HISTIDINE UTILIZATION IN BACILLUS SUBTILIS

枯草芽孢杆菌中组氨酸的利用

• 批准号: 6013585
• 负责人: SUSAN H. FISHER
• 金额: $ 7.01万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6013585
• 关键词: Bacillus subtilis; DNA footprinting; aminoacid metabolism; aminoacid transport; bacterial genetics; fermentation; gel mobility shift assay; gene expression; gene induction /repression; gene mutation; genetic regulation; histidine; microorganism metabolism; molecular cloning; mutant; nucleic acid sequence; transposon /insertion element

The initiation of sporulation and the production of antibiotics in gram- positive sporulating soil bacteria such as Bacillus subtilis occurs in response to nutrient limitation. However, nutrient limitation also activates the synthesis of a number of degradative pathways which provide nutrients for growth and adaptation during environmental stress. To begin to understand the network of metabolic signals and systems that regulate gene expression during nutrient-limited growth in this bacterium, regulation of the B. subtilis histidine utilization enzymes (hut) is being studied. Expression of the hut enzymes is controlled by three independent regulatory systems, histidine induction, carbon catabolite repression and amino acid repression. In contrast to the Klebsiella areogenes hut enzymes, hut expression in B. subtilis is not significantly derepressed by nitrogen-limited growth. The location of the cis-acting hut sites required for regulation by these three systems was identified by deletion analysis. Localization mutagenesis will be used to more precisely define these sites. The possibility that DNA looping is involved in catabolite repression of hut expression will be examined with (i) in vivo footprinting experiments, and (ii) by determining whether mutations that alter the spacing between the two cis-acting catabolite repression sites also affects the level of catabolite repression. transacting factors mediating catabolite repression and amino acid repression will be identified by isolating mutants with altered hut expression during growth on medium containing either repressing carbon sources or amino acids. DNA complementing these mutants will be cloned and sequenced. These studies should help define the paradigms that regulate gene expression in soil bacteria. In addition, they will provide both information and genetic tools for optimizing production of medically and agriculturally important compounds in these bacteria by commercial fermentation or during growth in the soil, where nutrients are relatively scarce.

孢子形成的起始和抗生素的产生以克- 阳性孢子形成土壤细菌如枯草芽孢杆菌出现在 对营养限制的反应。 然而，营养限制也 激活许多降解途径的合成， 在环境压力下生长和适应的营养素。 到 开始了解代谢信号和系统的网络， 在营养有限的生长过程中调节基因表达， 细菌、B的调节。枯草杆菌组氨酸利用酶 (hut)正在被研究。 hut酶的表达受 三个独立的调节系统，组氨酸诱导，碳 分解代谢物阻遏和氨基酸阻遏。 相对于 产气克雷伯菌hut酶，hut在B中表达。subtilis不是 氮限制的生长显著地解除抑制。 这些条例规管所需的顺式棚屋地点， 通过缺失分析确定了三个系统。 定位 诱变将用于更精确地确定这些位点。 的 DNA成环参与hut的分解代谢物阻遏的可能性 表达将用（i）体内足迹实验， 以及（ii）通过确定是否改变了 两个顺式作用分解代谢物阻遏位点也影响 分解代谢物阻遏 介导分解代谢物的转化因子 阻遏和氨基酸阻遏将通过分离 在含有以下物质的培养基上生长期间hut表达改变的突变体 抑制碳源或氨基酸。 DNA补充这些 突变体将被克隆和测序。 这些研究有助于确定 调节土壤细菌基因表达的范例。在 此外，它们还将提供信息和遗传工具， 优化医药和农业重要化合物的生产 在这些细菌中通过商业发酵或在 土壤，那里的养分相对稀缺。