title: A combination of luxR1 and luxR2 genes activates Pr-promoters of psychrophilic Aliivibrio logei lux-operon independently of chaperonin GroEL/ES and protease Lon at high concentrations of autoinducer.
abstract: Lux-operon of psychrophilic bacteria Aliivibrio logei contains two copies of luxR and is regulated by Type I quorum sensing (QS). Activation of lux-operon of psychrophilic bacteria A. logei by LuxR1 requires about 100 times higher concentrations of autoinducer (AI) than the activation by LuxR2. On the other hand, LuxR1 does not require GroEL/ES chaperonin for its folding and cannot be degraded by protease Lon, while LuxR2 sensitive to Lon and requires GroEL/ES. Here we show that at 10(-5) - 10(-4)М concentrations of AI a combination of luxR1 and luxR2 products is capable of activating the Pr-promoters of A. logei lux-operon in Escherichia coli independently of GroEL/ES and protease Lon. The presence of LuxR1 assists LuxR2 in gro(-) cells when AI was added at high concentration, while at low concentration of AI in a cell LuxR1 decreases the LuxR2 activity. These observations may be explained by the formation of LuxR1/LuxR2 heterodimers that act in complex with AI independently from GroEL/ES and protease Lon.
  
  
  
  This study expands current understanding of QS regulation in A. logei as it implies cooperative regulation of lux-operon by LuxR1 and LuxR2 proteins.
authors.affiliation: Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia.
authors.forename: Maria N
authors.initials: MN
authors.lastname: Konopleva
authors.affiliation: State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnii pr. 1, Moscow, 117545, Russia.
authors.forename: Svetlana A
authors.initials: SA
authors.lastname: Khrulnova
authors.affiliation: Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia; School of Systems Biology, George Mason University, 4400 University Drive, Fairfax, VA 22003, USA; Research Centre for Medical Genetics (RCMG) of RAMS, 1 Moskvorechie Str, Moscow, Russia.
authors.forename: Ancha
authors.initials: A
authors.lastname: Baranova
authors.affiliation: Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia.
authors.forename: Leonid V
authors.initials: LV
authors.lastname: Ekimov
authors.affiliation: State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnii pr. 1, Moscow, 117545, Russia; Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia.
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Bazhenov
authors.affiliation: State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnii pr. 1, Moscow, 117545, Russia; Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia.
authors.forename: Ignatiy I
authors.initials: II
authors.lastname: Goryanin
authors.affiliation: State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnii pr. 1, Moscow, 117545, Russia; Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia. Electronic address: manukhov@genetika.ru.
authors.forename: Ilya V
authors.initials: IV
authors.lastname: Manukhov
mesh_terms: D059706:Aliivibrio / Q000235:genetics*; D018834:Chaperonin 60 / Q000235:genetics*; D018833:Chaperonins / Q000235:genetics*; D003080:Cold Temperature; D009876:Operon / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D049070:Protease La / Q000235:genetics*; D053038:Quorum Sensing / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics*
chemical_list: D018834:Chaperonin 60; D012097:Repressor Proteins; D015534:Trans-Activators; C064778:LuxR autoinducer binding proteins; D049070:Protease La; D018833:Chaperonins
keywords: Aliivibrio; GroEL/GroES chaperonins; Lux-operon; LuxR; Protease Lon