title: The aprX-lipA operon of Pseudomonas fluorescens B52: a molecular analysis of metalloprotease and lipase production.
abstract: Extracellular protease and lipase production by psychrotrophic strains of Pseudomonas fluorescens is repressed by iron and regulated by temperature. The regulation of protease and lipase has been investigated in P. fluorescens B52. Whereas lipase production is increased below the optimum growth temperature ('low-temperature regulation'), protease production was relatively constant and only decreased above the optimum growth temperature. The genes encoding protease (aprX) and lipase (lipA) are encoded at opposite ends of a contiguous set of genes which also includes protease inhibitor, Type I secretion functions and two autotransporter proteins. Evidence is presented indicating that these genes constitute an operon, with a promoter adjacent to aprX which has been identified by S1 nuclease analysis. The regulation of aprX and lipA has been investigated at the RNA level and using lacZ fusion strains. Whereas the data are consistent with iron regulation at the transcriptional level, a lipA'-'lacZ fusion is not regulated by temperature, suggesting that temperature regulation is post-transcriptional or post-translational. The possibility of regulation at the level of mRNA decay is discussed.
authors.affiliation: School of Health Science, Griffith University, PMB 50 Gold Coast Mail Centre, Gold Coast, Qld 4217, Australia1.
authors.forename: Rick G
authors.initials: RG
authors.lastname: Woods
authors.affiliation: School of Health Science, Griffith University, PMB 50 Gold Coast Mail Centre, Gold Coast, Qld 4217, Australia1.
authors.forename: Michelle
authors.initials: M
authors.lastname: Burger
authors.affiliation: School of Health Science, Griffith University, PMB 50 Gold Coast Mail Centre, Gold Coast, Qld 4217, Australia1.
authors.forename: Carie-Anne
authors.initials: CA
authors.lastname: Beven
authors.affiliation: School of Health Science, Griffith University, PMB 50 Gold Coast Mail Centre, Gold Coast, Qld 4217, Australia1.
authors.forename: Ifor R
authors.initials: IR
authors.lastname: Beacham
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002265:Carboxylic Ester Hydrolases / Q000096:biosynthesis / Q000235:genetics*; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism; D007763:Lac Operon / Q000235:genetics / Q000502:physiology; D008049:Lipase; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011551:Pseudomonas fluorescens / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000235:genetics*; D013696:Temperature; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; C093610:Inh protein, bacteria; D011993:Recombinant Fusion Proteins; D007501:Iron; D002265:Carboxylic Ester Hydrolases; C113518:LipA protein, Pseudomonas; D008049:Lipase; D010450:Endopeptidases; C402704:AprX protein, bacteria; D012697:Serine Endopeptidases; C400323:prt protein, Pseudomonas