Regulatory circuits controlling transcription of TOL plasmid operon encoding meta‐cleavage pathway for degradation of alkylbenzoates by Pseudomonas
- 1 July 1987
- journal article
- Published by Wiley in Molecular Microbiology
- Vol. 1 (1), 293-300
- https://doi.org/10.1111/j.1365-2958.1987.tb01935.x
Abstract
TOL plasmid PWWO of Pseudomonas putida contains two operons that specify a pathway for the degradation of aromatic hydrocarbons. The ‘upper’ operon encodes enzymes for the oxidation of toluene to benzoate and xylenes to toluates, whereas the meta‐cleavage operon specifies the further oxidation of benzoate and toluates. Transcription of the upper pathway operon (s positively regulated by the XylR protein, which is activated by toluene/xylenes and their alcohol catabolic products, in combination with the NtrA protein, a sigma factor. Expression of the meta‐operon is positively controlled by the XylS protein which is activated by meta‐pathway substrates, and is Independent of NtrA protein. Expression of the meta pathway is also Induced by toluene/xylene‐activated XylR protein via a cascade regulatory system in which this protein in combination with NtrA protein stimulates transcription from the xylS gene promoter. Hyper‐production of XylS protein in turn provokes high level expression of the meta‐operon, which is independent of meta‐pathway substrates. The two promoters, which are activated by the XylR and NtrA proteins, the upper pathway promoter and the xylS gene promoter, exhibit three regions of homology centred at –12(5′–TTGCTÃG–3′), –24(5′ ‐TGGCPuT –3) and –45(5′‐TTAAATÃGPuPuGCGPuTc‐3′), with respect to their principal transcription initiation points. The possible physiological significance of activated XylR‐protein‐induced expression of the meta‐operon through amplification of XylS protein levels is considered.Keywords
This publication has 36 references indexed in Scilit:
- Redesigning Metabolic Routes: Manipulation of TOL Plasmid Pathway for Catabolism of AlkylbenzoatesScience, 1987
- POSITIVE CONTROL OF TRANSCRIPTION INITIATION IN BACTERIAAnnual Review of Genetics, 1984
- Nucleotide sequence of the promoter region of the xylDEGF operon on TOL plasmid of Pseudomonas putidaGene, 1984
- Regulation of the pho regulon in Escherichia coli K-12Journal of Molecular Biology, 1983
- Regulation of nitrogen metabolism genes by nifA gene product in Klebsiella pneumoniaeNature, 1983
- Positive control and autogenous regulation of the nifLA promoter in Klebsiella pneumoniaeNature, 1983
- GENETIC CONTROL OF NITROGEN ASSIMILATION IN BACTERIAAnnual Review of Genetics, 1982
- Specific-purpose plasmid cloning vectors II. Broad host range, high copy number, RSF 1010-derived vectors, and a host-vector system for gene cloning in PseudomonasGene, 1981
- Role of the nifA gene product in the regulation of nif expression in Klebsiella pneumoniaeNature, 1981
- Structure and Function of NitrogenaseAnnual Review of Biochemistry, 1979