Abstract
Density-dependent expression of luminescence in Vibrio harveyi is regulated by the concentration of extracellular signal molecules (autoinducers) in the culture medium. One signal-response system is encoded by the luxL,M,N locus. The luxL and luxM genes are required for the production of an autoinducer (probably beta-hydroxybutyl homoserine lactone), and the luxN gene is required for the response to that autoinducer. Analysis of the phenotypes of LuxL,M and N mutants indicated that an additional signal-response system also controls density sensing. We report here the identification, cloning and analysis of luxP and luxQ, which encode functions required for a second density-sensing system. Mutants with defects in luxP and luxQ are defective in response to a second autoinducer substance. LuxQ, like LuxN, is similar to members of the family of two-component, signal transduction proteins and contains both a histidine protein kinase and a response regulator domain. Analysis of signalling mutant phenotypes indicates that there are at least two separate signal-response pathways which converge to regulate expression of luminescence in V. harveyi.
Publication types
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Comparative Study
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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4-Butyrolactone / analogs & derivatives
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4-Butyrolactone / metabolism
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Amino Acid Sequence
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Bacterial Proteins / biosynthesis
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Bacterial Proteins / genetics
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Bacterial Proteins / physiology*
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Base Sequence
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Gene Expression Regulation, Bacterial*
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Luminescent Measurements*
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Models, Biological
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Molecular Sequence Data
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Mutagenesis, Insertional
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Phenotype
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Phosphorylation
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Phosphotransferases*
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Protein Kinases / biosynthesis
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Protein Kinases / genetics
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Protein Kinases / physiology*
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Protein Processing, Post-Translational
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Repressor Proteins / genetics
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Repressor Proteins / physiology
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Sequence Alignment
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Sequence Homology, Amino Acid
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Signal Transduction / physiology*
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Trans-Activators*
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Transcription Factors / genetics
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Transcription Factors / physiology
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Vibrio / genetics
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Vibrio / physiology*
Substances
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Bacterial Proteins
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LuxO protein, Vibrio harveyi
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LuxP protein, Vibrio
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Repressor Proteins
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Trans-Activators
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Transcription Factors
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luxL protein, Vibrio harveyi
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luxM protein, Vibrio harveyi
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LuxR autoinducer binding proteins
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N-(3-oxohexanoyl)-3-aminodihydro-2(3H)-furanone
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Phosphotransferases
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Protein Kinases
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luxN protein, Vibrio harveyi
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luxQ protein, Vibrio harveyi
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4-Butyrolactone