表达。我们假设恶性疟原虫向蚊子传播至少需要一种半胱氨酸蛋白酶，并建议鉴定和定位配子体表达的半胱氨酸蛋白酶(特定目标1)。针对这些酶的抗体将被用来确定它们在整个羽化过程中的亚细胞定位，这一数据将与羽化引起的与配子体寄生蜂液泡膜或配子体或红细胞质膜相关的蛋白质的变化进行比较。具有与蚊子配子发生、受精或随后发育过程中作用一致的表达模式的半胱氨酸蛋白酶的功能和靶点将通过靶向基因中断和抑制研究(特定目标2和3)进一步分析。除了增加我们对相关基因的了解外，这些信息还可以用来指导半胱氨酸蛋白酶抑制剂的设计，从而有效地阻止疟疾的传播。表演网站========================================Section End===========================================

EXCEED THE SPACE PROVIDED. Malaria caused by the protozoan parasite, Plasmodium falciparum is estimated to cause 1-2 million deaths a year. One of the major barriers to its control is the parasite's complex life cycle; each developmental stage is distinct and can respond differently to interventions. Therefore, it is important to have a comprehensive understanding of the molecular events involved throughout the life cycle. Transmission from one person to another requires that mature intraerythrocytic sexual-stage parasites, gametocytes, be taken up from an infected human host by a mosquito during a blood meal. This transition stimulates the gametocytes to emerge from erythrocytes and over the next 24 hours to develop into oocysts that produce thousands of sporozoites that are infectious to humans. We have demonstrated that the stimulation of emergence results in the proteolytic processing of gametocyte surface protein Pfs230 by a cysteine protease and our collaborators have preliminary evidence that the cysteine protease inhibitor, E64d blocks the ability of the parasite to infect mosquitoes. Recently, we have found that falcipains 1, 3 and PFL2290w are the primary cysteine proteases expressed in gametocytes and gametes. The other 6 genes identified in the P. falciparum genome that have homology to cysteine proteases are not expressed in these stages. We hypothesize that at least one cysteine protease is required for transmission of P. falciparum to the mosquito and propose to identify and localize the cysteine proteases expressed by gametocytes (Specific Aim 1). Antibodies specific for these proteases will be used to determine their subcellular localization throughout emergence and this data compared with the emergence-induced changes in proteins associated with the gametocyte parasitophorous vacuole membrane or the plasma membrane of the gametocyte or erythrocyte. The function and targets of cysteine proteases with expression patterns consistent with a role in gametogenesis, fertilization or subsequent development in the mosquito will be analyzed further by targeted gene disruption and inhibitor studies (Specific Aims 2 & 3). In addition to increasing our understanding of the genes involved, this information can be used to direct the design of cysteine protease inhibitors that will effectively block malaria transmission. PERFORMANCE SITE ========================================Section End===========================================