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Duplication of both xyl catabolic operons on TOL plasmid pWW15

K J O'Donnell1, P A Williams

  • 1School of Biological Sciences, University of Wales, Bangor, Gwynedd, UK.

Journal of General Microbiology
|December 1, 1991
PubMed

Insights

Pseudomonas fluorescens MT15 harbors the TOL plasmid pWW15, containing two upper and two meta pathway operon regions. One meta pathway region is complete, while the other is partially functional.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Pseudomonas fluorescens MT15 hosts the large TOL plasmid pWW15 (250 kbp).
  • TOL plasmids are crucial for microbial degradation of aromatic hydrocarbons.

Purpose of the Study:

  • To characterize the genetic organization of the TOL plasmid pWW15.
  • To identify and analyze the catabolic operons within pWW15.

Main Methods:

  • Hybridization techniques to detect homologous DNA sequences.
  • Molecular cloning for gene isolation and analysis.
  • Enzyme assays to confirm functional pathways.

Main Results:

  • pWW15 contains two distinct regions homologous to TOL plasmid upper pathway operons (xylCMABN).
  • Both upper pathway regions appear to encode complete sets of structural genes for catabolic enzymes.
  • pWW15 possesses two distinct regions homologous to meta pathway operons (xylXYZLTEGFJQKIH).
  • One meta pathway region encodes a complete functional pathway.
  • The second meta pathway region is incomplete, containing genes only from xylF downstream.

Conclusions:

  • The TOL plasmid pWW15 exhibits a complex organization with multiple homologous regions to known TOL catabolic operons.
  • pWW15 harbors a complete upper pathway and at least one complete meta pathway for aromatic compound degradation.
  • The presence of a partially functional meta pathway suggests potential for gene duplication or alternative regulatory mechanisms.

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