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Intracellular replication of choleraphage straight phi92
1Biophysics Division, Indian Institute of Chemical Biology, Calcutta, India.
Intervirology
|November 24, 1999
Summary
This study details the infection cycle of the broad host range choleraphage phi92, revealing its DNA replication strategy and identifying key phage proteins. It elucidates the temporal expression of early and late proteins during infection.
Area of Science:
- Microbiology
- Virology
- Molecular Biology
Background:
- Choleraphage phi92 is a broad host range virus with a linear double-stranded DNA genome.
- Bacteriophage infections involve complex interactions with host machinery for replication and protein synthesis.
Purpose of the Study:
- To characterize the molecular events following choleraphage phi92 infection.
- To identify and delineate the synthesis of phage-specific proteins during the infection cycle.
Main Methods:
- Infection of host cells with choleraphage phi92.
- Monitoring of host and phage macromolecular synthesis.
- Pulse labeling of infected cells and protein analysis.
- Identification of early and late viral proteins.
Main Results:
- Choleraphage phi92 possesses a 68 kb linear double-stranded DNA genome with cohesive ends.
- Host macromolecular synthesis is inhibited within 5 minutes post-infection.
- Phage DNA replication initiates as a circular intermediate associated with the membrane.
- Approximately 30 phage-specific proteins were identified, including 6 structural proteins, with 18 classified as early and 12 as late proteins.
Conclusions:
- The circular DNA form of choleraphage phi92 acts as a precursor for mature phage DNA synthesis.
- Phage protein synthesis occurs in distinct early and late phases during the infection cycle.
- Understanding these mechanisms provides insight into bacteriophage replication strategies.