Mechanisms Governing Translational Regulation During Plasmodium Transmission

项目摘要 新的疟疾感染开始于雌性按蚊的叮咬，这引入了子孢子形式 将疟原虫寄生虫植入人体皮肤。为了达到这一点，寄生虫必须 成功感染并在蚊子体内发展超过两周或更长时间，使用活性 来克服蚊子的防御。完成这一步后，子孢子必须 进入一种准备状态，准备好从蚊子身上传播回去的机会。 对哺乳动物宿主的影响在这项拟议的工作中，我们将确定子孢子可以 通过选择的mRNA的翻译调节来准备自身。 最近，发现子孢子使用两个重叠和正交的翻译程序， 抑制（程序1和2），使特定的mRNA的翻译只发生在关键时刻， 发展然而，虽然我们现在知道许多特定的mRNAs是由这些程序调控的， 不知道是什么蛋白质作用于它们，使它们沉默/被抑制（反式因子）。此外，委员会认为， 虽然我们知道这些程序在寄生虫的发育和传播过程中何时关闭， 我们不知道是什么环境信号启动了翻译调控的这种转变。 因此，在这项拟议的工作中，我们将研究允许选择性调节的蛋白质反式因子 已知对子孢子发育和传播至关重要的mRNA。通过这项工作，我们将 确定干扰这些调节程序的后果，环境刺激， 感觉到触发翻译抑制的释放，和专门的核糖体的核心作用， 在这些过程中发挥作用。这些实验问题将通过反向遗传学、蛋白质 生物化学、成像流式细胞术、转录组学、蛋白质组学和低温电子显微镜（cryoelectronmicroscopy，cryo-cell） EM）。在实现这一目标的过程中，我们的目标是确定控制疟疾寄生虫的关键调控特征， 子孢子发育和传播到新的哺乳动物宿主。

Project Summary New malarial infections start with a bite of a female Anopheles mosquito, which introduces the sporozoite form of the Plasmodium parasite into the skin of that individual. To get to this point, the parasite must have successfully infected and developed within the mosquito over the course of two weeks or more, using active responses to overcome the mosquito’s defenses. Having accomplished this, the sporozoite must now switch into a mode of preparation and become poised for a moment of opportunity to transmit from the mosquito back to its mammalian host. In this proposed work, we will identify key mechanisms by which the sporozoite can prepare itself through the translational regulation of selected mRNAs. Recently, it was discovered that sporozoites use two overlapping and orthogonal programs of translational repression (Programs 1 and 2) to allow translation of specific mRNAs to occur only at key moments in their development. However, while we now know many specific mRNAs that are regulated by these programs, we do not know what proteins act upon them to cause them to be silenced/repressed (trans factors). Moreover, while we know when these programs are turned off during development and transmission of the parasite, we do not know what environmental cues initiate this transition in translational regulation. Therefore, in this proposed work we will investigate the protein trans factors that allow for selective regulation of mRNAs that are known to be critical to sporozoite development and transmission. Through this work, we will identify the consequences of interfering with these regulatory programs, the environmental stimuli that are sensed to trigger the release of translational repression, and the central role that the specialized ribosome plays in these processes. These experimental questions will be addressed through reverse genetics, protein biochemistry, imaging flow cytometry, transcriptomics, proteomics, and cryogenic electron microscopy (cryo EM). In accomplishing this, we aim to identify crucial regulatory features of the malaria parasite that control sporozoite development and transmission to a new mammalian host.