title: Arrangement and regulation of the genes for meta-pathway enzymes required for degradation of phenol in Comamonas testosteroni TA441.
abstract: Comamonas testosteroni TA441 degrades phenol by a meta-cleavage pathway after the occurrence of a spontaneous mutation that derepresses the aphKLMNOPQB operon encoding phenol hydroxylase and catechol 2,3-dioxygenase, the enzymes for the initial two steps of the degradation pathway. A gene cluster, aphCEFGHJI, encoding the meta-pathway enzymes for degradation of 2-hydroxymuconic semialdehyde (HMS) to TCA cycle intermediates was found downstream of the aphK operon. The upstream operon and the downstream gene cluster were found to be separated by two open reading frames of unknown function and an oppositely oriented aphT gene, which is similar to regulatory genes for ortho-cleavage of catechol or chlorinated catechols. A promoter assay using an aphC::lacZ transcriptional fusion plasmid revealed that the aphC promoter activity is induced by both phenol and HMS. The phenol-dependent induction was mediated by AphR and the HMS-dependent induction was mediated by AphT. The aphC promoter in strain TA441 was not silenced, unlike the cases of the aphK and aphR promoters, and was highly induced by HMS.
authors.affiliation: Laboratory of Microbiology, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako, Saitama 351-0198, Japan1.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Arai
authors.affiliation: Laboratory of Microbiology, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako, Saitama 351-0198, Japan1.
authors.forename: Tohru
authors.initials: T
authors.lastname: Ohishi
authors.affiliation: Laboratory of Microbiology, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako, Saitama 351-0198, Japan1.
authors.forename: Mee Young
authors.initials: MY
authors.lastname: Chang
authors.affiliation: Laboratory of Microbiology, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako, Saitama 351-0198, Japan1.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kudo
mesh_terms: D001673:Biodegradation, Environmental; D050557:Catechol 2,3-Dioxygenase; D003001:Cloning, Molecular; D020604:Comamonas testosteroni / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D049308:Dioxygenases; D015536:Down-Regulation; D020868:Gene Silencing; D005798:Genes, Bacterial; D005809:Genes, Regulator; D006899:Mixed Function Oxygenases / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D009876:Operon; D010105:Oxygenases / Q000096:biosynthesis / Q000235:genetics; D019800:Phenol / Q000378:metabolism* / Q000494:pharmacology; D010802:Phylogeny
chemical_list: D019800:Phenol; D006899:Mixed Function Oxygenases; D010105:Oxygenases; D049308:Dioxygenases; D050557:Catechol 2,3-Dioxygenase; C022336:phenol 2-monooxygenase