title: Organisation of the tmb catabolic operons of Pseudomonas putida TMB and evolutionary relationship with the xyl operons of the TOL plasmid pWW0.
abstract: In Pseudomonas putida (Pp) TMB the genes involved in the catabolism of methyl-substituted aromatic hydrocarbons 1,2,4-trimethylbenzene, m- and p-xylene (tmb operon), are functionally and genetically homologous to the xyl genes of the plasmid pWW0, but are chromosomally encoded. We have analysed by cloning. Southern blotting and sequencing of selected regions the organisation of the tmb cluster. This analysis shows that the structural and regulatory genes of the tmb and xyl systems exhibit a high degree of homology and are similarly organised in operons. However the operons are differently arranged on the Pp TMB chromosome and on the pWW0 plasmid. Comparison of the two systems suggests that the operon arrangement found in pWW0 may have originated from that found in Pp TMB via cointegration mediated by replicative transposition or by intermolecular recombination between two copies of the insertion element IS1246.
authors.affiliation: Dipartimento di Genetica e di Biologia dei Microrganismi, Università degli Studi di Milano, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Favaro
authors.forename: C
authors.initials: C
authors.lastname: Bernasconi
authors.forename: N
authors.initials: N
authors.lastname: Passini
authors.forename: G
authors.initials: G
authors.lastname: Bertoni
authors.forename: G
authors.initials: G
authors.lastname: Bestetti
authors.forename: E
authors.initials: E
authors.lastname: Galli
authors.forename: G
authors.initials: G
authors.lastname: Dehò
mesh_terms: D001483:Base Sequence; D001555:Benzene Derivatives / Q000378:metabolism; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D005798:Genes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics*; D010957:Plasmids / Q000235:genetics*; D016958:Pseudomonas putida / Q000235:genetics*; D017421:Sequence Analysis; D014050:Toluene / Q000378:metabolism; D014992:Xylenes / Q000378:metabolism
chemical_list: D001555:Benzene Derivatives; D014992:Xylenes; C010313:pseudocumene; D014050:Toluene