Molecular mechanisms of Plasmodium fertilization

摘要 疟疾仍然是最具破坏性的传染病之一。它杀死了100多万人 每年在世界各地造成巨大痛苦和经济损失的同时。然而，许多 在了解寄生虫在人类宿主中的生命周期和在 在蚊子媒介方面，仍然存在着重大的知识空白。疟疾寄生虫的受精是一种 人们对蚊子肠道管腔内发生的过程知之甚少。这个过程是 重要的是因为自然界的生存完全依赖于寄生虫的能力 进行有性繁殖。 这项拟议的研究旨在确定受精过程中发生的分子相互作用。 疟疾寄生虫。该项目基于一种非正统的方法(多肽的鉴定 其结合到配子表面)通过一种重要工具的最近发展而成为可能， 一种产生红色荧光雌配子和绿色荧光雄性配子的转基因寄生虫 配子。来自该转基因寄生虫的疟疾雌、雄配子的纯种群 通过细胞分选分离，然后用于筛选噬菌体展示文库，以寻找 识别配子表面的分子。一种与雌配子结合的多肽(FG1) 另一种与雄配子结合的多肽(MG1)被鉴定出来。重要的是，当添加 到疟疾感染性血餐，这些多肽中的每一个都阻止了寄生虫受精， 提示这些多肽与受体结合并阻止其与配体的相互作用 异性的配子。我们的工作假设是，这种多肽在结构上模仿 配子配体与多肽和配体竞争结合到相应 受体。这项建议列出了一项研究计划，以确定FG1和 MG1多肽与配子上的配子结合及配子配子上的配子与两种多肽的性别相反 在结构上模仿。另一个目的是描述雌性动物表面的蛋白质组。 受精前后配子，以深入了解参与 受精和可能阻碍多精受精。 阐明受精机制不仅对理解受精的基本原理具有重要意义 疟疾和其他寄生虫病的生物学，但也可能导致识别新的 阻断传播和疾病传播的目标。此外，这些机制是否应该 如果保守的话，我们的发现可以扩展到高等生物受精的生物学领域。

ABSTRACT Malaria remains one of the most devastating infectious diseases. It kills over a million people every year while causing immense suffering and economic losses worldwide. Whereas much progress has been made in understanding the life cycle of the parasite in the human host and in the mosquito vector, significant gaps of knowledge remain. Fertilization of malaria parasites is a poorly understood process that takes place in the lumen of the mosquito gut. This process is important because survival in nature is completely dependent on the ability of the parasite to undergo sexual reproduction. The proposed research aims to identify molecular interactions that take place during fertilization of malaria parasites. This project is based on an unorthodox approach (identification of peptides that bind to the gamete surface) made possible by the recent development of an important tool, a transgenic parasite that produces red-fluorescent female gametes and green-fluorescent male gametes. Pure populations of malaria female and male gametes from this transgenic parasite were isolated by cell sorting and then used to screen a phage display library for peptides that recognize molecules on the gamete surfaces. A peptide (FG1) that binds to female gametes and another peptide (MG1) that binds to male gametes were identified. Importantly, when added to a malaria infectious blood meal, each of these peptides blocked parasite fertilization, suggesting that the peptides bound to a receptor and prevented its interaction with a ligand on the gamete of the opposite sex. Our working hypothesis is that the peptide structurally mimics the gamete ligand and that peptide and ligand compete for binding to the corresponding receptor. This proposal lays out a research plan to identify the receptor to which the FG1 and MG1 peptides bind and the ligands on the gametes of the opposite sex that the two peptides structurally mimic. An additional aim is to characterize the proteome on the surface of female gametes before and after fertilization, to gain insights on additional proteins involved in fertilization and possible block to polyspermy. Elucidation of mechanisms of fertilization is important not only for understanding the basic biology of malaria and other parasitic diseases but could also lead to the identification of new targets for blocking transmission and the spread of disease. Moreover, should the mechanisms be conserved, our findings could be extended to the biology of fertilization of higher organisms.