Relating cistrons and functions in bacteriophage PM2

Canelo, Eliana S.; Phillips, Olga M.; Roure, Roso Nicolau del

doi:10.1016/0042-6822(85)90373-3

Cited by 4 publications

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“…The organization of the genes and the transcriptional regulation of operons in the genome have been determined (39; R. H. Männistö, A. M. Grahn, D. H. Bamford, and J. K. H. Bamford, submitted for publication). The 10,079-bp genome replicates via a rolling-circle mechanism (18,28,39) while associated with the host cytoplasmic membrane (11).…”

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confidence: 99%

Bacteriophage PM2 Has a Protein Capsid Surrounding a Spherical Proteinaceous Lipid Core

Kivelä

Kalkkinen

Bamford

2002

J Virol

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The marine double-stranded DNA (dsDNA) bacteriophage PM2, studied since 1968, is the type organism of the family Corticoviridae, infecting two gram-negative Pseudoalteromonas species. The virion contains a membrane underneath an icosahedral protein capsid composed of two structural proteins. The purified major capsid protein, P2, appears as a trimer, and the receptor binding protein, P1, appears as a monomer. The C-terminal part of P1 is distal and is responsible for receptor binding activity. The rest of the structural proteins are associated with the internal phospholipid membrane enclosing the viral genome. This internal particle is designated the lipid core. The overall structural organization of phage PM2 resembles that of dsDNA bacteriophage PRD1, the type organism of the family Tectiviridae.PM2, the only isolate in the family Corticoviridae, is the first bacteriophage for which the presence of lipids in the virion was firmly demonstrated (15,24,26). It is a lytic virus, infecting two Pseudoalteromonas species: marine gram-negative Pseudoalteromonas espejiana BAL-31 (originally Pseudomonas sp. strain BAL-31), isolated along with the virus (25, 32), and Pseudoalteromonas sp. strain ER72M2, obtained from the East River, New York, by Leonard Mindich (38). Originally, considerable interest was directed toward this virus system (about 200 references), but since 1983, only a few studies have been published. Recently, we decided to examine this virus system (38, 39), as our laboratory is focused on lipid-containing bacterial viruses.The mass of the virion (ϳ4.5 ϫ 10 7 Da) is distributed among nucleic acid (14%), lipid (14%), and protein (72%) constituents (15,16,17). The average diameter of the icosahedral particle is ϳ60 nm (24,34,49), and the lipids are located internally (15,34). The sedimentation coefficient (s 20 , w ) of the particle is 293S, and buoyant densities in sucrose and cesium chloride are 1.26 and 1.28 g/cm 3 , respectively (16, 38). The stability of the virion is strongly dependent on sodium and especially on calcium ions, and the virion equilibrated in sucrose is inactive (38). Calcium ions are also essential in the final assembly process during PM2 infection (50).The PM2 genome is a highly supercoiled circular doublestranded DNA (dsDNA) molecule (27) with the highest number of negative supercoils (Ϫ51) observed in a natural molecule (33). The organization of the genes and the transcriptional regulation of operons in the genome have been determined (39; R. H. Männistö, A. M. Grahn, D. H. Bamford, and J. K. H. Bamford, submitted for publication). The 10,079-bp genome replicates via a rolling-circle mechanism (18, 28, 39) while associated with the host cytoplasmic membrane (11).The viral lipids are derived from the host cell membrane during the assembly process (26), and the composition is ϳ64% phosphatidylglycerol, ϳ27% phosphatidylethanolamine, ϳ8% neutral lipids, and small amounts of asylphosphatidylglycerol (15, 53). The proportion of the major phospholipids in the virion is nearly the inverse...

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Bacteriophage PM2 Has a Protein Capsid Surrounding a Spherical Proteinaceous Lipid Core

Kivelä

Kalkkinen

Bamford

2002

J Virol

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“…It is thought that DNA replication and assembly of the virus occur near the point of infection, at a site anchored to the inside of the host cytoplasmic membrane (Brewer 1978). The DNA replicates using a rolling circle mechanism (Canelo et al 1985). Transcription of PM2 genes is carried out by the host RNA polymerase, using the highly supercoiled PM2 DNA as a template (Zimmer and Millette 1975).…”

Section: Assemblymentioning

confidence: 99%

Structure and Function of Bacteriophages

2019

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The Complete Genome Sequence of PM2, the First Lipid-Containing Bacterial Virus To Be Isolated

et al. 1999

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Bacteriophage PM2 was isolated from the Pacific Ocean off the coast of Chile in the late 1960s. It was a new virus type, later classified as Corticoviridae, and also the first bacterial virus for which it was demonstrated that lipids are part of the virion structure. Here we report the determination and analysis of the 10, 079-bp circular dsDNA genome sequence. Noteworthy discoveries are the replication initiation system, which is related to the rolling circle mechanism described for phages such as φX174 and P2, and a 1.2-kb sequence that is similar to the maintenance region of a plasmid found in a marine Pseudoalteromonas sp. strain A28.

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Relating cistrons and functions in bacteriophage PM2

Cited by 4 publications

References 10 publications

Bacteriophage PM2 Has a Protein Capsid Surrounding a Spherical Proteinaceous Lipid Core

Bacteriophage PM2 Has a Protein Capsid Surrounding a Spherical Proteinaceous Lipid Core

Structure and Function of Bacteriophages

The Complete Genome Sequence of PM2, the First Lipid-Containing Bacterial Virus To Be Isolated

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