Plant virus interactions with insect viruses

我们建议利用这项计划项目赠款作为一个机会，探索一系列重要的生物学问题。这些主题与本PPG的合作主题非常吻合，并将使我的实验室能够探索结构病毒学的几个新的重要途径。这项资助的一个主要主题是利用结构生物学方法来研究植物病毒的媒介传播过程。使用黄瓜花叶病毒（CMV）作为一个模型，通过蚜虫传播的病毒，没有辅助蛋白，我们计划研究的结构基序，与蚜虫的口器相互作用，蚜虫传播所需的。初步工作已经确定了蚜虫传播的表面残留物。我们建议扩展当前CMV模型的分辨率。结合免疫学和冷冻TEM技术，将允许用于检查蚜虫-病毒相互作用。对于马铃薯Y病毒，蚜虫需要一种辅助蛋白HC-Pro来传播。HC-Pro的N-末端结构域富含半胱氨酸，负责整个植物的载体传播和系统传播。作为了解植物病毒传播的第三种方法，我们正在进行对卡莫病毒，豇豆斑驳病毒（CPMoV）的结构研究。我们已经确定了CPMoV的低分辨率（约23埃）结构，和衣壳组织是非常相似的Tombusviridae番茄丛矮病毒（TBSV）的另一个成员。然而，与TBSV不同的是，CPMoV对RNA酶不敏感-RNA酶被认为是其通过甲虫传播所必需的特性。这种病毒的结构细节应该阐明这些差异的原因在RNA酶敏感性。我们将开始对黄病毒的非结构蛋白进行晶体学研究。虽然这项工作刚刚开始，但PPG将促进对这些医学重要病毒的合作。

We propose to use this Program Project Grant as an opportunity to explore a diverse set of important biological issues. The topics fit in well with the collaborative theme of this PPG and will allow my laboratory to explore several new, important avenues of structural virology. A major theme of this grant is to use structural biology methods to examine the processes involved in the vector transmission of plant viruses. Using cucumber mosaic virus (CMV) as a model for viruses that are transmitted via aphids without helper proteins, we plan to examine the structural motifs that interact with aphid mouthparts and are required for aphid transmission. Preliminary work has identified surface residues for aphid transmission. We propose to extend the resolution of the current CMV model. This, combined with immunological and cryo-TEM techniques, will allow use to examine aphid-virus interactions. With poty viruses, a helper protein, HC-Pro, is required to be transmitted by aphids. The N-terminal domain of HC-Pro is cysteine rich and is responsible for vector transmission and systemic spread throughout the plant. As a third approach to understanding transmission of plant viruses, we are pursuing structural studies on the carmovirus, cowpea mottle virus (CPMoV). We have determined the low resolution (approximately 23 angstroms) structure of CPMoV, and the capsid organization is very similar to that of another member of the Tombusviridae tomato bushy stunt virus (TBSV). However, unlike TBSV, CPMoV is not sensitive to RNAse- a property thought to be essential for its transmission by beetles. Structural details of this virus should elucidate the reason underlying these differences in RNAse sensitivity. We will initiate crystallographic studies on the non-structural proteins of the flaviviruses. While this work is just beginning, the PPG will facilitate collaborative efforts on these medically important viruses.