Analysis of quorum-signaling crosstalk within the squid-vibrio symbiosis

描述（由申请人提供）：有益微生物对包括人类在内的真核生物的整体健康至关重要。为了探索有益微生物对宿主上皮组织慢性感染的基本原理，我一直在研究海洋细菌费氏弧菌（Vibrio fischeri）和夏威夷鱿鱼（Euprymna scolopes）之间的共生关系。特别是，我重点描述了fischeri弧菌的LuxU-LuxO信号系统，该信号系统在弧菌科的所有成员中都是保守的，包括霍乱弧菌和创伤弧菌等病原体。虽然这一信号系统调节致病弧菌的毒力因子，但我目前的研究表明，LuxU-LuxO信号对于V. fischeri与鱿鱼建立共生关系也很重要。最近，我发现多种传感器蛋白与LuxU-LuxO调控通路相互作用，这表明一个复杂的信号网络控制着参与细菌定植的基因的表达。在这里，我建议研究这种形式的信号串扰，因为它在自然中起作用。具体而言，我计划使用遗传和生化方法系统地表征LuxU与传感器蛋白之间的相互作用。我还将确定哪些传感器蛋白在宿主体内是活跃的，并确定其相应的规则。最后，我将确定LuxU-LuxO系统的信号传导是否对宿主粘液分泌有影响，这种影响在V. fischeri成功定殖乌贼后终止。这个K99奖将使我能够在博士的指导下完成博士后培训。爱德华·鲁比和玛格丽特·麦克福尔-恩盖，所以我可以启动一个综合的跨学科研究项目来研究宿主-微生物的相互作用作为一个独立的研究者在一个主要的研究机构。

DESCRIPTION (provided by applicant): Beneficial microbes are essential for the overall health of eukaryotic organisms, including humans. To explore the fundamental principles underlying chronic infections of host epithelial tissue by beneficial microbes, I have been studying the mutualistic symbiosis between the marine bacterium Vibrio fischeri and the Hawaiian squid Euprymna scolopes. In particular, I have focused on characterizing the LuxU-LuxO signaling system of V. fischeri, which is conserved in all members of the Vibrionaceae, including pathogens such as V. cholerae and V. vulnificus. While this signaling system regulates virulence factors in pathogenic vibrios, my current research shows that LuxU-LuxO signaling is also important for V. fischeri to establish the symbiosis with squid. Recently, I have discovered that multiple sensor proteins interact with the LuxU-LuxO regulatory pathway, suggesting that a complex signaling network controls the expression of genes involved in bacterial colonization. Here, I propose to examine this form of signaling crosstalk as it functions in nature. Specifically, I plan to systematically characterize the interactions between LuxU and the sensor proteins using both genetic and biochemical approaches. I will also identify which sensor proteins are active in the host and determine their corresponding regulons. Finally, I will determine whether signaling by the LuxU-LuxO system has an impact on host mucus secretion, which terminates after V. fischeri successfully colonizes the squid. This K99 award will enable me to complete my postdoctoral training under the mentorships of Drs. Edward Ruby and Margaret McFall-Ngai, so I may launch a comprehensive interdisciplinary research program to study host-microbe interactions as an independent investigator at a major research institution. PUBLIC HEALTH RELEVANCE: Bacteria must integrate multiple signaling inputs to coordinate responses appropriate to their environments. Examining cell signaling in a beneficial microbe within its natural host niche will uncover the fundamental principles of host-microbe interactions and contribute to our understanding of the roles microbes have on our health.