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Dehalogenase genes of Pseudomonas putida PP3 on chromosomally located transposable elements
J H Slater1, A J Weightman, B G Hall
1Department of Environmental Sciences, University of Warwick.
Molecular Biology and Evolution
|November 1, 1985
Summary
Pseudomonas putida PP3 mutants resistant to toxic halogenated alkanoic acids (HAA) suggest genes for HAA metabolism are on transposable elements. These elements can excise, explaining high mutation frequencies and environmental influence on gene expression.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Pseudomonas putida PP3 metabolizes halogenated alkanoic acids (HAA) as a sole carbon source.
- HAA metabolism involves specific dehalogenase enzymes and permease transporters.
- Mutations conferring resistance to toxic HAA analogs were investigated.
Purpose of the Study:
- To investigate the genetic basis for high-frequency mutations conferring resistance to halogenated alkanoic acids (HAA) in Pseudomonas putida PP3.
- To determine if these mutations involve transposable elements.
- To explore the relationship between gene location on mobile elements and gene expression.
Main Methods:
- Isolation and characterization of spontaneous HAA- mutants.
- Analysis of five distinct mutant classes.
- Confirmation of gene transposition via experimental evidence.
- Investigation of environmental factors influencing gene excision frequency.
Main Results:
- Spontaneous HAA- mutants arose at unexpectedly high frequencies.
- Analysis indicated dehalogenase and HAA permease genes reside on chromosomally located transposable elements.
- Experimental evidence confirmed the transposable nature of these genetic elements.
- The frequency of element excision was significantly affected by environmental conditions.
Conclusions:
- High mutation rates in Pseudomonas putida PP3 are attributed to the excision of transposable elements carrying HAA metabolism genes.
- Transposable elements play a significant role in the genetic adaptability of Pseudomonas putida PP3 to halogenated alkanoic acids.
- Environmental conditions modulate the frequency of transposable element excision, impacting gene expression and adaptation.