Recombination between the linear plasmid pPZG101 and the linear chromosome of Streptomyces rimosus can lead to exchange of ends |
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Authors: | Suada Pandza Goran Biukovi rea Paravi Ali Dadbin John Cullum & Daslav Hranueli |
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Institution: | LB Genetik, Universität Kaiserslautern, Postfach 3049, D-67653 Kaiserslautern, Federal Republic of Germany.,;PLIVA d.d., Research Institute, Prilaz baruna Filipovi?a 25, 10000 Zagreb, Republic of Croatia. |
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Abstract: | The 387 kb linear plasmid pPZG101 of Streptomyces rimosus R6 can integrate into the chromosome or form a prime plasmid carrying the oxytetracycline biosynthesis cluster. The integration of plasmid pPZG101 into the linear chromosome of S. rimosus R6-501 in mutant MV25 was shown to be due to a single cross-over at a 4 bp common sequence. pPZG101 had integrated into a 250 kb DNA sequence that was reiterated at a low level. This sequence includes the oxytetracycline biosynthesis cluster, so that homologous recombination generated a mixed population carrying different copy numbers of the region. The 1 Mb linear plasmid pPZG103 in mutant MV17 had also arisen from a cross-over between pPZG101 and the chromosome, so that one end of pPZG103 consists of c . 850 kb of chromosomal sequence including the oxytetracycline biosynthesis cluster. The plasmid pPZG101 was shown to consist of a unique central region of about 30 kb flanked by terminal inverted repeats of about 180 kb. Analysis of a presumed ancestor plasmid pPZG102 suggested that the long terminal repeats had arisen by a recombination event during the strain development programme. |
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