title: [Regulation of type III secretion system by Rhl and PQS quorum sensing systems in Pseudomonas aeruginosa].
abstract: OBJECTIVE
  To investigate the relationship between quorum sensing (QS) and type III secretion system (T3SS) in Pseudomonas aeruginosa.
  
  
  METHODS
  We constructed several gene knockout mutants of QS systems. The promoters of the T3SS genes, exoS, exoY, exoT and exsD-pscA-L were cloned and fused upstream of the luminescence reporter gene cluster, luxCDABE. The reporter constructs were integrated on the chromosome in the wild type strain PAO1 and the QS mutants respectively, and the expression of the T3SS genes in these strains was compared.
  
  
  RESULTS
  The expression of exoS and exoT in pqsR mutant was increased significantly. The Rhl system repressed the activities of the four T3SS genes and the Las system had no effect.
  
  
  CONCLUSIONS
  The results indicate that the Rhl and Pseudomonas quinolone signal (PQS) systems play an important role in regulating T3SS gene expression in Pseudomonas aeruginosa.
authors.affiliation: Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, Xi'an 710069, China. douzikwn@163.com
authors.forename: Weina
authors.initials: W
authors.lastname: Kong
authors.forename: Haihua
authors.initials: H
authors.lastname: Liang
authors.forename: Lixin
authors.initials: L
authors.lastname: Shen
authors.forename: Kangmin
authors.initials: K
authors.lastname: Duan
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D021381:Protein Transport; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology*; D053038:Quorum Sensing; D055571:Secretory Pathway
chemical_list: D001426:Bacterial Proteins