title: A σE-Mediated Temperature Gauge Controls a Switch from LuxR-Mediated Virulence Gene Expression to Thermal Stress Adaptation in Vibrio alginolyticus.
abstract: In vibrios, the expression of virulence factors is often controlled by LuxR, the master quorum-sensing regulator. Here, we investigate the interplay between LuxR and σE, an alternative sigma factor, during the control of virulence-related gene expression and adaptations to temperature elevations in the zoonotic pathogen Vibrio alginolyticus. An rpoE null V. alginolyticus mutant was unable to adapt to various stresses and was survival-deficient in fish. In wild type V. alginolyticus, the expression of LuxR-regulated virulence factors increased as the temperature was increased from 22°C to 37°C, but mutants lacking σE did not respond to temperature, indicating that σE is critical for the temperature-dependent upregulation of virulence genes. Further analyses revealed that σE binds directly to -10 and -35 elements in the luxR promoter that drive its transcription. ChIP assays showed that σE binds to the promoter regions of luxR, rpoH and rpoE at high temperatures (e.g., 30°C and 37°C). However, at higher temperatures (42°C) that induce thermal stress, σE binding to the luxR promoter decreased, while its binding to the rpoH and rpoE promoters was unchanged. Thus, the temperature-dependent binding of σE to distinct promoters appears to underlie a σE-controlled switch between the expression of virulence genes and adaptation to thermal stress. This study illustrates how a conserved temperature response mechanism integrates into quorum-sensing circuits to regulate both virulence and stress adaptation.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Guo
authors.affiliation: Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China.
authors.forename: Minjun
authors.initials: M
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.|Shanghai Collaborative Innovation Center for Biomanufacturing Technology, Shanghai, China.|Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China.
authors.forename: Yuanxing
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.|Shanghai Collaborative Innovation Center for Biomanufacturing Technology, Shanghai, China.|Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China.
authors.forename: Qiyao
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D047369:Chromatin Immunoprecipitation; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D015151:Immunoblotting; D016133:Polymerase Chain Reaction; D012097:Repressor Proteins / Q000096:biosynthesis*; D012808:Sigma Factor / Q000378:metabolism*; D013312:Stress, Physiological / Q000502:physiology; D013696:Temperature; D015534:Trans-Activators / Q000096:biosynthesis*; D014735:Vibrio Infections / Q000378:metabolism; D044149:Vibrio alginolyticus / Q000502:physiology*; D014774:Virulence / Q000502:physiology*; D037521:Virulence Factors / Q000096:biosynthesis*; D015027:Zebrafish
chemical_list: D012097:Repressor Proteins; D012808:Sigma Factor; D015534:Trans-Activators; D037521:Virulence Factors; C064778:LuxR autoinducer binding proteins