Regulation of the atrazine-degradative genes in Pseudomonas sp. strain ADP

• Published in: FEMS microbiology letters Vol. 310; no. 1; pp. 1 - 8
• Main Authors: Govantes, Fernando, García-González, Vicente, Porrúa, Odil, Platero, Ana Isabel, Jiménez-Fernández, Alicia, Santero, Eduardo
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.09.2010; Blackwell Publishing Ltd; Wiley-Blackwell; Oxford University Press
• Subjects: Adenosine diphosphate; Atrazine; Atrazine - metabolism; Bacteriology; Biodegradation; Biological and medical sciences; Bioremediation; Circuits; Cyanuric acid; Decontamination; Degradation; Deoxyribonucleic acid; DNA; DNA-directed DNA polymerase; DNA-directed RNA polymerase; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Bacterial; Gene regulation; general nitrogen control; Genes; genetics; Gram-negative bacteria; Herbicides; LysR-type transcriptional regulators; Metabolic Networks and Pathways; metabolism; Microbiology; Miscellaneous; Nitrogen; Nucleotide sequence; Operon; Promoter Regions, Genetic; Pseudomonas; Pseudomonas - genetics; Pseudomonas - metabolism; Repressor Proteins; Repressor Proteins - metabolism; RNA polymerase; Soil Pollutants; Soil Pollutants - metabolism; transcription (genetics); Transcription activation; transcription factors; Transcription Factors - metabolism; transcriptional activation; transcriptional regulation; Triazine; biodegradation; LysR-type transcriptional regulators; general nitrogen control; transcriptional regulation; Pseudomonadales; Biodegradation; Transcription; Pesticides; Pseudomonas; ADP; Herbicide; Strain; Regulation(control); Gene; Triazine derivatives; Bacteria; Pseudomonadaceae; Atrazine
• ISSN: 0378-1097; 1574-6968; 1574-6968
• DOI: 10.1111/j.1574-6968.2010.01991.x

The Gram-negative bacterium Pseudomonas sp. strain ADP is the best-characterized organism able to mineralize the s-triazine herbicide atrazine. This organism has been the subject of extensive biochemical and genetic characterization that has led to its use in bioremediation programs aimed at the decontamination of atrazine-polluted sites. Here, we focus on the recent advances in the understanding of the mechanisms of genetic regulation operating on the atrazine-degradative genes. The Pseudomonas sp. strain ADP atrazine-degradation pathway is encoded by two sets of genes: the constitutively expressed atzA, atzB and atzC, and the strongly regulated atzDEF operon. A complex cascade-like circuit is responsible for the integrated regulation of atzDEF expression in response to nitrogen availability and cyanuric acid. Mechanistic studies have revealed several unusual traits, such as the upstream activating sequence-independent regulation and repression by competition with σ⁵⁴-RNA polymerase for DNA binding occurring at the σ⁵⁴-dependent PatzR promoter, and the dual mechanism of transcriptional regulation of the PatzDEF promoter by the LysR-type regulator AtzR in response to two dissimilar signals. These findings have provided new insights into the regulation of the atrazine-biodegradative pathway that are also relevant to widespread bacterial regulatory phenomena, such as global nitrogen control and transcriptional activation by LysR-type transcriptional regulators.