Control of Heterocyst Differentiation in Free-Living and Symbiotic Cyanobacteria

自由生活和共生蓝藻异囊分化的控制

• 批准号: 9206130
• 负责人: John Meeks
• 金额: $ 33.8万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1996-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9206130&HistoricalAwards=false
• 关键词: Control; Heterocyst; Differentiation; Free; Living

The PI hypothesizes that the mechanisms regulating the differentiation of heterocysts (sites of aerobic N2 fixation by Nostoc sp. differ when Nostoc is in symbiotic association relative to growth in the free-living state. He plans to use physiological and molecular genetics to test the hypothesis with analyses in both free-living and symbiotic growth states. Existing mutants will be complemented by electroporation of genomic DNA after in vitro ligation into a plasmid. Insertional mutagenesis will be used to isolate additional mutants. Interrupted genes will be isolated by rescue of the insertion elements; genomic DNA adjacent to the insertions will be cloned form cosmid libraries and characterized. Transcriptional regulation of glucose-6-phosphate dehydrogenase (zwf) will be analyzed in response to nitrogen deprivation and symbiotic interaction using the recently cloned gene. Insertional mutants of zwf will be used to analyze its role in heterocyst function. Recently identified potential nitrogen and anaerobic regulatory genes will be isolated from cosmid libraries by heterologous hybridization and used to construct insertional mutants in Nostoc for analysis of heterocyst differentiation. The results will lead to an understanding of the environmental signals and mechanisms of regulation of cell differentiation in filamentous cyanobacteria in two different growth states.

PI假设，当发菜与自由生活状态下的生长处于共生关联时，调节异形囊分化的机制（发菜菌有氧N2固定的位点）有所不同。他计划利用生理学和分子遗传学，通过对自由生活和共生生长状态的分析来检验这一假设。现有的突变体将通过基因组电穿孔来补充 DNA在体外连接成质粒后。 插入诱变将用于分离额外的突变体。 通过挽救插入元件来分离中断的基因；邻近插入的基因组 DNA 将从粘粒文库中克隆并进行表征。 将分析葡萄糖-6-磷酸脱氢酶 (zwf) 对氮的反应的转录调节 使用最近克隆的基因进行剥夺和共生相互作用。 zwf 的插入突变体将用于分析其在异形细胞功能中的作用。 最近鉴定的潜在氮和厌氧调节基因将通过异源杂交从粘粒文库中分离出来，并用于在发菜中构建插入突变体以分析异形囊分化。 研究结果将有助于人们了解环境 丝状蓝细菌在两种不同生长状态下细胞分化调节的信号和机制。