Autoinducer binding by the quorum-sensing regulator TraR increases affinity for target promoters in vitro and decreases TraR turnover rates in whole cells.
TraR is an Agrobacterium transcriptional regulator whose activity requires the pheromone N-3-oxooctanoyl-L-homoserine lactone. TraR was purified as a complex with the pheromone and contained one pheromone molecule per protein monomer. TraR-pheromone complexes bound to a single DNA site and activated two promoters that flank this site. Promoter expression was elevated 30-fold by using a supercoiled template. Pheromone binding increased the affinity of TraR for this binding site. Pheromone also increased TraR abundance in vivo by causing a 20-fold decrease in TraR turnover rates.
Zhu
J
J
Section of Microbiology, Cornell University, Ithaca, NY 14853, USA.
Winans
S C
SC
D001426:Bacterial Proteins / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D007783:Lactones / Q000378:metabolism; D010675:Pheromones / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012231:Rhizobium / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D007783:Lactones; D010675:Pheromones; C080512:TraR protein, Agrobacterium tumefaciens; D014157:Transcription Factors; C080518:N-(beta-oxooctan-1-oyl)homoserine lactone; D006714:Homoserine