Anaplasma phagocytophilum induce Ixodes scapularis antifreeze glycoprotein gene e

描述(申请人提供)：硬蜱在美国东北部和中西部地区越冬，传播各种人类病原体，包括人类无浆体吞噬细胞性疾病。我的初步数据显示，扁虱体内的吞噬弧菌的存在增加了我的肩胛虫在寒冷中生存的能力。我已经鉴定了一种被命名为IAFGP的肩胛虫抗冻糖蛋白，并通过RNAi敲除研究证明了IAFGP对硬蜱在寒冷环境中生存的重要性。转基因研究还表明，IAFGP提高了酵母细胞在低温下的活力。值得注意的是，我发现吞噬细胞能诱导IAFGP的表达，从而提高我肩周炎的耐寒性。这些数据确定了吞噬弧菌和肩袖弧菌共生的分子基础。吞噬弧菌诱导IAFGP表达的机制尚不清楚。因此，有必要研究吞噬弧菌对载体基因表达的影响机制，以及载体宿主在低温下的存活情况。以下是了解其机制的具体目标：在目标1中，我将鉴定和鉴定肩胛肌中的IAFGP启动子。这方面的研究将探讨IAFGP启动子在吞噬弧菌感染时是否被激活。在目标2中，将进行研究，以确定可能参与IAFGP启动子诱导的宿主转录激活因子的作用。综上所述，这些研究不仅阐明了吞噬细胞性嗜血杆菌和肩部伊蚊共生的分子机制，而且为研究宿主与病原体的相互作用开辟了一条新的途径。 与公共卫生相关：在美国，传播几种人类病原体的肩部硬蜱的生活史涉及越冬阶段。我以前的研究表明，一种人类致病细菌吞噬细胞门与其节肢动物载体建立了共生关系，通过选择性地诱导一种新的抗冻糖蛋白(IAFGP)在肩部硬蜱中提高其在寒冷中的生存能力。本研究的目的是为了了解吞噬弧菌上调IAFGP基因表达的机制，以利于自身的利益和载体宿主在低温下的生存。

DESCRIPTION (provided by applicant): Ixodes scapularis ticks overwinter in the Northeast and Upper Midwest parts of United States, and transmit various human pathogens that include human anaplasmosis agent Anaplasma phagocytophilum. My preliminary data show that the presence of A. phagocytophilum in ticks increases the ability of I. scapularis to survive in the cold. I have identified an I. scapularis antifreeze glycoprotein, designated as IAFGP and demonstrate, via RNAi knockdown studies, the importance of IAFGP for the survival of ticks in a freezing environment. Transfection studies also show that IAFGP increases the viability of yeast cells subjected to low temperatures. Remarkably, I have found that A. phagocytophilum induce the expression of iafgp and thereby increase the cold tolerance of I. scapularis. These data define a molecular basis for symbiosis between A. phagocytophilum and I. scapularis. The mechanism by which A. phagocytophilum, induce iafgp expression is not understood. Therefore studies will be performed to elucidate the mechanism by which A. phagocytophilum influence vector gene expression for its own benefit as well as its vector host survival during freezing temperatures. Following are the specific aims that will be addressed to understand the mechanism: In aim 1, I will identify and characterize iafgp promoter in I. scapularis. The studies in this aim will address whether iafgp promoter is activated upon A. phagocytophilum infection. In aim 2, studies will be undertaken to characterize the role of host transcriptional activators that may be involved in iafgp promoter induction. Collectively, the proposed studies not only elucidate the molecular mechanisms of symbiotic association between A. phagocytophilum and I. scapularis ticks but also delineate a new approach to study host-pathogen interaction. PUBLIC HEALTH RELEVANCE: In United States, the life-cycle of Ixodes scapularis ticks that transmit several human pathogens involves overwintering stages. My previous studies show that a human pathogenic bacterium A. phagocytophilum establishes a symbiotic relationship with its arthropod vector to enhance survival in the cold, via the selective induction of a novel antifreeze glycoprotein (iafgp) in Ixodes scapularis. The goal of this proposal is to understand the mechanism by which A. phagocytophilum up-regulate iafgp gene expression for its own benefit and for its vector host survival in the cold temperature.