RUI: Gamma-Butyrolactone Autoregulatory Signaling In Thaxtomin- And Naphthoquinone Polyketide-Producing Streptomyces

RUI：Thaxtomin 和萘醌聚酮生产链霉菌中的 γ-丁内酯自动调节信号传导

• 批准号: 0442509
• 负责人: Frank Healy
• 金额: --
• 依托单位: Trinity University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0442509&HistoricalAwards=false
• 关键词: RUI; Gamma; Butyrolactone; Autoregulatory; Signaling

Gram-positive filamentous streptomycetes produce ?-butyrolactone (GBL) molecules in a growth rate- and cell density-dependent manner that regulate expression of genes involved in secondary metabolism and morphogenesis. GBL signaling involves the GBL autoregulator, required for GBL biosynthesis, and the GBL binding protein (GBLBP), a TetR-type transcriptional regulator with a GBL binding domain. Several streptomycetes produce secondary metabolite phytotoxins, thaxtomins, which are required for efficient host colonization and infection of plants. The elaboration of host-microbe interaction activities by many gram-negative prokaryotes relies on N-acylhomoserine lactone (AHSL) derivatives, which bear an appreciable structural similarity to GBLs. Since thaxtomins are potent secondary metabolite phytotoxins required for host-microbe interaction, a role for GBL compounds in the regulation of thaxtomin gene expression by gram-positive streptomycetes analogous to that of AHSLs in regulating gene expression in gram-negative organisms is envisioned. This project will employ genetic, physiological and biochemical methods to elucidate the role(s) played by GBL signaling in the biology of thaxtomin-producing organisms. GBL autoregulator and GBLBP mutants will be generated using disruption and replacement techniques and analyzed using physiological studies of growth and morphological development. Quantitative assays of production of thaxtomins and other metabolites will be carried out. Transcript mapping and growth-rate dependent transcriptional analysis of autoregulator and thaxtomin structural genes in wild type and mutant derivatives will be performed. Biochemical analysis of GBLBP will include electrophoretic mobility shift and DNase footprinting assays with DNA regulatory elements. With extensive undergraduate student involvement, the research is expected to advance the limited understanding of streptomycete GBL autoregulator-mediated quorum-sensing activities, particularly with regard to thaxtomin-dependent host-microbe interactions.

革兰氏阳性丝状链菌产生？-丁内酯（GBL）分子以生长速率和细胞密度依赖的方式调节参与次级代谢和形态发生的基因的表达。GBL信号包括GBL生物合成所需的GBL自动调节因子和GBL结合蛋白（GBLBP），一种具有GBL结合结构域的ter型转录调节因子。一些链霉菌产生次生代谢物植物毒素，这是有效的寄主定植和植物感染所必需的。许多革兰氏阴性原核生物的宿主-微生物相互作用活性依赖于n -酰基高丝氨酸内酯（AHSL）衍生物，其结构与gbl具有明显的相似性。由于梭菌素是宿主-微生物相互作用所需的有效次生代谢物植物毒素，因此可以设想GBL化合物在革兰氏阳性链菌中调节梭菌素基因表达的作用类似于ahsl在革兰氏阴性生物中调节基因表达的作用。本项目将采用遗传、生理和生化的方法来阐明GBL信号在产生thaxtomin的生物体的生物学中所起的作用。GBL自动调节体和GBLBP突变体将通过破坏和替代技术产生，并通过生长和形态发育的生理研究进行分析。将对thaxtomins和其他代谢物的生产进行定量分析。转录作图和生长速率依赖的转录分析的自调节和萨氏蛋白结构基因的野生型和突变衍生物将进行。GBLBP的生化分析将包括电泳迁移转移和DNA调控元件的DNA酶足迹测定。在广泛的本科生参与下，该研究有望促进对链霉菌GBL自调节介导的群体感应活动的有限理解，特别是关于梭托霉素依赖的宿主-微生物相互作用。