Exploring Tr1-regulated transcription networks underpinning adaptation of pathogenic Anaplasma to the tick host

项目摘要 壁虱传播的疾病正在增加，并且几乎是所有媒介传播疾病的罪魁祸首。 在美国。病媒传播的病原体面临着适应两种截然不同的宿主的双重挑战 环境：节肢动物媒介和哺乳动物宿主。扁虱含有不同的生理信号 包括体温、养分可获得性、生理结构和独特的 免疫压力。一旦进入扁虱，吞噬细胞性弧菌必须进一步适应，以构建一个复制体 节肢动物细胞内的生态位。对扁虱环境的反应不同，吞噬细胞门A. 与哺乳动物细胞培养相比，感染扁虱细胞时转录其41%的基因。目前尚不清楚 是什么控制着这种广泛的重新编程，或者它是如何促进吞噬细胞群适应扁虱的。一 预测的转录因子tr1在所有吞噬阿糖胞菌基因中显示出最高的扁虱特异性表达。 我们的结构模型确定TR1是异种生物中的同源二聚体螺旋-转角螺旋DNA结合蛋白 转录因子的反应元件家族。转座子插入对tr1基因的干扰没有影响 小鼠体内的细菌负荷或人类细胞系中的生长。然而，缺乏tr1的吞噬弧菌在很大程度上 因被壁虱感染而变弱，不能在壁虱细胞中存活。鉴于TR1对生存的重要性 在节肢动物载体及其作为转录开关的预测角色中，我们假设：TR1作为一种 通过协调壁虱特异基因网络的表达，控制壁虱适应的主要调节因子。在这项研究中 我们将鉴定与TR1结合的DNA序列及其转录调控模式。此外，我们还将 确定TR1如何有助于完成蜱细胞感染周期，并测量TR1如何重塑A。 蜱细胞感染过程中的吞噬细胞转录组。揭示吞噬细胞性假单胞菌如何适应感染 TICK细胞将打开开发载体靶向干预的大门，以降低病毒的传播性 病原体。

Project Summary Tick-borne diseases are on the increase and are responsible for nearly all of the vector-transmitted disease in the US. Vector-borne pathogens face the dual challenge of adaptation to two very different host environments: the arthropod vector and the mammalian host. Ticks contain distinct physiological cues including disparities in body temperature, nutrient availability, physiological architecture, and unique immunological pressures. Once in the tick, A. phagocytophilum must further adapt to construct a replicative niche within the arthropod’s cells. In response to the tick environment, A. phagocytophilum differentially transcribes 41% of its genes when infecting tick cells in comparison to mammalian cell culture. It is not known what controls this extensive reprogramming or how it facilitates A. phagocytophilum adaptation to the tick. One predicted transcription factor, tr1, displays the highest tick-specific expression of all A. phagocytophilum genes. Our structural modeling identifies Tr1 as a homo-dimeric helix-turn-helix DNA binding protein in the xenobiotic response element family of transcription factors. Disruption of tr1 by transposon insertion had no impact on bacterial burden in mice or growth in human cell lines. However, A. phagocytophilum lacking tr1 was greatly attenuated for acquisition by ticks and is unable to survival in tick cells. Given the importance of Tr1 for survival in the arthropod vector and its predicted role as a transcriptional switch, we hypothesize that: Tr1 operates as a master regulator for tick adaptation by orchestrating the expression of tick-specific gene networks. In this study we will identify the DNA sequences bound by Tr1 and its mode of transcription regulation. Further, we will identify how Tr1 contributes to completion of the tick cell infection cycle and measure how Tr1 remodels the A. phagocytophilum transcriptome during tick cell infection. Revealing how A. phagocytophilum adapts to infect tick cells will open the door to development of vector targeted interventions to reduce transmissibility of the pathogen.