Evidence for extrachromosomal location of prophage N15

Равин, В. К.; Shulga, M.G.

doi:10.1016/0042-6822(70)90125-x

Cited by 52 publications

(41 citation statements)

References 6 publications

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“…However, a few prophages, such as those of phages P1, N15, LE1, 20, and BB-1, are not integrated but replicate in the lysogen as low-copy-number plasmids (32,38,52,53,84). Of these, the Escherichia coli doublestranded DNA (dsDNA) tailed-phage N15 has an unusual linear prophage plasmid that has covalently closed hairpin telomeres (67, 68).…”

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confidence: 99%

The pKO2 Linear Plasmid Prophage ofKlebsiella oxytoca

et al. 2004

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Temperate bacteriophages with plasmid prophages are uncommon in nature, and of these only phages N15 and PY54 are known to have a linear plasmid prophage with closed hairpin telomeres. We report here the complete nucleotide sequence of the 51,601-bp Klebsiella oxytoca linear plasmid pKO2, and we demonstrate experimentally that it is also a prophage. We call this bacteriophage KO2. An analysis of the 64 predicted KO2 genes indicate that it is a fairly close relative of phage N15; they share a mosaic relationship that is typical of different members of double-stranded DNA tailed-phage groups. Although the head, tail shaft, and lysis genes are not recognizably homologous between these phages, other genes such as the plasmid partitioning, replicase, prophage repressor, and protelomerase genes (and their putative targets) are so similar that we predict that they must have nearly identical DNA binding specificities. The KO2 virion is unusual in that its phage -like tails have an exceptionally long (3,433 amino acids) central tip tail fiber protein. The KO2 genome also carries putative homologues of bacterial dinI and umuD genes, both of which are involved in the host SOS response. We show that these divergently transcribed genes are regulated by LexA protein binding to a single target site that overlaps both promoters.Temperate bacteriophages usually physically integrate their prophage DNAs into the host bacterium's chromosome when they establish lysogeny. However, a few prophages, such as those of phages P1, N15, LE1, 20, and BB-1, are not integrated but replicate in the lysogen as low-copy-number plasmids (32,38,52,53,84). Of these, the Escherichia coli doublestranded DNA (dsDNA) tailed-phage N15 has an unusual linear prophage plasmid that has covalently closed hairpin telomeres (67, 68). Although N15 has been studied in some detail (83,85,87), few other phages with similar linear DNA prophages have been described. While this paper was being prepared, another linear plasmid prophage, PY54, was reported for Yersinia enterocolitica (48). Furthermore, the linear, hairpin-ended plasmids Lp28-2 and Lp54 in the spirochete Borrelia burgdorferi B31-MI carry sequence similarities to dsDNA phage virion assembly genes (19, 33); however, they have not yet been shown to be bone fide prophages. Linear plasmids are very rare in the ␥-Proteobacteria, but it has been reported that Klebsiella oxytoca strain CCUG 15788 (a nickelresistant bacterium isolated from the mineral oil-water coolant-lubricant emulsion of a metal working machine in Göte-borg, Sweden, in 1989 [69]) harbors a linear plasmid, pKO2, of about 50 kbp (95). Since this is close to the size of the N15 linear plasmid prophage, we were prompted to investigate the possibility that this plasmid could be a prophage. We report here the complete nucleotide sequence of pKO2, a linear plasmid prophage that encodes the synthesis of a tailed-phage particle, and the analysis of some of its properties. MATERIALS AND METHODSBacterial strains and plasmid construction. The bacterial st...

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The pKO2 Linear Plasmid Prophage ofKlebsiella oxytoca

et al. 2004

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“…The linear molecules have covalently closed ends (hairpins). The only non-borrelial example of such structures among the prokaryotes is the prophage form of the coliphage N15, which exists as a linear plasmid (Ravin & Shulga, 1970;Svarchevskp & Rybchin, 1984). The left and right telomeres of the 16 kb linear plasmid of B. bnrgdyferi are identical at 16 of the 19 terminal bp (Hinnebusch ef al., 1990).…”

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confidence: 99%

Isolation of Borrelia burgdorferi genes encoding homologues of DNA-binding protein HU and ribosomal protein S20

Tilly

Fuhrman²,

Campbell³

et al. 1996

Microbiology

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Linear DNA with covalently closed ends is the predominant form of DNA in the spirochaete Borrelia burgdorferi. AH bacteria examined to date have small DNA-binding proteins related to the Escherichia coli IHF and HU proteins that appear to play roles in DNA compaction and replication, but such proteins had not been isolated from bacteria with linear genomes. We found a single gene in B. burgdorferi (named hbb) whose product (named Hbb) complements the defects for 1 DNA packaging found in Em coli strains mutant in the genes for IHF and HU. The sequence of the predicted B. burgdorferi protein is similar to those of HU and IHF-like proteins in other bacteria. The gene appears to be in an operon with the order rpsl-hbb+rf#, where the rpsr gene is a homologue of the Em coli gene encoding ribosomal protein S 2 0 and the orfH gene encodes a protein of unknown function. This operon is located upstream of the previously identified B. burgdorferi rho homologue.

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“…The Escherichia coli temperate bacteriophage N15 was discovered and investigated by V. Ravin et al (1)(2)(3). The N15 prophage is not integrated into the bacterial chromosome but exists as a low copy number plasmid (4).…”

Section: Introductionmentioning

confidence: 99%

“…The N15 prophage is not integrated into the bacterial chromosome but exists as a low copy number plasmid (4). Later it was shown that prophage N15 (plasmid N15) is a linear double-stranded DNA with covalenly closed ends (5,6).…”

Section: Introductionmentioning

confidence: 99%

Use of a linear multicopy vector based on the mini-replicon of temperate coliphage N15 for cloning DNA with abnormal secondary structures

Ravin

Равин

1999

Nucleic Acids Research

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A new cloning vector pN15L is described. It is a linear 13.8 kb plasmid based on the coliphage N15 minireplicon. The vector capacity exceeds 50 kb and the copy number is 250 per Escherichia coli chromosome. We show that some artificial and natural palindromes and~5% of human DNA BglII fragments can be cloned effectively in linear vector pN15L, whereas they either sharply reduce the copy number of circular vector pUC19 or cannot be cloned at all. We conclude that pN15L may be usefully employed to clone large imperfect palindromes and some abnormal sequences of human DNA.

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Evidence for extrachromosomal location of prophage N15

Cited by 52 publications

References 6 publications

The pKO2 Linear Plasmid Prophage ofKlebsiella oxytoca

The pKO2 Linear Plasmid Prophage ofKlebsiella oxytoca

Isolation of Borrelia burgdorferi genes encoding homologues of DNA-binding protein HU and ribosomal protein S20

Use of a linear multicopy vector based on the mini-replicon of temperate coliphage N15 for cloning DNA with abnormal secondary structures

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