Fineran Peter C, Everson Lee, Slater Holly, Salmond George P C
Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK.
Microbiology (Reading). 2005 Dec;151(Pt 12):3833-3845. doi: 10.1099/mic.0.28251-0.
Biosynthesis of the red, tripyrrole antibiotic prodigiosin (Pig) by Serratia sp. ATCC 39006 (39006) is controlled by a complex regulatory network involving an N-acyl homoserine lactone (N-AHL) quorum-sensing system, at least two separate two-component signal transduction systems and a multitude of other regulators. In this study, a new transcriptional activator, PigT, and a physiological cue (gluconate), which are involved in an independent pathway controlling Pig biosynthesis, have been characterized. PigT, a GntR homologue, activates transcription of the pigA-O biosynthetic operon in the absence of gluconate. However, addition of gluconate to the growth medium of 39006 repressed transcription of pigA-O, via a PigT-dependent mechanism, resulting in a decrease in Pig production. Finally, expression of the pigT transcript was shown to be maximal in exponential phase, preceding the onset of Pig production. This work expands our understanding of both the physiological and genetic factors that impinge on the biosynthesis of the secondary metabolite Pig in 39006.
粘质沙雷氏菌ATCC 39006（39006）合成红色三吡咯抗生素灵菌红素（Pig）的过程受一个复杂调控网络的控制，该网络涉及N-酰基高丝氨酸内酯（N-AHL）群体感应系统、至少两个独立的双组分信号转导系统以及众多其他调控因子。在本研究中，已对参与控制Pig生物合成的独立途径的一种新的转录激活因子PigT和一种生理信号（葡萄糖酸盐）进行了表征。PigT是一种GntR同源物，在没有葡萄糖酸盐的情况下激活pigA - O生物合成操纵子的转录。然而，向39006的生长培养基中添加葡萄糖酸盐会通过一种依赖PigT的机制抑制pigA - O的转录，导致Pig产量下降。最后，pigT转录本的表达在指数期最高，早于Pig产生的开始阶段。这项工作扩展了我们对影响39006中次生代谢产物Pig生物合成的生理和遗传因素的理解。
