Genetic Regulation of Bioluminescence in Marine Bacteria

海洋细菌生物发光的遗传调控

• 批准号: 9419862
• 负责人: Michael Silverman
• 金额: $ 31.5万
• 依托单位: Agouron Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-01-15 至 1997-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9419862&HistoricalAwards=false
• 关键词: Genetic; Regulation; Bioluminescence; Marine; Bacteria

9419862 Silverman The objective of this investigation is to understand the genetic control mechanisms which regulate expression of luminescence in the bacterium Vibrio harveyi. Expression of genes for luminescence (lux) in marine bacteria is controlled by cell density and a variety of environmental cues. Density-dependent regulation is a primary facet of lux regulation and is mediated by extracellular signal substances called autoinducers. Two autoinducer signaling pathways converge to control luminescence in V. harveyi. One pathway, signaling system 1, consists of functions for production of autoinducer 1 (AI-1 Signal) and for response to the cognate autoinducer (AI-1 Sensor). The luxL and luxM genes are required for AI-1 production, and luxN encodes the AI-1 Sensor. A second pathway, signaling system 2, consists of functions for production of autoinducer 2 (AI-2 Signal) and for response to this signal (AI-2 Sensor). The luxP and luxQ genes encode AI-2 Sensor proteins. Both signaling pathways intersect at a control function encoded by the luxO gene. The LuxO protein integrates the responses of both Sensors 1 and 2 and, with the participation of the luxR gene product, activates transcription of the luxCDABE operon encoding the luminescence enzymes. Lux regulation is apparently complicated, and many functions and interactions remain to be identified. This project includes mutant isolation to guide the cloning, sequencing and characterization of additional regulatory genes, particularly those required for production of autoinducter 2 (AI-2). Transcripts from various lux regulatory genes are being mapped and quantitated to analyze hierarchical and feedback relationships in the regulatory circuitry. Mutants defective both in sensor 1 and 3 function will be stimulated with a variety of environmental signals to detect cross-communication with other sensory systems. Site-directed mutagenesis will be used to obtain locked or aberrant Lux signaling proteins which will then be used to exam ine interactions of regulatory components and the biochemistry of signal transduction. %%% Analyzing the lux system should be valuable for understanding how bacteria perceive and react to their environment. The regulatory process is complex and involves both intercellular and intracellular signal transmission so interesting new mechanisms could be revealed. However, complexity should not be a barrier because the sensory input (chemical signals) and the output (light emission) can be conveniently controlled and measured, and the genetic methodology is well-developed. ***

9419862 Silverman本研究的目的是了解在细菌哈氏弧菌中调节发光表达的遗传控制机制。 海洋细菌发光基因的表达受细胞密度和各种环境因素的控制。 密度依赖性调节是照度调节的主要方面，并且由称为自身诱导物的细胞外信号物质介导。 两种自诱导物信号通路会聚以控制哈维氏弧菌中的发光。 一种途径，信号传导系统1，由产生自诱导物1（AI-1信号）和响应同源自诱导物（AI-1传感器）的功能组成。 luxL和luxM基因是生产AI-1所必需的，而luxN编码AI-1传感器。 第二个途径，信号传导系统2，由产生自诱导物2（AI-2信号）和响应该信号（AI-2传感器）的功能组成。 luxP和luxQ基因编码AI-2传感器蛋白。 两种信号通路在由luxO基因编码的控制功能处相交。 LuxO蛋白整合了传感器1和2的响应，并且在luxR基因产物的参与下，激活编码发光酶的luxCDABE操纵子的转录。 勒克斯调控显然是复杂的，许多功能和相互作用仍有待确定。 该项目包括突变体分离，以指导额外的调控基因的克隆，测序和表征，特别是那些生产autoinducter 2（AI-2）所需的。 各种照度调节基因的转录本正在被绘制和定量，以分析调节回路中的分层和反馈关系。 传感器1和3功能缺陷的突变体将被各种环境信号刺激，以检测与其他感觉系统的交叉通信。 定点诱变将用于获得锁定的或异常的Lux信号传导蛋白，然后将其用于检查调节组分的相互作用和信号转导的生物化学。 分析勒克斯系统对于了解细菌如何感知和反应环境应该是有价值的。 调控过程是复杂的，涉及细胞间和细胞内的信号传递，所以有趣的新机制可能会被发现。 然而，复杂性不应该成为障碍，因为感觉输入（化学信号）和输出（光发射）可以方便地控制和测量，遗传方法学也很发达。 ***