Cloning and expression of genes involved in 4-chlorobiphenyl transformation by Pseudomonas testosteroni: homology to polychlorobiphenyl-degrading genes in other bacteria.
The genes of Pseudomonas testosteroni strain B-356, specifying the transformation of 4-chlorobiphenyl (4-CB) into 4-chlorobenzoic acid (4-CBA) were cloned into Pseudomonas putida KT2440 using a broad-host-range cosmid, pPSA842. Of 10,000 clones tested, four were able to transform 4-CB. Gas chromatographic and mass spectrometric analysis of the catabolic products from two of the 4-CB-transforming clones carrying the hybrid plasmids, pDA1 and pDA2, demonstrated that pDA1 carried a complete set of structural genes involved in the transformation of 4-CB into 4-CBA, while pDA2 contained part of the pathway genes leading up to the meta-cleavage compound. Restriction endonuclease mapping and subcloning of pDA1 and pDA2 showed that the clones contained a common stretch of DNA of about 9.1 kb and that pDA2 carried gene(s) involved in regulation. Probing blots of genomic DNA from 13 different polychlorinated biphenyl(PCB)-degrading bacteria with radio-labelled pDA1 and pDA2, suggested that many PCB-degrading pathways have a common phylogenetic origin.
Ahmad
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Centre de Recherche en Microbiologie Appliquée, Institut Armand-Frappier, Université du Québec, Laval, Canada.
Massé
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Sylvestre
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D001713:Biphenyl Compounds / Q000378:metabolism*; D003001:Cloning, Molecular; D003360:Cosmids; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000235:genetics; D015870:Gene Expression; D005798:Genes, Bacterial; D005809:Genes, Regulator; D011549:Pseudomonas / Q000235:genetics*; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D001713:Biphenyl Compounds; D004269:DNA, Bacterial; C006983:4-chlorobiphenyl