title: The Pseudomonas aeruginosa global regulator MvaT specifically binds to the ptxS upstream region and enhances ptxS expression.
abstract: Exotoxin A production in Pseudomonas aeruginosa is regulated positively or negatively by several genes. Two such regulatory genes, ptxR and ptxS, which are divergently transcribed from each other, have been described previously. While computer analysis suggested that the ptxR-ptxS intergenic region contains potential binding sites for several regulatory proteins, the mechanism that regulates the expression of either ptxR or ptxS in P. aeruginosa is not known. The presence of a P. aeruginosa protein complex that specifically binds to a segment within this region was determined. In this study the binding region was localized to a 150 bp fragment of the intergenic region and the proteins that constitute the binding complex were characterized as P. aeruginosa HU and MvaT. Recombinant MvaT was purified as a fusion protein (MAL-MvaT) and shown to specifically bind to the ptxR-ptxS intergenic region. A PAO1 isogenic mutant defective in mvaT, PAODeltamvaT, was constructed and characterized. The lysate of PAODeltamvaT failed to bind to the 150 bp probe. The effect of mvaT on ptxS and ptxR expression was examined using real-time PCR experiments. The expression of ptxS was lower in PAODeltamvaT than in PAO1, but no difference was detected in ptxR expression. These results suggest that MvaT positively regulates ptxS expression by binding specifically to the ptxS upstream region.
authors.affiliation: Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
authors.forename: Landon W
authors.initials: LW
authors.lastname: Westfall
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.|Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
authors.forename: A Marie
authors.initials: AM
authors.lastname: Luna
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.
authors.forename: Michael San
authors.initials: MS
authors.lastname: Francisco
authors.affiliation: Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Diggle
authors.affiliation: Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Worrall
authors.affiliation: Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Williams
authors.affiliation: Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: Miguel
authors.initials: M
authors.lastname: Cámara
authors.affiliation: Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
authors.forename: Abdul N
authors.initials: AN
authors.lastname: Hamood
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D021901:DNA, Intergenic; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000502:physiology; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D021901:DNA, Intergenic; D004268:DNA-Binding Proteins; C111692:MvaT protein, Pseudomonas; C113064:PtxS protein, Pseudomonas aeruginosa; D012329:RNA, Bacterial; D012333:RNA, Messenger; D011994:Recombinant Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C040330:histone-like protein HU, bacteria; C073470:LysR protein, Bacteria