Biogenesis of Gas Vesicles in Halobacterium

盐杆菌中气体囊泡的生物发生

• 批准号: 9809906
• 负责人: Shiladitya DasSarma
• 金额: $ 46.61万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-10-01 至 2001-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9809906&HistoricalAwards=false
• 关键词: Biogenesis; Gas; Vesicles; Halobacterium

9809906StuartGas vesicles are unique organelles produced by many aquatic prokaryotic microorganisms and used presumably for flotation. They are bounded by an unusually stable proteinaceous membrane that enfolds a gas filled space. Although detected in numerous groups of prokaryotic species representing both archaea and true bacteria since their discovery in 1888 by Winogradsky, the general morphology of the vesicles appears very similar and at least the major proteins appear homologous. For many years, researchers hypothesized that gas vesicles were formed from a single self-associating protein. However, recent molecular genetic work by DasSarma and his colleagues, using the archaeal prokaryote Halobacterium as their model system, led to the discovery of a large cluster of genes involved in gas vesicle formation. Further, they were able to transfer the gene cluster to laboratory strains of E. coli and engineer the expression of gas vesicles in this bacterium, which does not naturally produce gas vesicles. The gene cluster is hypothesized to comprise three genes coding for structural proteins, in rightward transcriptional orientation, and ten or more genes encoding regulatory or initiation proteins, in leftward transcriptional orientation.DasSarma and his colleagues are continuing their work on biogenesis of gas vesicles in Halobacterium, using immunological and molecular-genetic methods to analyze the sequence and timing of steps in protein formation, assembly, and regulation to build functional gas vesicles. Individual proteins are to be tagged using immunological procedures, and then localized within the organism using immunogold cytological nethods. Mutants strains of Halobacterium will also be studied to determine the sequence of gene activation and action leading to vesicle formation. Complementation studies with mutants and purified protein products will help understand the dynamics of protein interactions in building the vesicle membrane. The overall goal is to describe the component proteins and regulatory signals in the biogenesis of gas vesicles and understand the sequence of genetic and metabolic events leading to their formation

9809906斯图尔特气体囊泡是由许多水生原核微生物产生的独特细胞器，并可能用于浮选。它们被一种异常稳定的蛋白质膜所包围，这种膜包裹着一个充满气体的空间。虽然自Winogradsky于1888年发现以来，在代表古生菌和真细菌的许多原核物种中检测到，但囊泡的一般形态似乎非常相似，至少主要蛋白质似乎是同源的。多年来，研究人员假设气体囊泡是由单个自缔合蛋白形成的。然而，DasSarma和他的同事最近的分子遗传学工作，使用古细菌原核生物Halobacterium作为他们的模型系统，导致发现了一大簇参与气泡形成的基因。此外，他们能够将基因簇转移到实验室的E。大肠杆菌，并在这种细菌中设计气泡的表达，这种细菌不会天然产生气泡。DasSarma和他的同事们正在继续他们对盐杆菌中气泡生物发生的研究，使用免疫学和分子遗传学方法来分析蛋白质形成、组装、组装和释放的顺序和时间，和调节来构建功能性气体囊泡。单个蛋白质将使用免疫程序标记，然后使用免疫金细胞学方法在生物体内定位。还将研究盐杆菌的突变菌株，以确定导致囊泡形成的基因激活和作用的序列。突变体和纯化的蛋白质产物的互补研究将有助于了解蛋白质相互作用的动态构建囊泡膜。总的目标是描述组成蛋白质和调控信号在生物成因的气体囊泡和了解序列的遗传和代谢事件导致其形成