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Isolation of heterogeneous circular DNA from induced lysogens of bacteriophage Mu-1
Abstract:
Covalently-closed circular DNA molecules are formed after induction of phage Mu cts4 and after infection with phage Mu cts4. The circular molecules obtained after induction have a molecular length range from 36.5 to 156.7 kilobases as measured by electron microscopic techniques. These heterogeneous molecules have no consistent correlation to exact multiples of a Mu genome equivalent (37.3 +/- 1.2 kilobases). Direct evidence is given that these molecules contain phage Mu DNA that is covalently linked to other DNA sequences.
Insights
Phage Mu cts4 DNA forms covalently-closed circular molecules after induction or infection. These heterogeneous circular DNA molecules contain phage Mu DNA linked to other DNA sequences.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Bacteriophages, such as Mu cts4, are viruses that infect bacteria.
- Understanding phage DNA replication and integration is crucial in molecular biology.
Purpose of the Study:
- To investigate the formation and characteristics of covalently-closed circular DNA molecules after Mu cts4 phage induction and infection.
- To determine the molecular size and composition of these circular DNA molecules.
Main Methods:
- Induction of Mu cts4 phage in bacteria.
- Infection of bacteria with Mu cts4 phage.
- Electron microscopy to measure the molecular length of circular DNA molecules.
Main Results:
- Covalently-closed circular DNA molecules were observed after both Mu cts4 induction and infection.
- The molecular length of these circular molecules ranged from 36.5 to 156.7 kilobases.
- These heterogeneous molecules showed no consistent correlation to multiples of a single Mu genome (37.3 +/- 1.2 kilobases).
- Direct evidence confirmed that these circular molecules contain phage Mu DNA covalently linked to other DNA sequences.
Conclusions:
- Mu cts4 phage DNA can form heterogeneous, covalently-closed circular molecules of varying lengths.
- These circular DNA molecules are not simple multimers of the Mu genome and contain integrated host DNA sequences.