The objective of this study was to determine whether the temperate Yersinia enterocolitica phage PY54 may interact with the related Escherichia coli phage N15 during both the lysogenic and the lytic cycle in the same cell. The PY54 and N15 prophages are linear plasmids which have been shown to be compatible and stably replicating in E. coli and Yersinia. In E. coli, the PY54 prophage does not r...

The mitotic stability of the linear plasmid-prophage N15 of Escherichia coli depends on a partition system closely related to that of the F plasmid SopABC. The two Sop systems are distinguished mainly by the arrangement of their centromeric SopB-binding sites, clustered in F (sopC) and dispersed in N15 (IR1 to IR4). Because two of the N15 inverted repeat (IR) sites are located close to elements...

The prophage of coliphage N15 is not integrated into the chromosome, but exists as a linear plasmid molecule with covalently closed ends. The only phage gene required for replication of circular N15 miniplasmids is repA (gene 37). Here we show that RepA-driven replication of the N15-based circular and linear miniplasmids is independent of host DnaB helicase protein, but requires the host DnaG p...

The prophage of coliphage N15 is not integrated into the chromosome but exists as a linear plasmid molecule with covalently closed hairpin ends (telomeres). Upon infection the injected phage DNA circularizes via its cohesive ends. Then, a phage-encoded enzyme, protelomerase, cuts the circle and forms the hairpin telomeres. N15 protelomerase acts as a telomere-resolving enzyme during prophage DN...

The physiological conditions and molecular interactions that control phage production have been studied in only a few families of temperate phages. We investigated the mechanisms that regulate activation of lytic development in lysogens of coliphage N15, a prophage that is not integrated into the host chromosome but exists as a linear plasmid with covalently closed ends. We identified the N15 a...

The chromosome of the temperate bacteriophage N15 replicates as a linear plasmid with covalently closed ends (or hairpins) when it forms a lysogen. I found that, in contrast to the cases for lambda and the low-copy-number plasmids F and P1, both phage and plasmid replication of N15 are independent of the heat shock proteins DnaJ, DnaK, and GrpE.

N15 is a temperate bacteriophage that forms stable lysogens in Escherichia coli. While its virion is morphologically very similar to phage lambda and its close relatives, it is unusual in that the prophage form replicates autonomously as a linear DNA molecule with closed hairpin telomeres. Here, we describe the genomic architecture of N15, and its global pattern of gene expression, which reveal...

N15 is the only bacteriophage of Escherichia coli known to lysogenize as a linear plasmid. Clear-plaque mutations lie in at least two regions of the 46-kb genome. We have cloned, sequenced, and characterized the primary immunity region, immB. This region contains a gene, cB, whose product shows homology to lambdoid phage repressors. The cB3 mutation confers thermoinducibility on N15 lysogens, c...