REGULATION OF GLUTAMINE SYNTHETASE IN STREPTOMYCES

链霉菌中谷氨酰胺合成酶的调控

• 批准号: 3135070
• 负责人: SUSAN H. FISHER
• 金额: $ 17.85万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-12-01 至 1994-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3135070
• 关键词: Streptomyces; antibiotics; bacterial genetics; biotechnology; deficient growth media; gene expression; genetic promoter element; genetic transcription; glutamate ammonia ligase; gram positive bacteria; microorganism metabolism; molecular cloning; mutant; nitrogen metabolism; nucleic acid sequence; protein sequence; sporogenesis; structural genes

Streptomyces species synthesize more than 70 medically useful antibioties as well as antitumor and antiparasitic agents. These compounds are synthesized from primary metabolites during nutritional limitation of growth and the initiation of sporulation. Surprisingly, very little is known about primary metabolism or the sechanisms that trigger antibiotic production and sporulation in these bacteria. In order to increase our understanding of Streptomyces basic physiology, the regulation of glutamine synthetase (GS), a key enzyme in ammoniin assimilation, is being studied in S. coelicolor. Analysis of the cloned I. coelicolor GS structural gene (sm) shows that transcription of the SM promoter is nitrogen regulated during vegetative growth. Two approaches are being used to identify tbe factors that mediate this regulation. First, nucleotide regions required for the regulation and expression of the LM pronoter are being identified by constructing glnA-xylE transcriptional fusions, and isolating nutations that alter expression and regulation of the glnA-xylE fusions. Secondly, glnA regulatory factors are being genetically identified by isolating mutants with altered expression of the glnA promoters. The glutamine-requiring ClassI GlnR mutants are unable to transcribe the nitrogen-regulated glnA promoter. The defective gene product in this nutant has been cloned by complementation and is being identified subcloned to facilitate DNA sequencing. Since expression of the nitrogen-regulated enzyme urease is also deficient in these mutants, a global nitrogen regulatory system may be present in .1. coelicolor. The cloned &W DNA will be used to study interactions between the &W promoters and the genetically identified glnA regulatory proteins, RNA polymerase and small nitrogencontaining metabolites. An understanding of nitrogen metabolism in 5. coelicolor should facilitate increased antibiotic production by genetic manipulation of primary uetabolite pools, or by choice of the appropriate growth nedium. Furthermore, since primary metabolism impinges on both antibiotic production and sporulation in Streptomyces, these studies may help define mechanisms that regulate these processes in Streptomyces.

链霉菌品种合成 70 多种药用物质 抗生素以及抗肿瘤剂和抗寄生虫剂。这些 化合物是在营养过程中由初级代谢物合成的 生长受限和孢子形成的开始。出奇， 对于初级代谢或初级代谢的机制知之甚少 触发这些细菌产生抗生素和孢子。在 为了增加我们对链霉菌基础生理学的了解， 谷氨酰胺合成酶 (GS) 的调节，这是氨中的关键酶 同化作用，正在天蓝色链球菌中进行研究。克隆分析 I.天蓝色GS结构基因(sm)表明SM的转录 启动子在营养生长过程中受氮调节。两种方法 正在被用来识别调节这一调节的因素。 首先，调节和表达所需的核苷酸区域 通过构建 glnA-xylE 来识别 LM 启动子 转录融合，以及分离改变表达的章动 和glnA-xylE融合的调节。其次，glnA监管 正在通过分离突变体来对因素进行遗传鉴定 glnA 启动子的表达改变。需要谷氨酰胺的I类 GlnR 突变体无法转录氮调节的 glnA 发起人。该坚果中的缺陷基因产物已被克隆 互补并正在鉴定亚克隆以促进 DNA 测序。由于氮调节酶脲酶的表达是 同样缺乏这些突变体，全球氮调节系统可能 出现在 .1 中。天蓝色。克隆的&W DNA将用于研究 &W 启动子和基因鉴定之间的相互作用 glnA 调节蛋白、RNA 聚合酶和小分子含氮蛋白 代谢物。 5.天蓝色氮代谢的理解 应通过遗传促进增加抗生素产量 操纵初级代谢物库，或通过选择 适当的生长培养基。此外，由于初级代谢 影响链霉菌的抗生素生产和孢子形成， 这些研究可能有助于定义调节这些过程的机制 在链霉菌中。