Collaborative Research: Functional Analysis of the Synechococcus PCC 7942 Genome

合作研究：聚球藻 PCC 7942 基因组的功能分析

• 批准号: 9907528
• 负责人: Patricia Hartzell
• 金额: $ 30万
• 依托单位: Regents of the University of Idaho
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-15 至 2001-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9907528&HistoricalAwards=false
• 关键词: Collaborative; Research; Functional; Analysis; Synechococcus

Many organisms, including bacteria, fungi, plants, and animals, have a circadian "clock" that coordinates rhythms of gene expression and physiology that serve to anticipate changes in the day/night cycle, and which persist under constant conditions in the absence of environmental cues. The photosynthetic Cyanobacteria are the simplest organisms known to display circadian rhythms; among the cyanobacteria, Synechococcus elongatus has the smallest known genome (~2.7 Mb). This unicellular organism requires light for growth, and offers many advantages for understanding the molecular mechanism of the circadian clock, including its transformability and efficient systems of homologous recombination. The genes required for clock function and synchronization by light in S. elongatus will be identified in the context of determining its complete genome sequence.Because S. elongatus has a very small genome, it is a model organism in which to isolate and characterize mutations that affect the clock mechanism, its sensitivity to light, and its connection to cellular functions. A cosmid library consisting of 45 kb inserts of S. elongatus genomic DNA will be made, then ordered by the genetic method of complementation. This ordering method will reveal the organization of this organism's biosynthetic functions, functions common to all complex genomes. Subclones in this library will be mutagenized with the insertion element MudS to generate mutant pools corresponding to each region of the genome. These MudS insertions will be crossed onto the S. elongatus genome to generate mutants, and simple screens will be used to identify insertions in genes required for clock function and regulation. These MudS insertions will also be used as starting points for the determination both of the genome sequence, and of the locations of these mutations within the genome sequence. This new function-based approach to genome mapping and sequencing will be more informative and less costly than current, random sequencing approaches. The sequence of the S. elongatus genome, when combined with an understanding of the effects of mutations in the genome, will reveal the most minimal set of functions required for both the clock mechanism and photosynthetic metabolism. Because of the close evolutionary relationship between S. elongatus and plant chloroplasts, understanding the S. elongatus genome will provide a simpler basis for understanding the more complex genomics of higher plants.

许多生物体，包括细菌、真菌、植物和动物，都有一个昼夜节律“时钟”，它协调基因表达和生理学的节律，用于预测昼夜周期的变化，并且在没有环境线索的恒定条件下持续存在。进行光合作用的蓝细菌是已知的最简单的具有昼夜节律的生物体。在蓝藻细菌中，细长聚球藻具有已知最小的基因组 (~2.7 Mb)。这种单细胞生物需要光才能生长，并为理解生物钟的分子机制提供了许多优势，包括其可变形性和高效的同源重组系统。 S. elongatus 的时钟功能和光同步所需的基因将在确定其完整基因组序列的背景下进行鉴定。由于 S. elongatus 的基因组非常小，因此它是一种模式生物，可用于分离和表征影响时钟机制、其对光的敏感性及其与细胞功能的联系的突变。将制备由 S. elongatus 基因组 DNA 的 45 kb 插入片段组成的粘粒文库，然后通过互补的遗传方法进行排序。这种排序方法将揭示该生物体的生物合成功能的组织，以及所有复杂基因组共有的功能。该文库中的亚克隆将使用插入元件 MudS 进行诱变，以生成与基因组每个区域相对应的突变体库。这些 MudS 插入将被杂交到 S. elongatus 基因组上以产生突变体，并且简单的筛选将用于识别时钟功能和调节所需的基因中的插入。这些 MudS 插入也将用作确定基因组序列以及这些突变在基因组序列中的位置的起点。这种新的基于功能的基因组作图和测序方法将比当前的随机测序方法提供更多信息且成本更低。 S. elongatus 基因组序列与对基因组突变影响的理解相结合，将揭示时钟机制和光合代谢所需的最小功能集。由于 S. elongatus 和植物叶绿体之间密切的进化关系，了解 S. elongatus 基因组将为了解高等植物更复杂的基因组学提供更简单的基础。