title: Identification of two linear plasmids in the actinomycete Planobispora rosea.
abstract: Two linear plasmids (pPR1, 27.5 kb, and pPR2, 16 kb) were identified in Planobispora rosea, an actinomycete that produces the antibiotic GE2270, an inhibitor of the elongation factor Tu. Strains lacking both plasmids still produce and are resistant to GE2270. The two plasmids share an internal region of high similarity, but no cross-hybridization was detected between their telomeric regions or between plasmid and chromosomal DNA. The 5' ends of the plasmids appear to be linked to terminal proteins. The telomeric regions of pPR2 were cloned after 3'-end homopolymer tailing and PCR amplification. The approximately 650 nt telomeric DNA sequences of pPR2 are repeated in inverted orientation and are rich in direct and inverted repeats; the 350 bp terminal region is less G + C-rich than the rest of the plasmid. The structural organization of these plasmids appears to be similar to Streptomyces linear replicons.
authors.affiliation: Dipartimento di Geneticae di Biologia dei Microrganismi, Universita degli Studi di MilanoVia Celoria 26, 20133 MilanoItaly.
authors.forename: Simona
authors.initials: S
authors.lastname: Polo
authors.affiliation: Dipartimento di Geneticae di Biologia dei Microrganismi, Universita degli Studi di MilanoVia Celoria 26, 20133 MilanoItaly.
authors.forename: Oscar
authors.initials: O
authors.lastname: Guerini
authors.affiliation: Biosearch ItaliaGerenzanoItaly.
authors.forename: Margherita
authors.initials: M
authors.lastname: Sosio
authors.affiliation: Dipartimento di Geneticae di Biologia dei Microrganismi, Universita degli Studi di MilanoVia Celoria 26, 20133 MilanoItaly.
authors.forename: Gianni
authors.initials: G
authors.lastname: Dehb
mesh_terms: D000192:Actinomycetales / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015139:Blotting, Southern; D002499:Centrifugation, Density Gradient; D002876:Chromosomes, Bacterial / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000494:pharmacology; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D016366:Open Reading Frames / Q000235:genetics; D010456:Peptides, Cyclic / Q000378:metabolism / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013302:Streptomyces / Q000235:genetics; D016615:Telomere / Q000235:genetics; D013844:Thiazoles / Q000378:metabolism / Q000494:pharmacology; D014764:Viral Proteins
chemical_list: D004268:DNA-Binding Proteins; D010456:Peptides, Cyclic; D013844:Thiazoles; D014764:Viral Proteins; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; C043586:exo protein, Bacteriophage lambda; C068122:GE 2270 A