C-Signal-Dependent Gene Expression in Myxococcus Xanthus

在自然界中，细菌通常作为称为生物膜的复杂群落的成员存在。细胞在生物膜内相互作用，相互发送信号，并改变它们的行为作为回应。了解细菌如何相互作用以及与宿主的相互作用是生物学中的一个基本挑战。在混合菌群中进行细胞间相互作用的分子分析是困难的。相比之下，某些细菌如黄色粘球菌很容易形成生物膜，其中细胞广泛相互作用。饿了，M。xanthus细胞移动到聚集中心并构建新生子实体。在子实体内，杆状细胞分化成球形休眠孢子。C-信号转导在M. Xanthus的发展正在为细菌细胞如何相互作用建立一个新的范例。C-信号传导涉及CsgA，这是一种在发育细胞中产生的蛋白质，与细胞表面结合。已经提出CsgA的蛋白水解片段在细胞之间的端对端接触时充当信号。C-信号传导在受体细胞中诱导几种反应。它调节细胞运动、基因表达和孢子形成。有趣的是，对C信号的不同反应需要不同水平的CsgA，并且CsgA的水平在发育过程中上升。因此，C-信号似乎决定了发展中期至晚期的事件顺序。该项目的长期目标是确定发育基因表达响应C信号的分子机制。这项研究更广泛的影响是，它将为细菌如何在生物膜中相互作用提供范例。所获得的见解将在环境清理，工业过程，农业实践和动物健康中得到应用。此外，该研究将有助于通过培养本科生、研究生和博士后学生来开发科学人力资源。

In nature, bacteria often exist as members of complex communities called biofilms. Cells interact within biofilms, sending signals to each other and changing their behavior in response. Understanding how bacteria interact with each other and with their hosts is a fundamental challenge in biology. Molecular analysis of cell-cell interactions in mixed populations of bacteria is difficult. In contrast, certain bacteria like Myxococcus xanthus readily form biofilms in which cells interact extensively. When starved, M. xanthus cells move to aggregation centers and construct a nascent fruiting body. Within the fruiting body, rod-shaped cells differentiate into spherical, dormant spores. Studies of C-signaling during M. xanthus development are establishing a new paradigm for how bacterial cells can interact. C-signaling involves CsgA, a protein produced in the developing cells that becomes associated with the cell surface. It has been proposed that a proteolytic fragment of CsgA serves as a signal upon end-to-end contact between cells. C-signaling induces several responses in recipient cells. It regulates cell movements, gene expression, and sporulation. Intriguingly, the different responses to C-signaling require different levels of CsgA, and the level of CsgA rises during development. Therefore, C-signaling appears to dictate the order of events during the middle to late stages of development. The long-term goal of this project is to determine the molecular mechanisms of developmental gene expression in response to C-signaling. The broader impact of the research is that it will provide paradigms for how bacteria might interact in biofilms. The insights gained will find application in environmental cleanup, industrial processes, agricultural practices, and animal health. Also, the research will contribute to the development of human resources in science through the training of undergraduates, graduate, and postdoctoral students.