Emerging Frontier 03: Functional Analyses of the Genome of the Phenotypically Complex, Multicellular Cyanobacterium Nostoc Punctiforme

这个项目的实验核心是蓝藻斑点藻的功能基因组分析。已完成了斑点孢螨9.25 Mbp基因组的霰弹枪测序，并在http://www.jgi.doe.gov上提供了一个带注释的数据库。点孢霉具有非常广泛的生态位、生理特性和细胞发育选择，包括在自由生活和植物共生生长状态下固定氮的非凡能力。固氮发生在被称为异囊的终末分化细胞中。除了异囊外，点状芽孢杆菌的营养细胞还能瞬间分化为静止细胞，即动胞细胞和活动细丝，即激殖细胞。工作的假设是，调控元件和途径控制细胞分化替代和共生相互作用的n点状蓝藻独特进化。因此，除了计算分析外，还需要功能性分析来识别基因组中存在的发育遗传元件和调控回路。了解这些电路是如何在n点虫中整合的，对复杂生物体的发育途径进化具有重要意义。该项目将利用全球基因表达分析的高通量基因组方法，使用DNA微阵列和诱变。所产生的资源，包括基因组中存在的所有单独扩增的基因，将提供给国内和国际蓝藻群落。研究人员在原则上的调查员，技术人员，博士后研究员，研究生和本科生的水平，将在开发和应用这些新的方法，以这种复杂的蓝藻互动；因此，该项目提供了一个综合培训的机会。

The experimental core of this project is functional genomic analyses of the cyanobacterium Nostoc punctiforme. The shotgun sequencing of the 9.25 Mbp genome of N. punctiforme has been completed and an annotated database is available at http://www.jgi.doe.gov . N. punctiforme has an extraordinarily wide range of ecological niches, physiological properties and cellular developmental alternatives, including the unusual ability of fixing nitrogen in both free-living and plant-associated symbiotic growth states. Nitrogen fixation occurs in terminally differentiated cells called heterocysts. In addition to heterocysts, N. punctiforme vegetative cells can transiently differentiate into resting cells termed akinetes and motile filaments called hormogonia. The working hypothesis is that the regulatory elements and pathways governing cellular differentiation alternatives and symbiotic interactions of N. punctiforme uniquely evolved in cyanobacteria. Therefore, functional, in addition to computational, analyses are required to identify the developmental genetic elements and regulatory circuits present in the genome. Understanding how these circuits are integrated in N. punctiforme has implications on the evolution of developmental pathways in complex organisms. This project will utilize high throughput genomic methodologies of global gene expression assays, using DNA microarrays, and mutagenesis. The resources generated, including all of the individually amplified genes present in the genome, will be made available to the national and international cyanobacterial community. Researchers at the level of principle investigators, technicians, postdoctoral fellows, graduate and undergraduate students, will interact in developing and applying these new methodologies to this complex cyanobacterium; thus, the project affords an integrative training opportunity.