Stable maintenance of an extrachromosomal selfish DNA

染色体外自私DNA的稳定维持

• 批准号: 6736898
• 负责人: Makkuni JAYARAM
• 金额: $ 23.2万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6736898
• 关键词: DNA replication; binding sites; chromosome movement; cytology; extrachromosomal DNA; fluorescence microscopy; fungal genetics; fungal proteins; genetic regulatory element; green fluorescent proteins; host organism interaction; immunoprecipitation; nucleic acid amplification techniques; nucleic acid sequence; parasitism; plasmids; virus replication; yeasts

DESCRIPTION (provided by applicant): The yeast plasmid 2 micron circle provides a simple model system to study the molecular mechanisms by which a 'benign parasite genome' optimizes its survival strategies without compromising the fitness of its host. The informational content and organization of the plasmid genome is designed for its stable maintenance in the population at a steady state copy number that does not strain the host metabolic machinery. One molecular component of this high copy self-propagation mechanism is a stability system that ensures equal distribution of replicated plasmid molecules to daughter cells during cell division. Two plasmid-encoded proteins, together with a cis-acting DNA sequence (called the STB locus), are essential for the normal operation of the stability system. In addition, host encoded factors may contribute towards equipartitioning of plasmids. The 2-micron circle has also devised an amplification system, which comes into operation only when there is a drop in copy number due to an occasional failure in equal segregation. Amplification is mediated by the Flp recombinase (Flp for flipping or inverting DNA), whose activity converts a single replication initiation event into a multiple copying mechanism, thus quickly restoring copy number. In this proposal, we describe experiments that attempt to shed light on how the plasmid and host encoded components interact to establish a functional stability system. We believe that some of the principles gleaned from this study will have global implications in the symbiotic relationships among host-parasite genomes in prokaryotes and eukaryotes.

描述（由申请人提供）：酵母质粒2微米圆圈提供 一个简单的模型系统，用于研究分子机制的良性机制 寄生虫基因组在不损害的情况下优化其生存策略 宿主的健身。质粒的信息内容和组织 基因组是为其在人口稳定的稳定维护而设计的 状态拷贝数不会劳累主机代谢机械。一 这种高拷贝自传播机制的分子成分是一种稳定性 确保复制的质粒分子相等分布到 细胞分裂期间的子细胞。两个质粒编码的蛋白，一起 带有顺式作用DNA序列（称为STB基因座），对于 稳定系统的正常操作。此外，主机编码的因素可能 有助于质粒的均衡。 2微米圆也有 设计了一个放大系统，仅在有 由于偶尔出现相等隔离而导致的拷贝数下降。 扩增由FLP重组酶（用于翻转或反转的FLP）介导 DNA），其活性将单个复制启动事件转换为 多个复制机制，因此快速恢复副本号。 在此提案中，我们描述了试图阐明如何阐明的实验 质粒和宿主编码的组件相互作用以建立功能 稳定系统。我们认为，一些原则从中得到了 研究将对之间的共生关系具有全球影响 原核生物和真核生物中的宿主寄生虫基因组。