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Versatile cloning vector for Pseudomonas aeruginosa
Abstract:
A pBR322:RSF1010 composite plasmid, constructed in vitro, was used as a cloning vector in Pseudomonas aeruginosa. This nonamplifiable plasmid, pMW79, has a molecular weight of 8.4 X 10(6) and exists as a multicopy plasmid in both P. aeruginosa and Escherichia coli. In P. aeruginosa strain PAO2003, pMW79 conferred resistance to carbenicillin and tetracycline. Characterization of pMW79 with restriction enzymes revealed that four enzymes (BamHI, SalI, HindIII, and HpaI) cleaved the plasmid at unique restriction sites. Cloning P. aeruginosa chromosomal deoxyribonucleic acid fragments into the BamHI or SalI site of pMW79 inactivated the tetracycline resistance gene. Thus, cells carrying recombinant plasmids could be identified by their carbenicillin resistance, tetracycline sensitivity phenotype. Deoxyribonucleic acid fragments of approximately 0.5 to 7.0 megadaltons were inserted into pMW79, and the recombinant plasmids were stably maintained in a recombination-deficient (recA) P. aeruginosa host.
Insights
A novel cloning vector, pMW79, was developed for Pseudomonas aeruginosa. This plasmid enables efficient cloning of chromosomal DNA fragments and selection of recombinant clones via antibiotic resistance markers.
Area of Science:
- Molecular Biology
- Microbiology
- Genetics
Background:
- Development of versatile cloning vectors is crucial for genetic manipulation in bacteria.
- Pseudomonas aeruginosa is an important opportunistic pathogen requiring effective genetic tools.
Purpose of the Study:
- To construct and characterize a novel cloning vector, pMW79, for use in Pseudomonas aeruginosa.
- To evaluate the utility of pMW79 for cloning chromosomal DNA fragments from P. aeruginosa.
Main Methods:
- In vitro construction of a composite plasmid (pBR322:RSF1010) designated pMW79.
- Characterization of pMW79 using restriction enzyme analysis.
- Cloning of P. aeruginosa chromosomal DNA fragments into pMW79.
- Transformation of P. aeruginosa and Escherichia coli, and selection of recombinant clones.
Main Results:
- pMW79 is a nonamplifiable, multicopy plasmid (8.4 X 10^6 MW) functional in both P. aeruginosa and E. coli.
- pMW79 confers carbenicillin and tetracycline resistance in P. aeruginosa.
- Unique restriction sites (BamHI, SalI, HindIII, HpaI) were identified in pMW79.
- Cloning into BamHI or SalI sites inactivated the tetracycline resistance gene, allowing selection of recombinants by carbenicillin resistance and tetracycline sensitivity.
- Stable maintenance of recombinant plasmids containing 0.5-7.0 Mdal DNA fragments in a recA P. aeruginosa host.
Conclusions:
- pMW79 is a functional and stable cloning vector for P. aeruginosa.
- The selectable marker system (Carb^R, Tet^S) facilitates identification of recombinant clones.
- This vector system supports the stable cloning of large chromosomal DNA fragments in P. aeruginosa.