CAREER: Elucidating the molecular mechanism of the Vibrio cholerae Vc2 cyclic di-GMP riboswitch

智力价值：所有生物面临的一个根本决定是，是定居在一个给定的环境中，还是迁移到一个新的环境中。对于细菌来说，这一决定包括在活动状态和固着生物膜形成存在之间的转换。生物膜的定义是包裹在保护性细胞外基质中的细菌的多细胞群落。生物膜是自然界中细菌生长的主要形式，使细菌能够在捕食、有毒化学物质和恶劣条件下生存。因此，生物膜在每个环境中都代表着重要的生态位，并影响着农业、生物能源和水净化等工业应用。在过去的十年中，很明显，细胞内的信号分子c-di-GMP(c-di-GMP)在绝大多数细菌控制运动和生物膜形成之间的过渡过程中发挥着基础性的作用。然而，c-di-GMP调控这些行为的分子机制还不是很清楚。本研究将探讨c-di-GMP发挥作用的新机制。在霍乱弧菌中，c-di-GMP与一种被称为核糖开关的保守RNA结构结合。传统上，核糖开关通过控制下游基因在同一RNA片段上的表达来发挥作用。在霍乱弧菌中，这种核糖开关被指定为VC2。然而，初步实验表明，c-di-GMP与VC2的结合实际上增加了上游小RNA(SRNA)的稳定性，从而似乎影响了细菌的行为。该项目将重点研究(A)c-di-GMP与VC2的结合如何稳定靶sRNAs；(B)VC2靶基因受到调控；以及(C)VC2 RNAs影响细菌的生物学。这项研究可能会揭示一种新的基因调控机制，它控制着生物膜形成的不同阶段之间的过渡。此外，该项目的发现将启发培养有益生物膜同时抑制有害生物膜的新方法。广泛的影响：该项目还将作为一个平台，让学术界成员和普通公众广泛参与科学教育和讨论。在该奖项期间，将教授和指导高级微生物学课程(微生物遗传学)和研究人员实验室的本科生和研究生，使他们成为未来科学界中训练有素的成员。调查员还将发起一系列活动，进一步吸引公众参与，例如在密歇根州兰辛的“印象5”科学中心组织一年一度的“微生物日”活动。这位研究人员还将开发和教授一个名为“科学热点”的继续教育项目，作为密歇根州立大学晚间学院课程的一部分。这门课将为当地社区的成年人提供一些公众意识中普遍存在的有争议的科学主题背后的科学原理。该项目团队还将指导当地高中科学教师关于密歇根州立大学“科学前沿”计划中的微生物生物膜。最后，研究团队将培训从密歇根州立大学提供的暑期研究机会(SROP)项目中招募的代表性不足的学生。

Intellectual Merit: A fundamental decision faced by all organisms is whether to colonize a given environment or migrate to new a one. For bacteria, this decision consists of transitioning between a motile state, and a sessile, biofilm forming existence. Biofilms are defined as multicellular communities of bacteria that are encased in a protective extracellular matrix. Biofilms are the predominant form of bacterial growth in nature, and allow bacteria to survive predation, toxic chemicals, and harsh conditions. Thus, biofilms represent important ecological niches in every environment and influence industrial applications such as agriculture, bioenergy and water purification. Over the last decade, it has become apparent that the intracellular signaling molecule cyclic di-GMP (c-di-GMP) plays a fundamental role in the vast majority of bacteria to control the transition between motility and biofilm formation. However, the molecular mechanisms by which c-di-GMP regulates these behaviors are not well understood. This research project will study a novel mechanism by which c-di-GMP exerts its function. In Vibrio cholerae, c-di-GMP binds to a conserved RNA structure called a riboswitch. Riboswitches traditionally function by controlling the expression of the downstream gene on the same RNA segment. In V. cholerae, this riboswitch is designated as Vc2. However, preliminary experiments suggest that binding of c-di-GMP to Vc2 actually increases the stability of an upstream small RNA (sRNA), which then appears to impact bacterial behaviors. This project will focus on how (a) binding of c-di-GMP to Vc2 stabilizes the traget sRNAs; (b)the Vc2 target genes are regulated; and (c) the Vc2 RNAs impacts the biology of the bacterium. This research is likely to uncover a novel genetic regulatory mechanism that governs the transitioning between distinct phases of biofilm formation. Moreover, discoveries from this project will inspire new approaches to cultivate beneficial biofilms while inhibiting harmful ones.Broader Impacts: This project will also serve as a platform to broadly engage members of the academic community and the general public in scientific education and discourse. During the period of this award, undergraduate and graduate students in an upper level microbiology course (Microbial Genetics) and in the investigator's laboratory will be taught and mentored to become highly trained members of the future scientific community. The investigator will also initiate a number of activities to further engage the general public such as the organization of an annual "Microbiology Day" at "Impression 5" science center located in Lansing, MI. The investigator will also develop and teach a continuing education program titled "Hot Topics in Sciences" as part of the Evening College curriculum at MSU. This class will provide adults from the local community with the scientific principles behind a number of controversial science topics prevalent in the public consciousness. The project team will also instruct local high-school science teachers about microbial biofilms in the MSU "Frontiers in Science" program. Finally, the research team will train underrepresented students recruited from the Summer Research Opportunities (SROP) program offered by Michigan State University.