QUORUM SENSING AND GENE EXPRESSION IN BACILLUS SUBTILIS

描述：细胞间信号传导控制着生物学中的许多过程。 世界，包括发展，发病机制，交配，转化。 信号传导过程通常由因子介导（e. 例如，在一个实施例中，荷尔蒙， 信息素，神经递质），由一些细胞产生，并通过 他人 在细菌中，感知和响应高种群的能力 密度是一种自分泌细胞-细胞信号传导， 群体感应 细胞产生细胞外信号分子， 随着人口密度的增加而积累， 在临界密度下发生。 这个项目的长期目标是了解群体感应 控制枯草芽孢杆菌中的基因表达和分化。 我们将 集中在两个肽信号因子，有助于群体感应， B。枯草芽孢杆菌：（1）ComX信息素，具有疏水性的10个氨基酸的肽， 色氨酸上的修饰，和（2）感受态和孢子形成刺激 因子，CSF，未修饰的五肽。 两种信号分子 当细胞生长到高密度时在培养基中积累， 转录因子ComA的激活（磷酸化）。 那里 通过ComX信息素和CSF进行信号传导需要许多步骤，包括 活性信号分子的产生以及与 合适的靶分子。 CSF通过一种 寡肽通透酶Spo0K是ATP依赖性的 转运蛋白，而ComX信息素可能与膜相互作用 受体组氨酸蛋白激酶复合物。我们计划解决以下问题 有关的问题都ComX信息素和CSF：什么是 生物活性的决定因素？ 什么控制生产？ 是什么 反应的机制以及反应的直接目标是什么 互动？ 哪些基因被细胞反应激活？ 我们 在这个相对简单的， 实验上可获得的微生物应该提供对一般 细胞-细胞信号传导、信号转导和调节的机制。

DESCRIPTION: Cell-cell signaling controls many processes in the biological world, including development, pathogenesis, mating, and transformation. Signaling processes are often mediated by factors (e. g., hormones, pheromones, neurotransmitters) that are produced by some cells and sensed by others. In bacteria, the ability to sense and respond to high population density is a type of autocrine cell-cell signaling often referred to as quorum sensing. Cells produce extracellular signaling molecules that accumulate as population density increases, and a physiological response occurs at a critical density. The long term goal of this project is to understand how quorum sensing controls gene expression and differentiation in Bacillus subtilis. We will focus on two peptide signaling factors that contribute to quorum sensing in B. subtilis: (1) ComX pheromone, a 10 amino acid peptide with a hydrophobic modification on a tryptophan, and (2) competence and sporulation stimulating factor, CSF, an unmodified pentapeptide. Both signaling molecules accumulate in culture medium as cells grow to high density and contribute to the activation (phosphorylation) of the transcription factor ComA. There are many steps required for signaling by ComX pheromone and CSF, including production of the active signaling molecules and interaction with the appropriate target molecules. CSF is transported into the cell via a the oligopeptide permease Spo0K, a member of the large family of ATP-dependent transporters, whereas ComX pheromone probably interacts with a membrane receptor histidine protein kinase ComP. We plan to address the following questions relating to both ComX pheromone and CSF: What are the determinants of biological activity? What controls production? What are the mechanisms of the response and what are the direct targets of interaction? What genes are activated by the cellular response? Our studies on quorum sensing and gene expression in this relatively simple, experimentally accessible microbe should provide insights into general mechanisms of cell-cell signaling, signal transduction, and regulation.