Development-Associated Linear Chromosome Segregation in Streptomyces

项目摘要 链霉菌是普遍存在的丝状产孢子型土壤细菌，在环境中很重要 因为它们降解和循环锁定在许多顽固的天然聚合物中的营养物质 土壤(如纤维素和甲壳素)，并产生广泛的生物活性的大部分 在人类和兽医中广泛使用的化合物(例如，抗生素，抗病毒， 抗癌、抗肿瘤、抗真菌、免疫抑制和驱虫药物)。 链霉菌也是众所周知的，它是提供土壤的化合物的主要生产者之一。 特有的泥土气味。这些生物有很大的线性基因组。人们对此知之甚少 链霉菌孢子线状染色体构型及其机制 控制与发育相关的基因组分离和孢子期间的类核凝聚 人们对队形知之甚少。拟议的基础研究的最终目标是有一个 更好地理解这些独特的生物的新的细胞过程 医学上的重要性。 链霉菌基因组不同寻常的菌丝生命周期和线性结构可能需要 一些独特的解决方案，解决了基因组分离和凝聚的根本问题。这个 该提案的第一个具体目标是表征一种新的小卷曲蛋白，它是独有的 这群有机体。一种遗传方法被用来提供证据，证明这种蛋白质是 参与发育相关的基因组分离。一种邻近标记方法，具有 混杂生物素连接酶融合正被用于鉴定与这种新蛋白相互作用的蛋白质。 在活体内。丙氨酸扫描和随机聚合酶链式反应指导的突变被用来鉴定残留物 对于与一个已知结合伙伴的蛋白质-蛋白质相互作用很重要。第二个具体目标是 III型分泌系统ATPase蛋白的特性。除了它们在蛋白质中的功能外 分泌，ATPase蛋白是兼职的，与发育相关的分离和类核 冷凝。将使用遗传学方法解剖第一个III型分泌物ATPase以 确定基因组分离所需的区域(S)。遗传方法也将被用来 确定两种III型分泌ATPase的部分，以确定正确的必需区域 孢子中的类核凝聚。缺乏同时编码III型分泌ATPase基因的突变体 基因组是否靠孢子外围(甜甜圈形状)排列，而不是浓缩 在孢子中心呈椭圆形的类核。

Project Summary Streptomyces are ubiquitous filamentous sporulating soil bacteria, important in the environment because they degrade and recycle the nutrients locked in many recalcitrant natural polymers in the soil (e.g., cellulose and chitin) and produce the majority of a wide range of biologically active compounds that are used extensively in human and veterinary medicine (e.g., antibiotic, antiviral, anticancer, antitumor, antifungal, immunosuppressant and anthelmintic pharmaceuticals). Streptomyces are also well known as one of the major producers of the compounds that give soil its characteristic earthy odor. These organisms have large linear genomes. Little is known about the architecture of the linear chromosome within the Streptomyces spore and the mechanisms which govern its development-associated genome segregation and nucleoid condensation during spore formation are poorly understood. The ultimate goal from the proposed basic research is to have a better understanding of the novel cellular processes of these distinctive organisms of tremendous medical importance. The unusual mycelial life cycle and linear structure of the Streptomyces genome are likely to require some unique solutions to the fundamental problems of genome segregation and condensation. The first specific aim of the proposal is to characterize a novel small coiled-coil protein that is exclusive to this group of organisms. A genetic approach was used to provide evidence that this protein is involved in development-associated genome segregation. A proximity-labeling approach, with a promiscuous biotin ligase fusion, is being used to identify proteins that interact with this novel protein in vivo. Alanine-scanning and random PCR-directed mutageneses are being used to identify residues important for protein-protein interaction with one known binding partner. The second specific aim is to characterize type VII secretion system ATPase proteins. In addition to their functions in protein secretion, the ATPase proteins are moonlighting in development-associated segregation and nucleoid condensation. A genetic approach will be used to dissect the first type VII secretion ATPase to identify the region(s) needed for genome segregation. A genetic approach will also be used to determine the parts of both type VII secretion ATPases to identify the regions necessary for correct nucleoid condensation in the spore. Mutants lacking genes encoding both type VII secretion ATPases have genomes organized against the spore periphery (doughnut-shaped) instead of being condensed as an ellipsoid nucleoid in the center of the spore.