title: Lux-operon of the marine psychrophilic bacteriumAliivibrio logei: a comparative analysis of the LuxR1/LuxR2 regulatory activity inEscherichia colicells.
abstract: Thelux-operon of the psychrophilic bioluminescent bacteriumAliivibrio logeiis regulated by quorum sensing (QS). The key components of this system are LuxI, which catalyses synthesis of the autoinducer (AI), and LuxR, which activates transcription of the entirelux-operon. Thelux-operon ofA. logeicontains two copies of theluxRgene:luxR1andluxR2. In the present study,lux-operon sequence analysis from 16 strains ofA. logei, isolated from cold habitats of the White, Baltic, Okhotsk and Bering seas, was carried out. Phylogenetic analysis showed that all isolated strains ofA. logeihave both copies ofluxRgenes which are homologous toluxRgenes of the relatedAliivibrio salmonicida. Evaluation of LuxR1 and LuxR2 activity showed that LuxR2 remains active at significantly lower concentrations of AI (10- 9M) than LuxR1, which is active only at high AI concentrations (10- 6M). As the QS response is already prominent at AI concentrations as low as 10- 8to 10- 9M, we conclude that LuxR2 is the main activator of thelux-operonof A. logei. The thermolabilities of LuxR1 and LuxR2 are similar and exceed that of LuxR of the mesophilic bacteriumAliivibrio fischeri. In contrast to LuxR2, LuxR1 is not a substrate of Lon protease and does not require the chaperonin GroEL/ES for its folding. This study expands our current understanding of QS regulation inA. logeias it implies differential regulation by LuxR1 and LuxR2 proteins.
authors: State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnii pr. 1, Moscow, 117545, Russia.
authors: Svetlana A
authors: SA
authors: Khrulnova
authors: 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: Ancha
authors: A
authors: Baranova
authors: 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: Sergey V
authors: SV
authors: Bazhenov
authors: 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: Ignatiy I
authors: II
authors: Goryanin
authors: Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia.
authors: Maria N
authors: MN
authors: Konopleva
authors: 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: Ivan V
authors: IV
authors: Maryshev
authors: Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia.
authors: Albina I
authors: AI
authors: Salykhova
authors: Laboratory of Molecular Genetics, Moscow Institute of Physics and Technology, 9 Instituitsky per., Dolgoprudny, Moscow Region, 141700, Russia.
authors: Alexandra V
authors: AV
authors: Vasilyeva
authors: 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: Ilya V
authors: IV
authors: Manukhov
authors: State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnii pr. 1, Moscow, 117545, Russia.
authors: Gennadii B
authors: GB
authors: Zavilgelsky