title: Regulatory feedback loop of two phz gene clusters through 5'-untranslated regions in Pseudomonas sp. M18.
abstract: BACKGROUND
  Phenazines are important compounds produced by pseudomonads and other bacteria. Two phz gene clusters called phzA1-G1 and phzA2-G2, respectively, were found in the genome of Pseudomonas sp. M18, an effective biocontrol agent, which is highly homologous to the opportunistic human pathogen P. aeruginosa PAO1, however little is known about the correlation between the expressions of two phz gene clusters.
  
  
  RESULTS
  Two chromosomal insertion inactivated mutants for the two gene clusters were constructed respectively and the correlation between the expressions of two phz gene clusters was investigated in strain M18. Phenazine-1-carboxylic acid (PCA) molecules produced from phzA2-G2 gene cluster are able to auto-regulate expression itself and activate the expression of phzA1-G1 gene cluster in a circulated amplification pattern. However, the post-transcriptional expression of phzA1-G1 transcript was blocked principally through 5'-untranslated region (UTR). In contrast, the phzA2-G2 gene cluster was transcribed to a lesser extent and translated efficiently and was negatively regulated by the GacA signal transduction pathway, mainly at a post-transcriptional level.
  
  
  CONCLUSIONS
  A single molecule, PCA, produced in different quantities by the two phz gene clusters acted as the functional mediator and the two phz gene clusters developed a specific regulatory mechanism which acts through 5'-UTR to transfer a single, but complex bacterial signaling event in Pseudomonas sp. strain M18.
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Yaqian
authors.initials: Y
authors.lastname: Li
authors.forename: Xilin
authors.initials: X
authors.lastname: Du
authors.forename: Zhi John
authors.initials: ZJ
authors.lastname: Lu
authors.forename: Daqiang
authors.initials: D
authors.lastname: Wu
authors.forename: Yilei
authors.initials: Y
authors.lastname: Zhao
authors.forename: Bin
authors.initials: B
authors.lastname: Ren
authors.forename: Jiaofang
authors.initials: J
authors.lastname: Huang
authors.forename: Xianqing
authors.initials: X
authors.lastname: Huang
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Xu
authors.forename: Yuquan
authors.initials: Y
authors.lastname: Xu
mesh_terms: D020121:5' Untranslated Regions; D001483:Base Sequence; D003001:Cloning, Molecular; D025461:Feedback, Physiological; D015964:Gene Expression Regulation, Bacterial; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D009690:Nucleic Acid Conformation; D010619:Phenazines / Q000737:chemistry; D020161:Physical Chromosome Mapping; D011549:Pseudomonas / Q000235:genetics*; D012323:RNA Processing, Post-Transcriptional; D014158:Transcription, Genetic
chemical_list: D020121:5' Untranslated Regions; D010619:Phenazines; C037165:1-phenazinecarboxylic acid