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Early intermediates in bacteriophage T4 DNA replication and recombination
Journal of Virology
|February 1, 1983
Summary
Bacteriophage T4 DNA replication and recombination occur very early in infected Escherichia coli. Recombination is essential for generating branched, concatemeric T4 DNA structures during vegetative growth.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Bacteriophage T4 DNA replication is a complex process.
- Understanding the interplay between replication and recombination is crucial.
Purpose of the Study:
- To investigate the timing and nature of T4 DNA replication intermediates.
- To elucidate the role of recombination in T4 DNA metabolism.
Main Methods:
- Density gradient centrifugation of vegetative T4 DNA.
- Electron microscopy of T4 DNA molecules.
Main Results:
- Single infections initiated replication with single loops.
- Multiple infections showed early recombinational intermediates (1 min post-replication onset).
- Complex, branched, concatemeric T4 DNA and tandemly arranged loops/branches appeared only in multiple infections.
Conclusions:
- Recombination in T4-infected cells initiates very early.
- Recombination drives the formation of branched and concatemeric T4 DNA structures.
- Replication initiation often occurs at recombinational intermediates, not solely at origin sequences.