The Experts below are selected from a list of 24 Experts worldwide ranked by ideXlab platform
Julia C Van Kessel - One of the best experts on this subject based on the ideXlab platform.
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integration host Factor and LuxR synergistically bind dna to coactivate quorum sensing genes in vibrio harveyi
Molecular Microbiology, 2016Co-Authors: Ryan R Chaparian, Stephen G Olney, Christine M Hustmyer, Dean A Rowemagnus, Julia C Van KesselAbstract:The cell-cell signaling process called quorum sensing allows bacteria to control behaviors in response to changes in population density. In Vibrio harveyi, the master quorum-sensing Transcription Factor LuxR is a member of the TetR family of Transcription Factors that both activates and represses genes to coordinate group behaviors, including bioluminescence. Here, we show that integration host Factor (IHF) is a key coactivator of the luxCDABE bioluminescence genes that is required together with LuxR for precise timing and expression levels of bioluminescence during quorum sensing. IHF binds to multiple sites in the luxCDABE promoter and bends the DNA in vitro. IHF and LuxR synergistically bind luxCDABE promoter DNA at overlapping, essential binding sites that are required for maximal gene expression in vivo. RNA-seq analysis demonstrated that IHF regulates 300 genes in V. harveyi, and among these are a core set of 19 genes that are also directly bound and regulated by LuxR. We validated these global analyses by demonstrating that both IHF and LuxR are required for Transcriptional activation of the osmotic stress response genes betIBA-proXWV. These data suggest that IHF plays an integral role in one mechanism of Transcriptional activation by the LuxR-type family of quorum-sensing regulators in vibrios.
E P Greenberg - One of the best experts on this subject based on the ideXlab platform.
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quorum sensing in vibrio fischeri probing autoinducer LuxR interactions with autoinducer analogs
Journal of Bacteriology, 1996Co-Authors: Amy L Schaefer, Brian L. Hanzelka, A Eberhard, E P GreenbergAbstract:The Vibrio fischeri luminescence genes are activated by the Transcription Factor LuxR in combination with a diffusible signal compound, N-(3-oxohexanoyl) homoserine lactone, termed the autoinducer. We have synthesized a set of autoinducer analogs. Many analogs with alterations in the acyl side chain showed evidence of binding to LuxR. Some appeared to bind with an affinity similar to that of the autoinducer, but none showed a higher affinity, and many did not bind as tightly as the autoinducer. For the most part, compounds with substitutions in the homoserine lactone ring did not show evidence of binding to LuxR. The exceptions were compounds with a homocysteine thiolactone ring in place of the homoserine lactone ring. Many but not all of the analogs showing evidence of LuxR binding had some ability to activate the luminescence genes. None were as active as the autoinducer. While most showed little ability to induce luminescence, a few analogs with rather conservative substitutions had appreciable activity. Under the conditions we employed, some of the analogs showing little or no ability to induce luminescence were inhibitors of the autoinducer.
Ryan R Chaparian - One of the best experts on this subject based on the ideXlab platform.
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integration host Factor and LuxR synergistically bind dna to coactivate quorum sensing genes in vibrio harveyi
Molecular Microbiology, 2016Co-Authors: Ryan R Chaparian, Stephen G Olney, Christine M Hustmyer, Dean A Rowemagnus, Julia C Van KesselAbstract:The cell-cell signaling process called quorum sensing allows bacteria to control behaviors in response to changes in population density. In Vibrio harveyi, the master quorum-sensing Transcription Factor LuxR is a member of the TetR family of Transcription Factors that both activates and represses genes to coordinate group behaviors, including bioluminescence. Here, we show that integration host Factor (IHF) is a key coactivator of the luxCDABE bioluminescence genes that is required together with LuxR for precise timing and expression levels of bioluminescence during quorum sensing. IHF binds to multiple sites in the luxCDABE promoter and bends the DNA in vitro. IHF and LuxR synergistically bind luxCDABE promoter DNA at overlapping, essential binding sites that are required for maximal gene expression in vivo. RNA-seq analysis demonstrated that IHF regulates 300 genes in V. harveyi, and among these are a core set of 19 genes that are also directly bound and regulated by LuxR. We validated these global analyses by demonstrating that both IHF and LuxR are required for Transcriptional activation of the osmotic stress response genes betIBA-proXWV. These data suggest that IHF plays an integral role in one mechanism of Transcriptional activation by the LuxR-type family of quorum-sensing regulators in vibrios.
Amy L Schaefer - One of the best experts on this subject based on the ideXlab platform.
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quorum sensing in vibrio fischeri probing autoinducer LuxR interactions with autoinducer analogs
Journal of Bacteriology, 1996Co-Authors: Amy L Schaefer, Brian L. Hanzelka, A Eberhard, E P GreenbergAbstract:The Vibrio fischeri luminescence genes are activated by the Transcription Factor LuxR in combination with a diffusible signal compound, N-(3-oxohexanoyl) homoserine lactone, termed the autoinducer. We have synthesized a set of autoinducer analogs. Many analogs with alterations in the acyl side chain showed evidence of binding to LuxR. Some appeared to bind with an affinity similar to that of the autoinducer, but none showed a higher affinity, and many did not bind as tightly as the autoinducer. For the most part, compounds with substitutions in the homoserine lactone ring did not show evidence of binding to LuxR. The exceptions were compounds with a homocysteine thiolactone ring in place of the homoserine lactone ring. Many but not all of the analogs showing evidence of LuxR binding had some ability to activate the luminescence genes. None were as active as the autoinducer. While most showed little ability to induce luminescence, a few analogs with rather conservative substitutions had appreciable activity. Under the conditions we employed, some of the analogs showing little or no ability to induce luminescence were inhibitors of the autoinducer.
Stephen G Olney - One of the best experts on this subject based on the ideXlab platform.
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integration host Factor and LuxR synergistically bind dna to coactivate quorum sensing genes in vibrio harveyi
Molecular Microbiology, 2016Co-Authors: Ryan R Chaparian, Stephen G Olney, Christine M Hustmyer, Dean A Rowemagnus, Julia C Van KesselAbstract:The cell-cell signaling process called quorum sensing allows bacteria to control behaviors in response to changes in population density. In Vibrio harveyi, the master quorum-sensing Transcription Factor LuxR is a member of the TetR family of Transcription Factors that both activates and represses genes to coordinate group behaviors, including bioluminescence. Here, we show that integration host Factor (IHF) is a key coactivator of the luxCDABE bioluminescence genes that is required together with LuxR for precise timing and expression levels of bioluminescence during quorum sensing. IHF binds to multiple sites in the luxCDABE promoter and bends the DNA in vitro. IHF and LuxR synergistically bind luxCDABE promoter DNA at overlapping, essential binding sites that are required for maximal gene expression in vivo. RNA-seq analysis demonstrated that IHF regulates 300 genes in V. harveyi, and among these are a core set of 19 genes that are also directly bound and regulated by LuxR. We validated these global analyses by demonstrating that both IHF and LuxR are required for Transcriptional activation of the osmotic stress response genes betIBA-proXWV. These data suggest that IHF plays an integral role in one mechanism of Transcriptional activation by the LuxR-type family of quorum-sensing regulators in vibrios.