title: Chromosomal insertion of the entire Escherichia coli lactose operon, into two strains of Pseudomonas, using a modified mini-Tn5 delivery system.
abstract: A 12-kb PstI fragment including the entire E. coli lactose operon (lacIPOZYA) was inserted in one copy into the chromosome of Pseudomonas putida, Pseudomonas fluorescens and an E. coli strain with lac- phenotype. This was made possible by improvements of an already existing mini-Tn5 transposon delivery system (de Lorenzo et al., 1990; Herrero et al., 1990), which integrates cloned DNA fragments at random sites on the chromosome of the recipient bacteria in single copies. This has resulted in: (a) the making of two useful low copy-number cloning vectors both with extensive multi-cloning regions flanked by NotI sites needed in the mini-Tn5 delivery system; (b) the generation of E. coli nonlysogenic strains expressing the pi protein thus being capable of maintaining and delivering R6K-based mini-Tn5 vectors to other E. coli strains; (c) the successful insertion of the E. coli lactose operon into the P. fluorescens chromosome giving P. fluorescens the ability to grow on lactose; (d) evidence from Southern blotting that contradicts the assumption that the mini-Tn5 delivery system always creates one-copy inserts. These improvements allow insertion of large DNA fragments encoding highly expressed proteins into the chromosome of a large variety of Gram-negative bacteria including E. coli.
authors.affiliation: Department of General microbiology, University of Copenhagen, Denmark.
authors.forename: L H
authors.initials: LH
authors.lastname: Hansen
authors.forename: S J
authors.initials: SJ
authors.lastname: Sørensen
authors.forename: L B
authors.initials: LB
authors.lastname: Jensen
mesh_terms: D002876:Chromosomes, Bacterial; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics*; D005838:Genotype; D007544:Isopropyl Thiogalactoside / Q000494:pharmacology; D007700:Kinetics; D007763:Lac Operon; D016254:Mutagenesis, Insertional / Q000379:methods*; D010641:Phenotype; D010957:Plasmids; D011551:Pseudomonas fluorescens / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D016958:Pseudomonas putida / Q000235:genetics*; D015183:Restriction Mapping
chemical_list: D004251:DNA Transposable Elements; D007544:Isopropyl Thiogalactoside