A Novel Fur Protein in Bradyrhizobium japonicum

铁是几乎所有生物体内的一种基本营养素。然而，铁在高浓度时也会对细胞产生毒性，因此生物体必须保持这种营养的适当平衡。该项目旨在了解细胞如何感知环境中铁的可获得性，并调节细胞中铁的浓度。本论文主要研究慢生型根瘤菌中铁的动态平衡，它是一种重要的农业细菌，也是研究基因表达代谢调控的良好模型。大多数细菌含有一种名为毛皮的蛋白质，它能感知铁并与铁结合，并调节与铁代谢有关的基因。毛皮功能的模型是，与铁的结合赋予蛋白质通过识别特定的靶DNA序列来负调控基因的能力。然而，来自B.Japan(BjFur)的毛皮蛋白(BjFur)具有独特的性质，表明了新的细胞角色。特别是，BjFur与其他Fur蛋白质识别的DNA序列结合，但也特定地与Fur不能识别的来自其他细菌的DNA元件结合。此外，最近的证据有力地表明，BjFur可以在铁限制下发挥作用，这在其他生物体中还没有报道。这些观察结果导致了一种假设，即毛皮在其活动和角色上的功能比通常认为的更多样化。将进行实验，以解决日本血吸虫毛皮蛋白的新特征。这项工作将涉及对研究生和本科生的培训，并将大力鼓励妇女和代表不足的少数族裔受训人员参与。

Iron is an essential nutrient in almost all living organisms. However, iron can also be toxic to cells in high concentrations, and therefore organisms must maintain the proper balance of this nutrient. This project aims to understand how cells sense the availability of iron in the environment and regulate its concentration in cells. The research focuses on iron homeostasis in Bradyrhizobium japonicum, a bacterium important to agriculture and a good model for studying the metabolic regulation of gene expression. Most bacteria contain a protein called Fur, which senses and binds to iron, and regulates genes involved in iron metabolism. The model for Fur function is that binding to iron confers on the protein the ability to negatively regulate genes by recognizing specific target DNA sequences. However, the Fur protein from B. japonicum (BjFur) has unique properties that indicate novel cellular roles. In particular, BjFur binds to DNA sequences recognized by other Fur proteins, but also binds specifically to a DNA element not recognized by Fur from other bacteria. In addition, recent evidence strongly suggests that BjFur can function under iron limitation, which has not been reported in other organisms. These observations lead to the hypothesis that Fur is functionally more diverse in its activities and roles than is generally assumed. Experiments will be carried out that address the novel features of the B. japonicum Fur protein. This work will involve the training of graduate and undergraduate students, and will strongly encourage participation by women and underrepresented minority trainees.